MONDAY, April 4 (HealthDay News) -- At first glance, patients suffering from heart failure because of blocked coronary arteries appear to fare as well in terms of overall survival whether they have bypass surgery or rely on medication alone, a new study seems to suggest.

However, after a closer look, the researchers found that bypass surgery does reduce the risk of dying from heart disease, and also the risk of death from any cause or hospitalization from heart disease, by as much as 50 percent, compared with medication alone.

"The trial supports bypass surgery on top of best medical therapy vs. best medical therapy alone to reduce cardiovascular morbidity and mortality," lead researcher Dr. Eric J. Velazquez, director of both the cardiac diagnostic unit and echocardiography laboratories at Duke University Medical Center, said during a Monday press conference.

Given these findings, heart failure patients who have never been assessed for coronary-artery disease should be, he added.

The results of the study, called the Surgical Treatment of Ischemic Heart Failure (STICH) trial, were presented Monday at the American College of Cardiology's annual meeting, in New Orleans.

For this multi-center study, 1,212 heart failure patients were randomly assigned to medication alone or medical therapy plus bypass surgery.

Over an average of five years of follow-up, the researchers found that patients who underwent bypass surgery reduced their risk of dying 14 percent compared with patients on medications alone. However, that reduction was not statistically significant, the researchers noted.

Bypass surgery did, however, significantly reduce the risk of dying from cardiovascular disease by 19 percent and the risk of death from any cause and hospitalization for heart disease by 26 percent, Velazquez said.

Going over the data, the researchers found that 55 patients who were supposed to have bypass surgery did not actually get the procedure, and 100 patients assigned to medication alone ended up having a bypass operation.

When the researchers straightened out these discrepancies, they found bypass surgery actually reduced the risk of dying from any cause by 30 percent to 50 percent compared with medication alone.

This finding comes with some caveats: there were more risks from bypass surgery than from medication alone. And, the survival benefit of bypass surgery only kicked in two years after the procedure, the researchers noted.

Two-thirds of the 6 million people in the United States with heart failure have clogged coronary arteries, the researchers said. Given the improvements in medical therapy, whether the risks of bypass surgery are worth it has not been clear, the researchers added.

Bypass surgery involves taking healthy arteries and veins from other parts of the body and using them to re-route blood around the blockages, to restore blood flow and normal heart function. It has been unclear whether the risks of bypass surgery were worth taking, given recent lifesaving advances in medical therapy.

Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, said that "the benefits and risks of coronary-artery bypass surgery in patients with chronic symptomatic heart failure have been uncertain and the results of the STICH trial have been eagerly awaited."

"These important new findings suggest that surgical revascularization should be considered for patients with heart failure and coronary-artery disease," he said.

In addition to these findings, the STICH researchers used data from the trial to look at whether imaging could identify patients most likely to benefit from bypass surgery. Scans were given to 601 of the patients in the trial.

After almost five years of follow-up, the researchers found that scans did not provide any clue to how effective bypass surgery would be for each patient.

However, these scans, which can identify viable heart tissue, were able to predict long-term survival. In fact, patients with living heart tissue were 40 percent more likely to survive, compared with patients with irreversible heart damage, the researchers found.

More information

For more on heart failure, visit the American Heart Association.