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Ann Thorac Surg 2005;79:S2214-S2216
© 2005 The Society of Thoracic Surgeons
Department of Surgery, Wright State University Medical School, Dayton, Ohio
Accepted for publication March 7, 2005.
* Address reprint requests to Dr DeWall, 421 Thornhill Rd, Dayton, OH45419 (E-mail: radwll{at}cs.com).
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.
Invent: To produce or contrive something previously unknown by the use of ingenuity or imagination. (Webster)
Owen H. Wangensteen, MD, set the stage for investigative thought and surgical research in 1931 with his invention of the nasogastric suction apparatus for the care of patients with bowel obstruction [1]. When Dr Wangensteen was advised to apply for a patent on his suction apparatus he declined. Doctor Wangensteen believed that it was wrong "to profit from his invention." (Sarah Wangensteen, Dr Wangensteen’s wife, recalled his response in conversations with Elaine Challacombe, curator of the Wangensteen Historical Library.)
Doctor Wangensteen continuously initiated innovative ideas in surgical research. In the late 1950s he developed an apparatus for gastric mucosal freezing for the treatment of duodenal ulcers. Doctor Wangensteen expected all of his students to have a strong interest in surgical physiology and research.
In the late 1940s the pediatric cardiology department of the university saw patients from a wide referral area in the Midwest. Doctors Paul Adams and Raymond Anderson directed that department. They saw many patients with inoperable intracardiac defects and for which they had inadequate solutions. Because of this large backlog of children with inoperable intracardiac congenital heart defects, Drs Adams and Anderson encouraged the surgery department to find methods for the correction of these defects.
After World War II cardiovascular surgical problems became a new challenge and attracted surgeons’ attention in many of the world’s surgical centers. In 1945 Dr Wangensteen suggested to a surgical staff member, Dr Clarence Dennis, that Dr Dennis might consider the development of a pump-oxygenator system to aid body support during cardiovascular surgical repairs [2]. Doctor Dennis and his team began research in 1947 to develop a rotating screen disc oxygenator, which was used clinically in April 1951. Doctor Dennis became Chairman of Surgery at the SUNY Downstate Medical Center in New York in 1951.
Doctor C. Walton Lillehei became a faculty member of the Surgery Department in 1951. He soon developed an interest in cardiac surgery. Doctor Lillehei was determined to find methods for operating within the heart chambers. Doctor Lillehei devoted his professional life to heart surgery and trained many dozens of surgeons from worldwide medical centers.
In 1952 Dr Lillehei and his surgical fellow, Dr Morley Cohen, began experiments to support an animal during intracardiac procedures. They used a dog’s autologous pulmonary lobe as an oxygenator [3]. The difficulties of cannulating the lobe of a dog’s own lung soon became apparent. Doctor Cohen’s wife was pregnant at this time. It occurred to Dr Cohen that a pregnant woman is a perfect oxygenated blood donor to a fetal recipient. Doctor Cohen thought that it might be possible to create a similar physiologic situation with dogs as donor and patient. He believed a large dog’s major artery and vein could be used as an oxygenator for a smaller dog. Intracardiac surgery would then be possible on the smaller animal.
In 1953 Dr Herbert Warden became a surgical fellow in Dr Lillehei’s research laboratory. Doctor Warden collaborated with Dr Cohen to demonstrate that a larger animal could safely be a donor to a smaller animal. They connected major arteries and veins of the large and small animal by cannulae and conduits with a balance blood flow controlled by an occlusive pump. It was then possible to open the smaller animal’s chest and work on the interior of the smaller dog’s heart. This procedure became known as controlled cross circulation [4].
Doctor Lillehei used a transverse thoracotomy incision on the first series of open heart surgical procedures. An alternative to this incision seemed appropriate. The open heart surgical team composed of Drs Lillehei, Richard Varco, Cohen, and Warden discussed using a vertical sternotomy incision. Two problems were apparent: would a vertical sternotomy incision heal well and would a surgically divided sternum grow naturally without stunting? The physicians elected to proceed with the transsternal approach. To the relief of all, no problems were encountered, and the vertical sternotomy became the standard approach to the heart.
At the same time of Dr Lillehei’s work on perfusion systems, Dr F. John Lewis, who was also a new faculty member, investigated hypothermia for use in open-heart surgery. The interior of the heart becomes accessible by obstructing the flow of venous blood into the heart. Circulatory arrest by venous inflow occlusion gives 10 minutes or more of a dry open heart at a body temperature of 80°F (25°C) and below. Interest in hypothermia for open-heart surgery attracted interest in many of the world’s surgical clinics. The metabolic rate decreases by half for each 10°F drop in core body temperature. Doctor Lewis achieved success on September 1, 1952, in repairing intracardiac defects with inflow occlusion and hypothermia [5]. Doctor Lewis became professor of surgery at Northwestern University in 1956. There he continued his interest in open-heart surgery using hypothermia and bubble and membrane oxygenator systems of his design.
A donor was necessary for controlled cross circulation. Doctor Herbert Warden, in 1954, proposed using eight units of arterialized venous blood to replace the donor. Perfusing this blood through the patient with a single pass and at low-flow perfusion rates permitted 10 minutes of perfusion time with the heart opened. The blood was used as a single pass through the patient and then discarded. The arterialized venous blood came from a donor after his arm was immersed in a water bath at 44°C (111°F) for 10 minutes. An arm warmed in the hot water bath opened arteriovenous shunts, effectively introducing arterial blood into the arm’s venous system. The short operating time permitted by the use of arterialized venous blood limited its usefulness [6].
Doctor Richard DeWall started working with Dr Warden in Dr Lillehei’s surgical laboratory in March 1954. He helped Dr Warden continue the perfusion physiology investigations as well as learning control of the pump for the cross-circulation experiments. Doctor DeWall’s experience in the laboratory enabled him to participate in the operating room as the perfusionist for all but the first cross-circulation clinical applications. After about a dozen cross-circulation clinical procedures, Dr Lillehei suggested to Dr DeWall that it would be a good research project to develop an oxygenator to avoid the need for a donor.
Doctor DeWall accepted the challenge. After many false starts, a bubble oxygenator system emerged. Venous blood and oxygen flowed into the bottom of a two-foot long, one-inch internal diameter, vertically positioned tube. Large bubbles were created by directing streams of oxygen through 18 size 22-gauge hypodermic needles into the base of the tube. It was concluded that large bubbles were more easily and safely managed than small or microbubbles. He used the same pumps as were used with the cross-circulation procedures.
Further experimentation determined that a blood reservoir consisting of a six-foot-long coiled one-inch internal diameter tube had a specific functional purpose in addition to service as a reservoir. With the tube reservoir filled, blood flowing down the tube layered with the heavier bubble-free blood sinking to the lower position of the incline of the tube. Any bubble-containing blood became trapped above the reconstituted arterialized blood, which flowed to the bottom of the tube. Normal oxygenated blood could then be evacuated from the bottom of the coiled reservoir [7, 8].
Although repair of intracardiac congenital heart defects became routine, a complication occasionally occurred, that of complete heart block. The main electrical conducting system between the atria and the ventricles courses along the margin of ventricular defects. This system coordinates the heart rate between the atria and ventricles. These circuits are not visible to ordinary inspection and could be easily damaged with repair of the defect. Because of the heart block problem a number of patients died after successful repair of their heart defects.
Doctor Jack Johnson, a member of the physiology department, regularly attended the surgery department’s mortality and morbidity conferences where there were discussions of the heart block problem after corrective surgery. Doctor Johnson suggested that a Grass stimulator, which he used in his research, could deliver a small measured electrical charge to stimulate muscle contraction.
Doctor Vincent Gott, a student of Dr Johnson’s, took that suggestion to the laboratory, where he surgically created a heart block in dogs. By inserting a fine insulated wire into the heart muscle of the dog, Dr Gott could drive that heart using two variables of the Grass stimulator: the intensity of the electrical charge and its frequency [9].
The size of the Grass stimulator approached the size of a portable typewriter. An ordinary electrical outlet powered it. The Grass stimulator connected to a patient required a 100-yard-long extension cord to move the patient from the operating room to the intensive care unit. Earl Bakken, an electrical engineer, did contract work for the surgery department. Doctor Lillehei prevailed on Mr Bakken to develop a small container with its own power supply to replace the Grass stimulator. These efforts resulted in the formation of Medtronic, Inc.
From the beginning of open-heart surgery, a common problem existed for all types of pump oxygenators. Each type of system required a priming volume of two to eight units of freshly drawn blood in addition to blood needed to replace operating losses. The bubble oxygenators required the least amount of blood prime, while the filming oxygenators demanded the most. These blood requirements created a heavy responsibility on the blood banks.
The most significant advance in open-heart surgery after the development of perfusion systems was the introduction of a nonblood prime. In 1960, Dr David Long investigated using low-molecular-weight dextran as a diluent for priming of the pump oxygenator. The dextran also served as an agent to protect the cellular components of blood during perfusion. Doctor Lillehei used low-molecular-weight dextran for a number of years with his clinical cases [10].
In 1961, Dr Nazi Zuhdi initiated the use of 5% dextrose in water as a total prime with his perfusion system [11]. About that same time, Dr Robert Litwak wrote of using a hemodilution prime of 5% dextrose in water [12]. Doctor Denton Cooley observed Dr Litwak’s experience and also began using a total prime of 5% dextrose in water with his low-prime oxygenator systems [13]. Doctors Litwak and Cooley were not graduates from Dr Wangensteen’s department. They had a significant influence on the use of nonblood priming for oxygenator systems.
In the mid to late 1940s, Dr Richard Varco, the chief of cardiovascular surgery, stimulated interest in surgery of the heart and blood vessels among the department members. Doctor K. Alvin Merindino, a contemporary of Dr Dennis, shared with Dr Dennis interest in cardiovascular surgical problems. In 1949, Dr Merindino became chairman of the Department of Surgery at the University of Washington, where he continued his research in cardiovascular surgery. There, his inventiveness included hypothermia studies and the development of his own bubble oxygenator [14].
Doctor Frederick Cross completed his surgical training under Dr Wangensteen in 1953. He then joined a cardiothoracic surgery practice in Cleveland, Ohio. His inventiveness produced a rotating disc oxygenator [15], which received worldwide acceptance. Doctor Cross also made significant contributions with the design and development of mechanical heart valves.
Doctor Norman Shumway has worldwide respect for his studies on transplantation physiology. He became the premier surgeon for heart transplantation [16]. Doctor F. John Lewis served as his mentor during his research laboratory days while at the University of Minnesota.
Doctor Christian Barnard, a contemporary of Drs Shumway and DeWall at the University of Minnesota, established a reputation by performing the world’s first human heart transplant in Cape Town, South Africa [17].
A concern developed from the start of the pump oxygenator surgery that there would be deleterious effects on the blood from direct contact with oxygen, which was an essential part of early pump oxygenator systems. This concern was addressed by placing a membrane between the blood and the oxygen. The membrane oxygenator solved this problem. Doctor Arnold Lande invented such a system, achieving clinical success in 1967 [18].
Many of the earliest advances in cardiovascular surgery originated at the University of Minnesota Department of Surgery under the leadership of Dr Own Wangensteen. Doctor Wangensteen created an atmosphere for inquisitive thought and surgical research, which found acceptance among his trainees. Doctor C. Walton Lillehei multiplied this philosophy many times over with his trainees.
This presentation is only an overview and is not intended to identify the many contributors at the University of Minnesota Surgery Department during this early period in the history of open-heart surgery.
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