CLINICAL INVESTIGATION Fibrin formation and platelet aggregation in patients with severe coronary artery disease: relationship with the degree of myocardial ischemia

Fibrinopeptide A (FpA) concentrations in plasma and in 24 hr urine specimens as well as betathromboglobulin (BTG) in plasma were measured in 17 patients with severe angina pectoris, including both stable and unstable angina, and in 19 patients with acute myocardial infarction. Patients with unstable angina had plasma FpA and BTG levels of 5.2 + 1.7 ng/ml and 91 23 ng/ml, respectively. The corresponding concentrations of FpA in the 24 hr urine specimens were 8.2 + 1.4 ,ug/24 hr. These values were similar to those measured in patients with acute myocardial infarction and higher than the corresponding levels in patients with stable angina (p < .05) and in normal control subjects (p < .01). The similarity of the platelet and coagulation findings in patients with unstable angina and in those with myocardial infarction favors the hypothesis that coronary thrombosis may play a major role in the pathogenesis of acute myocardial infarction. Circulation 72, No. 1, 27-30, 1985. CORONARY THROMBOSIS is frequently associated with acute myocardial infarction and with sudden death due to acute myocardial ischemia.'-3 Elevated plasma levels of betathromboglobulin (BTG), reflecting enhanced platelet aggregation,4 have been reported in patients with acute myocardial infarction.5We have recently found, in accordance with the results of other groups, that patients with acute myocardial infarction often present high plasma levels of fibrinopeptide A (FpA), a reliable index of fibrin formation in vivo.7-13 Whether FpA is elevated in patients with coronary artery disease without acute myocardial infarction remains controversial. Two recent studies reported elevated plasma levels of BTG but normal FpA values,6 8 whereas previous reports indicated elevated FpA values in these patients.'4' 15 We measured the plasma BTG and FpA levels in patients with severe coronary artery disease with stable and unstable angina pectoris and in the absence of acute myocardial infarction and compared them with the levels in patients with acute myocardial infarction. Since the course of patients with unstable angina is often complicated by acute myocardial infarction, parFrom the Thrombosis Research Laboratory, Department of Medicine, University of Bern, Bern, Switzerland. Address for correspondence: P. W. Straub, M.D, Department of Internal Medicine, University of Bern, Inselspital, CH-3010 Bern, Switzerland. Received Feb. 19, 1985; accepted April 4, 1985. Vol. 72, No. 1, July 1985 ticular attention was paid to the results in patients with unstable angina. We also measured 24 hr urinary excretion of FpA in all patients with angina and in most of the patients with acute myocardial infarction, since urinary FpA excretion appears to be a reliable parameter for assessing the cumulative effect of thrombin action on fibrinogen.16 Methods Patients Patients with angina pectoris. A total of 17 patients with severe angina pectoris were admitted to the study. Criteria for admission were: (1) absence of acute myocardial infarction during the last 3 months, (2) absence of thromboembolic events or other factors predisposing to a coagulation disorder (neoplasia, severe infection, collagen disorder, glomerulonephritis), and (3) absence of anticoagulant drugs within the preceding 3 months. Nine of the 17 patients had chronic stable effort angina without rest pain, and eight had unstable angina with recent increase in frequency or severity of chest pain, frequent pain at rest, and progressive decrease in exercise tolerance during the preceding 3 months. A total of nine patients had a history of previous myocardial infarction. All patients had three-vessel disease documented by coronary angiograms obtained within 3 months before the study; seven of 17 patients had decreased ejection fractions between 40% and 60%. All patients were treated with propranolol and longor short-acting nitrates. Patients with unstable angina also received nifedipine. No patient with stable angina complained of chest pain within 2 hr before blood sampling. Patients with acute myocardial infarction. FpA and BTG levels were also measured on admission in a group of 19 patients with acute myocardial infarction. Criteria for admission in this group were: (1) history of typical chest pain, (2) electrocardiographic changes ofQ waves and/or evolutionary ST-T changes, 27 by gest on A ril 2, 2017 http://ciajournals.org/ D ow nladed from