Coronary artery bypass surgery

The invention: The most widely used procedure of its type, coronary
bypass surgery uses veins from legs to improve circulation
to the heart.
The people behind the invention:
Rene Favaloro (1923-2000), a heart surgeon
Donald B. Effler (1915- ), a member of the surgical team
that performed the first coronary artery bypass operation
F. Mason Sones (1918- ), a physician who developed an
improved technique of X-raying the heart’s arteries
Fighting Heart Disease
In the mid-1960’s, the leading cause of death in the United States
was coronary artery disease, claiming nearly 250 deaths per 100,000
people. Because this number was so alarming, much research was
being conducted on the heart. Most of the public’s attention was focused
on heart transplants performed separately by the famous surgeons
Christiaan Barnard and Michael DeBakey. Yet other, less dramatic
procedures were being developed and studied.
Amajor problem with coronary artery disease, besides the threat
of death, is chest pain, or angina. Individuals whose arteries are
clogged with fat and cholesterol are frequently unable to deliver
enough oxygen to their heart muscles. This may result in angina,
which causes enough pain to limit their physical activities. Some of
the heart research in the mid-1960’s was an attempt to find a surgical
procedure that would eliminate angina in heart patients. The
various surgical procedures had varying success rates.
In the late 1950’s and early 1960’s, a team of physicians in Cleveland
was studying surgical procedures that would eliminate angina.
The team was composed of Rene Favaloro, Donald B. Effler, F.
Mason Sones, and Laurence Groves. They were working on the concept,
proposed by Dr. Arthur M. Vineberg from McGill University
in Montreal, of implanting a healthy artery from the chest into the
heart. This bypass procedure would provide the heart with another source of blood, resulting
in enough oxygen to overcome
the angina. Yet Vineberg’s
surgery was often
ineffective because it was
hard to determine exactly
where to implant the new
artery.
New Techniques
In order to make Vineberg’s
proposed operation
successful, better diagnostic
tools were needed. This was
accomplished by the work
of Sones. He developed a diagnostic procedure, called “arteriography,”
whereby a catheter was inserted into an artery in the arm,
which he ran all the way into the heart. He then injected a dye into the
coronary arteries and photographed them with a high-speed motionpicture
camera. This provided an image of the heart, which made it
easy to determine where the blockages were in the coronary arteries.
Using this tool, the team tried several new techniques. First, the
surgeons tried to ream out the deposits found in the narrow portion
of the artery. They found, however, that this actually reduced
blood flow. Second, they tried slitting the length of the blocked
area of the artery and suturing a strip of tissue that would increase
the diameter of the opening. This was also ineffective because it often
resulted in turbulent blood flow. Finally, the team attempted to
reroute the flow of blood around the blockage by suturing in other
tissue, such as a portion of a vein from the upper leg. This bypass
procedure removed that part of the artery that was clogged and replaced
it with a clear vessel, thereby restoring blood flow through
the artery. This new method was introduced by Favaloro in 1967.
In order for Favaloro and other heart surgeons to perform coronary
artery surgery successfully, several other medical techniques
had to be developed. These included extracorporeal circulation and
microsurgical techniques.Extracorporeal circulation is the process of diverting the patient’s
blood flow from the heart and into a heart-lung machine.
This procedure was developed in 1953 by U.S. surgeon John H.
Gibbon, Jr. Since the blood does not flow through the heart, the
heart can be temporarily stopped so that the surgeons can isolate
the artery and perform the surgery on motionless tissue.
Microsurgery is necessary because some of the coronary arteries
are less than 1.5 millimeters in diameter. Since these arteries
had to be sutured, optical magnification and very delicate and sophisticated
surgical tools were required. After performing this surgery
on numerous patients, follow-up studieswere able to determine
the surgery’s effectiveness. Only then was the value of coronary artery
bypass surgery recognized as an effective procedure for reducing angina
in heart patients.
Consequences
According to the American Heart Association, approximately
332,000 bypass surgeries were performed in the United States in
1987, an increase of 48,000 from 1986. These figures show that the
work by Favaloro and others has had a major impact on the
health of United States citizens. The future outlook is also positive.
It has been estimated that five million people had coronary
artery disease in 1987. Of this group, an estimated 1.5 million had
heart attacks and 500,000 died. Of those living, many experienced
angina. Research has developed new surgical procedures and
new drugs to help fight coronary artery disease. Yet coronary artery
bypass surgery is still a major form of treatment.