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`Edwards Lifesciences Corporation, et al. Exhi it 1005, p. 1 of 12
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`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 1 of 12
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`VOLUME 2
`
`Second Edition
`
`TEXTBOOK
`-•of
`INTERVENTIONAL
`CARDIOLOGY
`
`ERIC J. TOPOL, M.D.
`
`Chairman, Department of Cardiology
`Director, Center for Thrombosis and Vascular Biology
`Cleveland Clinic Foundation
`Professor of Medicine
`Cleveland Clinic Health Sciences Center
`Ohio State University
`Cleveland, Ohio
`
`W.B. SAUNDERS COMPANY
`A Division of Harcourt Brace & Company
`
`Philadelphia, London, Toronto, Montreal, Sydney, Tokyo
`
`tttUHIHffiIT
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 2 of 12
`
`
`
`W. B. SAUNDERS COMPANY
`A Division of Harcourt Brace & Company
`The Curtis Center
`Independence Square West
`Philadelphia, PA 19106
`
`Library of Congress Cataloging-In-Publication Data
`
`Textbook of interventional cardiology/ [edited by] Eric J. Topel -
`2nd ed.
`cm.
`p.
`Includes bibliographical references and index.
`ISBN 0·7216-6749-X (V. 1).-JSBN 0-7216-6750-3 (V. 2).(cid:173)
`ISBN 0-7216-6722-8 (Set)
`1. Angioplasty.
`2. Cardiovascular system-Diseases-Treatment.
`I. Topel, Eric J.
`[DNLM:
`1. Cardiovascular Diseases-surgery. 2. Angioplasty. WG
`168 T355 1994]
`RD598.5.T49 1994
`617.4'12059-dc20
`DNLM/DLC
`
`93-15130
`
`Textbook of INTERVENTIONAL CARDIOLOGY
`
`Volume 1 0-7216-6749-X
`Volume 2 0-7216-6750-3
`Set ISBN 0-7216-6722-8
`
`Copyright © 1994, 1990 by W. B. Saunders Company.
`All rights reserved. No part of this publication may be reproduced or transmitted in any form or by
`any means, electronic or mechanical, including photocopy, recording, or any information storage and
`retrieval system, without permission in writing from the publisher.
`Printed in the United States of America.
`Last digit is the print number:
`9
`8
`
`2
`
`
`
`7
`
`6
`
`5
`
`4
`
`3
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 3 of 12
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`
`
`75
`
`Percutaneous Expandable
`Prosthetic Valves
`·
`
`· Steven R. Bailey
`
`The introduction of percutaneous techniques for vascular
`intervention has resulted in the rapid development of new
`devices and techniques for the treatment of coronary and vas(cid:173)
`cular diseases. One important area of potential interest is the
`application of percutaneous techniques for the treatment of
`valvular heart disease. The exponential growth of percuta(cid:173)
`neous endovascular procedures is similar to that experienced
`in cardiovascular surgery after the introduction of cardiopul~
`monary bypass. The design of implantable prosthetic heart
`valves to be delivered using a percutaneous approach has
`become an important area for investigation.
`The initial implantation of a prosthetic heart.valve was per(cid:173)
`formed in 1952 and published in 1953 by Hufnagel and Har(cid:173)
`vey/ with a follow-up report in 1954.2 The Hufnagel valve is
`composed of a chamber with a central ball valve as seen in
`Figure 75-1. This bulky device was surgically placed in the
`descending aorta distal to the left subclavian artery. Patients
`did surprisingly well clinically despite the fact that only 75
`per cent of the regurgitant volume was diminished using this
`valve in the descending aorta. SuI?coronary placement of
`prosthetic valves became possible only after the introduction
`of cardiopulmonary bypass in 1960.3 The past three decades
`have seen significant improvements in the performance of
`mechanical, tissue, and homograft prosthetic valves, with nu(cid:173)
`merous alterations occurring in the designs of these prosthe(cid:173)
`ses.4 These changes have improved the functional orifice area
`as well as decreased the complications associated with valve
`replacement such as thrombus formation, embolism, and late
`valve dysfunction.
`Unfortunately, placement of prostht\tic heart valves re(cid:173)
`mains a relatively difficult and often dangerous procedure.
`The surgical risks rise rapidly in patients with serious prob(cid:173)
`lems such as acute valvular regurgitation and in patients
`whose valvular disease is associated with myocardial
`6
`ischernia. 5
`'
`The development of percutaneous catheter-based systems
`for stabilization and treatment of unstable patients with val(cid:173)
`vular disease, which could be performed at a lower risk to
`the patient, is therefore an important area for research. De(cid:173)
`veloping a chronically implanted catheter-based valve pros(cid:173)
`thesis is an exciting new frontier in interventional cardiology.
`
`1268
`
`HISTORY OF CATHETER-BASED VALVES
`
`The demonstrated success of the Hufnagel valve in treating
`aortic insufficiency precipitated the initial investigation in
`1965 by Hywel Davies7 of a catheter-mounted valve for tem(cid:173)
`porary relief of aortic insufficiency. This device, although
`crude by today's standards, was very interesting in design.
`As seen in Figure 75-2 this cone-shaped device was essen(cid:173)
`tially an inverted parachute. The valve closed during systole
`due to the forward flow of blood out of the ventricle, and
`opened during diastole as the regurgitant flow returned to
`the ventricle. It was anchored onto a 5-Fr. catheter with thin
`guy wires. No information was provided regarding the type
`of material from which this valve was constructed. Initial an(cid:173)
`imal experiments were promising, although no human inves(cid:173)
`tigations were ever reported. One significant problem dis(cid:173)
`played by this valve was the rapid development of thrombi
`at the base of the cone, a theme common to all prosthetic
`valves. This predisposition was probably enhanced by pro(cid:173)
`longed stasis of blood in the base of the conical valve.
`Moulopoulos et al.8 reported their investigations into
`catheter-mounted aortic valves in 1971. Utilizing the investi(cid:173)
`gators' experience in developing electrocardiographically
`(ECG) triggered intra-aortic balloon pumps, they designed
`and evaluated three separate systems (Fig. 75-3). One was a
`spherical balloon triggered by the ECG to inflate during di(cid:173)
`astole. The second was a ;;pherical balloon that was pressure
`responsive and deflated when systolic pressure exceeded a
`predetermined value. It inflated when pressure fell belm~ a
`specified diastolic value, resulting in diastasis. Their third
`system was an umbrella-shaped balloon similar to that used
`by Davies et al. They concluded that the relatively sirnl:'le
`umbrella system was best, significantly reducing the seventy
`of
`acute
`aortic
`insufficiency without major
`acute
`complications.
`There were several disadvantages of a catheter-based valve
`found by these investigators in the chronic animal model, in(cid:173)
`cluding the development of significant thrombi in the base of
`the umbrella in all animals followed chronically. Most im(cid:173)
`portantly, variable decreases in coronary flow also occurred
`in these animals. The decreased coronary flow was attributed
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 4 of 12
`
`
`
`75-PERCUTANEOUS EXPANDABLE PROSTHETIC VALVES
`
`1269
`
`HGURE 75-1. The Hufnagel valve, when
`assembled, consisted of a hollow plastic
`tube, the fixation rings on each end, and
`the polypropylene central ball.
`
`nGURE 75-2. The Davis valve was an in(cid:173)
`verted plastic cone anchored to the shaft
`of a 5-Fr. catheter. Note the guy wires used
`to stabilize the valve.
`
`SYSTOLE
`
`OiASTOLE
`
`t··
`
`HGURE 75-3. The top section demonstrates the valve motion during systole and diastole. The bottom left
`is a photograph of the ·umbrella valve and the middle is the balloon valve. The bottom right is a picture of
`the glass cast used to manufacture the umbrella valve.
`
`11! I
`
`
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`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 5 of 12
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`1270
`
`VIII-VALVULOPLASTY, CONGENITAL AND PERICARDIAL HEART DISEASE
`
`llll
`
`A
`
`B
`
`BGURI 75-4. A, The catheter with the bal(cid:173)
`loon mounted at the tip is shown. B, A close(cid:173)
`up view of the balloon. Note the small strip
`of plastic that fixes the valve to the catheter
`to prevent inversion of the valve.
`
`BGURI 75-5. This complicated valve
`consists of a 7-Fr. catheter with a distal
`balloon. The catheter has (a) a distal lu(cid:173)
`men, (b) latex balloon, (c) side hole distal
`to the balloon, (d) side hole proximal to
`balloon, {e) the latex valve, (ft 8-Fr. sheath,
`(g) 7-Fr. catheter shaft, Qi) a stopcock con(cid:173)
`nected to distal lumen, and (t) a lumen to
`inflate the balloon valve.
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 6 of 12
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`r.
`
`TABLE 75--1. HIGH-RISK PATIENTS WHO MIGHT BENEm
`FROM PERCUTANEOUS VALVI PLACEMENT
`
`TABLE 75-3. DESIGN PROBLEMS OF PERCUTANEOUS
`VALVES
`
`75-PERCUTANEOUS EXPANDABLE PROSTHETIC VALVES
`
`1271
`
`Mitra! regurgitation due to
`Acute myocardial infarction
`Bacterial endocarditis
`Flail mitral leaflet
`Decompensated chronic mitral regurgitation
`Aortic regurgitation due to
`Bacterial endocarditis
`Decompensated chronic aortic regurgitation
`Tricuspid regurgitation due to
`Bacterial endocarditis
`Pulmonary hypertension
`Right ventricular dysfunction
`
`Delivery sheath
`Size of sheath
`Material required to avoid ferchon
`Stiffness of sheath
`Delivery system
`Self-expanding
`Balloon expandable
`Mechanical expansion
`Type of valve
`Bioprosthetic
`Mechanical
`Polymer
`
`to the valve leaflets covering the coronary ostia during
`diastole.
`Phillips et . al.9 reported a modification of the balloon(cid:173)
`mounted valve concept in 1976. Figure 75-4 displays the seg(cid:173)
`mented polyurethane cusp mounted 1 cm from the distal end
`of the catheter that was used in their study. The distal end of
`the catheter contained side holes for monitoring pressure dur(cid:173)
`ing the procedure. In their dog model they demonstrated a
`significant reduction in aortic diastolic pressure, pulse pres(cid:173)
`sure, and left ventricular end-diastolic pressure. Coronary ar(cid:173)
`tery blood flow did not fall and in fact increased slightly; with
`their balloon system.
`The most recent investigation of a balloon catheter(cid:173)
`mounted valve was that of Matsubara et al. in 1992.10 They
`used the valve shown in Figure 75-5. This somewhat com(cid:173)
`plicated valve system cons~sts of an 8-Fr. catheter with a latex
`balloon mounted on the catheter. Using hemodynamic eval-_
`uation without angiography they demonstrated significant
`decreases in pulse pressure and left ventricular end-diastolic
`pressure as well as increases in aortic diastolic pressure. After
`placement of. the device, however, the experimental animals
`still had a significant_ tachycardia and a larger pulse pressure
`than at baseline, suggesting continued aortic regurgitation.
`Unfortunately, the severity of the persistent aortic regurgita(cid:173)
`tion was not quantitated by the authors.
`Although <;atheter-based balloon valve technology may of(cid:173)
`fer some acute relief from valvular aortic regurgitation, it is
`not a technology that could feasibly be used over an extended
`period of time as an indwelling device.
`
`BALLOON-EXPANDABLE VALVES
`
`The success of balloon-expandable endovascular stents has
`inspired some investigators to try to develop implantable,
`
`TABLE 75-2. LIMITATIONS OF CURRENT VALVE
`PROTHESES
`
`Mechanical
`Reduction in valve orifice
`Hemolysis
`Pannus formation
`Thrombotic
`Systelnic emboli
`Stroke
`Complications of anticoagulation
`Hemorrhagic stroke
`Gastrointestinal bleeding
`Infective endocarditis
`
`balloon-expandable valvular prostheses. Conceptually, a
`"stent" should provide a rigid frame, allowing the valve
`struts sufficient strength to remain stable during systole while
`anchoring the valve to the surrounding tissue. Following this
`premise, one should be able to develop a delivery system and
`valve· that can be delivered percutaneously from a large ar(cid:173)
`tery or even trans-septally from the femoral vein. This
`method of delivery might answer the immediate needs of
`acutely ill patients or those patients at very high surgical risk
`from valvular regurgitation for valve placement (Table 75-1 ).
`
`DESIGN PROBLEMS OF
`PERCUTANEOUS VALVES
`
`Current mechanical and prosthetic valves suffer from a
`number of problems (Table 75-2) including the predisposi(cid:173)
`tion to thrombus formation and embolization, perivalvular
`leak, infection, difficulty sizing valve to annulus, valve de(cid:173)
`generation, and pannus formation. The designer of any per(cid:173)
`cutaneously placed valve will need to consider these issues
`during its design and development in order to minimize these
`problems. A high probability exists that percutaneous valves
`will be used, at least initially, as a temporizing measure in
`patients who are not acceptable candidates for surgical valve
`replacement. The long-term problems of valve degeneration
`and calcification will therefore not be as important in the sub(cid:173)
`set of patients undergoing percutaneous valve insertion as a
`stabilizing procedure.
`The design of a new percutaneous valve is frought with a
`large number of problems as detailed in Table 75-3. The
`problems can be subdivided into three major categories: (1)
`the problem of a delivery sheath that will allow safe and ef(cid:173)
`fective delivery of a bulky balloon and valve; (2) a balloon
`system that is capable of precisely implanting the valve must
`be manufactured; and (3) modifications of current valves or
`development of new valvular prostheses mm;t occur.
`
`TABLE 75-4. BALLOON-EXPANDABLE VALVI
`
`Advantages
`Percutaneous arteriotomy
`Large expansion ratio of stent
`Approach to multiple valves with same system
`Ability to easily increase size of valve
`Disadvantages
`Closure of arteriotomy
`Technically demanding
`Possible dislodgment
`Myocardial ischelnia
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 7 of 12
`
`
`
`I
`I f i' -
`
`,r
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`' j UIIIIIIJ l
`
`1272
`
`VIII-VAL VULOPLASTY, CONGENITAL AND PERICARDIAL HEART DISEASE
`
`A
`
`C
`
`B
`
`DGURE 75-6, A, The stent ring is constructed of stainless-steel
`wires folded in loops. B, A porcine valve was mounted inside the
`rings and attached by means of suture. C, A view from above valve
`illustrating the intact valve with three cusps.
`
`Percutaneous Delivery System
`
`Large lumen sheaths and catheters (up to 22-Fr.) are cur(cid:173)
`rently used for vascular access for such procedures as cuta(cid:173)
`neous perfusion devices. Such a large arterial puncture is a
`major concern with any delivery system, due to the potential
`for injury to the artery, bleeding, or pseudoaneurysm for(cid:173)
`mation. New technologies are emerging for the local repair
`and sealing of large arteriotomies that should aid the percu(cid:173)
`taneous placement of valves. In the past, up to 25 per cent of
`arteriotomies performed for balloon valvuloplasty or cuta(cid:173)
`neous perfusion devices required direct surgical closure. 'Ihis
`repair if necessary, however, could be performed under local
`anesthesia and is a relatively minor surgical procedure com(cid:173)
`pared to valve replacement.
`Ideally, a successful percutaneous delivery system must be
`no larger than 20 Fr. (6.6 mm) in order to be used in a large
`number of patients. In addition, a removable trochar with a
`soft distal tip will be necessary to successfully deliver this
`guide sheath to the valve with the smallest amount of arterial
`trauma. Once the delivery sheath is appropriately positioned,
`the trochar can be removed.
`•
`A protective sleeve covering the balloon and valve will
`
`be required in order to minimize the friction between the
`balloon-valve and the guide catheter. 'Ihis sleeve might also
`serve the purposes of constraining the valve and preventing
`slippage or embolization of the valve. Alternatively, the bal(cid:173)
`loon catheter itself might have a sleeve covering just the stent
`to provide similar protection. After expansion of the valve
`the balloon could be retracted into the sheath to avoid arterial
`injury associated with removal of the balloon.
`
`TABLE 75-5, BALLOON DEPLOYABLE VALVE:
`THE OPTIMAL SYSTEM
`
`Requirements for valve
`Minimal vascular trauma
`Must not be dislodged
`During delivery
`During balloon withdrawal
`Valve must be matched to annulus
`Valve must remain competent
`Local tissue injury avoided
`Avoid myocardial ischemia
`No significant thrombosis
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 8 of 12
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`
`
`75--PERCUTANEOUS EXPANDABLE PROSTHETIC VALVES
`
`1273
`
`DGURE. 75-7. A, The compressed valve and stent are shown from
`the top view. B, The stent and valve have been mounted on the
`delivery balloon. Note the plastic wedges on either side of the stent
`to anchor it in place.
`
`A
`
`B
`
`TABLE 75-6. VALVE CONSJllUCTION DESIGN
`RIQ.UIREMINTS
`
`DELIVERY BALLOON CHARACTERISTICS
`
`Orifice
`Primary
`Central blood flow
`Secondary
`Area between primary orifice and occluder
`Tertiary
`Area between occluder and aortic wall
`Seating patterns
`Overlapping
`Full orifice
`Valve types
`Mechanical
`ljomograft
`Xenograft
`Materials used
`Metals used
`Stainless-steel
`Titanium
`Alloys
`Stellite 21
`Elgiloy
`Pyrollite
`Polymers
`Teflon
`Delrin
`Silastic
`Polypropylene
`
`An important issue central to the success of percutaneous
`valve placement will be the device or system used to implant
`the valve. The valve could be self-expanding, expandable
`by some mechanical device as yet undefined, or balloon ex(cid:173)
`pandable. In order to be practical, some form of a balloon(cid:173)
`expandable system will probably be required in order for
`such a system to be widely employed. A balloon-expandable
`system offers the advantages and disadvantages listed in
`Table 75-4. The advantages include the ability to use a rela(cid:173)
`tively small arterial puncture or arteriotomy in the placement
`of an introducer sheath. Additionally, the use of a balloon
`system will allow expansion of the device from a much
`smaller compressed state to the larger fully deployed state.
`This could result in an expansion ratio between three and ten
`times the compressed diameter. Such an expansion ratio
`might even allow percutaneous placement of large mitral and
`tricuspid valves. Such expansion ratios need not require an
`expandable metal mesh, but might occur in the form of a
`single ring designed much like a hose clamp that opens; even
`self-expanding alloys might be utilized if correctly designed.
`Placement techniques must be devised to assure site-specific
`localization and stabilization of such a device as well as an
`orientation that is coaxial to blood flow. In most cases these
`valves would be placed for severe valvular regurgitation, as(cid:173)
`suring a large-volume, high-velocity jet at the site of intended
`
`I
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 9 of 12
`
`
`
`i
`
`,:
`
`J
`
`i
`
`'
`i
`
`'
`
`11111
`
`1274
`
`VIII-VALVULOPLASTY, CONGENITAL AND PERICARDIAL HEART DISEASE
`
`A
`
`8
`
`DGUR£ 75-8. A, The expanded balloon with the stent still in
`place. The arrows indicate the elastic blocks used to keep the valve
`in place. B, The fully expanded valve is seen from the top.
`
`placement. Such a large blood volume may well require a
`secondary balloon or a novel stabilization method in order to
`assure exact valve placement. In addition, this delivery sys(cid:173)
`tem will need to be capable of angiographic injections to de(cid:173)
`termine exact location of the valve and to assure that coro(cid:173)
`nary ostia are not compromised. Several options are possible
`for such a delivery catheter, including a short segment of
`catheter distal to the valve prosthesis for sampling pressures
`and performing the angiographic injections,
`In order to successfully deploy a percutaneous valve, the
`delivery system will need to meet several criteria (Table 75-
`5). The first will be that the valve is not displaced from the
`balloon during delivery. Second, the balloon must expand to
`a large enough diameter to securely anchor the valve in place.
`Third, retraction of the balloon must not dislodge the valve.
`And fourth, the delivery balloon must not damage surround(cid:173)
`ing tissue.
`The delivery balloon could be constructed of multiple bal(cid:173)
`loons placed on a single catheter, although hourglass con(cid:173)
`struction of the variety currently employed bf the Inoue bal(cid:173)
`loon may be preferable. Multilobed balloons do allow a
`smaller diameter of the deflated balloon but are unstable in
`
`high-flow fields such as one would find in mitral or aortic
`regurgitation.
`The hourglass balloon might have two inflation lumens(cid:173)
`one for the distal balloon and a second for the proximal bal(cid:173)
`loon and valve. This technique will allow the valve to be im(cid:173)
`planted only after the qistal balloon has first been anchored
`in place at the site of the valve annulus. This type of balloon
`would also result,in less damage to surrounding tissue, since
`the largest diameter of such a balloon would be at its center,
`where the valve was situated. Additionally, this single bal(cid:173)
`loon would be less likely to become entangled in the valve
`and dislodge it. Finally, the hourglass shape is more adapt(cid:173)
`able to large and small diameters, allowing a single balloon
`design to function as the primary delivery device for all per(cid:173)
`cutaneous valve implants.
`
`VALVE CONSTRUCTION
`
`The specific material(s) from which a percutaneously
`placed valve is constructed is an area requiring further eval-
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 10 of 12
`
`
`
`75-PERCUTANEOUS EXPANDABLE PROSTHETIC VALVES
`
`1275
`
`RGURE 75-9, a, Angiography demonstrating the valve (arrow) placed in the subcoronary position. b, This
`panel demonstrates placement of the valve in the supracoronary position.
`
`uation. The types of valves and the materials currently used
`in the manufacture of valves are listed in Table 75-6. A valve
`requires two components: the occluder and the sewing ring.
`The occluder can be a mechanical device such as a ball also
`known as a poppet, a disk of multiple leaflets retained by
`struts. Biologic valves use tissue to perform as occluders. Bi(cid:173)
`ologic valves mcif be sewn onto a ring or stent as with peri(cid:173)
`cardia! valves or sewn in without a ring as homografts are
`placed. Since many valves require a sewing ring or stent with
`which to anchor the valve, placing tissue valves on metallic
`stent struts offers the opportunity for the marriage of two
`currently available technologies in a rapid fashion. Such a
`device will be discussed below. Other considerations include
`modifications of current mechanical devices to allow valve
`rings to increase in diameter once in place. Even the use of
`newer Rolymers in radical designs for replacement of valve
`leaflets 1 should be evaluated. Certainly, our concepts of what
`constitutes a "prosthetic valve" will be radically altered by
`the specific requirements for placement of percutaneous
`valves.
`The problems of currently used prosthetic valves will be
`even more important in any valve delivered percutaneously.
`Specific issues that must be addressed include assurance that
`the site of expansion is correct. We must avoid compromising
`the coronary ostia and causing myocardial ischernia at all
`costs. Consideration of perivalvular leaks, calcific degenera(cid:173)
`tion of valves, development of anticoagulation protocols, and
`methods of patient follow-up must each be addressed as this
`technique is employed.
`
`SITE-SPECIRC CONSIDERATIONS
`
`The indication for and the site of placement will play a
`major role in the design and deployment of any such percu-
`
`taneous valve. The aortic and pulmonic arteries are the easiest
`technical sites for implantation. The aortic and pulmonic ar(cid:173)
`teries offer relatively straight albeit short segments of smaller
`diameter vessels that could easily accept an expandable valve.
`Stabilization and placement of the catheter-valve system
`could be performed using a large guidewire with either fluor(cid:173)
`oscopic or perhaps even echocardiographic guidance.
`A major concern with placement of this valve in the aortic
`position is that seen with catheter-based valves; namely, the
`presence of myocardial ischernia. Ischernia could occur either
`because the valve physically covers the coronary ostia or is
`placed proximal to the ostia with inadequate diastolic flow
`to the coronary bed. There is probably little need for separate
`anchoring struts in these poi;itions, and such struts could po(cid:173)
`tentially be harmful if vessel perforation occurred.12
`The placement of a percutaneous valve in the rnitral and
`tricuspid positions will be more complex. Delivery of larger
`devices will be required and a relatively large trans-septa!
`puncture may be necessary to deliver the device to the rnftral
`valve. The trans-septa! puncture may not be a major concern
`if predilation of the interatrial septum occurs with a 12-Fr.
`device as we currently perform prior to a Inoue balloon rni(cid:173)
`tral cornrnissurotomy. The exact postioning of the valve, how(cid:173)
`ever, will probably be more complex if there is a significant
`regurgitant flow across the larger diameter annulus of the
`rnitral and tricuspid valves. We will also need a mechanism
`to anchor the prosthetic valve to both the atrial and ventric(cid:173)
`ular surfaces. Specific devices to perform this function are
`currently under active investigation in our laboratory.
`Assuming that the device can be successfully anchored to
`the annulus of the atrioventricular valves, an additional prob(cid:173)
`lem will be to assure that native valve tissue and chordae are
`not caught in the deployed stent, interfering with its function.
`Avoiding entrapment of the native valve structures will prob(cid:173)
`ably be facilitated by the use of an hourglass-shaped balloon
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 11 of 12
`
`
`
`.
`.
`
`I·
`i;;
`
`.
`
`;',
`
`..
`
`,
`
`1276
`
`VIII-VALVULOPLASTY, CONGENITAL AND PERICARDIAL HEART DISEASE
`
`that can be "floated" into the ventricle, since it is less likely
`to be caught inbetween _chordal structures than a system that
`is placed over a wire.
`
`CURRENT INVESTIGATIONS
`
`The most exciting published work in this area to date is
`the investigations -by Andersen et al. from Denmark pub(cid:173)
`lished in 1992.13 They reported on their work on developing
`a transluminal implantable heart valve. They began their in(cid:173)
`vestigations in 1987 and have developed an exciting catheter(cid:173)
`based technique that has been initially evaluated in a porcine
`model. Using 0.55-mm surgical grade stainless-steel wire,
`they formed a steel mesh 14 mm in length upon which por(cid:173)
`cine aortic valves were mounted with suture (Fig. 75~6). This
`allowed the stent to be compressed to 12 mm when folded
`and expanded to 32 mm with the delivery balloon (Fig. 75-
`7). A 41-Fr. introducer sheath was used to place the valve
`from a surgically created arteriotomy site (Fig. 75-8). The di(cid:173)
`rect introduction was required because of the small femoral
`arteries of the pigs they used for this evaluation. Placement
`was guided both by fluoroscopy and by echocardiography,
`although transthoracic echocardiography was abandoned be(cid:173)
`cause the echogenic nature of this valve did not allow accu(cid:173)
`rate imaging of the valve. Figure 75-9 demonstrates angio(cid:173)
`graphic images from animals that had subcoronary and
`supracoronary implantation of the valve.
`Although all of the protocol animals survived the initial
`implantation, two of the seven animals studied died of pro(cid:173)
`gressive left ventricular dysfunction secondary to myocardial
`ischemia. At necropsy no animals demonstrated dissection or
`hematoma. Three of four animals studied did demonstrate
`restriction of coronary flow. Finally, two of the seven valves
`still had mild degrees of aortic regurgitation.
`These investigations also were very creative in the creation
`of a delivery system. They used three balloons, each 15 mm
`in diameter and 70 mm in length, with small blocks placed
`on the balloon to anchor the stent in place.
`Although the above study presents only early data illus(cid:173)
`trating the large amount of work required before a device
`such as this can be used, it illustrates that such devices await
`only the focused evaluation and improvement of a few in(cid:173)
`vestigators. Without question, within the next few years de(cid:173)
`vices such as this will be used in selected high-risk patients
`for the treatment of valvular disease.
`
`CONCLUSIONS
`
`The development of percutaneous techniques for treatment
`of cardiovascular diseases will continue to provide us with
`
`new methods of stabilizing and treating patients. It is ex(cid:173)
`tremely likely that one of these technologies will be percu(cid:173)
`taneously implanted heart valves. Most certainly the treat(cid:173)
`ment of acute aortic insufficiency will be possible; treatment
`of other regurgitant lesions as well is likely. In 10 years we
`shall very probably look back on the pioneering work de(cid:173)
`scribed above in the same way we respect the work of Huf(cid:173)
`nagel, Gruentzig, and Palmaz today. Certainly, heart valves
`will undergo radical changes in design in the decade.
`
`R.eferences
`
`1. Hufnagel CA, Harvey WP: The surgical correction of aortic re(cid:173)
`gurgitation. Preliminary report. Bull Georgetown Univ Med
`Center 6:3-6, 1953.
`2. Hufnagel CA, Harvey WP, Rabil PJ, McDermott TF: Surgical
`correction of aortic insufficiency. Surgery 35:673-683, 1954.
`3. Harken DE, Soroff HS, Taylor WJ, Lefemine AA, Gupta SK,
`Lunzer- S: Partial and complete prosthesis in aorta insuffi(cid:173)
`ciency. J Thorac Cardiovasc Surg 40:744-762, 1960.
`4. Grunkemeier GL, Starr A, Rahimtoola SH: Prosthetic heart valve
`performance: Long term follow-up. Curr Prob Cardiol 6:333-
`.
`406, 1992.
`5. Fessatidis I, Hackett D, Oakley CM, et al: Ten-year clinical eval(cid:173)
`uation of isolated mitral valve and double valve replacement.
`Ann Thorac Surg 43:368-372, 1987.
`6. Perler P, Deloche A, Chanvaud S, et al: Clinical comparison of
`mitral valve replacement using porcine, Starr and Bjork pros(cid:173)
`theses. J Cardiovasc Surg 3:359-362, 1988.
`7. Davies H: Catheter mounted valve for temporary relief of aortic
`insufficiency. Lancet 1 :250, 1965.
`8. Moulopolous SD, Anthopolous L, Stamatelopolous S, Stefado(cid:173)
`rous M: Catheter-mounted aortic valves 11:423-430, 1971.
`9. Phillips SJ, Ciborski M, Freed PS, Cascade PN, Jaron D: A tem(cid:173)
`porary catheter-tip aortic valve: Hemodynamic effects on ex(cid:173)
`perimental acute aortic insufficiency. Ann Thorac Surg 21:
`134-137, 1976.
`10. Matsubara T, Yamazoe M, Tamura Y, Ohshima M, Yamazaki Y,
`Suzuki M, Izumi T, Shibata A: Niigata, Japan. Balloon catheter
`with check valves for experimental relief of acute aortic re(cid:173)
`gurgitation. Arn Heart J 124:1002-1008, 1992.
`11. Lo HB, Herold M, Reul H, et al: A tricuspid polyurethane heart
`valve as an alternative to mechanical prostheses or biopros(cid:173)
`theses. Trans Am Soc Artif Intern Organs 34:839-844, 1988.
`12. Boretos JW, Poirer RA: Aortic heart valve catheter. United States
`Patent (No. 4.056.854), 1977.
`13. Andersen HR, Knudsen LL, Hasenkam JM: Transluminal im(cid:173)
`plantation of artificial heart valves. Description of a new ex(cid:173)
`pandable aortic valve and initial results with implantation by
`catheter technique in closed chest pigs. Eur Heart J 13:704-
`708, 1992.
`
`
`
`Edwards Lifesciences Corporation, et al. Exhibit 1005, p. 12 of 12
`
`