Risks of discontinuing anticoagulant therapy in a selected group of patients with atherosclerotic heart disease: a prospective study.

In 134 patients with coronary artery disease, long-term oral anticoagulant therapy (mean duration, 56 months) for acute myocardial infarction (98 patients), acute coronary insufficiency (25 patients) or severe chronic angina (11 patients) was terminated abruptly in 50 patients (group 1) and gradually in 84 (group 2). The 134 patients represented a homogeneous population of patients with coronary artery disease since most patients older than 75 years and those with conditions known to increase the risks of thromboembolic complications were excluded. The two groups were comparable in terms of sex, age, presence of risk factors, duration of anticoagulant therapy, and presence of angina and abnormal resting electrocardiograms during therapy. Patients were evaluated 6 months after cessation of anticoagulant therapy and, since abrupt withdrawal of therapy did not carry a higher risk than gradual discontinuation, data for groups 1 and 2 were tabulated together.Of the 84 patients with angina at the end of therapy 15 experienced an increase in its severity and this symptom appeared in another patient (relapse rate, 18%). Angina progressed to fatal acute myocardial infarction in four (mortality, 3%) and nonfatal infarction in two; however, all six had extensive coronary artery disease and poor left ventricular function. The results of this study suggest that neither abrupt nor gradual cessation of anticoagulant therapy is associated with an inordinate exacerbation of heart disease.