Newmarket, Ontario (April 2, 2008) – A study by a group of Canadian cardiologists has found a safer and more effective way to treat heart attack patients. The researchers discovered that transferring heart attack patients to specialized hospitals to undergo angioplasty within six hours after receiving clot-busting drugs results in better outcomes than the current practice of transferring patients only when the clot-busting drugs fail.
Preliminary results of the study – called the Trial of Routine Angioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI) – were presented Sunday by Dr. Warren Cantor, medical director of the interventional and invasive program at Southlake Regional Health Centre in Newmarket, at a conference held by the Society for Cardiovascular Angiography and Interventions and the American College of Cardiology in Chicago.
The research, led by Dr. Cantor and Dr. Shaun Goodman, associate head of cardiology at St. Michael’s Hospital in Toronto, was supported by the Canadian Institutes of Health Research and coordinated by the Canadian Heart Research Centre. The study involved 1,059 heart attack patients treated with clot-busting drugs at community hospital emergency departments in Ontario, Manitoba and Quebec. The largest randomized trial of its kind, the study compared a strategy of transferring heart attack patients to hospitals with on-site angioplasty facilities to undergo angioplasty within six hours of having clot-busting drugs administered, as opposed to the traditionalapproach of transferring only those patients whose clot-busting drug treatments are unsuccessful.
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 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.
“Based on the results of our study, angioplasty using contemporary techniques and newer anti-clotting medications appears to be safe and result in better outcomes,” Dr. Goodman said.
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.
The preliminary results of the study are dramatic, Dr. Cantor said. Overall, 17 per cent of patients receiving standard care had serious complications within 30 days, compared with 11 per cent of those transferred immediately for angioplasty. That represents a 46 per cent reduction in potentially life-threatening complications, including repeat heart attacks, he explained, adding that there was no difference in major bleeding complications between the two groups.
“This indicates 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.”
“Ultimately, by adopting strategies to rapidly transfer heart attack patients to specialized cardiac centres, patients will have access to the best treatments regardless of where they live,” he said.
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