Randomized trial of late elective angioplasty versus conservative management for patients with residual stenoses after thrombolytic treatment of myocardial infarction. Treatment of Post-Thrombolytic Stenoses (TOPS) Study Group.

BACKGROUND

After thrombolytic therapy for patients with acute myocardial infarction (MI), percutaneous transluminal coronary angioplasty (PTCA) is frequently performed because of the presence of a "significant" infarct vessel stenosis demonstrated at predischarge coronary angiography. Several studies have shown PTCA performed early after thrombolysis to be unnecessary or even harmful. However, PTCA in these trials was generally performed 1-3 days after MI, when the milieu in the infarct artery may be unsuited for PTCA, and the incidence of major ischemic complications was high. To date, no trial has assessed whether delayed PTCA (4-14 days) should be performed in patients without evidence of ischemia on stress testing.

METHODS AND RESULTS

To test the hypothesis that delayed PTCA might provide clinical benefit compared with medical therapy alone, 87 patients treated within 6 hours of chest pain onset with thrombolytic therapy and with negative functional test were randomized between PTCA to be performed 4-14 days after MI versus no PTCA. Both groups received medical therapy. Patients with postinfarct angina or prior Q wave infarction in the infarct distribution were excluded. The primary study end point was increase in left ventricular ejection fraction with exercise measured by radionuclide studies 6 weeks after MI, a parameter known from other studies to correlate inversely with future ischemic events. Clinical outcome was also monitored for 12 months. There were no differences between the study groups for any prerandomization variable recorded. Mean age was 57 +/- 10 years, 84% of patients were male, 21% had prior MI, 36% had anterior MI, 7% had multivessel disease, and the infarct stenosis measured 70 +/- 17% before randomization. PTCA was successful in 38 of 42 patients (88%) but resulted in non-Q wave MI due to acute closure of the treated site in three of 42 (9.5%). There was no difference in 6-week resting ejection fraction or increase in ejection fraction with exercise between the two groups (47 +/- 12% and 6 +/- 8%, respectively, in the PTCA group; 49 +/- 10% and 5 +/- 9% in the no-PTCA group; p = NS for both.) There were no deaths in either group. Actuarial 12-month infarct-free survival was 97.8% in the no-PTCA group and 90.5% in the PTCA group (p = 0.07).

CONCLUSIONS

There was no functional or clinical benefit from routine late PTCA after MI treated with thrombolytic therapy in this relatively low-risk cohort of patients. These data strongly suggest that patients with an uncomplicated MI after thrombolytic therapy, even if they have a "significant" residual stenosis of the infarct vessel, should be treated medically if they are without evidence of ischemia on stress testing before hospital discharge.