Past IX – Valves And Veins – Standing on Tall Shoulders – The History of Cardiac Surgery by Thomas N Muziani PA-C, CP
“Innovation distinguishes between a leader and a follower” – Steve Jobs
1960-1970- The advent of prosthetic heart valves and coronary artery bypass surgery
With the general acceptance and practical utility provided by extracorporeal circulation, innovation in cardiac surgery blossomed, analogous to a butterfly emerging from its chrysalis . Surgeons throughout the world formulated ingenious methods for reparative procedures of valvular heart disease. All of them knew only too well what they really needed was a non-clotting, bio-compatible prosthetic replacement valve. As a result, unfortunately, many different prosthetic valves were introduced prematurely during this period with only limited success.
There evolved a modicum of good short-term success with aortic valve replacement utilizing prosthetic trileaflet valves. The initial valves were made of uncoated and coated Teflon fabric or silicone rubber, attempting to mimic the natural valve’s characteristics. These usually failed, in sometimes dramatic fashion, after 1 to 2 years.
Then, in 1958, a diminutive fire-ball of a surgeon, Dr. Albert Starr from University of Oregon in Portland, was graced with a moment of serendipity. Lowell Edwards, a brilliant but struggling engineer, decided to pay Starr a visit. Lowell Edwards’ vision was to build a totally artificial heart. He had listened to Albert Starr speak before and realized this tenacious individual would be the perfect partner in creating just such a device. However Starr ,completely understanding the technical hurtles involved in bringing an artificial heart to fruition, cautioned against the Herculean project. He believed starting with an artificial heart valve would provide invaluable empirical knowledge in order to progress to a totally artificial heart. As Albert Starr once mentioned: “My greatest fear was anonymity. I wanted not only to accomplish something important, but also to have the world recognize me for my accomplishments.”
Within a few weeks, Lowell Edwards returned to Portland with a prototype valve. While in the animal Lab performing experiments on dogs, they discovered the initial valve designs facilitated blood clots to form in “dead space” (areas of the valve where there was not constant flow), causing most dogs to die within a few days. At this point, Starr and Edwards decided to abandon the idea of trying to mimic a biological heart valve, utilizing a set of flaps.
As circumstances would have it, while on vacation during a snorkeling excursion, Albert Starr had an epiphany. The top of his snorkel had the ever familiar conventional cage to encapsulate a ping pong ball configuration. Exhale and the ball moved up against the cage providing an opening for exhalation. Dive underwater and Newtonian physics took over, providing a tight seal against water aspiration without leakage. Why couldn’t this same principle be applied to an aortic valve?
As blood is ejected from the left ventricle, the ball is pushed up against the cage allowing free flow with minimal turbulence. Then, as the heart goes into its resting phase, the pressure drops allowing the ball to fall back forming a tight seal and occlude the opening.
One of my personal experiences with the Starr-Edwards valve I will never forget. The early versions of his valves came with the ball removed from the cage. This was to ensure complete sterilization of the valve. Our Mayo stands, which held all the surgical instruments at the foot of the operating table, also provided an area to keep the ball and cage assembly to create a completed aortic valve.
When the valve was needed, the scrub nurse would assemble the valve and hand it to the surgeon. One day, a rather “anxious” scrub nurse picked up the ball to the valve…and promptly lost grip of it. The ball fell on the floor and literally rolled out of the operating room and down the hallway. The circulating nurse, a rather cherubic woman, waddled down the hallway to retrieve the ball. Returning ashen faced and trembling to the OR…she didn’t know what to do. The surgeon very calmly held out a beaker and asked to have it filled with Betadine solution. He then told the circulator to drop the ball into the solution. With ball in Betadine, he calmly stirred the solution as if he were mixing a martini…removed the ball, replaced it back in its rightful cage and sewed the valve into the aorta. The patient did very well with an uneventful outcome…God is always kind and forgiving to surgeons.
Albert Starr and Lowell Edwards gained worldwide recognition for their seminal accomplishment. Lowell Edwards’ Laboratory in Irvine, California became an incubator for some of the greatest medical engineering minds to disrupt the status quo in the progress of medicine. Performing surgery in the Midwest or the West Coast also provided another benefit. As Pancho Barnes, the female pioneer aviator, who later in life opened the “Happy Bottom Riding Club” at Edwards Air Force Base in Mojave, California like to say: “We don’t tolerate Peckerwoods here”. There was no room for divisive or derisive language when it came to innovation. Failure, and sometimes death, was part of the learning curve. True innovation invites risk.
Dwight McGoon and his colleagues at Mayo Clinic graphically displayed the benefit of a steep learning curve with the dramatic improvement in results from replacing aortic valves on a daily basis. Mayo’s survival rate increased from 45% in 1960 to 85% by mid-1963. During 1963-1964, they achieved 100% survival in the first 100 patients in whom they implanted the Starr-Edwards valve.
A second major breakthrough of the 1960’s was the introduction in 1967 of coronary artery bypass grafting (CABG). One of the greatest surgeons I had the privilege to meet, Dr. Rene’ Geronimo Favaloro, while at Cleveland Clinic devised an operation to mitigate the damage from an all too common killer. Initially utilizing the saphenous vein, this procedure became the first truly effective surgical treatment for coronary artery disease. There had been numerous attempts to treat this disease over the years, all of them discarded due to minimal benefit. One medieval procedure that comes to mind was bilateral internal mammary artery (IMA) ligation. This horrible procedure originated by Fieschi, Zoja, Casa-Bianchi, Battezzati and others in Italy.
Dr. Arthur M. Vineberg, while at McGill University in Montreal in 1960 experimented with implanting the internal mammary artery (IMA) into the myocardium. Years earlier, in 1946, Vineberg had demonstrated that implanting the IMA into the myocardium of dogs, created an anastomoses with the coronary arteries. In November 1950, he successfully accomplished the procedure in humans. In 1958 he reported his results in 57 patients. Few people paid much attention to the procedure until Sones in 1962 provided graphic evidence utilizing angiography that, indeed, the Vineberg procedure would work. By 1968, Cleveland Clinic reported their results with 1,100 patients. However, the procedure was abandoned in favor of the saphenous vein implant.
By 1968, the revolution of coronary artery bypass grafting (CABG) that began with Favaloro at Cleveland Clinic spread like wildfire around the country. However, one individual stood out during this time. W. Dudley Johnson, out of Milwaukee stated that after hearing of the work at the Cleveland Clinic, he performed his first aortocoronary saphenous vein graft in January 1968. What made his procedure different was his technique of implanting his grafts end-to-side to the distal coronary artery, as opposed to the original end-to-end anastomosis as proposed at Cleveland. By 1968, most institutions adopted Dudley Johnson’s technique.
In the spring of 1969, Dudley Johnson gave a presentation on CABG that is generally considered the tipping point on treating patients with coronary artery disease. He suggested and demonstrated that CABG procedure could mitigate the existing disease by placing multiple grafts distal to all diseased coronaries. He advocated the use of cardiopulmonary bypass (CPB) with intermittent cross-clamp (15 minutes or less) in order to provide a dry, quiet field. These basic tenets revolutionized direct coronary artery surgery and provided the foundation for how the procedure is accomplished today.