Bypass surgery more likely than angioplasty to relieve coronary artery disease pain

Oct 17 2007

Patients with mid-range coronary artery disease are more likely to get relief from painful angina and less likely to have repeat procedures if they get bypass surgery rather than balloon angioplasty with or without a stent, according to a new report by the Agency for Healthcare Research and Quality, part of the U.S. Department of Health and Human Services.

The analysis drew on 23 randomized controlled trials that compared treatments for patients with mid-range coronary disease treatable with either angioplasty or bypass surgery. As defined by the report, mid-range disease may occur in three ways: a single blockage of the vital left anterior descending artery, blockage of two arteries or some forms of less-severe blockage of three arteries.

The report also found that for mid-range coronary artery disease, bypass surgery and angioplasty patients had about the same survival rates and similar numbers of heart attacks, but that bypass surgery presents a slightly higher risk of stroke within 30 days of the procedure. A summary of the report is posted today in the online version of Annals of Internal Medicine .

“Choosing a treatment for coronary disease has long been a difficult challenge,” said AHRQ Director Carolyn M. Clancy, M.D. “But this new evidence-based report provides a vital reference to help doctors, patients, and their families make the best possible decision.”

Coronary artery disease, a common type of heart disease, affects about 15 million Americans and is the leading cause of death for men and women. It occurs when cholesterol and fibrous tissue clog arteries that supply blood to the heart. When arteries narrow, diminished blood flow may starve the heart muscle of oxygen and nutrients. Intense and potentially disabling chest pain, called angina, occurs when the blood supply to the heart muscle is insufficient during exercise or stress. If blood flow through a coronary artery is stopped, a heart attack - the death of a small part of the heart muscle - may result.

In cases where drug therapy does not adequately relieve symptoms, patients have two choices: In bypass surgery, surgeons use a blood vessel harvested from the chest, leg or arm to reroute blood flow around narrowed heart arteries. In angioplasty, a catheter is used to inflate a balloon inside the plaque-narrowed artery. A mesh tube called a stent is usually inserted to keep the artery open.

For many patients, the best treatment choice is clear. For those with most extensive disease that limits blood flow in several arteries, bypass surgery is typically used. For those with the least extensive disease, less-invasive angioplasty is the standard choice. The new federal study, funded by AHRQ's Effective Health Care program and completed by the Agency's Stanford-UCSF Evidence-based Practice Center, compared the outcomes and risks of the procedures in patients with mid-range coronary disease, where either procedure might be chosen.

Among the conclusions:

• The odds of surviving either procedure are high: about 98.5 percent of patients survive beyond 30 days for both bypass surgery and angioplasty (with or without a stent).
• Long-term survival rates are likely to be comparable. About 96 percent of patients live at least 1 year following both procedures. About 90 percent live 5 years or more. Further research is needed to clarify survival benefits for patients at either extreme of the mid-range spectrum.
• About 84 percent of patients who undergo bypass surgery are free of angina pain 1 year after the procedure, compared with about 75 percent of patients who receive angioplasty. The difference narrows but remains substantial 5 years after treatment.
• About 4 percent of patients who have bypass surgery undergo a repeat procedure within 1 year, and 10 percent within 5 years. The need is significantly higher among patients who receive angioplasty – 24 percent more at 1 year and 33 percent more at 5 years.
• About 0.6 percent more patients receiving bypass have a stroke during the first 30 days after the procedure than patients receiving angioplasty.
• Studies that measured patients' quality of life 6 months to 3 years after undergoing the procedures found significantly more improvement for bypass surgery patients than for balloon angioplasty patients. The difference, which equalizes after 3 years, was attributed to angina relief.

The new report, Comparative Effectiveness of Percutaneous Coronary Interventions and Coronary Artery Bypass Grafting for Coronary Artery Disease, is the latest analysis from AHRQ's Effective Health Care program. That program compares alternative treatments for significant health conditions and makes the findings public. It is intended to help patients, doctors, nurses, and others choose the most effective treatments. More about the program and other reports can be found at http://effectivehealthcare.ahrq.gov.