Episode17: First bypass surgery
Once a coronary angiography allows us to see the blockages of the coronary arteries, what is next?
How can we overcome the blockages that limit the oxygen supply to this relentless muscle that continuously contracts?
Dr. Charles Bailey, in Philadelphia, had his idea on this. He had a method of removing atheromatous plaques that had formed in the large arteries of the legs. He tried to use the same process in the coronary arteries.
However, as they are much smaller caliber and do not forgive mistakes, the results were catastrophic. The removal of the plaques in these small vessels caused blood clots to completely clog the coronary artery and thus cause a heart attack.
Dr. Claude Beck, in Cleveland, believed he could get around the blockages in the coronary arteries by pushing more oxygenated blood into the veins of the heart. He named this procedure: retroperfusion. It consists in connecting the aorta to the big vein of the heart, the venous sinus.
He abandoned this technique following the death of his only patient the day after the surgery.
A Canadian cardiac surgeon, Dr. Arthur Vineberg, had another idea to improve oxygen delivery to the heart: "Why not bring oxygenated blood directly into the heart muscle?” To do this, he used the artery found on each side of the thorax called the internal mammary artery. The technique, which will eventually be named after its inventor, involves deflecting one of these arteries and implanting it inside the heart muscle.
The Vineberg procedure had some beneficial effect as a reduction of angina episodes was noted. However, some cardiologists remained skeptical. They believed the patients felt better because of either the placebo effect (the effect created by the simple fact of having had a Vineberg surgery) or because of a loss of pain associated with angina following the severing of small nerves during surgery.
Dr. Mason Sones thought he could put an end to these suppositions and demonstrated, by means of an angiography of this artery implanted in the muscle, that this one works well in more than 92% of the patients. In addition, the circulation brought by the internal mammary artery forms a small network of connections with branches of the coronary arteries in 54% of these individuals.
However, was it so obvious? No! So, the conclusion may lie somewhere between the 3 effects raised.
In 1967, nine years after the arrival of coronarographies and the demonstration of blockages in the coronary arteries, the world of cardiology was again shaken by a surgical procedure intended to overcome coronary stenosis.
It was then that Dr. René Favaloro, an Argentinian surgeon, announced that he had restored the circulation of a blocked coronary artery. This was more than just revolutionary, as the symptoms of angina had disappeared in this patient.
René Favaloro's career was not easy. During the Second World War, he was a student at Medical school. His political ideologies under the Perón regime had cost him several years of practice until he left for Clevelant. Under the supervision of Dr. Donald Effler, head of thoracic surgery at the Cleveland Clinic, he went from being a surgeon without any specialization to a candidate with great potential. He refused a prestigious position within this team to return home, in Argentina, to develop heart surgery.
Surgery for the blockages of the coronary arteries known as coronary heart disease was his specialty. He begins by creating openings in the arteries to enlarge them with patches. He first used patches of pericardium, the heart’s envelope, and then pieces of veins. These two options lead to the same result: the formation of blood clots blocking the artery. The use of patches had to be abandoned.
Then, the idea of making bridges over the obstruction came to mind. A vein in the leg was going to be this bridge; the first end attached to the aorta and the second end attached to the sick artery, above the blockage. Bridging surgery was born.
The mortality rate related to his bypass surgery was about 4%, so extremely low for the time.
Dr. George Green retook this concept, but used an artery instead of a vein. He used Dr. Vineberg's procedure that diverted the left internal mammary artery and connected it to the affected artery behind the obstruction.
Already, we compare one technique to the other and, after a 5-year follow-up, we notice that 1 out of 5 bridges occluded after this time lapse while 95% of the mammary arteries are still functional.
Today, the risks related to bypass surgery are well documented. The risk of a stroke is 3%, the mortality rate is 2% and the risk of a heart attack is 1%.
It relieves angina in 95% of people and 90% of patients who have been operated on have a survival rate of 5 years.