October 21, 1996
Heart attack outcomes are similar with anti-clotting drugs and balloon angioplasty
Heart attack patients admitted to community hospitals show nearly identical survival rates, whether treated with powerful anti-clotting drugs or with balloon angioplasty.
This conclusion is drawn by University of Washington researchers publishing results of their study of more than 3,000 patients in the Oct. 24 issue of the New England Journal of Medicine. Using data gathered as part of the UW’s Myocardial Infarction Triage and Intervention (MITI) Project, the researchers compared the death rates, both during hospitalization and over the following three years, among 2,095 patients treated with thrombolytic therapy and 1,050 patients treated with primary angioplasty, at 19 Seattle-area hospitals between 1988 and 1994.
They found no difference in mortality, either in the hospital or after release, between those treated with drug therapy and those treated with primary angioplasty (so-called when performed within the first few hours), said Dr. Nathan R. Every, UW assista nt professor of medicine and lead author of the study. The death rate was 5.6 percent for patients treated with anti-clotting drugs versus 5.5 percent for patients treated with angioplasty.
Balloon angioplasty is a procedure increasingly used by cardiologists in the first hours after a heart attack. “There has been a substantial increase in the use of primary angioplasty since publication of several randomized trials in 1993 that showed pat ients treated with the procedure had lower hospital mortality than those treated with thrombolytic therapy,” said Every. But he noted that these earlier studies were done at medical centers that perform more primary angioplasties than the average communit y hospital.
“Many community cardiologists used the results of these trials to switch from thrombolytic therapy to primary angioplasty,” said Every. “We undertook the study in part because we were concerned that results in the community may not be quite as good as th ose in the published trials. We are also concerned that there may be a delay in treatment when community hospitals feel the need to transport patients to a center that performs large numbers of angioplasties.”
The study also showed that medical costs, as well as the number of additional procedures, were lower among patients treated with thrombolytic therapy, in both the short and the long term. There were 33 percent fewer coronary angiograms, 20 percent fewer coronary angioplasties, and 14 percent lower medical costs after three years of follow-up. Hospital costs averaged $3,000 less among patients receiving drug therapy.
“From our results,” said Every, “we feel that hospitals should decide which strategy is best for them, and develop expertise either in delivering the drug or in performing angioplasty quickly. Hospitals should not feel obligated to start a primary angiop lasty program or transfer patients (to a large medical center) to undergo this procedure.”
“Cardiologists have taken hold of primary angioplasty,” said Every. “The argument is that it saves more lives. Our message is that the two therapies are equally effective.”
Every’s co-investigators were Lori S. Parsons, Dr. Mark Hlatky, Jenny Martin and Dr. W. Douglas Weaver, director of the MITI Project. The research was supported by the Department of Veterans Affairs, the National Heart, Lung and Blood Institute, and the Agency for Health Care Policy and Research.