Coronary Artery Disease and Treatment Options

TN THE EARLY PART OF THIS CEN-jQj I tury, Nobel Prize-winning surgeon Dr. _l_Alexis Carrel attempted what may have been the first bypass of a coronary artery. Without a heart-lung machine, however, his animal trial met with limited success.

Little else happened in the dawning field until 1930, when a French surgeon named Dr. Rene Leriche developed a method to attach skeletal muscle to the heart in animals, in hopes that new blood vessels would form. This line of research was pursued by Dr. Claude Beck in Cleveland, who confirmed that new blood vessels did indeed grow into the heart muscle from tissues wrapped around the heart. In his first attempt to treat coronary disease in a human patient, Beck roughened the outer surface of the heart with a burr and sutured a graft of skeletal muscle from the chest to the heart. New vessels formed, and the patient recovered. The patient's angina also disappeared. Beck went on to perform variations of this operation in sixteen patients.

In 1946, a Canadian surgeon named Dr. Arthur Vineberg performed an operation on a patient with a coronary artery blockage. He tunneled the internal mammary artery from the chest wall into the patient's heart muscle but did not directly connect it to one of the heart's arteries. He was hoping new blood vessels would sprout from the mammary artery and connect with the blocked blood vessels in the heart. Over the next several months, new vessels formed, giving the heart a new blood supply. Although the Vineberg operation enjoyed some popularity in the following decades, the chief drawback, as with Beck's operation, was that it took months for new blood vessels to form — if they formed at all.

At about the same time, surgeons began to perform a procedure called endarterectomy, which basically meant cleaning out atherosclerotic material from the coronary arteries. Endarterectomies were often quite extensive and sometimes involved almost the entire length of the artery. Although the results were good with larger arteries in the body, the early results with coronary arteries were not good. Some patients survived for years, but in many cases the coronary arteries clotted off soon after the surgery. The high mortality rate was considered unacceptable, and doctors continued searching for new and better ways to treat coronary artery disease. Today, coronary endarterec-

Endarterectomy:

A surgical procedure in which atherosclerotic material in an artery is removed and the artery is either sewn back together or a patch is placed over the surgical incision.

Fig. 8.2: Coronary Arteriography:

The process of obtaining a coronary arteriogram or an x-ray picture of the arteries of the heart. This is done by injecting a ra-diopaque dye that shows up on x-ray film.

Coronary Artery Bypass Grafting (CABG):

A surgical technique in which one's own veins or other arteries are used to route blood around a blocked area in a coronary artery.

Dr. Rene Favaloro, below, performed early saphenous vein bypass graft operations to treat coronary artery disease.

tomy is still used by some surgeons, but it's done in conjunction with coronary artery bypass grafting.

Q The Coronary Bypass Evolves

Even while endarterectomy was being tested on patients, teams of surgeons were approaching the first successful modern coronary artery bypass graft surgery. The story of the bypass begins as early as 1952, when the renowned Soviet surgeon Dr. Vladimir Demikhov was joining the internal mammary artery, which is under the breast bone, to the left coronary artery in dogs. Other surgeons soon began to study coronary artery bypass grafting in experimental animals.

In 1962, the technique received a major boost when Dr. Mason Sones at the Cleveland Clinic reported on a technique called selective coronary arteriography (Fig. 8.2). In this procedure, a catheter is threaded up through an artery in either the groin or the arm and used to inject ra-diopaque contrast material directly into the coronary arteries. This technique supplied the road maps for the surgical treatment of coronary artery disease. For the first time, chest surgeons were able to see the exact location of blockages and plan their surgery.

Meanwhile, the idea of using a piece of the patient's own vein for a bypass graft of a blocked artery was gaining acceptance. During the Korean War, surgeons were more commonly using the saphe-nous vein from the leg, which is a superficial vein that runs from the groin to the ankle area and is totally expendable (Fig. 8.3), to bypass arteries in the leg that were injured and blocked. As the concept gained widespread acceptance, some doctors began to envision using vein grafts to bypass blocked coronary arteries, and sporadic attempts were made throughout the early part of the decade.

In 1967, at the height of the Cold War, a Soviet surgeon, Dr. V.I. Kolessov from tomy is still used by some surgeons, but it's done in conjunction with coronary artery bypass grafting.

Leningrad, reported in an American surgical journal his experience with internal mammary artery-coronary artery anastomosis for the treatment of coronary artery blockages in six patients. Operations were performed through an incision in the left chest without the heart-lung machine. The following year, Dr. Charles Bailey and Dr. Teruo Hirose from New York published a report on surgery in which the internal mammary artery was used to bypass blockages in the right coronary artery in two patients. In 1968, Dr. George Green, also from New York, used the heart-lung machine to bypass a patient's left anterior descending coronary with the internal mammary artery.

That same year, Dr. Rene Favaloro, a surgeon from the Cleveland Clinic, used the saphenous vein technique to bypass blockages of the coronary arteries in fifteen patients. This group had also had the Vineberg operation, in which a mammary artery was tunneled into the heart to increase blood flow. The saphe-nous vein bypass graft was inserted between the aorta and the right coronary artery. The bypass was performed by dividing the coronary artery and sewing

the vein graft end-to-end beyond the blockage in the right coronary artery. In an addendum to the published paper, fifty-five more cases were added — fifty-two for blockages of the right coronary artery and three others for diseases in the left circumflex coronary artery.

Most surgeons, however, remained extremely skeptical of the coronary bypass operation, especially that in which the saphenous vein was used. This was because, although the saphenous vein bypass grafts worked relatively well for bypassing arterial blockages in the legs, it was not uncommon for these bypasses to clot off and require urgent surgery to save the leg. It was feared that if saphe-nous veins were used to bypass coronary arteries, particularly those supplying the left ventricle, a blood clot would result in instant death.

By May 1969, all of this was about to change. At the annual meeting of the American Surgical Association, a young surgeon who had recently completed his heart surgery training, Dr. W. Dudley Johnson from Marquette University in Milwaukee, reported on a series of 301 patients who had undergone various operations for coronary disease since February 1967. Many of the techniques he described are still used today. In that report, which was published later that year in a major surgical journal, Johnson stated:

"The vein graft technique was expanded and used in all major branches (of the coronary arteries). Vein grafts to the left-sided arteries run from the aorta over the pulmonary artery and down to the appropriate coronary (blood) vessel. Right-sided grafts run along the atrial-ventricular groove and also attach directly to the aorta. There is almost no limit to the potential (coronary) arteries to be bypassed. Veins can be sutured into the distal (far end) anterior

The saphenous vein runs from the groin to the ankle.

The saphenous vein runs from the groin to the ankle.

The saphenous vein bypass graft, a common bypass technique, using saphenous veins from the legs, is used to bypass blocked portions of the coronary arteries. A double bypass is shown.

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