DALLAS (American Heart Association) -- Surgery or angioplasty to improve blood flow in patients with moderate to severe levels of blood flow restriction to the heart reduces the risk of cardiac death more than medication alone, researchers report in the rapid access issue of Circulation: Journal of the American Heart Association.

In an observational study, researchers noted fewer deaths among patients who underwent revascularization procedures with coronary artery bypass surgery or angioplasty (2 percent) compared to those given drug therapy (6.7 percent). However, patients with little or no blood flow restriction fared better on medical therapy.

Narrowed heart arteries can reduce blood flow and oxygen to the heart during stress (ischemia). Patients with this form of stable coronary artery disease have the choice of revascularization or medical therapy to prevent a heart attack.

Researchers at Cedars-Sinai Medical Center in Los Angeles compared the survival benefits of both medical and revascularization approaches to care. They reviewed data on 10,627 patients (ages 55 to 76) who underwent a form of stress testing known as stress myocardial perfusion single photon emission computed tomography (SPECT). This is designed to determine the body's ability to deliver blood and oxygen to the heart at rest and under stress. None of the patients had a history of heart attack.

During followup, there were 146 cardiac-related deaths (1.4 percent) for all patients.

Statistical analysis showed that when patients had more than 10 percent of their heart affected by ischemia they had a lower mortality rate with revascularization than with medical therapy.

"The greater the degree of ischemia, the greater the risk of cardiac death and also the greater the benefit of revascularization. On the other hand, patients with no ischemia had lower mortality rates with medical therapy than with revascularization," says lead author Rory Hachamovitch, M.D.

Hachamovitch also notes that "by using a sophisticated statistical analysis which 'levels the playing field' between patients undergoing revascularization and those undergoing medical therapy alone, we are able to make assessments from this kind of observational study that approximate those that would be seen in a randomized clinical trial, without having the drawback of narrow patient sample that frequently characterize randomized trials."

Overall death rates as well as lives saved per 100 patients treated with revascularization were greater in women - particularly diabetic women and in the elderly. More than 17 percent of diabetic women with large parts of their heart affected by ischemia were predicted to die if they took drugs compared to 4.4 percent if they had revascularization.

"We have previously shown how SPECT can be used to determine the risk of death in cardiac patients. The present study is the first time we have been able to show that SPECT is potentially of even greater use in predicting which patients will benefit from a particular form of therapy. The results of this study may allow physicians to more accurately weigh the benefit of revascularization compared to medications alone in the management of their patients with the common condition of chronic coronary artery disease, potentially resulting in improved long term outcomes in their patients," says senior author Daniel S. Berman, M.D., Director of Cardiac Imaging at Cedars-Sinai Medical Center.