Researchers say heart attack patients in the U.S. are more likely to be treated aggressively with surgical procedures to repair clogged or damaged arteries, such as angioplasty or bypass surgery, than more conservative treatment with clot-busting drugs alone.
The study shows that the conservative pattern of care in Canada might be having a negative effect on mortality rates from heart disease in that country.
"The five-year death rate was 19.6% among U.S. patients and 21.4 percent among Canadian patients," says researcher Padma Kaul, PhD, assistant professor at the University of Alberta, Edmonton, Canada, in a news release. "After adjusting for differences in patient characteristics, we found that Canadian patients' risk for dying was 17% higher compared to U.S. patients."
"But once we adjusted for whether patients had revascularization procedures or not, that difference disappeared. So, the higher death rate in Canada was explained by the difference in revascularization rates."
The results of the study appear in the Sept. 21 issue of Circulation: Journal of the American Heart Association.
Americans Get More Aggressive Heart Attack Care
For the study, researchers reviewed death rates within five years after heart attack for 23,105 U.S. and 2,898 Canadian heart attack patients who were part of a clinical trial conducted in the early 1990s.
The findings confirmed that Canadians' death rates from heart attacks were higher than the Americans, but the type of care they received seemed to account for that difference, with those receiving aggressive care in Canada faring just as well as Americans heart attack patients.
The study showed that heart attack patients in the U.S. were nearly three times as likely to have heart surgery to repair damage as those in Canada. Specifically:
- Almost a third (30%) of American heart attack patients received an angioplasty, versus 11% of Canadians.
- More than 13% of heart attack patients in the U.S. had bypass surgery, compared with 4% of those in Canada.
Kaul says that the United States and Canada differ substantially in how they organize, deliver, and pay for health care. In Canada's regionalized system, the availability of hospital centers, which specialize in these surgeries, is restricted to selected care centers, and these services are more widely available in the U.S.
"It is therefore not surprising that Canada uses substantially fewer invasive procedures compared with the United States," says Kaul.
Kaul says more research is needed to confirm these results, and these findings should be of global interest because angioplasty and heart bypass rates in many European countries are lower than those in Canada.