Bypassing Certain Risks

Coronary bypass grafting (CABG) surgery may result in damage to heart muscle, causing increased risk of death, even in patients who appear to do well after the procedure.

A new study from Mount Sinai School of Medicine finds that small elevations of the cardiac enzymes troponin and creatine phosphokkinase are released from heart-muscle cells when damaged during CABG surgery, correlates directly with mortality risk. These elevations were once thought unimportant.

Lead author Michael J. Domanski, MD, Professor, Cardiology, Mount Sinai School of Medicine, and Director of Heart Failure Research, said the greater the elevation in these enzymes, the greater the risk of death following surgery. Even low enzyme levels represent some death risk, he said, which continues for years.

The study, which followed 19,000 bypass patients, may prove useful in evaluating procedures performed on the heart, Domanski said.

Coronary bypass grafting (CABG) surgery is one of the most commonly performed major operations in the United States. The surgery is performed when arteries are significantly narrowed and blocked, depriving the heart muscle of oxygen-rich blood and putting patients at high risk of cardiovascular events such as heart attack. About 427,000 coronary artery bypass graft surgeries were performed in the United States in 2004, according to the American Heart Association.