Bypass heart surgery is becoming safer, according to doctors who say the risk of stroke in the operating room has been dropping since the late 1980s at their medical center.

Over three decades, 1.6 percent of the patients who underwent coronary artery bypass graft surgery, or CABG (pronounced ‘cabbage’), at the Cleveland Clinic had a stroke during or shortly after the procedure.

The stroke rate declined slowly from a peak of 2.6 percent in 1988, although patients coming to have the operation were arriving in poorer condition.

“The patients are at significantly higher risk than they used to be 5 or 10 years ago,” said Dr. Farzan Filsoufi, a heart surgeon at The Mount Sinai Medical Center in New York City, who was not involved in the new work.

“Despite the increase in risk factors, the incidence of strokes has decreased in most studies.”

Nearly 800,000 Americans suffer a stroke every year, with more than a sixth of them dying of it and many more left disabled.

The risk is much higher during heart surgery, partly because there are many common risk factors for stroke and heart disease - such as high blood pressure and diabetes - and partly because of the surgical procedure itself.

For instance, some of the fatty buildup clogging the heart’s arteries can break off, travel to the brain and block blood flow there. Or blood pressure can drop very low during the surgery, preventing the brain from getting enough oxygen.

Some doctors have used the stroke threat to push for a less invasive procedure called percutaneous coronary intervention, or PCI, said Filsoufi.

PCI is done through an artery in the leg, or less commonly, the arm. A small mesh tube called a stent is threaded into the clogged artery in the heart to prop it open - a procedure experts say is done on more than a million Americans every year, whereas surgery is performed on a few hundred thousand.

With the lower stroke rates seen at some hospitals today, Filsoufi said stroke concern was no longer a good argument to choose PCI over surgery.

“CABG is a very safe operation today,” he told Reuters Health.

For the current study, published in the Journal of the American Medical Association, the Cleveland Clinic researchers looked at data from more than 45,000 patients who had CABG surgery between 1982 and 2009.

Of the 705 people who suffered a stroke, 40 percent did so during the operation and nearly 60 percent had one later, peaking at about 2 days. Ten years later, 68 percent of those who didn’t have a stroke were still alive, compared to only 37 percent of those who did.

Certain types of surgery were tied to a lower stroke risk. During CABG, a small part of a blood vessel from a different part of the body is grafted onto the heart so the blood flow can bypass the clogged artery. Sometimes this is done while the heart is still beating, and sometimes the heart is stopped and a pump is used to keep the blood flowing.

Patients whose hearts were left beating had the lowest risk of stroke - as low as 0.14 percent during the surgery - while those on pumps with stopped hearts were at higher risk.

The stroke rate climbed with age and the degree of heart disease.

“If you tailor the operation to the patient, you can bring the risk down to that seen in PCI,” said Dr. Joseph Sabik, who worked on the study and heads the heart surgery department at the Cleveland Clinic.

He said the reason for the decline in stroke rates over time was probably related to this approach.

“It has to do with picking the right procedure for the patient,” he said, “and then there are also the things you do before and after the surgery, such as giving better medicines.”

Sabik added that while PCI might be right for some patients, surgery is more effective at preventing later deaths from heart attacks and the need for new interventions.

For patients, the take-home message of the study is not that one intervention is necessarily better than another, he said, but to make sure they get the one that suits their needs best.

“If you need to have heart surgery, ask your surgeon how he’s going to do it, and why he is going to do it that way,” Sabik urged. “If he says, ‘That’s just the way I do it,’ that’s not a good answer.”

SOURCE:  JAMA/Journal of the American Medical Association, January 25, 2011.