Effects of early captopril administration after thrombolysis on regional wall motion in relation to infarct artery blood flow

Objectives. To determine whether early administration of captopril lessens infarct zone regional wall motion abnormalities when infarct artery blood flow is abnormal. Background. The interaction between angiotensin-converting enzyme (ACE) inhibitor therapy, ventricular function and infarct artery blood flow has not been well described. Methods. total of 493 patients aged ≤75 years with first infarctions, presenting within 4 h of symptom onset, were randomized to receive 6.25 mg captopril, increasing to 50 mg t.d.s. or matching placebo 2.1 ± 0.4 h after commencing intravenous streptokinase (1.5 × 106 U over 30 to 60 min). Trial therapy was stopped 48 h prior to angiography at 3 weeks, to determine regional wall motion and infarct artery flow. Results. There were no differences in ejection fractions or end-systolic volumes between patients randomized to receive captopril and those randomized to receive placebo. Among patients with anterior infarction (n = 216), randomization to captopril resulted in fewer hypokinetic chords (40 ± 13; vs. 44 ± 13; p = 0.028) and trend toward fewer chords >2 SD below normal (26 ± 17 vs. 30 ± 17; p = 0.052) in the infarct zone. In patients randomized to receive captopril who had anterior infarction and Thrombolysis in Myocardial Infarction (TIMI) 0–2, flow there were fewer hypokinetic chords (44 ± 12 vs. 50 ± 9; p = 0.043) and trend toward fewer chords >2 SD below normal (33 ± 15 vs. 39 ± 13; p = 0.057). Patients receiving captopril who had anterior infarction and corrected TIMI frame counts >27 had fewer hypokinetic chords (42 ± 13 vs. 46 ± 12; p = 0.015) and fewer chords >2 SD below normal (27 ± 17 vs. 32 ± 17; p = 0.047). Captopril had no effect in patients with inferior infarction. There were 20 late cardiac deaths (median follow-up 4 years) in the captopril group and 35 in the placebo group (p = 0.036). Conclusions. Randomization to receive captopril 2 h after streptokinase improved regional wall motion at 3 weeks. The greatest benefit was seen in patients with anterior infarction particularly when infarct artery blood flow is reduced.