U.S. patent application number 11/974147 was filed with the patent office on 2008-04-24 for pulmonary artery banding device.
Invention is credited to Samy Renato Assad, Alexander Moreira Marra, Melchiades De Cunha Neto.
Application Number | 20080097497 11/974147 |
Document ID | / |
Family ID | 36870039 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080097497 |
Kind Code |
A1 |
Assad; Samy Renato ; et
al. |
April 24, 2008 |
Pulmonary artery banding device
Abstract
Pulmonary artery banding device (1) includes an inflating
banding ring (2), to be installed around the patient's pulmonary
artery (PA), an extending tube (3), and an insufflating button (4),
the extending tube (3) connecting insufflating button (4) to the
banding inflating ring, the banding ring being configured as a
C-shape hydraulic sleeve forming a support for an inflating
balloon, whose external wall (2a) is formed by a thin rigid silicon
layer, and whose inside wall (2b) is formed by a thin flexible
silicon layer, at the apart ends of the banding ring two brims
being disposed (2c) to facilitate the size banding adjustment
according with the pulmonary artery calibre (PA). The banding ring
are provided with holes (2e) for passage of sutures fixating the
ring on the pulmonary artery of the patient; the insufflating
button being configured as a cylindrical reservoir and being
provided with holes (4a) for sutures.
Inventors: |
Assad; Samy Renato; (Sao
Paulo, BR) ; Marra; Alexander Moreira; (Sao Paulo,
BR) ; Neto; Melchiades De Cunha; (Goiania Goias,
BR) |
Correspondence
Address: |
TRASK BRITT
P.O. BOX 2550
SALT LAKE CITY
UT
84110
US
|
Family ID: |
36870039 |
Appl. No.: |
11/974147 |
Filed: |
October 10, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/BR2006/000064 |
Apr 4, 2006 |
|
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11974147 |
Oct 10, 2007 |
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Current U.S.
Class: |
606/157 |
Current CPC
Class: |
A61B 17/12 20130101;
A61B 2017/00809 20130101; A61B 17/135 20130101; A61B 2017/00557
20130101 |
Class at
Publication: |
606/157 |
International
Class: |
A61B 17/08 20060101
A61B017/08 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2005 |
BR |
PI0505102-9 |
Claims
1. Improvements introduced in an pulmonary artery banding device,
device (1) constituted by an inflating banding ring (2), to be
installed around the patient pulmonary artery (PA), by an extending
tube (3), and by an insufflating button (4), implanted subcutaneary
in the patient's thorax; said extending tube (3) connecting
insufflating button (4) to the banding inflating ring (2), keeping
everybody linked to each other, characterized by the fact of the
said banding ring (2) configured by a hydraulic sleeve in the shape
of "C," forming a support for an inflating balloon, whose external
wall (2a) is formed by a thin rigid silicon layer, or similar, that
prevents the ring radial distention from within inside to outside
(centrifugal distention), and whose inside wall (2b) is formed by a
thin flexible silicon layer, or similar, that allows the outside
ring radial distention from within outside to inside (centripetal
distention), at the apart ends of the said banding ring (2), two
brims are disposed (2c) to facilitate the size banding adjustment
according with the pulmonary artery caliber (PA); said banding ring
(2) is still provided of an appropriate number of holes or loops
with holes (2e), along all extension of his non apart borders,
placed equidistant and spaced to each other, for fixation points
(sutures) passage of the said ring in the pulmonary artery
patient's; the extending tube (3), also of silicon, or similar,
provides the communication between the banding ring (2) and the
insufflating button (4), with the purpose to transmit an
appropriate liquid injected in the button for the banding ring
sleeve; the insufflating button (4) is configured by a cylindrical
reservoir made in auto-stamped silicon, or similar, whose base
presents a preferable porcelain metallic plate, to limit the
introduction injection liquid needle point; said button (4) is
provided of a multiplicity of holes (4a) disposed close to outlying
border, to passed the fixation points (sutures) of said button (4)
in the patient's thoracic wall, allowing the banding ring (2)
insufflation or "unsufflation" by percutaneous path.
2. An improvement in an ADJUSTABLE BANDING SYSTEM (1), adapted to
restrict blood flow through the small pulmonary arteries of
neonates, comprising: an inflating banding ring (2), to be
implanted around the neonate PA branches, a connecting tubing (3),
and a self-sealing inflating reservoir (4), implantable in the
patient's subcutaneous thorax, all parts of the Banding System
being of or covered by medical grade silicone and produced with
radiopaque material to be visualized on a chest roentgenogram, in
order to provide information regarding the position of the
implanted device, said banding ring (2) being configured as a "C"
shape hydraulic cuff, with an outer wall (2a) formed by a thin
non-distensible silicone layer, or similar, that prevents
centrifugal distention of the hydraulic cuff, further including
some small flanges to attach the banding ring to the PA adventitia
with sutures to keep said banding ring from migrating distally, the
inner portion (2b) of said banding ring being formed by a thin
flexible and distensible silicone balloon, or similar, that allows
inward distension as it is inflated, the "C" shaped banding ring
ending in two apart ends (2c) for adequate sizing of the band
according to neonate's PA size, the twist-resistant and
non-distensible flexible connecting tube (3) providing
communication between the banding ring (2) and the inflating
reservoir (4), with the purpose of taking the fluid injected
percutaneously in the inflation reservoir to the banding ring, thus
varying the PA diameter according to the volume of injected fluid,
the inflating reservoir (4) being configured by a ceramic
cylindrical sink, with a self-sealing silicone diaphragm at the top
and a lateral aperture connected hermetically to the tube, a 3 mm
thick silicone base having four small holes (4a) around the rim to
enable suturing to subcutaneous tissue, wherein the banding ring
constriction is adjustable by injecting or removing fluid
percutaneously from the inflation reservoir.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT International
Patent Application No. PCT/BR2006/000064, filed on Apr. 4, 2006,
designating the United States of America, and published, in
English, as PCT International Publication No. WO 2007/059594 A1 on
May 31, 2007, which application claims priority to Brazilian Patent
Application No. PI0505102-9 filed Nov. 22, 2005, the entire
contents of each application is hereby incorporated herein by this
reference.
TECHNICAL FIELD
[0002] This invention relates to improvements introduced in the
Pulmonary Artery (PA) banding device that resulted in an adjustable
device designed for treatment of several congenital heart lesions,
such as those with excessive pulmonary blood flow, transposition of
great arteries (TGA) and congenitally corrected transposition of
the great arteries (CCTGA).
BACKGROUND
[0003] In general, the heart is the organ responsible for the blood
circulation throughout the body. It is divided into four
"compartments," namely, right atrium, left atrium, right ventricle
and left ventricle.
[0004] To explain how the heart works, we describe the blood
circulation through the four compartments of this organ by means of
a diagram (FIG. 1): the blood comes from the body (B) to the right
atrium (RA) via vena cava (VC), passes to the right ventricle (RV)
through the tricuspid valve and is pumped through the pulmonary
valve to the main pulmonary artery (PA). After going through the
two lungs (L) where blood gases are exchanged, the now oxygenated
blood returns to the heart, more specifically to the left atrium
(LA), through the pulmonary veins (PV), thus completing the cycle
known as "small circulation." Now, blood goes through the mitral
valve to the left ventricle (LV), from where it is ejected through
the aortic valve to the aorta (Ao), and from there throughout the
body. The "great circulation" circuit is now completed by the
venous blood return to the right atrium.
[0005] Therefore, the right ventricle is responsible for pumping
blood to the lungs for gas exchange, while the left ventricle is in
charge of pumping oxygenated blood to the whole body. For this
reason, it is named as the systemic ventricle, much more overloaded
than the right ventricle.
[0006] Some congenital heart lesions are associated with excessive
pulmonary blood flow, in some special circumstances requiring
palliative treatment to somehow diminish this excessive pulmonary
blood flow until subsequent definitive treatment is possible.
[0007] Among the lesions commonly producing heart failure beyond
age one to two weeks when diminished pulmonary vascular resistance
allows substantial left-to-right shunting, is the multiple
ventricular septal defect, more specifically between the right and
left ventricles. In these cases, the right ventricle, besides
receiving blood from the right atrium, also receives blood from the
left ventricle through these multiple orifices, promoting excessive
pulmonary blood flow. Babies born with this anomaly usually have
feeding difficulties and failure to gain weight and grow.
[0008] However, some small infants may be very sick, making it
difficult to completely repair the lesion. This is one example of
congenial heart malformation whose palliative treatment aims to
limit excessive pulmonary blood flow. Surgical treatment can be
well managed initially by PA banding to limit the excessive blood
flow to the lungs, resulting in deferred repair until the patient
can be submitted to definitive surgery.
[0009] The PA banding technique continues as a valuable therapeutic
intervention for complex defects even during the era of total
correction of congenital cardiac anomalies during the neonatal
period. It consists of placing a band well proximal to the
pulmonary artery bifurcation. The band is tightened and secured by
suture to narrow the main pulmonary artery, bringing about a
balance of pulmonary and aortic blood flow by equalizing outflow
resistance. Excessive blood flow to the lungs is therefore
diminished by constricting the circumference of the pulmonary
artery, thereby achieving the desired limitation of the pulmonary
flow.
[0010] However, adjustment of the required degree of pulmonary and
aortic blood flow is the most difficult aspect of the procedure. We
rely on pressure measurements in the aorta and PA distal to the
band. The main PA is narrowed until the pressure distal to the band
is one-third to one-half that of the aorta. Nevertheless, skill and
accuracy of the surgery, supplemented by good fortune, are most
likely to assure success in this imprecise procedure.
[0011] In addition, the band commonly used is fixed and unchanged
in the postoperative course. In other words, it does not allow for
postoperative adjustability, that is, it is not possible to control
precisely and accurately the cross-sectional diameter of the
pulmonary artery according to the patient's clinical condition. It
means that the adjustment of the traditional band is unpredictable
and empiric, performed under artificial conditions, different from
the postoperative period.
[0012] There are also other congenital heart lesions that may
benefit from an adjustable PA banding system. One example is the
Transposition of the Great Arteries (TGA). For a better
understanding of this congenital malformation, FIG. 2 schematically
describes this condition:
[0013] TGA is a condition in which the atria and the ventricles are
concordant, while the ventricular-arterial relationship is
discordant. Therefore, the aorta (Ao) arises anteriorly from the
right ventricle (RV), while the pulmonary artery (PA) arises
posteriorly from the left ventricle (LV), i.e., babies born with
this malformation have the great arteries, PA and Ao, inverted. The
anatomical arrangement results in two separate and parallel
circulations: firstly, oxygenated blood coming from the lungs
returns successively to the lungs without being delivered
throughout the body; secondly, blood goes to and returns from the
body totally unoxygenated (since it does not exchange gases through
the lungs).
[0014] Thus, as shown in FIG. 2, unoxygenated systemic venous blood
returns from the body (B) to the right atrium (RA) via vena cava
(VC), as usual. The bloodstream goes on to the RV through the
tricuspid valve, but instead of being pumped to the main PA, it is
directed inappropriately to the Ao and systemic circulation. On the
other hand, oxygenated pulmonary venous blood coming from the lungs
via the pulmonary veins (PV) is directed to the LA and then to the
LV, to be ejected back to the pulmonary circulation, where it is
re-oxygenated.
[0015] A baby born with this anomaly presents with inadequate gas
exchange and suffers from cyanosis. Life is sustained exclusively
through connections between the two circuits. If not treated, more
than 50% of patients die during the first months of life, unless
there is communication between these two circulations.
[0016] Basically, there are two options for TGA repair: redirection
of venous inflow or redirection of ventricular outflow. The first
one redirects pulmonary venous return toward the tricuspid valve
and systemic venous return toward the mitral valve, known as atrial
switch operation or Senning operation.
[0017] Secondly, the operation consists of switching the great
arteries, a technique introduced by Jatene in 1975, also known as
arterial switch operation. In this technique, the aorta is
surgically connected to the LV and the main PA to the RV. It is now
recognized that the Jatene operation can be done only with a LV
conditioned to pump against systemic resistance. Therefore, the
procedure must be performed during the neonatal period, due to the
following reasons:
[0018] 1. When the baby with TGA is still in the mother's womb, the
two ventricles work together (in parallel), because of two
communications between the compartments of the heart: the foramen
ovale at the atrial level and the ductus arteriosus at the arterial
level (communication between the great arteries). This has an
important physiological implication since the two ventricles
present with the same muscular mass.
[0019] 2. Accordingly, when the baby is born, the postnatal LV
ejects blood into the low-resistance pulmonary vasculature and,
therefore, does not increase its muscle mass relative to the right
(systemic) ventricle (or relative to a normal left ventricle).
Consequently, within weeks, the LV myocardium loses its capacity to
maintain an adequate cardiac output against a systemic afterload.
Therefore, LV muscle growth is retarded because the afterload
(pulmonary resistance) is low. Instead, the RV assumes the
function, and also the necessary muscle mass, to overcome systemic
resistance. These significant differences in LV and RV muscle mass
progress over time and may assume considerable importance if the LV
is suddenly required to perform against systemic resistance, as in
the arterial switch operation.
[0020] It is important to take advantage of these anatomic features
during the neonatal period, in which both ventricles present the
same muscle mass, to carry out the Jatene operation, when the LV is
still adequate to handle systemic circulation.
[0021] 3. In case of late referral (beyond the neonatal period),
the primary Jatene Operation will no longer be possible. There is
increasing likelihood that the LV will be unable to accommodate the
increased workload. The LV, connected to the low pulmonary vascular
resistance, becomes more and more hypotrofic, while the RV,
connected to the high systemic vascular resistance, becomes more
and more hypertrofic.
[0022] A number of circumstances can arise that cause postponement
of surgery beyond the "safe" period for an arterial switch
operation. For example, a neonate may be seriously ill with
necrotizing enterocolitis, renal or hepatic failure, or a
hemorrhage in the central nervous system. Also, the neonate may be
geographically distant from a center offering the arterial switch
operation.
[0023] Because of these possibilities, the arterial switch
operation must be performed after preliminary pulmonary artery
banding, with or without a systemic to pulmonary artery shunt, to
stimulate the development of LV muscle mass, followed by an
arterial switch operation some months later, a concept introduced
by Yacoub et al. in 1977. In the first stage, the LV must be
stimulated by systolic overload of PA banding to retrain the
ventricle and promote muscle mass acquisition. The retraining
period between the two stages will allow the LV to function as a
systemic pump. In the second stage, once the ideal LV mass
acquisition has been achieved to support systemic circulation, the
Jatene operation can be performed.
[0024] With the advance of molecular biology in the 80's,
laboratory studies in rats have demonstrated surprisingly rapid
induction (within 48 hours) of the genes responsible for the
isozyme adaptation of the myocardial myosin, actin, and tropomyosin
in response to an acute pressure load. It has been demonstrated
that the process of cardiac hypertrophy is associated with changes
in the genetic expression of the cardiomyocytes and fetal
contractile proteins when a systolic load is applied to the
ventricle. In fact, cardiomyocyte systolic load can trigger a
genetic response that increases the protein synthesis, the
beginning of hypertrophic process.
[0025] Some years later, the Boston Children's Hospital introduced
the concept of rapid, two-stage arterial switch operation for TGA,
limiting the interval between the first and the second operation to
an average of seven days. However, the good results obtained by the
Boston Group were not reproduced in other centers, where high
morbidity and mortality rates were present. That is why application
of the two-stage arterial switch operation to this subset of
patients became of interest to many investigators. Several studies
have been carried out to achieve the most physiological way to
obtain this LV retraining, with no impairment of late LV
function.
[0026] Nevertheless, some inconvenient aspects of PA banding
deserve to be mentioned:
[0027] Traditional PA banding with a fixed tape stir up a great
deal of surgical skill and ability to be placed properly during
surgery, proximal enough to avoid distortion of the PA branches.
Fine adjustment of such banding is hard to achieve.
[0028] The difficulty in achieving an appropriate tightness of the
band can be readily explained when it is recalled that Poiseuille's
law predicts that blood flow is related to the fourth power of the
radius of the vessel. Therefore, a minor alteration in diameter
will have a large impact on flow and pressure gradient across the
band site.
[0029] Banding adjustment is made in an anesthetized, mechanically
ventilated patient with an open chest, and the physiology is
clearly quite different from that in an awake and spontaneously
breathing child.
[0030] There is yet another possibility of clinical application of
adjustable PA banding device, called "Congenitally Corrected
Transposition of the Great Arteries" (CCTGA), in which there are
both atrioventricular and ventriculoarterial discordant
connections. For a better understanding of this condition, FIG. 3
describes such connections.
[0031] Babies born with this condition present correct blood
circulations, but morphologically speaking, their right and left
ventricles are inverted. Unoxygenated blood coming from the body
(B) via vena cava (VC), reaches the right atrium (RA), which
connects through a morphologic mitral valve with a rightward and
anteriorly positioned morphologic left ventricle. This finely
trabeculated ventricle connects with an outflow tract and then with
a somewhat posteriorly positioned pulmonary artery. Bloodstream
follows to the lungs (L) where gases are exchanged. Oxygenated
blood returns to the heart via pulmonary veins (PV). The left
atrium connects through the tricuspid valve with a coarsely
trabeculated right ventricle (RV). The right ventricular outflow
tract is located anteriorly and leads to a leftward-positioned
aortic valve and ascending aorta. RV then ejects oxygenated blood
to the whole body circulation. Therefore, this arrangement allows
for a normal circulation in the absence of other defects.
[0032] Although the survival of patients with CCTGA is dictated
largely by the associated defects, life expectancy is diminished
for patients even with the isolated form of the condition. A number
of studies have confirmed that life expectancy is substantially
diminished even for patients who have reached adulthood. The most
common cause of death is congestive heart failure secondary to
morphologically right (systemic) ventricular dysfunction, often
associated with regurgitation of the tricuspid valve. The
traditional surgical approach to the treatment of patients with
CCTGA maintains the morphologically RV and tricuspid valve in the
systemic circulation. However, dysfunction of the systemic
(morphologically right) ventricle or systemic atrioventricular
(tricuspid) valve tends to develop and worsen with time, which may
lead to significant morbidity and mortality. Tricuspid
regurgitation has been addressed by replacement of the systemic
atrioventricular valve. Nevertheless, this procedure is often
unsuccessful in preventing or reversing right ventricular
dysfunction.
[0033] There are indeed anatomical and physiological considerations
that support the assumption that the left ventricle is more
suitable than the right to serve the systemic circulation. First of
all, the left ventricle (with its cylindric shape, its concentric
contraction pattern, and both the inlet and outlet orifices
situated in close proximity) seems ideally adapted to work as a
pressure pump, whereas the right ventricle (with its
crescent-shaped cavity, its large internal surface area-to-volume
ratio, its bellows-like contraction pattern, and its more separated
inlet and outlet segments) seems better suited to serve as a
low-pressure volume pump chamber. Also, the left ventricle has two
coronary arteries (left anterior descending and circumflex), while
the right ventricle has only one (right coronary).
[0034] Furthermore, the papillary muscles of the RV are small and
numerous, originating both from the septum and from the right
ventricular free wall, in contrast to the two papillary muscles of
the LV. This architecture allows the tricuspid valve to be pulled
apart as the right ventricle dilates, leading to tricuspid
regurgitation. In long-term, patients with CCTGA begins to dilated
RV and the tricuspid annulus (which is the systemic valve),
allowing RV blood regurgitation during ventricular contraction and,
consequently, pulmonary congestion and dyspnea.
[0035] The high rate mortality associated with the traditional
approach has stimulated a number of groups to propose a more
anatomic repair on the basis of the hypothesis that establishment
of atrioventricular and ventriculoarterial concordance would
improve the long-term survival of patients with this anomaly. This
approach has been named as the double switch operation, i.e.,
atrial level circulation switch by the Senning procedure and
arterial switch operation by the Jatene procedure at the same time.
Such approach has the appealing theoretic advantage of placing the
morphologically LV and mitral valve in the systemic circulation,
thus relieving the hemodynamic burden on the RV and tricuspid
valve.
[0036] Many of these patients are older and are seen because of
right ventricular failure, usually with tricuspid valve
regurgitation and often without associated defects. As would be
expected in these cases, the LV is physiologically unprepared to
sustain systemic pressure and resistance because it has been
working as the pulmonary ventricle. Therefore, double switch
procedure must be performed after a preliminary PA banding
procedure to recondition the LV. Because of the high degree of
variability among these patients, optimal band tightness is not
always achieved on the first effort and is often limited by the
onset of LV dysfunction.
[0037] The retraining process of the LV, especially in older
patients, may take months before obtaining the necessary LV
hypertrophy to sustain systemic pressure and vascular resistance.
In addition, as has been described in the literature, there is the
need for subsequent reoperations to readjust PA banding in cases
where a patient cannot achieve adequate LV hypertrophy.
[0038] In the light of what has been described above, it sounds
like traditional PA banding used to treat the above-mentioned heart
lesions (those with pulmonary congestion, TGA and CCTGA), is
inconvenient in that it does not allow late and fine adjustment
according to the patient's clinical condition. In addition, it does
not afford precise and accurate alteration in PA diameter over time
and, therefore, always requires new interventions to achieve
that.
[0039] To deal with those problems, some researchers have
endeavored to create a banding device that allows postoperative PA
diameter fine adjustment with no need for reinterventions, the
so-called "adjustable PA banding devices."
[0040] Some of the historical aspects conceptually-related to our
prototype are described here. The idea of adjustable banding
devices composed of a hydraulic cuff and a self-sealing button was
first proposed in 1957. In fact, Jacobson and McAllister proposed a
device that consisted of a rubber cuff with a lateral opening and
connected to a reservoir protected by self-sealing rubber. It was
used on the great vessels of dogs, aiming a congestive heart
failure model. Complications in handling the device were observed.
In 1969, Bishop and Cole improved the Jacobson and McAllister
device by covering the cuff with silicone, with the aim of reducing
local tissue reaction. They induced RV hypertrophy and congestive
heart failure in a dog model. In 1972, Edmunds and associates
introduced two main changes: an external, nondeformable layer on
the hydraulic cuff and silicone, instead of rubber. However, they
observed asymmetric inflation or rupture of the cuff, and leakage
of the injected material prevented it from clinical use. In 1985, a
new device made of biologically stable material (medical grade
silicone) was introduced by Park et al. The cuff was covered with
reinforced braid and coated with silicone. The self-sealing button
has a silicone diaphragm which did enable repeated needle puncture,
avoiding leaking through the button. The device implanted in dogs
and lambs was easily and effectively adjusted. In that same year,
Solis et at proposed a similar device to the previous one, intended
to prepare the subpulmonary ventricle for the two-stage Jatene
operation for the first time in the literature. Nevertheless, when
the system was submitted to a high gradient pressure, as in the
systemic circulation, dilation of the reservoir and the connecting
tube occurred. In addition, there was a tendency of the cuff to
bulge laterally under high pressure. In another study, the same
group improved the strength of the material by reinforcing the cuff
and the connecting tube with a spiral of 4-0 silk to withstand
systemic arterial pressure. Again, they experienced bulging of the
cuff due to a loosing silk.
[0041] Given the numerous problems encountered in all of these
studies described above, at the present, an adjustable PA banding
device that could be safely applied to humans and afford fine PA
diameter adjustments is not available yet.
SUMMARY OF THE INVENTION
[0042] This patent refers precisely to improvements introduced in
our PA banding device, published in the Journal of Thoracic and
Cardiovascular Surgery, volume 124, pages 999 through 1006, in the
year of 2002. Our prototype was made of three parts: banding ring,
extension tube, and inflation button. The banding ring was a
U-shaped hydraulic cuff, with 10 mm internal diameter and 5 mm
width. Its outer layer consisted of 1 mm thick rigid silicone,
which kept it from deforming. The inner surface had a deformable
layer of silicone, which expanded, compressing the lumen of the
vessel, according to the volume injected into the inflation button.
At the two ends of the cuff, there were small orifices that were
used for securing the ring to the PT. The extension tube, also made
of silicone, linked the banding ring with the inflation button. It
had a 2 mm inner diameter and was 25 cm long. The inflation button
was a separate circular reservoir made of self-sealing silicone, in
which base included a metal plate. The reservoir had a port, which
was connected to the extension tube. This button was implanted
subcutaneously, thus permitting the inflation or deflation of the
banding ring percutaneously. However, the connection between the
inflation button and the extension tube used began to leak over
time due to the developed high internal pressure and to the fact
that is was not hermetically sealed.
[0043] Improvements of the PA banding device proposed here resulted
in an adjustable and more delicate banding system, completely
hermetic, and percutaneously adjustable, to be used in the
congenital heart lesions described above.
[0044] With improvements, the device is now comprised of the
following components:
[0045] 1. A banding ring C-shaped hydraulic cuff with a thinner
outer layer, less than 0.5 mm thickness silicone, reinforced with a
Dacron mesh, that keeps it from deforming centrifugally;
[0046] 2. An inflation button to be implanted subcutaneously in the
patient's thorax, connected hermetically to each other (sealed
during manufacturing) with a thinner extension tube (inner diameter
less than 1.5 mm). The extension tube takes the liquid injected
percutaneously in the inflation button to the banding ring, thus
varying the PA diameter according to the amount of injected
liquid.
[0047] The inner wall of the banding ring is formed by a very thin
and flexible silicone that allows centripetal distension. The
applied material in the banding ring is potentially able to
increase 500% in volume size, promoting a wide range of reversible
constriction of the banded blood vessel.
[0048] Therefore, our new PA banding device prototype differs from
earlier experimental models in that it presents a Dacron mesh that
reinforces the outer layer and makes it thinner, keeping it from
centrifugal distension when inflated.
[0049] In addition, the outer layer prolongs besides the silicone
cuff at the distal ends of the banding ring, making it possible to
choose the appropriate diameter of the banding ring according to
the vessel diameter. These outer layer prolongations can be sutured
to fix the diameter of the band. The Dacron mesh reduces the
likelihood that the sutures will cut through the banding
material.
[0050] The outer layer of the banding ring also presents some small
side straps to attach the banding ring to the PA adventitia with
sutures to keep it from migrating distally and impinging on the PA
bifurcation.
[0051] The inflation button is configured by a cylindrical
reservoir made of a thick self-sealing silicone whose base has a
plate (preferably made of porcelain) to limit the needle
introduction for liquid injection. The button comes with multiple
side holes around its base to fix it with sutures in the
subcutaneous tissue.
[0052] Once the adjustable banding ring has been placed in the
patient's PA and the inflation button placed subcutaneously in the
chest wall, the banding ring constriction can be adjusted after
full recovery from anesthesia. It will be possible to control
precisely and accurately the cross-sectional diameter of the PA in
the postoperative period, according to the patient's clinical
condition. It means that PA banding adjustment will be predictable
and performed under chronic conditions in an ambulatory patient. By
injecting or removing liquid percutaneously from the inflation
button, the banding ring is inflated or deflated, thereby
determining the desired flow and pressure in the distal pulmonary
artery, according to the specific congenital heart lesion being
treated.
[0053] All of the reasons mentioned above ensure that improvements
established in this PA banding system can offer a biocompatible
device that is easy to implant and efficient for reversible and
adjustable percutaneous PA banding. It can be used in situations to
control excessive pulmonary blood flow, as well as for LV
retraining. The device may, therefore, be used in the treatment of
several congenital malformations.
[0054] The improved PA banding device permits a percutaneous
control of PA diameter and a perfectly precise regulation of
pulmonary blood flow and pressure, producing a fine and reversible
adjustment that has not been achieved by previous banding
devices.
[0055] This invention refers to improvements introduced in the
adjustable banding system, comprised of a mini inflatable banding
ring (4 mm diameter) to be placed around the patient's pulmonary
artery, and an inflation reservoir to be implanted subcutaneously
in the patient's chest wall, connected hermetically to each other
from industry by means of connecting tubing. Its dimensions were
planned for use in low birth neonates, considered as high-risk
patients for more traditional approaches. All parts of the
Adjustable Banding System are made of biologically stable material
(medical grade silicone) and produced with radiopaque material to
be visualized on chest roentgenogram, in order to provide
information regarding the position of the implanted device.
[0056] The device is comprised of a banding ring C-shaped hydraulic
cuff. The inner wall of the banding ring is formed by a very thin
and flexible silicone that allows centripetal distension, and
covered with a thin layer (0.5 mm thick) of silicone reinforced
with a polyester mesh. The banding ring balloon is potentially able
of 500% increase in volume size, promoting a wide range of
reversible constriction of the banded blood vessel. When the cuff
is uninflated, the measured diameter can be as low as 4 mm. There
are two apart ends of the hydraulic cuff, a prolongation of the
non-distensible outer wall, planned for further fine adjustment of
the hydraulic cuff, when placed around the artery, by suturing
together the ends. The outer layer of the banding ring presents
some small flanges along the non-apart borders, which are used for
securing it firmly with sutures to the adventitia of the artery.
This keeps the adjustable banding system from migrating distally
and impinging on the pulmonary artery bifurcation. The connecting
tubing has 0.9 mm inner diameter.
[0057] The inflation reservoir used to pump fluid to the hydraulic
cuff consists of a ceramic cylindrical reservoir, with a
self-sealing silicone diaphragm at the top, which keeps the banding
system leak proof after repeated needle punctures of the reservoir.
The reservoir has four small holes around the rim to enable
suturing to subcutaneous tissue. It allows percutaneous adjustment
of the pulmonary artery banding cuff volume as many times as
needed, with no need for further surgical interventions.
[0058] The invention may further be viewed as the improvements in
an ADJUSTABLE BANDING SYSTEM, adapted to restrict blood flow
through the small pulmonary arteries of neonates, comprises an
inflating banding ring, to be implanted around the neonate PA
branches, a connecting tubing and a self-sealing inflating
reservoir, implanted in the patient's subcutaneous thorax. All
parts of the Banding System are made of or covered by medical grade
silicone and are produced with radiopaque material to be visualized
on chest roentgenogram, in order to provide information regarding
the position of the implanted device.
[0059] The banding ring is configured as a "C" shape hydraulic
cuff, with an outer wall formed by a thin non-distensible silicone
layer, or similar, that prevents centrifugal distention of the
hydraulic cuff. Some small flanges may also be present to attach
the banding ring to the PA adventitia with sutures to keep said
banding ring from migrating distally. The inner portion of said
banding ring is formed by a thin flexible and distensible silicone
balloon, or similar, that allows inward distension as it is
inflated.
[0060] The "C" shaped banding ring ends in two apart ends for
adequate sizing of the band according to neonate's PA size. The
twist-resistant and non-distensible flexible connecting tube
provides the communication between the banding ring and the
inflating reservoir, with the purpose of taking the fluid injected
percutaneously in the inflation reservoir to the banding ring, thus
varying the PA diameter according to the volume of injected
fluid.
[0061] The inflating reservoir is configured by a ceramic
cylindrical sink, with a self-sealing silicone diaphragm at the top
and a lateral aperture connected hermetically to the tube. A 3 mm
thick silicone base has four small holes around the rim to enable
suturing to subcutaneous tissue. The banding ring constriction can
be adjusted by injecting or removing fluid percutaneously from the
inflation reservoir.
[0062] In a further embodiment the instant invention is directed to
improvements introduced in the adjustable banding system, comprised
of a mini inflatable banding ring (4 mm diameter) to be placed
around the patient's pulmonary artery, and an inflation reservoir
to be implanted subcutaneously in the patient's chest wall,
connected hermetically to each other from industry by means of
connecting tubing. Its dimensions were planned for use in low birth
neonates, considered as high-risk patients for more traditional
approaches.
[0063] All parts of the Adjustable Banding System are made of
biologically stable material (medical grade silicone) and produced
with radiopaque material to be visualized on chest roentgenogram,
in order to provide information regarding the position of the
implanted device.
[0064] The device is comprised of a banding ring C-shaped hydraulic
cuff. The inner wall of the banding ring is formed by a very thin
and flexible silicone that allows centripetal distension, and
covered with a thin layer (0.5 mm thick) of silicone reinforced
with a polyester mesh. The banding ring balloon is potentially able
of 500% increase in volume size, promoting a wide range of
reversible constriction of the banded blood vessel. When the cuff
is uninflated, the measured diameter can be as low as 4 mm. There
are two apart ends of the hydraulic cuff, a prolongation of the
non-distensible outer wall, planned for further fine adjustment of
the hydraulic cuff, when placed around the artery, by suturing
together the ends.
[0065] The outer layer of the banding ring presents some small
flanges along the non apart border, which are used for securing it
firmly with sutures to the adventitia of the artery. This keeps the
Adjustable Banding System from migrating distally and impinging on
the pulmonary artery bifurcation. The connecting tubing has 0.9 mm
inner diameter.
[0066] The inflation reservoir used to pump fluid to the hydraulic
cuff consists of a ceramic cylindrical reservoir, with a
self-sealing silicone diaphragm at the top, which keeps the banding
system leak proof after repeated needle puncture of the reservoir.
The reservoir has four small holes around the rim to enable
suturing to subcutaneous tissue. It allows percutaneous adjustment
of the pulmonary artery banding cuff volume as many times as
needed, with no need for further surgical interventions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] For didactic purposes, diagrams of this device are listed
below:
[0068] FIG. 1 shows the normal functioning of the heart;
[0069] FIG. 2 shows the schematic diagram of Transposition of the
Great Arteries (TGA);
[0070] FIG. 3 shows the schematic diagram of Congenitally Corrected
Transposition of the Great Arteries (CCTGA);
[0071] FIGS. 4 and 5 illustrate the PA banding device from the top
and in a lateral view;
[0072] FIG. 6 is a schematic illustration of PA banding
implantation;
[0073] FIG. 7 is a front elevational view of an alternative
embodiment of the mini adjustable banding system of the instant
invention;
[0074] FIG. 8 is a side elevational view of the mini adjustable
banding system of FIG. 7;
[0075] FIG. 9 is a cross sectional view of the mini adjustable
banding system of FIG. 7 taken along section lines Q-Q;
[0076] FIG. 10 is a sectional view of a heart illustrating the
implantation of the banding system of FIG. 7 in the HLHS; and
[0077] FIG. 11 is a sectional view of a hear illustrating the
implantation of the banding system of FIG. 7 in the Left Ventricle
for retraining.
DETAILED DESCRIPTION OF THE INVENTION
[0078] The object of the present patent of invention refers to
improvements introduced in the pulmonary artery banding device, the
device (1) thus constituted by a banding inflating ring (2) to be
installed around the patient's pulmonary artery (PA) by an
extending tube (3), and by an insufflating button (4), implanted
subcutaneary in the patient's thorax, being the extending tube (3)
connecting the insufflating button (4) to the banding inflating
ring (2), keeping everybody linked to each other.
[0079] According to the present improvements and as showed in FIGS.
4 and 5, the banding ring (2) is configured by a hydraulic sleeve
in the shape of "C," forming a support for an inflating balloon,
whose external wall (2a) is formed by a thin rigid silicon layer,
composed by a Dacron mesh, that prevent the radial distention of
the ring from within inside to outside (centrifugal distention),
and whose inside wall (2b) is formed by a thin flexible silicon
layer that allows the outside radial distention of the ring from
within outside to inside (centripetal distention).
[0080] This way, the banding ring (2) of the device is now improved
and differs from the previous experimental models by being thinner
and presenting a reinforcement through a screen in the sleeve
outside wall that prevents the centrifugal distention, when
insufflating. Thus, the banding ring (2) has the property of not
centrifugal stretching out, but has the plenty centripetal
stretching out, could increase of volume, meaning, until up to 500%
from the initial volume.
[0081] At the apart ends of the banding ring (2), two brims are
foreseen (2c) that facilitate the size banding adjustment according
to the pulmonary artery caliber (PA), through fastening and
fixation passage points (sutures) between the same ones.
[0082] The banding ring (2) is still provided of an appropriate
number of holes or loops with holes (2e), along all extensions of
its non apart borders, placed equidistant spaced to each other, for
fixation points (sutures) passage of the ring in the patient's
pulmonary artery to avoid the banding ring migration (displacement)
to the pulmonary artery, along the blood flow that goes by the
interior of the body.
[0083] The extending tube (3), also of silicon, provides the
communication between the banding ring (2) and the insufflating
button (4), with the purpose of transmitting an appropriate liquid
injected into the button for the banding ring sleeve.
[0084] The insufflating button (4) is configured by a cylindrical
reservoir made in auto-stamped silicon, whose base presents a
porcelain metallic plate to limit the introduction injection liquid
needle point; the button (4) is provided with a multiplicity of
holes (4a) disposed close to the outlying border, to passed the
fixation points (sutures) of the button (4) in the patient's body,
more specifically, in the patient subcutaneous (under the skin),
allowing the banding ring (2) insufflation or "unsufflation" by
percutaneous path.
[0085] Thus, in the surgery, once the banding ring (2) of the
improved device (1) implanted in the patient pulmonary artery (PA),
and once housed the insufflating button (4) in the subcutaneous
thoracic wall, as shown in FIG. 6, the insufflating button is
tested by an insulin needle puncture, being aspired of all the air
of the system.
[0086] Then an appropriate liquid is insufflated through a needle
to inside insufflating button (4), which, can be made in
auto-stamped material to prevent leaking. That liquid is
transmitted through the extending tube (3) until the banding ring
(2) already fastened around the pulmonary artery, and already it's
insufflated.
[0087] The banding ring (2) is forced to insufflate radial inside
(centripetal distention), causing the pulmonary artery compression
(PA), and consequently, the internal caliber reduction.
[0088] Through echocardiogram and pulse oximetrics, it is verified
if the pressure disposed by the banding ring (2) over the pulmonary
artery (PA) is the ideal for the moment. Through the injection of
other liquid or the liquid already injected evacuated, insufflated
or "uninsufflated," the banding ring (2), thus, being determined,
the desired pulmonary artery pressure.
[0089] Once the implants device surgery is completed, the patient
goes by the normal postoperative procedures, staying under the
specific medical care for each cardiopathy that is being
treated.
[0090] With the improved banding device, the perfect banding
pulmonary artery adjustment is obtained, as well as the gradative
squeeze pressure adjustment applied on the pulmonary artery,
without any demand for new surgeries.
[0091] FIGS. 7-11 illustrate an alternative embodiment of the
invention wherein similar elements to those described with
reference to the first embodiment are identified with like element
reference numbers.
* * * * *