Newmarket, Ontario (June 24, 2009) – Transferring heart attack patients to specialized hospitals to undergo angioplasty within six hours after receiving clot-busting drugs reduces the risk of life-threatening complications, according to a Canadian-led study published today.
The findings, published in the New England Journal of Medicine, suggest that routine early transfer of patients after clot-busting drugs are administered results in significantly better outcomes than the current practice of transferring patients only when the clot-busting drugs fail.
The results of the study – the largest randomized trial of its kind – are dramatic, said Dr. Warren Cantor, medical director of the interventional and invasive program at Southlake Regional Health Centre in Newmarket, who spearheaded the study with Dr. Shaun Goodman, associate head of cardiology at St. Michael’s Hospital in Toronto. Called the Trial of Routine Angioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI), the study involved a large group of Canadian cardiologists, internists, emergency department physicians and paramedics. It was supported by the Canadian Institutes of Health Research and coordinated by the Canadian Heart Research Centre.
The study followed 1,059 heart attack patients who were treated with clot-busting drugs at community hospital emergency departments in Ontario, Manitoba and Quebec. It compared a strategy of transferring heart attack patients to hospitals with on-site angioplasty facilities to undergo angioplasty within six hours after administration of clot-busting drugs, as opposed to the traditionalapproach of transferring only those patients when clot-busting drug treatments are unsuccessful.
All patients in the study initially sought treatment at a hospital without angioplasty capability and were treated with tenecteplase, a newer clot-busting drug. Patients were then randomly assigned to one of two groups: urgent transfer for angioplasty within six hours, or standard care (no transfer for angioplasty within the first 24 hours unless the clot-busting medication failed to restore blood flow in the blocked artery). Patients who received standard care often underwent angioplasty 1-3 days after the heart attack.
Overall, 17 per cent of patients receiving standard care had serious cardiac complications within 30 days, compared with 11 per cent of those transferred immediately for angioplasty. That represents a 36 per cent reduction in potentially life-threatening complications, including repeat heart attacks, with no difference in major bleeding complications between the two groups.
Angioplasty – which uses a combination of catheter-mounted balloons and stents to open a completely blocked coronary artery and restore blood flow to the heart – is accepted by the medical community as the best initial treatment for heart attacks when performed within 90 minutes of arrival at a hospital.
“The challenge, though, is that this is a goal that few hospitals in the world can achieve unless they have angioplasty facilities on site,” explained Dr. Cantor, adding that less than 25 per cent of hospitals in North America have these resources. Until now, physicians have been reluctant to transfer patients to another hospital to undergo angioplasty soon after administering clot-busting medication as a result of earlier studies that revealed excess bleeding and no benefit with this approach.
“This study confirms that patients who receive clot-busting drugs at hospitals without angioplasty facilities should be transferred to an angioplasty centre to undergo the procedure within six hours,” Dr. Cantor emphasized. “Although many hospitals cannot transfer patients for angioplasty within 90 minutes of hospital arrival, stabilizing patients initially with clot-busting medications, followed by angioplasty within six hours, is highly practical and realistic in most parts of the world.”
Dr. Cantor explained that Southlake Regional Health Centre has been incorporating this treatment strategy gradually into its practice over the last year, with positive results. “Southlake has been bringing regional hospitals on board to rapidly transfer their heart attack patients to Southlake’s specialized cardiac centre to ensure that the patients have access to the best treatments regardless of where they live.”
The hospitals currently involved in Southlake’s program include Royal Victoria Hospital in Barrie, Headwaters Health Care Centre in Orangeville, Collingwood General and Marine Hospital in Collingwood, Orillia Soldier’s Memorial Hospital in Orillia and Stevenson Memorial Hospital in Alliston.