Canadian researchers have settled a long-debated question: how long should patients with mild heart attacks wait before undergoing bypass surgery or angioplasty?
The results suggest that rushing patients into surgery, as many hospitals in the U.S. choose to do, doesn't significantly improve survival than waiting a few days.
In a study published in this week's New England Journal of Medicine, researchers from McMaster University in Hamilton, Ont., found similar rates of death, recurrent heart attack or stroke in patients who had surgery very early after they arrived in hospital versus if they had their procedure a day and a half or more later.
However, one out of three patients who were at high risk of having another stroke or heart attack did appear to benefit if they underwent surgery quickly.
The study's lead investigator, Dr. Shamir R. Mehta, an associate professor in the Michael G. DeGroote School of Medicine and director of interventional cardiology at Hamilton Health Sciences, calls the study's findings "good news for patients and physicians."
"While we have known for a long time that patients with a full blown heart attack benefit from receiving angioplasty as early as possible, we did not know the optimal timing of angioplasty in patients with threatened or smaller heart attacks," said Mehta.
"These second group of patients represent a large burden to the health care system and outnumber patients with full blown heart attacks by about 2:1. They often respond well to initial therapy with aspirin and other anti-clotting medications."
Angioplasty is a technique for reopening narrowed or blocked arteries in the heart using balloon stents. It is less invasive surgery than a heart bypass, which reroutes blood around clogged heart arteries.
The study randomly assigned 3,031 patients from 17 countries to receiving angiography within 24 hours of hospital admission (median time: 14 hours) or within 50 hours of admission (median time: 50 hours).
Six months after the surgeries, 9.6 per cent of patients who received early intervention went on to have another heart attack, stroke or to die. That compared to 11.3 per cent in the delayed intervention group.
"Early intervention did not differ greatly from delayed intervention in preventing the primary outcome, but it did reduce the rate of the composite secondary outcome of death, myocardial infarction, or refractory ischemia and was superior to delayed intervention in high-risk patients," the authors conclude.
The study's findings are good news for those Canadians who live far from hospitals that have advanced cardiac facilities, and often can't get angioplasty treatment quickly.
"In large parts of Canada that do not have timely access to these procedures, patients coming to hospital with small or threatened heart attacks can be treated with aspirin and other anti-clotting medications and be transferred to a catheterization laboratory a few days later, without undue harm," Mehta said.
"Higher-risk patients and those with full blown heart attacks should still be transferred earlier."
Mehta said these findings imply that hospital resources should be directed at performing angioplasty in patients with large, full-blown heart attacks as soon as possible.
"For patients with smaller or threatened heart attacks, only those who are at high risk... need to have angioplasty early. The majority can be safety treated a few days later."
