U.S. patent application number 17/241446 was filed with the patent office on 2021-08-12 for devices, systems, and methods for vessel assessment.
The applicant listed for this patent is PHILIPS IMAGE GUIDED THERAPY CORPORATION. Invention is credited to David ANDERSON, Fergus MERRITT, Andrew TOCHTERMAN.
Application Number | 20210244299 17/241446 |
Document ID | / |
Family ID | 1000005542418 |
Filed Date | 2021-08-12 |
United States Patent
Application |
20210244299 |
Kind Code |
A1 |
TOCHTERMAN; Andrew ; et
al. |
August 12, 2021 |
DEVICES, SYSTEMS, AND METHODS FOR VESSEL ASSESSMENT
Abstract
Devices, systems, and methods for visually depicting a vessel
and evaluating risk associated with a condition of the vessel are
disclosed. In one embodiment, a method of evaluating a vessel of a
patient includes obtaining physiology measurements from a first
instrument and a second instrument positioned within the vessel of
the patient while the second instrument is moved longitudinally
through the vessel from a first position to a second position and
the first instrument remains stationary within the vessel;
outputting the physiology measurements and an image of the vessel
on a display, the output image including visualizations based on
the obtained physiology measurements; and evaluating whether to
perform to surgical procedure based on the physiology measurements
and the image of the vessel.
Inventors: |
TOCHTERMAN; Andrew;
(CARLSBAD, CA) ; ANDERSON; David; (TEMECULA,
CA) ; MERRITT; Fergus; (EL DORADO HILLS, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHILIPS IMAGE GUIDED THERAPY CORPORATION |
San Diego |
CA |
US |
|
|
Family ID: |
1000005542418 |
Appl. No.: |
17/241446 |
Filed: |
April 27, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14522952 |
Oct 24, 2014 |
10993628 |
|
|
17241446 |
|
|
|
|
61895909 |
Oct 25, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 6/481 20130101;
A61B 5/02158 20130101; A61B 6/504 20130101; A61B 6/463 20130101;
A61B 6/032 20130101 |
International
Class: |
A61B 5/0215 20060101
A61B005/0215; A61B 6/00 20060101 A61B006/00 |
Claims
1. A system for providing information of a vessel of a patient to
assist in evaluating the vessel, comprising: a pressure-sensing
guidewire sized and shaped for introduction into the vessel of the
patient; and a processing system in communication with the
pressure-sensing guidewire and a pressure-sensing instrument, the
processing system configured to: obtain pressure measurements from
the pressure-sensing instrument and the pressure-sensing guidewire
while the pressure-sensing guidewire is moved longitudinally
through the vessel of the patient from a first position to a second
position while the pressure-sensing instrument is maintained in a
fixed longitudinal position with respect to the vessel; calculate,
based on the pressure measurements from the pressure-sensing
instrument and the pressure-sensing guidewire, a plurality of
pressure ratios along the vessel; define a plurality of regions of
the vessel based on a comparison of the plurality of pressure
ratios with a threshold value such that each region of the
plurality of regions comprises a respective severity; automatically
determine a location between two regions of the plurality of
regions having different severities; and output an image of the
vessel on a display in communication with the processing system,
wherein the image comprises a two-dimensional angiographic image
and a marking of the location between the two regions.
2. The system of claim 1, wherein the processing system is further
configured to identify an area of interest extending from the
location between the two regions to a second location, wherein the
image further comprises a visualization of the area of
interest.
3. The system of claim 2, wherein, to identify the area of
interest, the processing system is configured to automatically
determine the second location between two additional regions of the
plurality of regions having different severities, and wherein the
visualization of the area of interest comprises the marking of the
location between the two regions and a marking of the second
location between the two additional regions.
4. The system of claim 1, wherein the image further comprises an
indicator comprising a numerical value of a first pressure ratio of
the plurality of pressure ratios displayed in association with the
marking of the location between the two regions.
5. The system of claim 1, wherein the processing system is further
configured to: receive a user input moving the marking to a second
location along the vessel; and output a modified image including
the marking displayed at the second location.
6. The system of claim 1, wherein the image is an extravascular
image.
7. The system of claim 1, wherein the processing system is further
configured to: calculate a risk score based on at least one of the
plurality of pressure ratios; and output the risk score on the
display, the risk score associated with at least one of the
plurality of regions.
8. The system of claim 7, wherein the risk score predicts a
probability of success of a surgical procedure for the vessel.
9. The system of claim 1, wherein the processing system is further
configured to: associate the plurality of regions with one or more
pre-defined anatomical segments of the vessel.
10. The system of claim 1, wherein the image further comprises a
visualization of the plurality of regions.
11. The system of claim 1, wherein the location between the two
regions comprises a border between the two regions.
12. The system of claim 1, further comprising the pressure-sensing
instrument.
13. The system of claim 1, further comprising the display.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/522,952, filed Oct. 24, 2014, now U.S. Pat.
No. 10,993,628, which claims the benefit of the filing date of U.S.
Provisional Application No. 61/895,909, filed Oct. 25, 2013. The
entire disclosures of these applications are incorporated herein by
this reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the assessment
of vessels and, in particular, the assessment of the severity of a
blockage or other restriction to the flow of fluid through a
vessel. Aspects of the present disclosure are particularly suited
for evaluation of biological vessels in some instances. For
example, some particular embodiments of the present disclosure are
specifically configured for the evaluation of a stenosis of a human
blood vessel.
BACKGROUND
[0003] A currently accepted technique for assessing the severity of
a stenosis in a blood vessel, including ischemia causing lesions,
is fractional flow reserve (FFR). FFR is a calculation of the ratio
of a distal pressure measurement (taken on the distal side of the
stenosis) relative to a proximal pressure measurement (taken on the
proximal side of the stenosis). FFR provides an index of stenosis
severity that allows determination as to whether the blockage
limits blood flow within the vessel to an extent that treatment is
required. The normal value of FFR in a healthy vessel is 1.00,
while values less than about 0.80 are generally deemed significant
and require treatment. Common treatment options include
percutaneous coronary intervention (PCI or angioplasty), stenting,
or coronary artery bypass graft (CABG) surgery. As with all medical
procedures, certain risks are associated with PCI, stenting, and
CABG procedures. In order for a surgeon to make a better-informed
decision regarding treatment options, additional information about
the risk and likelihood of success associated with the treatment
options is needed.
[0004] A patient's vasculature can be visualized using angiography.
However, the locations of stenoses in a vessel can be difficult to
visualize in a black and white angiographic image. Moreover, the
severity of stenosis can also be better understood when efficiently
visualized in relation to an angiographic image. Further, a more
complete diagnosis of the patient can be made when the effects of
both focal and diffuse stenoses are evaluated.
[0005] Accordingly, there remains a need for improved devices,
systems, and methods for assessing the severity of a blockage in a
vessel and, in particular, a stenosis in a blood vessel. In that
regard, there remains a need for improved devices, systems, and
methods for providing visual depictions of vessel that allow
assessment of the vessel and, in particular, any stenosis or lesion
of the vessel. Further, there remains a need for improved devices,
systems, and methods of objectively evaluating risk associated with
and likelihood of success for one or more available treatment
options for the vessel.
SUMMARY
[0006] Embodiments of the present disclosure are configured to
assess the severity of a blockage (or multiple blockages) in a
vessel and, in particular, a stenosis in a blood vessel. In some
particular embodiments, the devices, systems, and methods of the
present disclosure are configured to provide visual depictions of a
vessel that allow assessment of the vessel and, in particular, any
stenosis or lesion of the vessel. Further, in some embodiments the
devices, systems, and methods of the present disclosure are
configured to allow planning of one or more treatment options for
the vessel based on objective measures of risk and/or success.
[0007] In one embodiment, a method of evaluating a vessel of a
patient are provided. The method includes obtaining physiology
measurements from a first instrument and a second instrument
positioned within the vessel of the patient while the second
instrument is moved longitudinally through the vessel from a first
position to a second position and the first instrument remains
stationary within the vessel; outputting the physiology
measurements and an image of the vessel on a display, the output
image including visualizations based on the obtained physiology
measurements; and evaluating whether to perform to a surgical
procedure based on the physiology measurements and the image of the
vessel.
[0008] In some implementations, the visualizations include markings
representative of a location of obtained physiology measurements
from the first and second instruments. In some implementations, the
markings are movable along the image of the vessel. In some
implementations, the visualizations include indicators
representative of a region of interest based on the obtained
pressure measurements from the first and second instruments. In
some implementations, the indicators are movable along the image of
the vessel. In some implementations, the visualizations include
numerical values of a pressure ratio of the obtained pressure
measurements from the first and second instruments. In some
implementations, the visualizations include a heat map
representative of a pressure ratio of the obtained pressure
measurements from the first and second instruments. In some
implementations, a first visual characteristic of the heat map is
associated with pressure ratios above a threshold value and a
second visual characteristic of the heat map is associated with
pressure ratios below the threshold value. In some implementations,
the first visual characteristic of the heat map is a first color
and the second visual characteristic of the heat map is a second
color visually distinguishable from the first color. In some
implementations, the image is an extravascular image. In some
implementations, the extravascular image is at least one of a two
dimensional angiographic image, a three dimensional angiographic
image, and a computed tomography angiographic (CTA) image. In some
implementations, the surgical procedure is at least one of coronary
artery bypass graft and a percutaneous coronary intervention. In
some implementations, the method further includes calculating a
risk score associated with the obtained physiology measurements;
outputting the risk score on the display; and evaluating whether to
perform to surgical procedure based on the risk score. In some
implementations, calculating a risk score includes providing the
physiology measurements to a risk calculator, wherein the risk
calculator includes a calculator for determining at least one of a
SYNTAX score, a fractional flow reserve (FFR)-guided SYNTAX score
(referred to as a functional SYNTAX score), an indication of
perfusion benefit, and an indication of graft patency; and
calculating the risk score with the risk calculator using at least
one of the physiology measurements and a patient history. In some
implementations, calculating a risk score includes providing the
physiology measurements into an algorithm for predicting the
benefits of perfusion resulting from placement of a coronary bypass
graft.
[0009] In one embodiment, a system for evaluating a vessel of a
patient is provided. The system includes a first instrument sized
and shaped for introduction into the vessel of the patient; a
second instrument sized and shaped for introduction into the vessel
of the patient; a processing system in communication with the first
and second instruments, the processing unit configured to: obtain
physiology measurements from the first and second instruments while
the second instrument is moved longitudinally through the vessel of
the patient from a first position to a second position while the
first instrument is maintained in a fixed longitudinal position
with respect to the vessel; output the physiology measurements and
an image of the vessel on a display in communication with the
processing system, the output image including visualizations based
on the obtained physiology measurements; and evaluate whether to
perform a surgical procedure based on the physiology measurements
and the image of the vessel.
[0010] In some implementations, the visualizations include markings
representative of a location of obtained physiology measurements
from the first and second instruments. In some implementations, the
markings are movable along the image of the vessel. In some
implementations, the visualizations include indicators
representative of a region of interest based on the obtained
pressure measurements from the first and second instruments. In
some implementations, the indicators are movable along the image of
the vessel. In some implementations, the visualizations include
numerical values of a pressure ratio of the obtained pressure
measurements from the first and second instruments. In some
implementations, the visualizations include a heat map
representative of a pressure ratio of the obtained pressure
measurements from the first and second instruments. In some
implementations, a first visual characteristic of the heat map is
associated with pressure ratios above a threshold value and a
second visual characteristic of the heat map is associated with
pressure ratios below the threshold value. In some implementations,
the first visual characteristic of the heat map is a first color
and the second visual characteristic of the heat map is a second
color visually distinguishable from the first color. In some
implementations, the image is an extravascular image. In some
implementations, the extravascular image is at least one of a two
dimensional angiographic image, a three dimensional angiographic
image, and a computed tomography angiographic (CTA) image. In some
implementations, the surgical procedure is at least one of coronary
artery bypass graft and a percutaneous coronary intervention. In
some implementations, the processing unit is further configured to
calculate a risk score associated with the obtained physiology
measurements; output the risk score on the display; and evaluate
whether to perform to surgical procedure based on the risk score.
In some implementations, calculating a risk score includes
providing the physiology measurements to a risk calculator, wherein
the risk calculator includes a calculator for determining at least
one of a SYNTAX score, a fractional flow reserve (FFR)-guided
SYNTAX score (functional SYNTAX score), an indication of perfusion
benefit, and an indication of graft patency; and calculating the
risk score with the risk calculator using at least one of the
physiology measurements and a patient history. In some
implementations, calculating a risk score includes providing the
physiology measurements into an algorithm for predicting the
benefits of perfusion resulting from placement of a coronary artery
bypass graft.
[0011] Additional aspects, features, and advantages of the present
disclosure will become apparent from the following detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Illustrative embodiments of the present disclosure will be
described with reference to the accompanying drawings, of
which:
[0013] FIG. 1 is a diagrammatic perspective view of a vessel having
a stenosis according to an embodiment of the present
disclosure.
[0014] FIG. 2 is a diagrammatic, partial cross-sectional
perspective view of a portion of the vessel of FIG. 1 taken along
section line 2-2 of FIG. 1.
[0015] FIG. 3 is a diagrammatic, partial cross-sectional
perspective view of the vessel of FIGS. 1 and 2 with instruments
positioned therein according to an embodiment of the present
disclosure.
[0016] FIG. 4 is a diagrammatic, schematic view of a system
according to an embodiment of the present disclosure.
[0017] FIG. 5 is an annotated version of a stylized image of a
patient's vasculature according to an embodiment of the present
disclosure.
[0018] FIG. 6 is a visual depiction of an index of the severity of
stenoses according to an embodiment of the present disclosure.
[0019] FIG. 7 is an annotated version of a stylized image of a
vessel according to another embodiment of the present
disclosure.
[0020] FIG. 8 is an annotated version of a stylized image of a
vessel according to another embodiment of the present
disclosure.
[0021] FIG. 9 is an annotated version of an angiographic image of a
vessel according to an embodiment of the present disclosure.
[0022] FIG. 10 is an annotated version of an angiographic image of
a vessel according to another embodiment of the present
disclosure.
[0023] FIG. 11 is an annotated version of a stylized image of a
vessel according to another embodiment of the present
disclosure.
[0024] FIG. 12 is an annotated version of a stylized image of a
vessel according to another embodiment of the present
disclosure.
[0025] FIG. 13 is a flow diagram of a method of assessing risk
according to an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0026] For the purposes of promoting an understanding of the
principles of the present disclosure, reference will now be made to
the embodiments illustrated in the drawings, and specific language
will be used to describe the same. It is nevertheless understood
that no limitation to the scope of the disclosure is intended. Any
alterations and further modifications to the described devices,
systems, and methods, and any further application of the principles
of the present disclosure are fully contemplated and included
within the present disclosure as would normally occur to one
skilled in the art to which the disclosure relates. In particular,
it is fully contemplated that the features, components, and/or
steps described with respect to one embodiment may be combined with
the features, components, and/or steps described with respect to
other embodiments of the present disclosure. For the sake of
brevity, however, the numerous iterations of these combinations
will not be described separately.
[0027] Physiological data and the coronary angiogram typically
behave as complementary, yet segregated sources of information. The
coronary angiogram has been used to make treatment decisions. More
recently, physiological data (including, but not limited to,
pressure and/or flow measurements, both at Hyperemia and rest) have
shown that better decisions can be made based on the severity of a
blockage by measuring the change in underlying physiological
conditions from the beginning of a target artery to the end.
Treating a patient based on the severity of this change or delta
has shown to improve outcomes and reduce waste from unnecessary
procedures. In one or more aspects of the present disclosure, the
physiological data, as collected real-time, is linked to a
schematic of the coronary arteries or an angiogram. The data are
depicted in a way that allows a clinician to interact and assess
where severity changes, by sliding markings as placed on the image
of the vessel and correlated with the collected physiological data.
One or more embodiments described herein are also able
automatically to make updates based on the collected data to a risk
calculator such as a Functional Syntax Score or a model for
predicting changes in perfusion to create a Coronary Artery Bypass
Graft ("CABG") Map.
[0028] One aspect of the present disclosure includes super-imposing
real-time collected pressure and/or flow data (or other physiologic
data) onto an angiogram, or a schematic of anatomy and representing
the data in a way that helps a clinician determine how/where to
intervene (including but not limited to CABG mapping and PCI
planning). One aspect of the present disclosure includes using the
pressure, flow or other physiologic data with a computational
algorithm to predict probabilities of graft patency and perfusion
improvement during coronary artery bypass grafting (CABG). One
aspect of the present disclosure includes interacting with
super-imposed physiologic data to isolate "regions of interest"
where severity of physiologic data changes substantially for the
purposes of determining how/where to intervene. One aspect of the
present disclosure includes using the physician-determined regions
of interest to auto-calculate a risk score including but not
limited to a Functional Syntax Score. Whether to perform to
surgical procedure can be evaluated based on one or more of
physiology measurements, an image of the vessel with one or more
visualizations, and relevant risk & perfusion calculations.
[0029] In some embodiments, PCI planning is facilitated by the
graphical overlay of physiologic data and the ability to add/delete
and drag markings that allow the user to size and isolate
blockages. Using the guide catheter and/or the guide wire as a
calibrated and known length permits these markings, and
co-registered physiologic data to estimate lesion lengths. These
data can be inputted into a risk calculator including but not
limited to a Functional Syntax Score. The use of the markings,
length, and physiologic data permit the interventionalist to plan a
percutaneous coronary intervention whereby the number of stents,
and length of stents can be estimated.
[0030] In some embodiments, CABG mapping is facilitated by the
graphical overlay of physiologic data and the ability to add/delete
and drag the markings that allow the user to size and isolate the
blockages. In planning a bypass surgery (CABG), the data allows the
physician to identify where on the artery the disease starts and
stops. This results in a CABG map, where the ideal placement of a
graph can be determined and the prediction of graft patency and
perfusion benefit can be identified to support decision making. The
benefit of this is optimizing outcomes like graft patency and
reducing costs like unnecessary grafting and time.
[0031] Referring to FIGS. 1 and 2, shown therein is a vessel 100
having a stenosis according to an embodiment of the present
disclosure. In that regard, FIG. 1 is a diagrammatic perspective
view of the vessel 100, while FIG. 2 is a partial cross-sectional
perspective view of a portion of the vessel 100 taken along section
line 2-2 of FIG. 1. Referring more specifically to FIG. 1, the
vessel 100 includes a proximal portion 102 and a distal portion
104. A lumen 106 extends along the length of the vessel 100 between
the proximal portion 102 and the distal portion 104. In that
regard, the lumen 106 is configured to allow the flow of fluid
through the vessel. In some instances, the vessel 100 is a blood
vessel. In some particular instances, the vessel 100 is a coronary
artery. In such instances, the lumen 106 is configured to
facilitate the flow of blood through the vessel 100.
[0032] As shown, the vessel 100 includes a stenosis 108 between the
proximal portion 102 and the distal portion 104. Stenosis 108 is
generally representative of any blockage or other structural
arrangement that results in a restriction to the flow of fluid
through the lumen 106 of the vessel 100. Embodiments of the present
disclosure are suitable for use in a wide variety of vascular
applications, including without limitation coronary, peripheral
(including but not limited to lower limb, carotid, and
neurovascular), renal, and/or venous. Where the vessel 100 is a
blood vessel, the stenosis 108 may be a result of plaque buildup,
including without limitation plaque components such as fibrous,
fibro-lipidic (fibro fatty), necrotic core, calcified (dense
calcium), blood, fresh thrombus, and mature thrombus. Generally,
the composition of the stenosis will depend on the type of vessel
being evaluated. In that regard, it is understood that the concepts
of the present disclosure are applicable to virtually any type of
blockage or other narrowing of a vessel that results in decreased
fluid flow.
[0033] Referring more particularly to FIG. 2, the lumen 106 of the
vessel 100 has a diameter 110 proximal of the stenosis 108 and a
diameter 112 distal of the stenosis. In some instances, the
diameters 110 and 112 are substantially equal to one another. In
that regard, the diameters 110 and 112 are intended to represent
healthy portions, or at least healthier portions, of the lumen 106
in comparison to stenosis 108. Accordingly, these healthier
portions of the lumen 106 are illustrated as having a substantially
constant cylindrical profile and, as a result, the height or width
of the lumen has been referred to as a diameter. However, it is
understood that in many instances these portions of the lumen 106
will also have plaque buildup, a non-symmetric profile, and/or
other irregularities, but to a lesser extent than stenosis 108 and,
therefore, will not have a cylindrical profile. In such instances,
the diameters 110 and 112 are understood to be representative of a
relative size or cross-sectional area of the lumen and do not imply
a circular cross-sectional profile.
[0034] As shown in FIG. 2, stenosis 108 includes plaque buildup 114
that narrows the lumen 106 of the vessel 100. In some instances,
the plaque buildup 114 does not have a uniform or symmetrical
profile, making angiographic evaluation of such a stenosis
unreliable. In the illustrated embodiment, the plaque buildup 114
includes an upper portion 116 and an opposing lower portion 118. In
that regard, the lower portion 118 has an increased thickness
relative to the upper portion 116 that results in a non-symmetrical
and non-uniform profile relative to the portions of the lumen
proximal and distal of the stenosis 108. As shown, the plaque
buildup 114 decreases the available space for fluid to flow through
the lumen 106. In particular, the cross-sectional area of the lumen
106 is decreased by the plaque buildup 114. At the narrowest point
between the upper and lower portions 116, 118 the lumen 106 has a
height 120, which is representative of a reduced size or
cross-sectional area relative to the diameters 110 and 112 proximal
and distal of the stenosis 108. Note that the stenosis 108,
including plaque buildup 114 is exemplary in nature and should be
considered limiting in any way. In that regard, it is understood
that the stenosis 108 has other shapes and/or compositions that
limit the flow of fluid through the lumen 106 in other instances.
While the vessel 100 is illustrated in FIGS. 1 and 2 as having a
single stenosis 108 and the description of the embodiments below is
primarily made in the context of a single stenosis, it is
nevertheless understood that the devices, systems, and methods
described herein have similar application for a vessel having
multiple stenosis regions.
[0035] Referring now to FIG. 3, the vessel 100 is shown with
instruments 130 and 132 positioned therein according to an
embodiment of the present disclosure. In general, instruments 130
and 132 may be any form of device, instrument, or probe sized and
shaped to be positioned within a vessel. In the illustrated
embodiment, instrument 130 is generally representative of a guide
wire, while instrument 132 is generally representative of a
catheter. In that regard, instrument 130 extends through a central
lumen of instrument 132. However, in other embodiments, the
instruments 130 and 132 take other forms. In that regard, the
instruments 130 and 132 are of similar form in some embodiments.
For example, in some instances, both instruments 130 and 132 are
guide wires. In other instances, both instruments 130 and 132 are
catheters. On the other hand, the instruments 130 and 132 are of
different form in some embodiments, such as the illustrated
embodiment, where one of the instruments is a catheter and the
other is a guide wire. Further, in some instances, the instruments
130 and 132 are disposed coaxial with one another, as shown in the
illustrated embodiment of FIG. 3. In other instances, one of the
instruments extends through an off-center lumen of the other
instrument. In yet other instances, the instruments 130 and 132
extend side-by-side. In some particular embodiments, at least one
of the instruments is as a rapid-exchange device, such as a
rapid-exchange catheter. In such embodiments, the other instrument
is a buddy wire or other device configured to facilitate the
introduction and removal of the rapid-exchange device. Further
still, in other instances, instead of two separate instruments 130
and 132 a single instrument is utilized. In some embodiments, the
single instrument incorporates aspects of the functionalities
(e.g., data acquisition) of both instruments 130 and 132.
[0036] Instrument 130 is configured to obtain diagnostic
information about the vessel 100. In that regard, the instrument
130 includes one or more sensors, transducers, and/or other
monitoring elements configured to obtain the diagnostic information
about the vessel. The diagnostic information includes one or more
of pressure, flow (velocity), images (including images obtained
using ultrasound (e.g., IVUS), OCT, thermal, and/or other imaging
techniques), temperature, and/or combinations thereof. The one or
more sensors, transducers, and/or other monitoring elements are
positioned adjacent a distal portion of the instrument 130 in some
instances. In that regard, the one or more sensors, transducers,
and/or other monitoring elements are positioned less than 30 cm,
less than 10 cm, less than 5 cm, less than 3 cm, less than 2 cm,
and/or less than 1 cm from a distal tip 134 of the instrument 130
in some instances. In some instances, at least one of the one or
more sensors, transducers, and/or other monitoring elements is
positioned at the distal tip of the instrument 130.
[0037] The instrument 130 includes at least one element configured
to monitor pressure within the vessel 100. The pressure monitoring
element can take the form a piezo-resistive pressure sensor, a
piezo-electric pressure sensor, a capacitive pressure sensor, an
electromagnetic pressure sensor, a fluid column (the fluid column
being in communication with a fluid column sensor that is separate
from the instrument and/or positioned at a portion of the
instrument proximal of the fluid column), an optical pressure
sensor, and/or combinations thereof. In some instances, one or more
features of the pressure monitoring element are implemented as a
solid-state component manufactured using semiconductor and/or other
suitable manufacturing techniques. Examples of commercially
available guide wire products that include suitable pressure
monitoring elements include, without limitation, the PrimeWire
PRESTIGE.RTM. pressure guide wire, the PrimeWire.RTM. pressure
guide wire, and the ComboWire.RTM. XT pressure and flow guide wire,
each available from Volcano Corporation, as well as the
PressureWire.TM. Certus guide wire and the PressureWire.TM. Aeris
guide wire, each available from St. Jude Medical, Inc. Generally,
the instrument 130 is sized such that it can be positioned through
the stenosis 108 without significantly impacting fluid flow across
the stenosis, which would impact the distal pressure reading.
Accordingly, in some instances the instrument 130 has an outer
diameter of 0.018'' or less. In some embodiments, the instrument
130 has an outer diameter of 0.014'' or less.
[0038] Instrument 132 is also configured to obtain diagnostic
information about the vessel 100. In some instances, instrument 132
is configured to obtain the same diagnostic information as
instrument 130. In other instances, instrument 132 is configured to
obtain different diagnostic information than instrument 130, which
may include additional diagnostic information, less diagnostic
information, and/or alternative diagnostic information. The
diagnostic information obtained by instrument 132 includes one or
more of pressure, flow (velocity), images (including images
obtained using ultrasound (e.g., IVUS), OCT, thermal, and/or other
imaging techniques), temperature, and/or combinations thereof.
Instrument 132 includes one or more sensors, transducers, and/or
other monitoring elements configured to obtain this diagnostic
information. In that regard, the one or more sensors, transducers,
and/or other monitoring elements are positioned adjacent a distal
portion of the instrument 132 in some instances. In that regard,
the one or more sensors, transducers, and/or other monitoring
elements are positioned less than 30 cm, less than 10 cm, less than
5 cm, less than 3 cm, less than 2 cm, and/or less than 1 cm from a
distal tip 136 of the instrument 132 in some instances. In some
instances, at least one of the one or more sensors, transducers,
and/or other monitoring elements is positioned at the distal tip of
the instrument 132.
[0039] Similar to instrument 130, instrument 132 also includes at
least one element configured to monitor pressure within the vessel
100. The pressure monitoring element can take the form a
piezo-resistive pressure sensor, a piezo-electric pressure sensor,
a capacitive pressure sensor, an electromagnetic pressure sensor, a
fluid column (the fluid column being in communication with a fluid
column sensor that is separate from the instrument and/or
positioned at a portion of the instrument proximal of the fluid
column), an optical pressure sensor, and/or combinations thereof.
In some instances, one or more features of the pressure monitoring
element are implemented as a solid-state component manufactured
using semiconductor and/or other suitable manufacturing techniques.
Currently available catheter products suitable for use with one or
more of Siemens AXIOM.RTM. Sensis, Mennen Horizon XVu, and Philips
Xper.RTM. IM Physiomonitoring 5 and include pressure monitoring
elements can be utilized for instrument 132 in some instances.
[0040] In accordance with aspects of the present disclosure, at
least one of the instruments 130 and 132 is configured to monitor a
pressure within the vessel 100 distal of the stenosis 108 and at
least one of the instruments 130 and 132 is configured to monitor a
pressure within the vessel proximal of the stenosis. In that
regard, the instruments 130, 132 are sized and shaped to allow
positioning of the at least one element configured to monitor
pressure within the vessel 100 to be positioned proximal and/or
distal of the stenosis 108 as necessary based on the configuration
of the devices. In that regard, FIG. 3 illustrates a position 138
suitable for measuring pressure distal of the stenosis 108. In that
regard, the position 138 is less than 5 cm, less than 3 cm, less
than 2 cm, less than 1 cm, less than 5 mm, and/or less than 2.5 mm
from the distal end of the stenosis 108 (as shown in FIG. 2) in
some instances. FIG. 3 also illustrates a plurality of suitable
positions for measuring pressure proximal of the stenosis 108. In
that regard, positions 140, 142, 144, 146, and 148 each represent a
position that is suitable for monitoring the pressure proximal of
the stenosis in some instances. In that regard, the positions 140,
142, 144, 146, and 148 are positioned at varying distances from the
proximal end of the stenosis 108 ranging from more than 20 cm down
to about 5 mm or less. Generally, the proximal pressure measurement
will be spaced from the proximal end of the stenosis. Accordingly,
in some instances, the proximal pressure measurement is taken at a
distance equal to or greater than an inner diameter of the lumen of
the vessel from the proximal end of the stenosis. In the context of
coronary artery pressure measurements, the proximal pressure
measurement is generally taken at a position proximal of the
stenosis and distal of the aorta, within a proximal portion of the
vessel. However, in some particular instances of coronary artery
pressure measurements, the proximal pressure measurement is taken
from a location inside the aorta. In other instances, the proximal
pressure measurement is taken at the root or ostium of the coronary
artery.
[0041] In some embodiments, at least one of the instruments 130 and
132 is configured to monitor pressure within the vessel 100 while
being moved through the lumen 106. In some instances, instrument
130 is configured to be moved through the lumen 106 and across the
stenosis 108. In that regard, the instrument 130 is positioned
distal of the stenosis 108 and moved proximally (i.e., pulled back)
across the stenosis to a position proximal of the stenosis in some
instances. In other instances, the instrument 130 is positioned
proximal of the stenosis 108 and moved distally across the stenosis
to a position distal of the stenosis. Movement of the instrument
130, either proximally or distally, is controlled manually by
medical personnel (e.g., hand of a surgeon) in some embodiments. In
other embodiments, movement of the instrument 130, either
proximally or distally, is controlled automatically by a movement
control device (e.g., a pullback device, such as the Trak Back.RTM.
II Device available from Volcano Corporation). In that regard, the
movement control device controls the movement of the instrument 130
at a selectable and known speed (e.g., 2.0 mm/s, 1.0 mm/s, 0.5
mm/s, 0.2 mm/s, etc.) in some instances. Movement of the instrument
130 through the vessel is continuous for each pullback or push
through, in some instances. In other instances, the instrument 130
is moved step-wise through the vessel (i.e., repeatedly moved a
fixed amount of distance and/or a fixed amount of time). Some
aspects of the visual depictions discussed below are particularly
suited for embodiments where at least one of the instruments 130
and 132 is moved through the lumen 106. Further, in some particular
instances, aspects of the visual depictions discussed below are
particularly suited for embodiments where a single instrument is
moved through the lumen 106, with or without the presence of a
second instrument.
[0042] In some instances, use of a single instrument has a benefit
in that it avoids issues associated with variations in pressure
measurements of one instrument relative to another over time, which
is commonly referred to as drift. In that regard, a major source of
drift in traditional Fractional Flow Reserve (FFR) measurements is
divergence in the pressure reading of a guidewire relative to the
pressure reading of a guide catheter. In that regard, because FFR
is calculated as the ratio of the pressure measurement obtained by
the guidewire to the pressure measurement obtained by the catheter,
this divergence has an impact on the resulting FFR value. In
contrast, where a single instrument is utilized to obtain pressure
measurements as it is moved through the vessel, drift is negligible
or non-existent. For example, in some instances, the single
instrument is utilized to obtain relative changes in pressures as
it is moved through the vessel such that the time period between
pressure measurements is short enough to prevent any impact from
any changes in pressure sensitivity of the instrument (e.g., less
than 500 ms, less than 100 ms, less than 50 ms, less than 10 ms,
less than 5 ms, less than 1 ms, or otherwise).
[0043] Referring now to FIG. 4, shown therein is a system 150
according to an embodiment of the present disclosure. In that
regard, FIG. 4 is a diagrammatic, schematic view of the system 150.
As shown, the system 150 includes an instrument 152. In that
regard, in some instances instrument 152 is suitable for use as at
least one of instruments 130 and 132 discussed above. Accordingly,
in some instances the instrument 152 includes features similar to
those discussed above with respect to instruments 130 and 132 in
some instances. In the illustrated embodiment, the instrument 152
is a guide wire having a distal portion 154 and a housing 156
positioned adjacent the distal portion. In that regard, the housing
156 is spaced approximately 3 cm from a distal tip of the
instrument 152. The housing 156 is configured to house one or more
sensors, transducers, and/or other monitoring elements configured
to obtain the diagnostic information about the vessel. In the
illustrated embodiment, the housing 156 contains at least a
pressure sensor configured to monitor a pressure within a lumen in
which the instrument 152 is positioned. A shaft 158 extends
proximally from the housing 156. A torque device 160 is positioned
over and coupled to a proximal portion of the shaft 158. A proximal
end portion 162 of the instrument 152 is coupled to a connector
164. A cable 166 extends from connector 164 to a connector 168. In
some instances, connector 168 is configured to be plugged into an
interface 170. In that regard, interface 170 is a patient interface
module (PIM) in some instances. In some instances, the cable 166 is
replaced with a wireless connection. In that regard, it is
understood that various communication pathways between the
instrument 152 and the interface 170 may be utilized, including
physical connections (including electrical, optical, and/or fluid
connections), wireless connections, and/or combinations
thereof.
[0044] The interface 170 is communicatively coupled to a computing
device 172 via a connection 174. Computing device 172 is generally
representative of any device suitable for performing the processing
and analysis techniques discussed within the present disclosure. In
some embodiments, the computing device 172 includes a processor,
random access memory, and a storage medium. In that regard, in some
particular instances the computing device 172 is programmed to
execute steps associated with the data acquisition and analysis
described herein. Accordingly, it is understood that any steps
related to data acquisition, data processing, instrument control,
and/or other processing or control aspects of the present
disclosure may be implemented by the computing device using
corresponding instructions stored on or in a non-transitory
computer readable medium accessible by the computing device. In
some instances, the computing device 172 is a console device. In
some particular instances, the computing device 172 is similar to
the s5.TM. Imaging System or the s5i.TM. Imaging System, each
available from Volcano Corporation. In some instances, the
computing device 172 is portable (e.g., handheld, on a rolling
cart, etc.). Further, it is understood that in some instances the
computing device 172 comprises a plurality of computing devices. In
that regard, it is particularly understood that the different
processing and/or control aspects of the present disclosure may be
implemented separately or within predefined groupings using a
plurality of computing devices. Any divisions and/or combinations
of the processing and/or control aspects described below across
multiple computing devices are within the scope of the present
disclosure.
[0045] Together, connector 164, cable 166, connector 168, interface
170, and connection 174 facilitate communication between the one or
more sensors, transducers, and/or other monitoring elements of the
instrument 152 and the computing device 172. However, this
communication pathway is exemplary in nature and should not be
considered limiting in any way. In that regard, it is understood
that any communication pathway between the instrument 152 and the
computing device 172 may be utilized, including physical
connections (including electrical, optical, and/or fluid
connections), wireless connections, and/or combinations thereof. In
that regard, it is understood that the connection 174 is wireless
in some instances. In some instances, the connection 174 includes a
communication link over a network (e.g., intranet, internet,
telecommunications network, and/or other network). In that regard,
it is understood that the computing device 172 is positioned remote
from an operating area where the instrument 152 is being used in
some instances. Having the connection 174 include a connection over
a network can facilitate communication between the instrument 152
and the remote computing device 172 regardless of whether the
computing device is in an adjacent room, an adjacent building, or
in a different state/country. Further, it is understood that the
communication pathway between the instrument 152 and the computing
device 172 is a secure connection in some instances. Further still,
it is understood that, in some instances, the data communicated
over one or more portions of the communication pathway between the
instrument 152 and the computing device 172 is encrypted.
[0046] The system 150 also includes an instrument 175. In that
regard, in some instances instrument 175 is suitable for use as at
least one of instruments 130 and 132 discussed above. Accordingly,
in some instances the instrument 175 includes features similar to
those discussed above with respect to instruments 130 and 132 in
some instances. In the illustrated embodiment, the instrument 175
is a catheter-type device. In that regard, the instrument 175
includes one or more sensors, transducers, and/or other monitoring
elements adjacent a distal portion of the instrument configured to
obtain the diagnostic information about the vessel. In the
illustrated embodiment, the instrument 175 includes a pressure
sensor configured to monitor a pressure within a lumen in which the
instrument 175 is positioned. The instrument 175 is in
communication with an interface 176 via connection 177. In some
instances, interface 176 is a hemodynamic monitoring system or
other control device, such as Siemens AXIOM.RTM. Sensis, Mennen
Horizon XVu, and Philips Xper.RTM. IM Physiomonitoring 5. In one
particular embodiment, instrument 175 is a pressure-sensing
catheter that includes fluid column extending along its length. In
such an embodiment, interface 176 includes a hemostasis valve
fluidly coupled to the fluid column of the catheter, a manifold
fluidly coupled to the hemostasis valve, and tubing extending
between the components as necessary to fluidly couple the
components. In that regard, the fluid column of the catheter is in
fluid communication with a pressure sensor via the valve, manifold,
and tubing. In some instances, the pressure sensor is part of
interface 176. In other instances, the pressure sensor is a
separate component positioned between the instrument 175 and the
interface 176. The interface 176 is communicatively coupled to the
computing device 172 via a connection 178.
[0047] Similar to the connections between instrument 152 and the
computing device 172, interface 176 and connections 177 and 178
facilitate communication between the one or more sensors,
transducers, and/or other monitoring elements of the instrument 175
and the computing device 172. However, this communication pathway
is exemplary in nature and should not be considered limiting in any
way. In that regard, it is understood that any communication
pathway between the instrument 175 and the computing device 172 may
be utilized, including physical connections (including electrical,
optical, and/or fluid connections), wireless connections, and/or
combinations thereof. In that regard, it is understood that the
connection 178 is wireless in some instances. In some instances,
the connection 178 includes a communication link over a network
(e.g., intranet, internet, telecommunications network, and/or other
network). In that regard, it is understood that the computing
device 172 is positioned remote from an operating area where the
instrument 175 is being used in some instances. Having the
connection 178 include a connection over a network can facilitate
communication between the instrument 175 and the remote computing
device 172 regardless of whether the computing device is in an
adjacent room, an adjacent building, or in a different
state/country. Further, it is understood that the communication
pathway between the instrument 175 and the computing device 172 is
a secure connection in some instances. Further still, it is
understood that, in some instances, the data communicated over one
or more portions of the communication pathway between the
instrument 175 and the computing device 172 is encrypted.
[0048] It is understood that one or more components of the system
150 are not included, are implemented in a different
arrangement/order, and/or are replaced with an alternative
device/mechanism in other embodiments of the present disclosure.
For example, in some instances, the system 150 does not include
interface 170 and/or interface 176. In such instances, the
connector 168 (or other similar connector in communication with
instrument 152 or instrument 175) may plug into a port associated
with computing device 172. Alternatively, the instruments 152, 175
may communicate wirelessly with the computing device 172. Generally
speaking, the communication pathway between either or both of the
instruments 152, 175 and the computing device 172 may have no
intermediate nodes (i.e., a direct connection), one intermediate
node between the instrument and the computing device, or a
plurality of intermediate nodes between the instrument and the
computing device.
[0049] Diagnostic information within a vasculature of interest can
be obtained using one or more of instruments 130, 132, 152, and
175. For example, diagnostic information is obtained for one or
more coronaries arteries, peripheral arteries, cerebrovascular
vessels, etc. The diagnostic information can include
pressure-related values, flow-related values, etc. Pressure-related
values can include FFR, Pd/Pa (e.g., a ratio of the pressure distal
to a lesion to the pressure proximal to the lesion), iFR (e.g., a
pressure ratio value calculated using a diagnostic window relative
to a distance as a first instrument is moved through a vessel
relative to a second instrument, including across at least one
stenosis of the vessel), etc. Flow-related values can include
coronary flow reserve or CFR (e.g., maximum increase in blood flow
through the coronary arteries above the normal resting volume),
basal stenosis resistance index (BSR), etc.
[0050] In some embodiments, the diagnostic information can include
angiographic images and/or other two-dimensional or
three-dimensional depictions of a patient's vasculature. The
diagnostic information and/or data obtained by instruments 130,
132, 152, and/or 175 are correlated or co-registered to
angiographic image(s) and/or other two-dimensional or
three-dimensional depictions of a patient's vasculature.
Co-registration can be completed using techniques disclosed in U.S.
Pat. No. 7,930,014, issued on Apr. 19, 2011, titled "VASCULAR IMAGE
CO-REGISTRATION," which is hereby incorporated by reference in its
entirety, based on the known pullback speed/distance, based on a
known starting point, based on a known ending point, and/or
combinations thereof. In some embodiments, diagnostic information
and/or data is correlated to vessel images using techniques similar
to those described in U.S. Patent Publication No. 2014/0187920 A1,
titled "DEVICES, SYSTEMS, AND METHODS FOR ASSESSMENT OF VESSELS"
and published on Jul. 3, 2014, which is hereby incorporated by
reference in its entirety. In some embodiments, co-registration
and/or correlation can be completed as described in U.S. patent
application Ser. No. 14/335,603, titled "DEVICES, SYSTEMS, AND
METHODS FOR ASSESSMENT OF VESSELS" and filed on Jul. 18, 2014,
which is hereby incorporated by reference in its entirety.
[0051] The discussion below generally refers to FIGS. 5-12. FIGS.
5, 7, 8, 11, and 12 are annotated versions of stylized images of a
vessel according to embodiments of the present disclosure. FIG. 5
includes a stylized image 200 of one or more coronary arteries.
FIG. 7 includes stylized images 240 and 260 of one or more coronary
arteries. FIG. 8 is a stylized image 280 of one or more coronary
arteries. FIG. 11 includes a stylized image 340 of one or more
peripheral arteries. FIG. 12 includes a stylized image 360 of one
or more cerebrovascular vessels. FIGS. 9 and 10 are annotated
versions of angiographic images of one or more coronary arteries
according to embodiments of the present disclosure. FIG. 6 is a
visual depiction of an index 220 for assessing the severity of one
or more lesions and/or stenoses according to an embodiment of the
present disclosure. FIGS. 5 and 7-12 also include index 220. FIGS.
5-12 can be displayed on a display of system assessing a patient's
vasculature. That is, one or more components (e.g., a processor
and/or processing circuit) of the system can provided display data
to cause the display of the images shown in FIGS. 5-12.
[0052] The images of vessels in FIGS. 5 and 7-12 are annotated with
one or more visualizations configured to assist in identifying one
or more lesions and/or stenoses, and/or assess the severity
thereof. The visualizations are based on physiology values obtained
from an instrument (e.g., instrument 130) as the instrument is
moved through the vessel. The vessels of FIGS. 5 and 7-12 can be
colorized and/or otherwise visualized using a heat map that
illustrates changes in pressure measurements obtained as the
instrument is moved through the vessel. In that regard, in some
instances the pressure measurements shown in the heat map are
representative of a pressure differential between a fixed location
within the vessel and the moving position of the instrument as the
instrument is moved through the vessel. For example, in some
instances a proximal pressure measurement is obtained at a fixed
location within the vessel while the instrument is pulled back
through the vessel from a first position distal of the position
where the proximal pressure measurement is obtained to a second
position more proximal than the first position (i.e., closer the
fixed position of the distal pressure measurement). For clarity in
understanding the concepts of the present disclosure, this
arrangement will be utilized to describe many of the embodiments of
the present disclosure. However, it is understood that the concepts
are equally applicable to other arrangements. For example, in some
instances, the instrument is pushed through the vessel from a first
position distal of the proximal pressure measurement location to a
second position further distal (i.e., further away from the fixed
position of the proximal pressure measurement). In other instances,
a distal pressure measurement is obtained at a fixed location
within the vessel and the instrument is pulled back through the
vessel from a first position proximal of the fixed location of the
distal pressure measurement to a second position more proximal than
the first position (i.e., further away from the fixed position of
the distal pressure measurement). In still other instances, a
distal pressure measurement is obtained at a fixed location within
the vessel and the instrument is pushed through the vessel from a
first position proximal of the fixed location of the distal
pressure measurement to a second position less proximal than the
first position (i.e., closer the fixed position of the distal
pressure measurement).
[0053] The pressure differential between the two pressure
measurements within the vessel (e.g., a fixed location pressure
measurement and a moving pressure measurement) is calculated as a
ratio of the two pressure measurements (e.g., the moving pressure
measurement divided by the fixed location pressure measurement), in
some instances. In some instances, the pressure differential is
calculated for each heartbeat cycle of the patient. In that regard,
the calculated pressure differential is the average pressure
differential across a heartbeat cycle in some embodiments. For
example, in some instances where a hyperemic agent is applied to
the patient, the average pressure differential across the heartbeat
cycle is utilized to calculate the pressure differential. In other
embodiments, only a portion of the heartbeat cycle is utilized to
calculate the pressure differential. The pressure differential is
an average over the portion or diagnostic window of the heartbeat
cycle, in some instances. In that regard, in some embodiments a
diagnostic window is selected using one or more of the techniques
described in U.S. Patent Publication No. 2013/0046190 A1, published
on Feb. 21, 2013 and titled "DEVICES, SYSTEMS, AND METHODS FOR
ASSESSING A VESSEL," which is hereby incorporated by reference in
its entirety. As discussed therein, the diagnostic windows and
associated techniques are particularly suitable for use without
application of a hyperemic agent to the patient. In general, the
diagnostic window for evaluating differential pressure across a
stenosis without the use of a hyperemic agent is identified based
on characteristics and/or components of one or more of proximal
pressure measurements, distal pressure measurements, proximal
velocity measurements, distal velocity measurements, ECG waveforms,
and/or other identifiable and/or measurable aspects of vessel
performance. In that regard, various signal processing and/or
computational techniques can be applied to the characteristics
and/or components of one or more of proximal pressure measurements,
distal pressure measurements, proximal velocity measurements,
distal velocity measurements, ECG waveforms, and/or other
identifiable and/or measurable aspects of vessel performance to
identify a suitable diagnostic window.
[0054] In some embodiments, the determination of the diagnostic
window and/or the calculation of the pressure differential are
performed in approximately real time or live to identify the
section 212 and calculate the pressure differential. In that
regard, calculating the pressure differential in "real time" or
"live" within the context of the present disclosure is understood
to encompass calculations that occur within 10 seconds of data
acquisition. It is recognized, however, that often "real time" or
"live" calculations are performed within 1 second of data
acquisition. In some instances, the "real time" or "live"
calculations are performed concurrent with data acquisition. In
some instances the calculations are performed by a processor in the
delays between data acquisitions. For example, if data is acquired
from the pressure sensing devices for 1 ms every 5 ms, then in the
4 ms between data acquisitions the processor can perform the
calculations. It is understood that these timings are for example
only and that data acquisition rates, processing times, and/or
other parameters surrounding the calculations will vary. In other
embodiments, the pressure differential calculation is performed 10
or more seconds after data acquisition. For example, in some
embodiments, the data utilized to identify the diagnostic window
and/or calculate the pressure differential are stored for later
analysis.
[0055] By comparing the calculated pressure differential to a
threshold or predetermined value, a physician or other treating
medical personnel can determine what, if any, treatment should be
administered. In that regard, in some instances, a calculated
pressure differential above a threshold value (e.g., 0.80 on a
scale of 0.00 to 1.00) is indicative of a first treatment mode
(e.g., no treatment, drug therapy, etc.), while a calculated
pressure differential below the threshold value is indicative of a
second, more invasive treatment mode (e.g., angioplasty, stent,
etc.). In some instances, the threshold value is a fixed, preset
value. In other instances, the threshold value is selected for a
particular patient and/or a particular stenosis of a patient. In
that regard, the threshold value for a particular patient may be
based on one or more of empirical data, patient characteristics,
patient history, physician preference, available treatment options,
and/or other parameters.
[0056] In that regard, the coloring and/or other visually
distinguishing aspect of the physiology values (e.g., pressure
differential measurements) depicted in FIGS. 5 and 7-12 are
configured based on the threshold value. FIG. 6 is an index or
severity key 220 showing the colors 222 and their corresponding
physiological values 224. For example, a first color (e.g., green,
medium grey, or otherwise) is utilized to represent values well
above the threshold value (e.g., where the threshold value is 0.80
on a scale of 0.00 to 1.00, values above 0.85), a second color
(e.g., yellow, white, or otherwise) is utilized to represent values
near but above the threshold value (e.g., where the threshold value
is 0.80 on a scale of 0.00 to 1.00, values between 0.82 and 0.84),
a third color (e.g., orange, light grey, or otherwise) is utilized
to represent values near the threshold value (e.g., where the
threshold value is 0.80 on a scale of 0.00 to 1.00, values between
0.79 and 0.81), and a fourth color (e.g., red, dark grey, or
otherwise) is utilized to represent values equal to or below the
threshold value (e.g., where the threshold value is 0.80 on a scale
of 0.00 to 1.00, values of 0.79 and below).
[0057] Area 232 of FIGS. 5-12 indicates parts of the vessel with
low severity (e.g., areas with a relatively high FFR value). Area
234 indicates parts of the vessel with greater severity compared to
area 232 (e.g., areas with a moderately high FFR value). Area 236
indicates parts of the vessel with a moderate severity (e.g., areas
with a moderately low FFR value). Area 238 indicates parts of the
vessel with a high severity (e.g., areas with a low FFR value). It
is appreciated that any number of color combinations, scalings,
categories, and/or other characteristics can be utilized to
visually represent the relative value of the pressure differential
to the threshold value. However, for the sake of brevity Applicants
will not explicitly describe the numerous variations herein.
[0058] In some embodiments, the heat map included in FIGS. 5 and
7-12 is based on a cumulative or total pressure differential, where
the color selected for a particular point is determined based on
the pressure differential between the instrument at that point
being moved through the vessel and the stationary or fixed
instrument. In other embodiments, the heat map is based on
localized pressure differential, where the color selected for a
particular point is determined based on differences between the
pressure differential of that point with one or more of the
surrounding points. In that regard, the localized pressure
differential is calculated as the difference between the
immediately preceding point in some instances. For example, the
localized pressure differential for point P.sub.n is equal to the
cumulative or total pressure differential for point P.sub.n minus
the total or cumulative pressure differential for point P.sub.n-1.
In other instances, the localized pressure differential is
calculated as the difference between that point and a point a fixed
amount of time (e.g., 10 ms, 5 ms, 2 ms, 1 ms, or otherwise) or
distance (e.g., 10 mm, 5 mm, 2 mm, 1 mm, or otherwise) away from
that point. By utilizing a localized pressure differential the
location of significant changes in pressure differential values,
which are often associated with the presence of a lesion or
stenosis, can be identified.
[0059] FIGS. 5 and 7-12 includes transition points or areas of the
vessel wherein the physiology values between portions of the vessel
change by a threshold amount. In some embodiments, the threshold
amount can be fixed, while in other embodiments, the threshold
amount can vary between patients. The one or more transition points
can be indicated by visualizations. In FIGS. 5 and 7-12, the
visualizations are markings 202. Markings 202 can be described as
tick marks. In some embodiments, markings 202 can extend
transversely across the vessel. In other embodiments, markings 202
can take different shapes (e.g., circles, squares, etc.), be in
different positions relative to the vessel (beside, within, etc.),
be differently sized, etc. The transition points can be
representative of a boundary of a lesion or stenosis of the vessel
that results in an increased or decreased pressure differential,
which is illustrated by the change in color of the vessel. As a
result, one or more visualizations (e.g., the change in color,
markings 202, etc.) can be utilized to both identify the location
of the lesion or stenosis within the vessel and assess the severity
of the lesion or stenosis.
[0060] FIGS. 5 and 7-12 include visualizations for providing
diagnostic information collected by one or more instruments at a
corresponding location of the vessel on the display. In that
regard, value indicators 204 can be disposed adjacent to markings
202 to indicate the location within the patient's vasculature to
which the measurement corresponds. In other embodiments, value
indicators 204 are displayed further away from markings 202, but an
additional visual element (e.g., an arrow, a straight line, a
curved line, marking 202 and value indicator 204 are the same or
similar colors, etc.) is provided to indicate the location of the
measurement. In some embodiments, the value indicators 204 include
only the value of the physiological measurement (e.g., "0.96"),
while in other embodiments, the value indicators 204 include the
value and type of physiological measurement (e.g., "0.95 FFR"). In
yet other embodiments, additional information, such as the time the
measurement was taken, severity of the stenosis or lesion, etc. can
also be provided. For example, a user may provide a user input
(e.g., a selection from a drop-down menu, toggle through the
available options, etc.) selecting the types of information that
should be displayed in value indicators 204. Labels 206, for each
of the value indicators 204, can also be provided. Labels 206 can
include alphabetical, numeric, and/or other symbolic characters.
Labels 206 may assist in identifying markings 202 and/or value
indicators 204 (e.g., to distinguish between different
markings/value indicators and/or to facilitate discussion of the
vessel depictions).
[0061] In some embodiments, markings 202 and/or value indicators
204 can be positioned automatically. The system can be configured
to select locations within the vessel that are clinically
significant based on the diagnostic information (e.g., locations
where the physiology value changes significantly). In some
embodiments, markings 202 can be moved along the length of the
vessel. For example, a user may provide a user input (e.g., click
and drag the marking, click the marking to select it and then click
a new location to which it should move, etc.) to cause movement of
the markings 202. Value indicators 204 may be correspondingly
updated with data that is based on the new location and/or move
based on new location. That is, value indicators 204 can display
diagnostic information along the length of the vessel. In this
manner, a user may select a region of interest of the vessel by
moving marking 202 and/or value indicator 204 to indicate an area
of a vessel with a higher pressure differential, a lesion, and/or
stenosis.
[0062] In some embodiments, visualizations to indicate a region of
interest include multiple markings and a connector between the
markings. For example, markings 210 and 212 of FIG. 7 are joined by
connector 208. In some embodiments, markings 210 and 212 may be
individually moved and connector 208 corresponding lengthens or
shortens to span the space between them. In other embodiments,
markings 210 and 212 and connector 208 are collectively translated
along the vessel. Moving marking 210 in a direction along the
vessel away from marking 212 may cause marking 212 to move away
from marking 210 and cause connector 208 to lengthen. Moving
marking 210 in a direction along the vessel towards markings 212
may cause marking 212 to move towards marking 210 and cause
connector 208 to shorten. Movement of marking 212 may cause similar
movement by marking 210.
[0063] The one or more visualizations of FIGS. 5 and 7-12 can
include labels 214 and/or labels 216 for various predefined
segments of the patient's vasculature. Labels 216 can be textual
indications providing the names of major and/or minor vessels or
segments thereof. Labels 214 can include alphabetical, numeric,
and/or other symbolic characters. In some embodiments, labels 214
can correspond to a listing of parts of patient's vasculature. For
example, labels 214 can be based on parts of the patient's
vasculature identified by one or more risk calculators. The
segments identified by labels 214 and/or 216 include, but are not
limited to, right coronary artery (RCA), left main coronary artery,
circumflex coronary artery, left anterior descending (LAD), RCA
proximal, RCA mid, RCA distal, LAD proximal, LAD mid, LAD apical,
first diagonal, additional first diagonal, second diagonal,
additional second diagonal, proximal circumflex,
intermediate/anterolateral, obtuse marginal, distal circumflex,
left posterolateral, posterior descending, among others.
[0064] One or more images of a vessel, the visualizations in those
images, and/or the measured physiological values can be used to
evaluate whether and/or how to perform a surgical procedure. For
example, the surgical procedure can be a CABG or PCI. For CABG
planning, the measured physiological values and/or the images of
the vessels, which indicate the location, extent, and severity of
one or more lesions or stenoses, can be used to predict
probabilities of graft patency and perfusion change. The regions of
interest can be used to determine how and/or where in the
vasculature to intervene. For PCI planning, the measured
physiological values can be obtained using a guide catheter and/or
a guide wire of calibrated and known lengths. Thus, the location,
extent, and severity of one or more lesions or stenoses, can be
used to estimate the number of stents, the length of stents, etc.
The physiological values can also be used to calculate a numerical
or otherwise objective indication of risk/benefit, as described
herein. The objective indication of risk/benefit can be used to
evaluate whether and/or how to perform a surgical procedure.
[0065] The one or more visualizations of FIGS. 5-12 can include or
be supplemented with information regarding characteristics of the
lesion or stenosis and/or the vessel using one or more other vessel
data-gathering modalities. The other representations of the lesion
or stenosis and/or the vessel can include, e.g., IVUS (including
virtual histology), OCT, ICE, Thermal, Infrared, flow, Doppler
flow, and/or other vessel data-gathering modalities. The additional
information can provide a more complete and/or accurate
understanding of the vessel characteristics and/or assist in
evaluating a risk associated with a lesion or stenosis. For
example, in some instances the information can include the
occlusive value of the vessel. The occlusive value of the vessel
and/or other additional information may be utilized to calculate an
objective measure of the risk associated with the stenosis or
lesion.
[0066] It is understood that numerous other visualization
techniques may be utilized to convey the information of FIGS. 5-12
in the context of an angiographic image or other image of the
vessel (including both intravascular and extravascular imaging
techniques, such as IVUS, OCT, ICE, CTA, etc.) to help the user
evaluate the vessel. In that regard, while the examples of the
present disclosure are provided with respect to angiographic
images, it is understood that the concepts are equally applicable
to other types of vessel imaging techniques, including
intravascular and extravascular imaging
[0067] In some instances, a user is able to select what information
should be included or excluded from the displayed image. In that
regard, it should be noted that these visualization techniques
related to conveying the pressure measurement data in the context
of an angiographic or other image of the vessel can be utilized
individually and in any combinations. For example, in some
implementations a user is able to select what visualization mode(s)
and/or portions thereof will be utilized and the system outputs the
display accordingly. Further, in some implementations the user is
able to manually annotate the displayed image to include notes
and/or input one or more of the measured parameters.
[0068] The images of vessels in FIGS. 5 and 7-12 can include
three-dimensional, two-dimensional, angiographic, a computed
tomography angiographic (CTA), and/or other suitable forms of
images. In some embodiments, a three-dimensional image may be
rotated about a vertical axis. In some embodiments, a
two-dimensional image may include multiple views about a vertical
axis such that different two-dimensional views are shown when the
image is rotated. In some implementations, the three dimensional
model is displayed adjacent to a corresponding two dimensional
depiction of the vessel. In that regard, the user may select both
the type of depiction(s) (two dimensional (including imaging
modality type) and/or three dimensional) along with what
visualization mode(s) and/or portions thereof will be utilized. The
system will output a corresponding display based on the user's
preferences/selections and/or system defaults.
[0069] While the visual representations of FIGS. 5-12 have been
described separately, it is understood that a system may display
any combination of these visual representations in series,
simultaneously, and/or combinations thereof. In some instances, a
system provides the user the ability to select which individual
visual representation and/or combination of visual representations
will be displayed.
[0070] FIG. 13 is a flow diagram of a method 380 for assessing risk
according to an embodiment of the present disclosure. Method 380
can be implemented by a system described herein. At step 382,
method 380 includes evaluating the severity of a lesion or stenosis
along a patient anatomy. One or more diagnostic measurements (e.g.,
pressure-based including FFR and iFR, flow-based including CFR,
etc.) can be used to characterize the existence and/or severity of
a lesion. For example, when FFR is used, areas of a patient's
vasculature that have a relatively high FFR (e.g., greater than
0.80) are characterized as not having a lesion or stenosis, while
areas with a relatively low FFR (e.g., less than 0.80) are
characterized as having a lesion or stenosis. The severity can be
evaluated based on the heat map described herein.
[0071] At step 384, method 380 includes correlating the determined
severity with predefined regions of the patient anatomy. The
predefined regions of anatomy may correspond to the labels 214 used
to identify segments of a patient's vasculature. For example, the
RCA proximal segment may have a high severity due to a lesion or
stenosis, while the LAD proximal segment may have a low severity
because no lesion or stenosis is present. At step 386, the regions
of the patient anatomy and associated severity are provided to a
risk calculator. In various embodiments, the risk calculator can
include one or more algorithms for calculating the likelihood of
mortality, the likelihood of success when treating the lesion or
stenosis, etc. The risk calculator may output a quantity that is an
objective measure of the risk associated with the patient's
condition. The risk calculator may include a fractional flow
reserve (FFR)-guided SYNTAX score (SS) or functional SYNTAX score
(FSS), as described in Chang-Wook Nam, et al., Functional SYNTAX
Score for Risk Assessment in Multivessel Coronary Artery Disease,
Journal of the American College of Cardiology 2011; 58(12):
1211-1218, which is incorporated by reference herein in its
entirety. The risk calculator may also include any modified SYNTAX
score or any numerical or otherwise objective risk score that
incorporates physiologic measurements, including, but not limited
to, flow-based (CFR, etc.) and/or pressure-based (FFR, iFR, etc.)
parameters. The risk calculator may also generate an indication of
perfusion benefit and an indication of graft patency. For example,
the risk calculator may quantify the predicted perfusion change
should CABG be selected as the revascularization strategy.
[0072] At step 388, method 380 includes calculating the risk score
based on the provided data and any additional relevant patient
history. The provided data and/or patient history can be a binary
(e.g., yes or no) or continuous (e.g., percentage of narrowing of
the vessel). The provided data may be based on measured diagnostic
information (as evaluated in step 382). The provided data can
include one or more of existence of mitral stenosis, existence of
aortic stenosis, existence of total occlusion, existence of
trifurcation and how many diseased segments involved, existence of
bifurcation, existence of aorto ostial lesion, existence of severe
tortuosity in the vessel, whether length of the lesion is greater
than 20 mm, existence of heavy calcification, existence of
thrombus, if and which segments are diffusely diseased and/or
narrowed, number of lesions, percentage of narrowing, involvement
of proximal LAD lesion, etc. Other relevant patient history can
include one or more of age; gender; whether the patient has
diabetes, hypertension, hypercholesterolemia, peripheral vascular
disease; whether the patient is currently smoking; whether the
patient has a positive family history of heart disease; whether the
patient has had a previous myocardial infarction and/or previous
PCI; the ventricular ejection fraction percentage, etc. At step
390, the method 380 includes providing the calculated risk to a
display. In some implementations, calculating a risk score includes
providing the physiology measurements into an algorithm for
predicting the benefits of perfusion resulting from placement of a
coronary bypass graft.
[0073] Persons skilled in the art will also recognize that the
apparatus, systems, and methods described above can be modified in
various ways. Accordingly, persons of ordinary skill in the art
will appreciate that the embodiments encompassed by the present
disclosure are not limited to the particular exemplary embodiments
described above. In that regard, although illustrative embodiments
have been shown and described, a wide range of modification,
change, and substitution is contemplated in the foregoing
disclosure. It is understood that such variations may be made to
the foregoing without departing from the scope of the present
disclosure. Accordingly, it is appropriate that the appended claims
be construed broadly and in a manner consistent with the present
disclosure.
* * * * *