Platelet and leukocyte activation after myocardial infarction. Influence of enalapril.

ABSTRACT

In this double-blind placebo-controlled study with enalapril, 74 patients with acute myocardial infarction were followed at 0, 7, 30, 60 and 180 days after the event. Platelets and leukocytes were activated during the first 7 days. During the 6-month period fibrinogen, leukocytes, elastase, and B beta 30-43 remained elevated in 50, 15, 30 and 80% of the patients, respectively, but there was no detectable angiotensin converting enzyme activity in platelets. Enalapril did not modulate fibrinogen, leukocyte count or elastase, while B beta 30-43 peptide showed decreased levels, although the proportion of patients with values above the reference limit did not differ from placebo. In conclusion, in the 6-month post acute myocardial infarction period, while platelet function is activated only during the first week after acute myocardial infarction, fibrinogen and leukocyte function continue to be activated throughout the 6 months in a considerable proportion of patients. These signs may indicate an ongoing atherosclerotic process. Enalapril has no major influence on these reactivities.