ANAHEIM, CALIF. – One out of three patients worldwide who suffer a second heart attack shortly after being hospitalized for a first heart attack are not receiving the best care available, according to a new analysis by Duke University Medical Center researchers.
They said that many of these patients continue to be treated conservatively in spite of newer and more aggressive therapies shown by the researchers to improve mortality rates almost threefold.
About 4 percent of patients hospitalized with a heart attack and treated with thrombolytic agents, or clot-busters, will suffer a second heart attack event, or re-infarction, during the initial hospital stay; of those, approximately 17 percent will die within 30 days, the researchers said.
"This is a group of patients that has not been well studied," said Dr. Michael Hudson, cardiology fellow at the Duke Clinical Research Institute. "The results of our analysis show that instead of taking a conservative approach, physicians should to be treating these patients more aggressively."
For the study, re-administration of the thrombolytic agent, or an emergency revascularization procedure, such as angioplasty or coronary artery bypass surgery, were considered the aggressive therapies by the researchers. The conservative approach entailed not employing either of those strategies.
"In our analysis, the patients treated with either aggressive treatment strategy had a mortality rate after 30 days of about 10 percent, compared to 28 percent for those treated conservatively," Hudson said.
Hudson prepared the results of his analysis for presentation Tuesday at the 47th annual scientific sessions of the American College of Cardiology.
The Duke team analyzed data gathered from two large international, multi-center thrombolytic trials conducted six years apart: GUSTO-I, conducted from 1990-1993, involved 41,021 patients; and ASSENT II, conducted from 1997-98, involved 16,950 patients. Both studied the effectiveness of different clot-busters in reducing mortality following myocardial infraction, or heart attack.
"After comparing the results of the two trials, we noticed a worldwide shift toward emergency revascularization and less frequent re-administration of clot-busters, but despite this change in treatment strategy, still one-third of re-infarction patients received conservative therapy," Hudson said.
Specifically, in the early 1990s, 38 percent of these patients in the United States were treated conservatively; and by the late 1990s, that figure dropped to 33 percent. The repeat use of clot-busters dropped from 29 percent to 19 percent, and emergency revascularization jumped from 33 percent to 48 percent.
Outside of the United States, the conservative approach declined from 41 percent to 35 percent during the same period. Re-administration of clot-busters dropped from 51 percent to 42 percent, while revascularization procedures jumped from 8 percent to 23 percent.
Although Hudson's study shows that an aggressive approach is likely the most effective way of treating this group of patients, he said the next step is to conduct a large study that compares re-administration of clot-busters head-to-head against emergency revascularization procedures.
While the use of emergency procedures is on the rise, Hudson said he believes that many physicians still need to be educated about the re-administration of clot-busting drugs and how and when to use them.
"Many doctors do not have much experience in the re-administration of clot-busters, so they are hesitant in using them in these situations because of the potential for bleeding complications," Hudson said.
"Our analysis of the data shows that under 2 percent of these patients will suffer from a stroke, less than 1 percent will have an intracranial bleed after re-administration of the drug, and survival will be comparable to an emergency revascularization strategy," he continued. "Compared to the benefits provided by this therapy, these findings should give physicians the confidence to take this approach for their patients."
The GUSTO-I study was funded by Bayer, New York; CIBA-Corning, Medfield, Mass.; Genentech Inc., South San Francisco; ICI Pharmaceuticals, Wilmington, Del.; and Sanofi Pharmaceuticals, Paris. The ASSENT trial was funded by Genentech and Boehringer Ingelheim, Ingelheim, Germany. Hudson's analysis of the data was supported by the Duke Clinical Research Institute.
Also part of the research team were, from Duke, Dr. Christopher Granger, Karen Pieper, Dr. E. Magnus Ohman and Dr. Robert Califf. Also participating were Gabriel Barbash, Sourasky Medical Center, Tel Aviv, Israel; Yochai Birnbaum, Rabin Medical Center, Petah Tiqva, Israel; Katrijn Houbraacken and Frans Van de Werf, Gasthuisberg University Hospital, Leuven, Belgium; and Dr. Eric Topol, Cleveland Clinic.