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Ann Thorac Surg 2005;79:S2217-S2220
© 2005 The Society of Thoracic Surgeons
Department of Pediatrics, Unidad de Cirugia Cardiovascular de Guatemala, Guatemala
Accepted for publication March 7, 2005.
* Address reprint requests to Dr. Castañeda, 9a. Avenida 8-00, zona 11 Guatemala, Department of Pediatrics, Unidad de Cirugía Cardiovascular de Guatemala, Guatemala. (E-mail: unicarp{at}terra.com.gt).
Presented at the 4th Annual Lillehei Heart Institute Symposium Celebrating the 50th Anniversary of Open-Heart Surgery by Cross Circulation, Minneapolis, MN, Oct 19–20, 2004.
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Primary morphogenesis of the human heart is completed 60 days after conception. The embryonic heart, initially a tubular structure includes the truncus, conus, bulbo cordis, ventricle (left), and atria. Obeying genetic commands, the heart undergoes looping (more commonly dextro-looping) to become, after 2 months, the final four-chambered, four-valved organ. The original left ventricle is the primary pump of the phylum Chordata, whereas the right ventricle makes its first appearance in reptiles, hence in land-locked animals that depend on a pulmonary circuit. Amphibians still have only one ventricle (the left ventricle) whereas reptiles have two atria and two ventricles, albeit still interconnected. Cardiogenic ontogeny recapitulates cardiogenic phylogeny.
According to more recent information single genes can cause single cardiac malformations, and mutation in a single locus may demonstrate different penetration, expression, and hence phenotype, whereas mutations in different loci may induce the same phenotype. Geneticists now believe that at least 75% of congenital cardiac malformations have a genetic origin. The earlier the insult during embryogenesis, the more complex the malformations. During the remaining 7 months of intrauterine existence and in the presence of an important primary defect, additional in utero-acquired cardiac disease may significantly complicate the primary congenital cardiac lesion.
One of the first depictions of a congenital cardiac defect was by Leonardo daVinci, who clearly drew a partial anomalous pulmonary venous connection of the right pulmonary veins to the right atrium [1]. The first successful operation for correction of an extracardiac lesion, namely ligation of a patent ductus arteriosus, was accomplished by Gross and Hubbard [2] on August 8, 1938, at the Children’s Hospital in Boston. This epic operation ushered in the era of pediatric cardiovascular surgery. Six years later on October 10, 1944, Crafoord and Nylin [3], at the Karolinska Hospital in Sweden, repaired successfully a coarctation of the aorta. On November 9 of the same year, Blalock and Taussig [4] carried out the first subclavian artery to pulmonary artery anastomosis to palliate cyanosis-producing malformations, particularly tetralogy of Fallot. In 1952 Muller and Dammann [5] introduced pulmonary artery banding to protect the pulmonary arterioles from developing pulmonary vascular obstructive lesions, a consequence of increased intravascular pressure and shear stress. The more those indications were diagnosed, the more it became apparent that most congenital cardiac defects were indeed intracardiac. The challenge during the late forties and early fifties was how to gain access to the interior of the heart. Several ingenious half-measures were proposed, including Gross’s atrial well technique [6]. Although useful in some patients, this and similar makeshift attempts proved too limiting and inadequate for the repair of most intracardiac defects. Clearly, surgeons needed to be able to see how to carry out the repair inside the heart.
Haecker [7], in 1907, using normothermic superior and inferior vena cava occlusion, learned that dogs did not tolerate circulatory occlusion for more than 3 minutes; beyond that time dogs either died or exhibited central nervous system damage. Using this background information, surgeons started to experiment with ways to prolong these 3 minutes. Boerema and associates [8] in Amsterdam, Bigelow and colleagues [9] in Toronto, and Lewis and Taufic [10] at the University of Minnesota began to use total body hypothermia, both moderate at 28°C and profound at 18°C. Their purpose was to lower metabolic demands, particularly of the central nervous system, hoping to consequently allow for longer and safer period of caval occlusion. When the University of Minnesota team convinced themselves that at 28°C the central nervous system was sufficiently protected to withstand 10 minutes of circulatory arrest and that a simple ostium secundum defect could be closed within less than 10 minutes, F. John Lewis and collaborators succeeded on September 2, 1952, in closing an atrial septal defect in a 5-year-old girl, under direct vision, using moderate hypothermia and caval inflow occlusion [10]. This operation was soon adopted by other surgeons principally by Swan and associates [11] in Denver and Derra and colleagues [12] in Düsseldorf, Germany.
Although this technique represented an important advance, it was nevertheless far from ideal. Clearly a system was needed that would substitute both the pumping function of the heart and the respiratory function of the lungs. In 1933 John Gibbon, at that time a surgical resident at Jefferson University, while on a clinical rotation at the Massachusetts General Hospital in Boston, witnessed the death of a young woman from a pulmonary embolus. Gibbon recognized that removal of the saddle embolus could have saved the life of this otherwise healthy young woman. Despite little support from the senior staff at the Massachusetts General Hospital, Gibbon obstinately persisted in developing an artificial heart-lung machine. Twenty years later and after many research trials, Gibbon succeeded on May 9, 1953, to close an atrial septal defect in a young woman using a screen oxygenator of his own design and a roller pump [13]. Unfortunately, a previous attempt at closing a ventricular septal defect in an infant and four other open heart operations after the successful second patient ended in death of all 5 patients. Gibbon became so discouraged by his results and those of other surgeons, obtained between 1951 and 1954 (Table 1), that he offered to lead a move to ban, for an unforeseeable time, other attempts at open heart procedures in the United States. The generalized pessimism that affected the cardiologic community was based on the conviction that the sick or malformed heart simply could not withstand surgical manipulations.
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What were the circumstances that authorized at the University of Minnesota the first open heart operations under direct vision, using moderate hypothermia and caval inflow occlusion and also the daring controlled cross-circulation experience as well as some other firsts? One reason was Dr Owen H. Wangensteen, the Chief of the Department of Surgery, who fostered at the University of Minnesota a very special intellectual environment, stimulated scientific curiosity, and provided through the various research and doctoral opportunities the tools to pursue new knowledge. The cardiac surgical leadership at that time also included Dr Richard L. Varco, a very erudite individual, intellectually versatile with a deductive intelligence, a synthesizer of knowledge and masterful surgeon. Doctor Lillehei was a visionary surgeon, innovative, an unrelenting pioneer, emotionally hardy iconoclast, and outwardly flamboyant. Clearly, the controlled cross-circulatory idea carried his imaginative seal. John Kirklin accompanied by Mr Richard Jones, an engineer also from the Mayo Clinic, paid a visit to Gibbon’s laboratory to study in detail his heart-lung machine. Kirklin and Jones succeeded in improving and simplifying Gibbon’s screen oxygenator, called from then on the Mayo-Gibbon pump oxygenator. Kirklin, using this machine in early 1955, inaugurated the outstanding accomplishments in cardiac surgery of the Mayo Clinic Group [15]. The first patient was a child with a ventricular septal defect. In the meantime, Richard DeWall at the University of Minnesota developed a very simple, easy to assemble and to use, bubble oxygenator [16]. (This accomplishment has also been covered by a prior presentation at this meeting.) For nearly 2 years, all open heart operations in the world were carried out in Minnesota in two institutions located 90 miles apart. Subsequently, and in great measure thanks to the simplicity and low cost of the DeWall bubble oxygenator, open heart centers spread rapidly, first in the United States and then throughout the world. Note also that at the beginning all open heart operations were indicated for repair of congenital cardiac lesions.
During the 1950s and 1960s the prevailing impression was that open heart operations were poorly tolerated by the very young, as demonstrated by the cross-circulation experience and other sporadic attempts at open heart repair in infancy. Therefore, symptomatic neonates and infants were first subjected to palliative procedures, while intracardiac repair was delayed until age 5 to 7 years. This therapeutic policy presented serious disadvantages, including (1) the need for two operations; (2) the palliative operation did not always accomplish its purpose; (3) iatrogenic damage was not uncommonly produced by the palliative procedure itself; (4) the emotional burden placed on child and parents living with the threat of another operation; and (5) the increased cost of two operations. In the late sixties and early seventies, Horiuchi and coworkers [17] and Hikasa and associates [18] in Japan and Barrat-Boyes and colleagues [19] in New Zealand started to obtain good results with primary repair in infants.
In 1972, at Boston Children’s Hospital we followed this lead and accumulated as well a large and satisfactory experience with open heart operations in infancy [20]. However, review of our data from the New England Infant Cardiac Program [21] showed that deaths from complex congenital cardiac defects occurred mostly during the first few weeks of life. Based on this information and also, after reviewing our midterm and late results with the atrial switch operations (Senning and Mustard) for transposition of the great arteries, we became convinced that complex cardiac lesions should, by preference, be repaired during the neonatal period to reduce early deaths and to minimize secondary organ damage, including the heart, lungs, and central nervous system. This early approach would also allow normal postnatal development, such as physiologic myocardial hyperplasia or hypertrophy, coronary angiogenesis, and pulmonary angiogenesis and alveolar genesis. Also, preliminary laboratory experiments in 2-kg puppies subjected to 2 hours of cardiopulmonary bypass convinced us that the effects of this 2-hour period of extracorporeal bypass on both the formed elements of blood and the lungs (air and fluid static volume-pressure measurements as well as alveolar bubble stabilizations) revealed only minor, transitory, and rapidly reversible changes that were well tolerated by these very young animals [22].
Consequently, on January 2, 1983, we performed our first arterial switch operation (Jatene) in an 11-day-old neonate with transposition of the great arteries and an intact ventricular septum [23]. The results, both early and late, of the arterial switch operation in the neonate have been very satisfactory (Table 2) [24]. We had established to our satisfaction that optimal management of dextro-transposition of the great arteries with an intact ventricular septum was achieved by an arterial switch operation, performed ideally within the first 2 weeks of life. However, a substantial number of patients were referred to our institution for an arterial switch operation beyond the first month of life for various reasons, including sickness or late referral by parents or physicians.
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To become a well-trained and competent pediatric cardiac surgeon, it is important to include at least 6 to 12 months of additional specialized training in an institution with a large volume of children with complex cardiac pathology. Also, future pediatric cardiac surgeons interested in an academic career should ideally include a research experience either in molecular cardiology or biology, genetics, biophysics (tissue engineering), immunobiology (xenotransplantation), pharmacology, neurobiology (central nervous system protection), or ethics.
Past efforts of pediatric cardiac surgeons and of pediatric cardiologists, anesthesiologists, intensivists, perfusionists, and pathologists, all concerned with the diagnosis and treatment of congenital cardiac malformations, have produced impressive advances over these many years. Yet, I am convinced that the most exciting advances of our specialty are still before us. We, the few remaining old residents of the University of Minnesota surgical training program, can look back and proudly extol: It almost all began here at the University of Minnesota, 50 years ago.
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