When to Bypass the Bypass

By Claudia Wallis

Surgery is not always the answer for some heart patients

When it was introduced 15 years ago it was hailed as the biggest medical breakthrough of the decade. Since then, bypass surgery has become the most commonly performed heart operation in the U.S. (170,000 last year). It is a $3 billion industry, and thanks to the news media, which have faithfully chronicled operations on such notables as Henry Kissinger, Alexander Haig, Rock Hudson and Arthur Ashe, it has even achieved a certain social cachet. The bypass boom has led some doctors to fear that the operation is being overused. Now a study funded by the National Heart, Lung and Blood Institute has confirmed their doubts. The ambitious $24 million study, ten years in the making, found that about one in eight bypass patients would live just as long with drug treatment instead of surgery. "In the past we have tended to believe that the operation prolongs survival," says Detroit Cardiologist Thomas Killip, who helped direct the study. "Now we are more skeptical."

The purpose of bypass surgery is, quite literally, to find a way around fat-clogged arteries in order to keep blood flowing to the heart. This is done by taking a segment of a blood vessel, usually from the leg, and grafting it into the chest, where it is used to create a detour around the obstruction. For patients with blockages in the left main coronary artery, the heart's principal conduit, a bypass offers the best hope of prolonging life. The procedure is also the treatment of choice for those with crippling pain due to several clogged coronary arteries.

The institute's study does not challenge these applications of surgery. Instead, it focuses on whether or not bypass operations extend the life of patients with less severe heart disease. Some of those selected for the study were suffering from mild to moderate angina, the viselike chest pains that signal a decreased supply of blood to the heart; others had a history of one or more heart attacks but did not have recurrent chest pains. The 780 participants, all under age 65, were randomly treated either with bypass surgery or with drugs, such as nitroglycerin and diuretics, that ease pain and help relieve the strain on the heart. The result after six years: survival rates of about 90% in both groups. In addition, there was no difference between the groups in the frequency of heart attacks or in the ability to return to work.

Nonetheless, bypass surgery did have some advantages. Says University of Ala bama Cardiologist William Rogers, a principal investigator in the study: "There are striking differences when one looks at the quality of life." Indeed, the bypass patients suffered fewer chest pains, had greater endurance on exercise tests and required less medication.

Given these advantages, why not always use the bypass? The answer lies in the nature of coronary heart disease. Arteriosclerosis, the buildup of fatty deposits in the arteries, continues to worsen no matter what the treatment (although patients who quit smoking, reduce fat in their diets and exercise regularly may improve their prognoses). So relentless is the disease that in 10% of bypass patients the newly grafted blood vessel becomes completely blocked within six months of surgery. For the more fortunate majority, blood will continue to flow through the bypass graft for years; however, other arteries may become clogged.

The ultimate result is that five years after surgery about half of all bypass patients are no better off than they were before, and many are candidates for a second bypass. "That second operation may be difficult and risky because the tissues are so damaged and scarred," explains noted Harvard Cardiologist Eugene Braunwald, chief of medicine at both Beth Israel Hospital and Brigham and Women's Hospital in Boston. To avoid a second operation, Braunwald and a growing number of his colleagues believe that the first bypass should be put off as long as possible by controlling symptoms like angina with drugs. "What we're doing with drugs is buying time," he explains. The institute's study has shown that this can be done safely.

As heart research continues, the ability to buy time improves. In the mid-1970s, the availability of beta blockers, a class of drugs that help reduce the burden on the heart, made it possible for certain patients to postpone or avoid surgery altogether. Patients may also benefit from the introduction in the U.S. two years ago of substances called calcium channel blockers, which can reduce blood pressure, relieve some types of angina and help the heart work more efficiently.

There are other alternatives to the bypass. In the mid-1970s, Swiss Cardiologist Andreas Gruntzig developed an ingenious method of unclogging arteries using a small balloon. In angioplasty, now performed on about 12,000 patients a year, a narrow tube, or catheter, is threaded into the diseased artery until it reaches the clogged area. At that point a tiny balloon at the tip of the catheter is repeatedly inflated so that it flattens the deposits against the arterial wall and widens the channel.

Angioplasty works best on patients with only one blocked artery, but fails when the deposits are too hard to be compressed or cannot be reached with the catheter. For such cases another technique may soon be available. Taking his inspiration from the laser swords in Star Wars, Cardiologist Garrett Lee, of the Western Heart Institute in San Francisco, has developed a catheter similar to the one used in angioplasty but with the addition of a pinpoint laser.

Once the catheter is in place, the laser is carefully aimed and fired at the obstruction. The lumps of fat "melt like butter," says Lee. The debris is swept up through a vacuum tube. The so-called laserscope has been tested on animals, and Lee hopes to begin trials involving humans within six months.

Even with the development of such brave new techniques, bypass surgery is not about to become obsolete. For patients with advanced arteriosclerosis, it remains "a great operation," says Braunwald. Many who can be treated initially with drugs or angioplasty will ultimately need surgery as their disease progresses. The real challenge in treating heart disease is to find a way to prevent or reverse the inexorable process of arteriosclerosis. Only then can the bypass be bypassed once and for all. --By Claudia Wallis.

Reported by Dick Thompson/Los Angeles and Sue Wymelenberg/Boston

With reporting by Dick Thompson/Los Angeles, Sue Wymelenberg/Boston This file is automatically generated by a robot program, so viewer discretion is required.