By Lead writer: Chris Woolston
Updated February 29, 2016
Risks, though small, include cognitive problems, kidney failure, and death.

Risks, though small, include cognitive problems, kidney failure, and death.(MIKE KEMP/RUBBERBALL/VEER)

Bypass surgery—using clean blood vessels from elsewhere in the body to create a detour around clogged arteries near the heart—has been hailed as "one of the great success stories in medicine."

In 2005 about 280,000 Americans underwent this procedure to prevent heart attacks and relieve symptoms of heart disease. It's really the only treatment option for patients with severely clogged arteries and people with three or more blockages.

A safer bypass operation
Failed bypasses are uncommon, especially in the hands of an experienced surgeon. Still, it happens often enough that agencies keep track of such setbacks as a way to grade hospitals.

Some state health agencies—including those of California and New York—issue annual report cards that show which hospitals are performing the most bypass surgeries and getting the best results. In 2003 Consumer Reports compiled a list of links to hospital report cards from state agencies and various independent ratings services.

Volume doesn't necessarily matter
Don't assume that you're guaranteed good results just because your hospital performs lots of operations. A 2004 study found that sheer volume doesn't matter much when it comes to bypass surgery. The veritable bypass factories might be somewhat safer for patients over 65, but a big difference has not been shown.

Risks of bypass surgery
No matter which hospital you choose, bypass surgery always comes with risks. About 2% of patients die in the hospital or within one month of the operation. A study in 2001 found that about one in four patients developed cognitive problems that remained evident six months after the operation. Another recent study found that more than 7% of all bypass patients experience acute kidney failure.

Some patients are especially likely to suffer complications. Patients in their 70s and beyond are automatically more vulnerable. The operation is also riskier for people who have an additional serious illness, such as diabetes, emphysema, or kidney failure.