Cardiac Reconstructions with Allograft Valves R. A. Hopkins Cardiac Reconstructions with Allograft Valves With Contributions by V.J. Ferrans S.L. Hilbert M. Jones P.L. Lange L. Wolfinbarger, Jr. Illustrations by Thomas Xenakis With 169 Figures Springer-Verlag N ew York Berlin Heidelberg London Paris Tokyo RICHARD A. HOPKINS, M.D. Department of Surgery Georgetown University Medical Center Washington, DC 20007, USA Library of Congress Cataloging-in-Publication Data Cardiac reconstructions with allograft valves. Includes bibliographies and index. 1. Heart-Valves-Surgery. 2. Homografts. I. Hopkins, Richard A. [DNLM: 1. Heart Valves-trans plantation. 2. Transplantation, Homologous. we 169 C2667] RD598.C3435 1989 617'.4120592 88-29466 Printed on acid-free paper © 1989 by Springer-Verlag New York Inc. Softcover reprint of the hardcover 1st edition 1989 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag, 175 Fifth Avenue, New York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names, trademarks, etc. in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Typeset by Arcata Graphics/Kingsport, Kingsport, Tennessee. 9 8 765 4 321 ISBN-13: 978-1-4612-8159-7 e-ISBN-13: 978-1-4612-3568-2 DOl: 10.1007/978-1-4612-3568-2 This work is dedicated to Jenny Preface Human cadaver tissues (homografts) were used clinically for vascular reconstructions as initially reported by Gross in 1948 and based on the experimental work of Carrel and others earlier in the century. An aortic homograft allowed the first abdominal aneurysm operation by DuBost in 1951, and valved tissues were utilized during the 1950s and early 1960s prior to the general availability of mechanical or xenograft valve prostheses. However, the continued use of homograft valves (allografts) in cardiac reconstructions has subsequently been limited to a few centers. This limitation has been partly because processing homograft valves for sterility and preservation (e.g., irradiation, glutaraldehyde) resulted in poor durability, and "fresh" valves stored in nutrient media with antibiotics were logistically difficult to bank and probably not truly viable. Now, however, use is increasing and interest greatly heightened for a number of reasons. First, human allograft valves do indeed have hydraulic performance superior to that of synthetic prostheses when harvested, sized, and implanted prop erly. Second, availability is increasing owing to the expanded use of multiple organ harvests. Third, cardiologists and cardiac surgeons are increasingly dissatisfied with "prosthetic valvular disease" in regard to thromboembolic and anticoagulation compli cations associated with mechanical prostheses and the poor durability of xenografts, especially in young patients. Lastly, improved performance and durability of allograft valves are being demonstrated with new cryopreservation techniques that result in cellular viability of valves "banked" in vapor-phase liquid nitrogen. It is clear that these allograft cardiovascular tissues have special advantages in certain anatomic situations, for many patients requiring aortic or pulmonary valve replacements, and for pediatric cardiac reconstructions requiring conduit procedures. Thus we are entering a new era of cardiac reconstructions that utilize transplanted viable human tissues-distinct from the era of nonviable homo grafts and mechanical/xeno graft prosthetics. Although allograft cardiovascular tissues are being used in a number of applications, the focus of this volume is on valved ventricular outflow tract reconstructions. As with all materials used in surgery, surgeons must learn the technical features specific to the new materials in order to fully exploit their potential benefits and unique characteristics. For allograft valves and conduits, this knowledge involves an amalga mation of old and new methods. Viable allograft tissue is a more forgiving and easier material with which to reconstruct outflow tracts than rigid prostheses. Allo- viii PREFACE grafts lend themselves to somewhat different reconstructive techniques that solve tricky anatomic problems while preserving physiological principles. This book is primarily designed as a guide to the practicing cardiac surgeon for the use of allograft valves and conduits in cardiac reconstructions. Full descriptions are given for their use in various lesions, including indications, sizing, and specific surgical techniques for both simple implants and complex reconstructions. The cryo biology of viable human cardiovascular tissue cryopreservation is reviewed in Chap ters 3, 4 and 5. An understanding of the principles and techniques is necessary for the safe participation in harvesting, thawing, preparation, and handling of these allografts. Certain conventions are used in the book. Half-tone or carbon dust figures are used to depict surgical techniques as viewed from the surgeon's perspective. When figures are drawn from a nonsurgical view to make anatomic or other points, pen and-ink line drawings are used. There is some repetition of steps in the depiction of various surgical techniques so readers can be spared page flipping to follow a procedure from beginning to end. The older term "homograft" is used generically, particularly when referring to information gained from the precryopreservation era (when the term was universally used), and the term "allograft" is adopted for more recent series, particularly when there is an expectation, or intention, of some element of donor cellular viability in the transplanted tissues. While not inherent in the vocabulary, this convention nicely separates the older from the current literature. All surgeons performing valve replacements and congenital cardiac surgery should be interested in these methods. Cardiothoracic residents will hopefully benefit from the illustrations and descriptions as well. Cardiologists who time the referral of patients for valve surgery based on expected performance of various types of valve replacements will also be interested in human valve transplants. All of the techniques depicted have been used by the author; they are based on original classic descriptions but as modified by a modest experience of 85 personally performed surgeries in neonates, children, and adults. The surgical techniques are, of course, derived from those of the pioneers in the field-Sir Brian Barratt-Boyes, Mr. Donald Ross, Dr. William W. Angell, Dr. Mark O'Brien, Mr. Magdi Yacoub, Professor Francis Fontan, Mr. Jaroslav Stark, and Dr. John Kirklin-as well as others cited in the text. One of the goals of this volume was to collate techniques into one resource. Our own variations are noted. When these techniques vary significantly from those previously promulgated, the rationale is given as well as indications for alternative methods. Allograft valve transplants involve the use of biologic tissues, which lend themselves to many creative reconstructions. Learning and mastering a flexible range of techniques is important and allows improved solutions to complex problems in ventricular outflow reconstructions. Expanding the ranks of surgeons facile with the use of cardiovascular allografts is the fundamental purpose of this book. RICHARD A. HOPKINS Acknowledgments This work could not have been finished without the help of numerous people. The collaboration with Tom Xenakis, the illustrator, has been a superb intellectual exercise, and his contributions cannot be overemphasized. I am especially grateful to the London teachers who first introduced me to the use of homografts, Jaroslav Stark and Marc de Leval. It is with great appreciation that I acknowledge Professor David C. Sabiston, Jr., for whose support, teaching and 'training I am grateful. My Norfolk colleagues contributed with thoughts and suggestions. Contributors to Chapters 3,4, and 5, Perry Lange, Lloyd Wolfinbarger, Stephen Hilbert, Victor Ferrans, and Michael Jones, are all experts in their fields, and their contributions are superb. The dedicated professionals at the Virginia Tissue Bank have invested tremendously in the development of improved cryopreservation techniques and have given freely of their time and expertise. In addition to Perry Lange and Lloyd Wolfinbarger, special thanks go to Scott Bottenfield, Helen Leslie, Bill Anderson, and Dr. Richard Hurwitz. The assistance of Debbie Davenport with the typing is gratefully acknowledged. Contents Preface ..................................................... vii Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. xiii Section I-Principles 1 Historical Development of the Use of Homograft Valves. . . . . . . . . . . . . 3 RICHARD A. HOPKINS Early Homograft Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Fresh Wet-Stored Homograft Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Prosthetic Valve Disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 London Homografts ........................................ 6 New Zealand Homografts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Right Ventricular Outflow Tract Reconstructions. . . . . . . . . . . . . . . . . . . 7 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2 Rationale for Use of Cryopreserved Allograft Tissue for Cardiac Reconstructions ........................................... 15 RICHARD A. HOPKINS Brisbane Experience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15 Right Ventricular Outflow Reconstructions with Allografts. . . . . . . . . . . . 17 Clinical Use of Allograft Valve Transplants: Unresolved Issues ........ 18 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 3 Biology of Heart Valve Cryopreservation ........................ 21 LLOYD WOLFINBARGER JR. and RICHARD A. HOPKINS Factors Affecting Cellular Viability . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 Biochemical and Histologic Characteristics of Allograft Heart Valves . . . . 27 Application of Cryopreservation to Heart Valves . . . . . . . . . . . . . . . . . .. 29 Effects of Loss of Cellular Viability in Cryopreserved Heart Valves. . . . . 30 Problems of Quantification of Cell Viability. . . . . . . . . . . . . . . . . . . . . .. 31 Direction of Future Basic Research . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34 xii CONTENTS 4 Allograft Valve Banking: Techniques and Technology 37 PERRY L. LANGE and RICHARD A. HOPKINS Donor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37 Procurement ............................................. 39 Dissection ............................................... 40 Sterilization and Disinfection ................................. 44 Cryopreservation .......................................... 46 Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52 Transportation and Distribution ............................... 53 Thawing and Dilution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 55 Quality Assurance and Quality Control . . . . . . . . . . . . . . . . . . . . . . . . .. 58 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 60 5 Effects of Preimplantation Processing on Bioprosthetic and Biologic Cardiac Valve Morphology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 65 STEPHEN L. HILBERT, VICTOR J. FERRANS, and MICHAEL JONES Preimplantation Processing and Sterilization . . . . . . . . . . . . . . . . . . . . .. 65 Morphology of Unimplanted Heart Valve Substitutes ............... 76 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 88 Section II-Surgical Techniques 6 Left Ventricular Outflow Tract Reconstructions . . . . . . . . . . . . . . . . . . . . 97 RICHARD A. HOPKINS "Freehand" Aortic Valve Replacement with Aortic Allograft Valve Transplant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97 Surgical Technique for Annulus Enlargement in the Small Aortic Root for Concomitant Use with Allografts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 122 Aortoplastic Techniques for Problematic Aortic Root Geometry. . . . . . .. 126 Aortic Root Replacement with Aortic Allograft Conduit . . . . . . . . . . . . .. 135 Aortoventriculoplasty with Aortic Allograft (Aortic Root Replacement with Konno) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 142 Postoperative Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 152 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 153 7 Right Ventricular Outflow Tract Reconstructions . . . . . . . . . . . . . . . . . .. 155 RICHARD A. HOPKINS Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 156 Standard Right Ventricle to Pulmonary Artery Aortic Allograft Conduit in Children and Infants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 156 Pulmonary Valve Replacement in Adults. . . . . . . . . . . . . . . . . . . . . . . .. 165 Anterior Ventricle to Pulmonary Artery Allograft Conduit in Corrected Transposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 168 Reconstruction of Right Ventricular Outflow with Abnormal Pulmonary Arteries ................................................. 173 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 186 Appendix Valve Diameters ...................... , . . . . . . . . . . . . . . . . . . .. 189 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 190 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 191 Contributors VICTOR J. FERRANS, Ph.D., M.D. Chief, Ultrastructural Section, Pathology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA STEPHEN L. HILBERT, Ph. D. Experimental Pathologist, Office of Science and Technology, Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD 20852, USA RICHARD A. HOPKINS, M.D. Director, Pediatric Cardiac Surgery, Department of Surgery, Georgetown University Hospital and Medical School, Washington, DC 20007, USA~ Medical Director, Cardiovascular Tissues Program, Virginia Tissue Bank, Virginia Beach, VA 23455, USA MICHAEL JONES, M.D. Senior Surgeon, Surgery Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA PERRY L. LANGE, B.S., C.S.A. Technical Coordinator, Cardiovascular Services, Virginia Tissue Bank, Virginia Beach, VA 23455, USA LLOYD WOLFINBARGER, JR., Ph.D. Director, Center for Biotechnology, Research and Development, Virginia Tissue Bank, Virginia Beach, VA 23455, USA