LIPOPROTEIN(A) AND OXYGEN-FREE RADICALS IN SURVIVORS OF ACUTE MYOCARDIAL-INFARCTION - EFFECTS OF CAPTOPRIL

Long-term treatment of survivors of an acute myocardial infarction wit h angiotensin-converting enzyme inhibitors has a beneficial impact on their long-term outcome. We tested the hypothesis that captopril could reductively cleave the lipoprotein(a) molecule and in addition act as a scavenger of oxygen free radicals. In a double-blind trial, 20 pati ents were randomized to receive either captopril 50 mg daily or corres ponding placebo. Patients were followed for a period of 30 days. Blood samples were drawn prior to randomization and after 30 days of treatm ent. Plasma concentrations of lipoprotein(a) and malondialdehyde were evaluated. Captopril treatment produced a significant reduction in pla sma content of lipoprotein(a) (p < 0.05) and at day 30 the plasma cont ent of lipoprotein(a) was also significantly lower than that in the pl acebo group (p < 0.05). Furthermore, on day 30 plasma concentrations o f malondialdehyde, an indicator of oxidative damage, were significantl y lower in the captopril group when compared to baseline values and co rresponding placebo group values (p < 0.05). The observed effect of ca ptopril treatment on lipoprotein(a) and malondialdehyde might be ascri bed to the sulfhydryl group in the captopril molecule.