Early revascularisation of no benefit in mild heart attacksBMJ 1998; 316 doi: https://doi.org/10.1136/bmj.316.7149.1928a (Published 27 June 1998) Cite this as: BMJ 1998;316:1928
Conservative treatment for mild heart attacks is superior to early revascularisation, according to an American trial.
More than 900 patients, mostly men, with non-Q wave infarctions were enrolled in the study and randomly assigned either to invasive or to conservative management (New England Journal of Medicine 1998;338:1785-92). The invasive group underwent coronary angiography followed by either balloon angioplasty or a bypass procedure.
Conservative management consisted of non-invasive testing, medical treatment, and thrombolytics, if necessary. Patients randomised to conservative management who had recurrent ischaemia within 72 hours after their initial heart attack were able to switch to aggressive treatment. Both groups received aspirin and diltiazem.
The investigators found no clear benefit for an aggressive approach to treatment and, moreover, found that early mortality was worse for patients randomised to the revascularisation arm. During an average follow up of 23 months, 152 events (80 deaths and 72 non-fatal heart attacks) occurred in 138 patients enrolled in the invasive group, while 59 deaths and 80 non-fatal infarcts occurred in the 123 patients in the conservative group.
Although these overall mortality results were insignificant, clinical outcomes for the aggressively treated arm were much worse than the conservative arm at discharge, at one month, and at 12 months (21 deaths in the invasive group at discharge versus 6 in the medical arm; 23 versus 9 at one month; 58 versus 36 at one year).
In the invasively treated group 96% of the patients underwent cardiac catheterisation and angiography, and 44% of these patients underwent revascularisation. For the conservatively treated group, 48% underwent angiography at some point during the study, with 33% undergoing a revascularisation procedure sometime during follow up. The conservative strategy was not mere watchful waiting but allowed selective intervention.
The researchers concluded: “Most patients with non Q wave myocardial infarction do not benefit from routine early invasive management consisting of coronary angiography and revascularisation. A conservative initial strategy based on an ischemia guided approach to management after infarction is both safe and effective.”
Non-Q wave myocardial infarctions, in which only a small amount of heart muscle is damaged, are the most common type of heart attack in the United States. Coronary angiography and early revascularisation have become standard treatments in the United States despite the absence of evidence that this approach is beneficial. Patients in the United States are much more likely to undergo aggressive intervention than are their Canadian and European counterparts.
This latest study is the fourth major trial to show that conservative management is preferable to early aggressive treatment in acute coronary syndromes. In an accompanying editorial, Drs Richard Lange and David Hillis of the University of Texas South Western Medical School point out that “with remarkable clarity and consistency all four studies show that routine angiography and revascularisation do not reduce the incidence of nonfatal infarction and death as compared to the more conservative ischemia guided approach.”
Many believe that one reason invasive treatment has become standard is because of the explosion in cardiologists trained in invasive techniques. The number of balloon angioplasty procedures rose 6000% between 1980 and 1992 in the United States, mirroring the growth of cardiologists who perform cardiac catheterisations.
Dr William Boden, chief investigator of the trial, suggested that reform would only occur when insurance stopped paying for non-indicated procedures.