Newer drug-eluting stents like this one were not included in the analysis. (AP Photo/Boston Scientific, File )

Heart bypass surgery may be less deadly than angioplasty for some seniors and those with diabetes, a review suggests.

For most people, there was not much difference between the two.

But among people aged 65 to 75 and those patients with diabetes, bypass surgery resulted in lower mortality over the average followup period of 5.9 years, researchers reported in this week's issue of the Lancet medical journal.

Before coming to that conclusion, Mark Hlatky of Stanford University in California and an international team of colleagues analyzed data from 10 different trials involving 7,812 patients.

In bypass surgery, a vein is grafted to direct blood around a clogged artery leading to the heart. Angioplasty is a less invasive procedure in which a tiny wire called a catheter is inserted into the artery to break up the clot while a tiny mesh tube props open the artery.

Overall, mortality was similar in both groups: 15 per cent of patients given coronary artery bypass graft surgery or CAGB died over the course of the study versus 16 per cent for angioplasty.

However, patients with diabetes were 30 per cent less likely to die if given bypass surgery than if given angioplasty.

Patients aged 65 to 75 years who had bypass surgery were 18 per cent less likely to die than those who had angioplasty.

Those younger than 55 years given bypass were 25 per cent more likely to die than those given the less invasive approach.

"Long-term mortality is similar after [both procedures] in most patient subgroups with multivessel coronary artery disease, so choice of treatment should depend on patient preferences for other outcomes," the researchers concluded.

"CABG might be a better option for patients with diabetes and patients aged 65 years or older because we found mortality to be lower in these subgroups."

They noted that the finding can't be applied to people over 75. Only five per cent of study participants were above that age.

None of the studies used newer, drug-eluting stents that released medicines to help keep blood vessels from closing around the mesh tube.

In a commentary accompanying the study, cardiac surgeon Dr. David Taggart, a professor of cardiovascular surgery at the University of Oxford, England, agreed with the conclusions.

But Taggart also pointed to the results of a trial of 1,800 patients that suggested angioplasty might be a good option for patients who are ineligible for bypass surgery or refuse it, at least in the short term.

The study was funded by the U.S. Agency for Healthcare Research and Quality.