Study advocates medical management of mild MIs
Here's a bird's eye view of the latest addition to a burgeoning pile of evidence for conservative treatment of mild heart attacks.
The study's1 principal investigator, William E. Boden, MD, chief of medical service at the VA (Veterans Affairs) Upstate New York Healthcare System at Syracuse states, "In the great majority of these heart attack patients who do not have complications, such as recurrent angina, heart failure, or markedly abnormal stress tests within the first several days after MI [myocardial infarction], we found no clear benefit from routine, early heart catheterization and revascularization."
"In fact," he continues, "the rate of death or recurrent heart attack was two to three times higher than in patients conservatively managed during the first month after an acute non-Q-wave [narrowed, but not blocked, artery] MI." The controlled, randomized study - known as the Veterans affairs non-Q-wave infarction strategies in hospital (VANQWISH) - was conducted at 15 VA medical centers from 1993 to 1996.
r Subjects: Of 920 moderate to high-risk patients, 462 were randomly selected for invasive treatment strategies, 458 for conservative strategies. Men comprised 97% of the study population. Forty percent of the subjects were 65 or older; 8% were 76 or older.
r Aggressive treatment strategies: Catheterization was used followed by (1) angioplasty (insertion of a miniature balloon to open narrowed arteries), (2) heart bypass surgery, or (3) insertion of stents, devices that prop open narrowed arteries.
r Conservative treatment strategies: Clot-busting medications, ace inhibitor, or nitroglycerine were prescribed. (For more on drugs that improve heart attack care and outcomes, see QI/TQM, February 1998, pp. 13-19.)
r Patient outcomes: During the follow-up period that ranged from 12 to 44 months, the aggressively managed group incurred 80 deaths and 72 MIs. The conservatively managed group incurred 59 deaths and 80 MIs.
While the overall mortality rates between the groups did not significantly differ, Boden explains that the aggressive treatments pose real problems for patients' well-being as well as a waste of health care resources.
"With angioplasty, we run the risk of a torn artery or an abrupt closure of a narrowed artery at the site of the balloon. With stents, we see recurrent stenosis [narrowing] at the site in 40% of the cases within six months." More than half of the patients in the conservatively managed group remained clinically stable, Boden adds.
In the research report, he and his colleagues write, "No subgroup of patients with non-Q-wave infarction appeared to benefit from an early invasive approach to treatment." Due to the small percentage of women in the study population, the researchers caution that the findings only be applied to male patients. (For more news on treatment of female heart attack patients, see related story, "Heart surgery endangers women in lower-risk groups," p. 134.)
Taking peers to task
In a commentary on the clinical trial, a pair of physicians bluntly question the motives of colleagues who routinely apply aggressive approaches for mild heart attacks. "The treatment of patients whose course is uncomplicated should be guided by the results of the relevant trials such as VANQWISH, rather than physicians' preference or other, nonmedical incentives," write Richard A. Lange, MD, and L. David Hillis, MD, both from the University of Texas Southwestern Medical Center in Dallas.
They explain that in studies comparing U.S. practices with Canadian practices, the chief predictors of angiography use in the United States were relatively young age of the patients and the availability of a catheterization facility. Regional variations emerge as well.
They write, "A strong relation was noted between the availability of angiography in a geographic area and the likelihood that aggressive management would be chosen. However, the increased use of invasive procedures did not reduce the incidence of recurrent infarction or death."
Lange and Hillis argue that four factors are responsible for the divergence between clinical evidence and physician practice:
1. Many patients and their families insist on aggressive management. "The term 'conservative management' may project the impression - to physicians and patients alike - of obsolescence, inadequacy, and inferiority rather than of thoughtful reflection and the application of scientifically based, ischemia-guided therapy." Physicians also cite concern about liability as a factor in decisions to pursue aggressive strategies.
2. Physicians express skepticism about the applicability to their patients of results from trials like VANQWISH.
3. Physicians are likely to embrace the recommendations of studies that confirm existing notions. For example, write Lange and Hillis, "Many physicians in the United States, even today, continue to believe that all patients with acute coronary syndromes are best treated with prompt coronary angiography and revascularization, despite the absence of scientific support for such an approach."
4. Compared to Canada and Europe, "The United States has an abundance of facilities for prompt angiography and revascularization, physicians trained to perform these procedures, and monetary remuneration to the facilities and physicians."
References
1. Boden WE, O'Rourke RA, Crawford MH, et al. Outcomes in patients with acute non-Q-wave myocardial infarction randomly assigned to an invasive as compared with a conservative management strategy. N Engl J Med 1998; 338:1,785-1,792.
2. Lange RA, Hillis LD. Use and overuse of angiography and revascularization for acute coronary syndromes. N Engl J Med 1998; 338:1,838-1,839.
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