News Release

Clot-buster – angioplasty duo may be a winner after all

Peer-Reviewed Publication

American Heart Association

DALLAS, August 7 – Individuals whose arteries open spontaneously before angioplasty – a technique to treat blocked coronary arteries – are more likely to survive, suggesting that drugs that help speed this along may be useful in combination with angioplasty after all, researchers say in today’s Circulation: Journal of the American Heart Association.

Using data from studies of heart attack patients who underwent angioplasty, researchers found that those whose blood flow had improved due to spontaneous dissolving of some of the blood clot before angioplasty had less disability and death than those whose vessels remained blocked. Heart attacks are caused by blood clots or blockages in the coronary arteries, and are treated with clot-dissolving drugs, or with angioplasty. Angioplasty uses a tiny balloon to widen blood vessels.

For many heart attack patients, angioplasty provides superior results over clot-buster drugs, because it restores blood flow more completely, and is not associated with intracranial bleeding. For others, clot-busting drugs offer advantages, because they can open the artery very rapidly and be used for patients who live in communities where angioplasty procedures are not offered.

“Both techniques independently increase survival and decrease death if given quickly. So, it seems logical that patients who receive both would do better than those receiving only one,” says Gregg W. Stone, M.D., director of cardiovascular research and education at the Cardiovascular Research Foundation and the Lenox Hill Heart and Vascular Institute, New York.

However, several major studies in the mid-1980s that tested the two therapies together found the combination provided no added benefit. “If anything, there may have been harm, and that soured the whole concept,” says Stone. “However, major advances in drug therapy and angioplasty techniques justified re-examining the potential of the combination.”

Stone and his colleagues pooled data from more than 2,500 patients who had participated in four previous studies called the Primary Angioplasty in Myocardial Infarction (PAMI) trials. Primary angioplasty referes to angioplasty being used without clot-busting efforts as a first treatment for a heart attack in progress. None of the patients received clot-busting drugs.

“This study is unique because no one had really looked at the significance of the artery being open before angioplasty,” said Stone.

Before and after angioplasty, researchers measured the patients’ thrombolysis in myocardial infarction (TIMI) scores – which indicates blood flow in the blocked artery that caused the heart attack on a scale from TIMI-0 (no flow) to TIMI-3 (normal flow). TIMI scores were determined for 2,327 (93 percent) of the pooled patients. Of these, 15.7 percent had TIMI-3 flow before their angioplasty, meaning their blood flow had spontaneously returned to normal. The body makes its own anti-clotting factors that act similar to clot-busting drugs and these factors sometimes restore full blood flow early after a heart attack.

When the team compared patients with normal flow before their heart procedure to those with less than normal flow, they found significant differences in outcomes. Patients with TIMI-3 flow before angioplasty were more likely to emerge from the procedure with normal flow and less likely to die in the hospital, develop congestive heart failure and/or high blood pressure, or require a breathing tube. And they spent fewer days in the hospital.

Six months after their angioplasty, patients with TIMI-3 flow before their procedure had the lowest mortality (0.5 percent), compared to those with TIMI-2 (2.8 percent) and TIMI-1 or TIMI-0 (4.4 percent).

“The implication is clear,” says Stone. “We need to perform studies with a cocktail of anti-clotting drugs versus placebo, followed by angioplasty, in a large number of patients.”

Christopher P. Cannon, M.D., assistant professor of medicine at Harvard Medical School, who wrote an accompanying editorial in today’s Circulation, said the study reinforces the “central goal of achieving TIMI 3 flow as early as possible” and that more studies are needed to determine the best means of improving outcome.

He says that pending these trials, physicians should focus their efforts on reducing time delays in re-opening arteries, both for clot-busters and angioplasty.

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Co-authors are David Cox, M.D.; Eulogio Garcia, M.D.; Bruce R. Brodie, M.D.; Marie-Claude Morice, M.D.; John Griffin, M.D.; Luiz Mattos, M.D.; Alexandra J. Lansky, M.D.; William W. O’Neill, M.D.; and Cindy L. Grines, M.D.

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