HISTORY |
From the Department of Pediatrics (Emeritus) and Cardiovascular Research Institute, University of California, San Francisco, California
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ABSTRACT
Dr Abraham Rudolph is one of the most distinguished pediatric cardiologists in the world. He entered pediatric cardiology (almost by accident) when the subject was still in its infancy and was present atand indeed contributed tomost of its advances. He is best known for his studies on the pathophysiology of congenital heart diseases and for imaginative studies of fetal cardiovascular development and the transition to postnatal life.
Key Words: pathophysiology of congenital heart disease fetal circulation neonatal circulation patent ductus arteriosus radioactive microsphere method
In October 2001, Dr Abraham M. Rudolph received the Founders Award of the Cardiology section of the American Academy of Pediatrics. The presenter of the award remarked that Dr Rudolph was responsible for much of what we know about congenital heart diseases. That is certainly true, but it occurred to me that the younger pediatricians might not know exactly what his contributions were and might be interested in learning about his career. As a colleague of Dr Rudolph, who has been my mentor and friend for most of my professional life, I offer this brief discussion of his career.
Abraham Morris Rudolph was born in Johannesburg, South Africa, in 1924. He entered the medical school at the University of the Witwatersrand in Johannesburg in 1941. During medical school, he won almost all of the prizes that students could be awarded, and he graduated summa cum laude and received his MB, BCh degree in 1946. The South African Medical Council had a regulation that forbade medical graduates from practicing medicine in or outside a hospital until they were 22 years old, so Dr Rudolph became an instructor in the Department of Anatomy until he was able to start his internship. After the required internships of 6 months of internal medicine and 6 months of surgery, he decided to become a pediatrician, and did the equivalent of his residency training at the Transvaal Memorial Hospital for Children under 2 superb clinical pediatricians, Dr Samuel Javett and Dr Seymour Heymann.
In 1949, Dr Rudolph spent almost a year in the United Kingdom, and in that time he passed the examinations for Membership of the Royal College of Physicians of London and also the Royal College of Physicians of Edinburgh. The pass rate for first-time takers of these examinations was at that time 15%. He also spent 6 weeks with the great Scandinavian pediatric cardiologist Edgar Mannheimer.
He returned to South Africa, where, in addition to gaining experience in pediatrics, he wrote a thesis on hemophilia to obtain his MD degree. For personal and professional reasons, he then decided to move to the United States, and he wrote to the heads of the Departments of Pediatrics at Yale and Johns Hopkins Medical Schools and at Boston Childrens Hospital to explore the possibility of receiving additional training there. The first 2 institutions had nothing to offer him, but Dr Charles Janeway in Boston informed him that he could work either in hematology with Dr Louis K. Diamond or in cardiology with Dr Alexander S. Nadas. With Dr Rudolphs interest in hematology, Dr Diamond was well known to him, but he had never heard of Dr Nadas. Unfortunately, neither position carried any salary. A few weeks later, Dr Janeway wrote to let Dr Rudolph know that he would be able to pay him $3000 annually to work in pediatric cardiology, so Dr Rudolph accepted this opportunity, and he and his family moved to Boston in 1951. Seldom has an investment of $3000 paid off so well.
Dr Rudolph soon became head of the cardiac catheterization laboratory that, until his arrival, had only had a part-time head, Dr Walter Goodale, an adult cardiologist with an interest in congenital heart disease. He spent some time with the great physiologist Dr Clifford Barger at Harvard Medical School, and their studies of renal function in congestive heart failure resulted in several important publications on fluid retention and congestive heart failure1,2 and 1 on chronic catheterization of the renal artery in dogs. Dr Rudolph also set up his own experimental animal laboratory.
In his first few years in Boston, Dr Rudolph participated in a number of important clinical studies, now classics in the field, involving the use of digitalis in infants and children,3 pulmonic stenosis, atrial septal defect, aortic stenosis, patent ductus arteriosus, ventricular septal defect,4 complete atrioventricular block, tetralogy of Fallot, and transposition of the great arteries.5 In subsequent years, his interest in different aspects of congenital heart diseases continued, and he published many articles that have contributed to our modern understanding of these lesions. Much of his insight into congenital heart disease formed the basis of his unique book Congenital Diseases of the Heart: Clinical-Physiologic Considerations, first published in 1974 and revised in 2001.6
The techniques of studying conscious animals that he learned from Dr Barger were initially put to use when Dr Rudolph and Dr Milton H. Paul described chronic catheterization of the pulmonary and systemic circulations,7 a technique that avoided the extensive artifacts inevitable in the study of anesthetized animals. At this time, cardiovascular studies of conscious animals were rarely done; the only notable scientists involved in this field were Dr Robert F. Rushmer at the University of Washington in Seattle and Dr Edward Hawthorne at Howard University in Washington, DC.
In the late 1950s, too, Dr Rudolph also began his work on pulmonary hypertension, both in its clinical form in congenital heart disease and in a number of animal studies that examined the effect of a variety of agonists and antagonists on pulmonary vasomotion.8,9 Later, he made many other contributions in this area.1015
Before effective treatment of congenital heart lesions, the vast majority of deaths occurred in the first few months after birth. This convinced Dr Rudolph of the need to catheterize infants, and he began to do this in 1956. Dr Rudolph and Dr Glen Cayler described their techniques that were soon copied by other pediatric cardiologists.16 Perhaps the only others interested in catheterization of small infants at that time were Dr Richard Rowe and Dr Stanley James at Babies and Childrens Hospital, Columbia University, in New York.
Dr Rudolphs interests also extended to prematurely born infants, and Dr Rudolph pursued this vigorously. His interest was facilitated by the close friendship of Dr Alexander Nadas with Dr Clement Smith, the head of the neonatal service at the Boston Lying-In Hospital, just across the road from the Childrens Hospital. At that time, the mortality rate from respiratory distress syndrome was very high; adequate ventilatory support had not yet been developed. Dr Rudolph was the first to perform cardiac catheterization on these tiny infants. I can remember clearly how confused I was when Dr Rudolph told me that premature infants with respiratory distress syndrome and completely opaque lung fields on chest radiograph had large left-to-right shunts through a patent ductus arteriosus.17 The belief at that time was that they would have a high pulmonary vascular resistance from hypoxic pulmonary vasoconstriction and therefore would not have had significant left-to-right shunts.
In 1961, Dr Rudolph moved to Albert Einstein College of Medicine in New York City, where he continued his clinical and experimental work. Additional studies on pulmonary vascular reactivity were published in this period, and Dr Rudolphs interest in pulmonary vascular adjustments after birth began. He also published many clinical studies about treatment, mechanisms of disease, and diagnostic methods.
In 1964, Dr Michael Heymann joined the pediatric cardiology group, and his interests in fetal and neonatal problems led him to join Dr Rudolph in studying the fetal circulation. It was difficult to study because its many interconnected pathways made it hard to use conventional methods of measuring flow, such as indicator dilution curves or the Fick principle. Furthermore, most studies of the fetal circulation relied on exteriorized fetuses that remained attached to the placenta but were in fact deteriorating preparations from the onset. One day, Dr Rudolph was sitting in a dentists waiting room and reading a magazine. He came across an advertisement placed by the 3M Corporation to seek uses for its newly developed radioactive plastic microspheres. The company had originally developed these to treat tumors, the idea being to inject the microspheres into the blood supply to the tumor, where they would be trapped and deliver a high radiation dose locally. Unfortunately, many tumors had large arteriovenous shunts that placed the patients at risk of systemic embolism, so clinical application of the microspheres was abandoned. Dr Rudolph realized that these microspheres might be used to measure organ blood flows, and he and Dr Heymann began preliminary experiments to use these microspheres. They offered a great advantage over existing methods of measuring flow. The microspheres could be injected into conscious animals after implanting a catheter into an appropriate blood vessel; they would travel to each organ and each part of each organ in proportion to the blood flow to that organ or organ part, so if one could measure the total cardiac output, then multiplying that output by the proportion of microspheres in an organ would give that organs blood flow. Because different radionuclides could be placed in the microspheres, it was possible to measure several different sets of flows at different times in each animal. Initially, cardiac output was measured by a separate technique, but subsequently Drs Rudolph and Heymann adopted a method introduced by Drs Giovanni Meschia and Frederick Battaglia of drawing a reference sample of blood and measuring the proportion of microspheres in this sample.
In 1966, Dr Rudolph, Dr Heymann, and I, together with some of the fellows, moved to the University of California, San Francisco, where we became members of the Department of Pediatrics, under the chairmanship of Dr Melvin M. Grumbach, and the Cardiovascular Research Institute, then under the inspired guidance of Dr Julius H. Comroe, Jr. Drs Rudolph and Heymann perfected their microsphere method and made the first studies of cardiac output and organ blood flow in undisturbed, healthy, conscious fetal lambs.18,19 This was one of the major advances in cardiovascular techniques, and it has remained, with variations, one of the most used methods for measuring total and regional blood flows.
Dr Rudolph and his colleagues exploited the microsphere method in several ways. They used it to study the development of total and regional flows throughout fetal development and, by measuring pressures as well, also assessed the changes in total and regional vascular resistances.20,21 They showed, too, how abnormal the flows measured in anesthetized and exteriorized fetal lambs were. In other studies, they examined changes in distribution of blood flow with hemorrhage22 and also with endotoxin.
Soon after Dr Rudolph moved to San Francisco, there was a major change in the methods of treating respiratory distress syndrome when Drs George Gregory and William Tooley introduced continuous positive airway pressure for ventilating these infants. This was a revolution in treatment that resulted in greatly increased survival of these preterm infants. It also introduced a new epidemic disease, clinically significant patent ductus in preterm infants. I can recall Dr Rudolphs asking me to see a premature infant, the son of one of our residents, to confirm his diagnosis, but he would not tell me what it was. My findings agreed with his: the child had a typical large patent ductus arteriosus. We persuaded the cardiac surgeon, Dr Henry Edmunds, to ligate the ductus, and the child improved. That was probably one of the first, if not the first, successful ligation of a ductus arteriosus in a premature infant to treat respiratory distress. (In fact, approximately 5 years earlier in Boston, Dr Rudolph had persuaded Dr Robert Gross to ligate the ductus arteriosus in a very sick premature infant, but the infant died after a few days.)
The ductus epidemic led Dr Rudolph to begin a detailed study of ductus physiology and pharmacology in fetal lambs. In 1972, he published an article with Drs Dorothy McMurphy, Michael Heymann, and the late Kenneth Melmon on the response of the fetal ductus to oxygen and vasoactive substances.23 There followed a series of articles on the regulation of patency of the fetal ductus arteriosus.2433 Parallel to these experimental studies was a series of clinical studies on the diagnosis and treatment of the ductus arteriosus in prematurely born infants,3437 starting with surgery and then progressing to treatment with the prostaglandin synthesis inhibitor indomethacin.38 It was natural to follow the successful closure of the premature ductus with attempts to keep the ductus open in ductus-dependent congenital heart disease by infusing prostaglandin E1.39,40
While these studies were being done, Dr Rudolph continued to pursue his interests in fetal development and the transition from fetal to early postnatal life. Some of these studies concerned developmental aspects of the autonomic nervous system.4146 Other studies dealt with factors that affect congenital heart lesions before and after birth.4750 Still others dealt with the stresses that might be imposed on normal infants by the birth process and the early postnatal period.4865
His interest in fetal development and response to stress led to collaborations with obstetricians, perinatologists, and pharmacologists, and jointly they studied the uteroplacental circulation and the responses of the fetus to a variety of stresses.4868 Many of the insights derived from these studies can be applied to the stressed human fetus.
Dr Rudolph is best known for his experimental studies of developmental and postnatal physiology and pathophysiology and his application of the insights derived from these studies to the understanding and management of clinical disease. He has not, however, ignored pharmacology, as mentioned above, and has also investigated a variety of biochemical changes in the fetus and the newborn.6973 He has both initiated and collaborated in studies of hormonal development and function.7477 Although he has concentrated on the heart and circulatory system, he has also done important experiments on various regional circulations and functions.7885 Even after his official retirement, he continued to do experiments and initiated studies of the effect of cortisol on myocardial development.86,87
With all the time he devoted to clinical work and experimentation, he still had time for university and public service, including stints on the Cardiovascular Study Section and the National Advisory Heart Council of the National Institutes of Health, council membership of the Society for Pediatric Research, council membership and then the presidency of the American Pediatric Society, chairman of the Section on Cardiology of the American Academy of Pediatrics, membership of the Research Study and the Publications Committees of the American Heart Association, and the editorial boards of several prominent scientific publications. He has served on several city and state commissions concerned with cardiac care as well as fetal and neonatal physiology. His many contributions were recognized by his election as a member of the National Institute of Medicine of the National Academy of Sciences. Besides all of these activities, he has been an active and much sought-after teacher and lecturer locally, nationally, and internationally. Not the least of his contributions to teaching were his stint as chairman of the Department of Pediatrics at the University of California, San Francisco, and his editorship of the highly successful general pediatric text Rudolphs Pediatrics as well as the companion Rudolphs Fundamentals of Pediatrics.
Dr Rudolphs career has been marked by imagination and creativity and a devotion to the care of children with heart disease. He has moved from careful consideration of the pathophysiology of congenital heart disease to the experimental laboratory, from which he has obtained insights that have allowed him to return to the clinical arena with improvements in clinical care. He has collaborated with investigators in several disciplines and with a large group of superb research fellows who came for training and returned to become leaders in their respective fields and countries. His selection to receive the Founders Award of the American Academy of Pediatrics is in recognition of his many invaluable contributions to the care of children with heart disease and to the ways in which research can be invoked to help them.
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ACKNOWLEDGMENTS
This study was supported, in part, by Program Project grant HL25847 from the National Heart, Lung, and Blood Institute and the National Institutes of Health.
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Reprint requests to (J.I.E.H.) Cardiovascular Research Institute, Box 0544, Rm M1331, University of California, 505 Parnassus Ave, San Francisco, CA 94143. E-mail: jhoffman{at}pedcard.ucsf.edu
REFERENCES
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G. S. Gilchrist In the Footsteps of Abraham Jacobi, an Early International Medical Graduate: Contributions of a Single South African Medical School to US Pediatrics Pediatrics, March 1, 2004; 113(3): 601 - 607. [Full Text] [PDF] |
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