Technology & Science

One-third of bypass surgery deaths could be prevented, data indicates

Less than two per cent of patients who undergo cardiac bypass die after their surgery, but an Ontario study suggests about one-third of these fatalities could have been prevented.

Less than two per cent of patients who undergo cardiac bypass die in hospital after their surgery, but an Ontario study suggests about one-third of these fatalities could have been prevented.

In a study of records from nine Ontario hospitals that routinely perform bypass surgery, researchers found that 111 of 347 randomly selected cases that resulted in death could have potentially been avoided.

The study, published in Tuesday's edition of the American Heart Association journal Circulation, was undertaken by the Institute for Clinical Evaluative Sciences (ICES) to determine quality of patient care and how it might be improved.

"Obviously, we're all very unhappy when someone dies," said co-author Dr. Christopher Feindel, a heart surgeon at Toronto General Hospital.

"I think the important thing is when someone dies for whatever reason, it's exceedingly important to look at that specific case, to learn from it, to figure out if it was an inevitable event or if something could have been done differently in retrospect to maybe have changed the outcome."

"It obviously won't help that particular individual, but ... there's a very good chance it will help someone in the future because of whatever was learned from that particular unfortunate case," said Feindel, noting that the findings would likely mirror those in the rest of Canada.

To conduct the study, highly seasoned cardiac surgeons reviewed patient charts for all bypass deaths between 1998 and 2003, randomly selecting 347. Two reviewers looked at each death and a third reviewer was used when the others disagreed.

The first two reviewers judged 52 deaths to have been preventable. One of the two considered another 114 deaths preventable — of which the third reviewer determined 59 could have been avoided.

Feindel said most of the preventable deaths were related to problems that occurred either during surgery or while patients were recovering in intensive care, and many were attributed to lapses in established hospital procedures.

"We did what we often do in mortality and morbidity rounds," he said, referring to in-house meetings of physicians and other health professionals in which patient deaths and unexpected complications are discussed.

"With hindsight and knowing that the outcome was bad, the reviewers looked back at each particular case and assumed that had everything gone perfectly in retrospect, had things been different, might this patient have survived?"

"And if there were … issues that were found, the reviewer probably would have labelled that death preventable."

Various factors involved

Feindel said those issues could have been related to unexpected bleed-outs during surgery, a patient's heart function being poorer than initially thought, a problem with the veins used as cardiac artery bypasses or even staffing problems in post-operative intensive care unit.

"These are really not errors in the sense that there's negligence or anything like that involved," he said. "I think this is looking back in a fairly complex operation, lots of things going on, knowing down the road that something went wrong and looking back and saying, 'Gee, if we'd had to do this all over again, is there something that we might have done differently?"'

More than 40,000 bypass operations were done during the study period, he said.

"To put it in perspective, for each surgeon that was operating in Ontario at that time, around 40, 45, we figured out that's probably one preventable death per surgeon every two years."

Periodic report cards that grade individual hospitals' quality of care performance have determined that death rates across Ontario centres range from 1.3 per cent to 3.1 per cent.

Lead author Dr. Veena Guru, an ICES research fellow, said the findings underscore the need to find better ways to evaluate hospital performance than the report card model.

"It's appealing to see public report cards in health care as a cure-all," she said. "This study shows that we can't just publish post-operative death rates if we want to continue to improve the quality of care."

Perhaps surprisingly, the highest risk of death was among bypass patients considered at low risk for dying and among females.

Studies over the last 10 to 15 years have suggested that overall, women having bypass surgery do not have similar outcomes to men. Questions have been raised as to whether this is the result of some kind of gender bias, that physicians may not see women as being in as much danger for heart attack as men because cardiovascular disease tends to strike females later in life.

Feindel said the occurrence of preventable deaths among females may relate to women typically having "very small coronary arteries," as do males of smaller stature, which makes bypass surgery more difficult.

"So there has been quite a bit of controversy. Is it body size or actually a gender issue?"

In an accompanying editorial, Dr. Harlan Krumholz, a professor of medicine, epidemiology and public health at the Yale University School of Medicine, said the study suggests a large percentage of bypass deaths are preventable with optimal care.

Noting that the findings offer important lessons with implications beyond cardiac surgery, Krumholz wrote that medicine must develop a culture in which such examinations are part of every hospital and should be expected by every clinician and patient.

"How else will we attain the goal of creating the high-reliability, high-performance institutions that we prefer for our practices and that our patients deserve?"