INCIDENCE OF THROMBOEMBOLIC EVENTS IN CONGESTIVE-HEART-FAILURE

Background. The incidence of thromboembolism and the benefit of antico agulation in congestive heart failure are controversial. Mdhods and Re sults. The data base provided by the Veterans Affairs Vasodilator-Hear t Failure Trials (V-HeFT I and II) was examined retrospectively to add ress these issues. In V-HeFT I, 642 men with heart failure were follow ed an average of 2.28 years, providing 1,464 patient-years of follow-u p. In V-HeFT II, 804 men were followed an average of 2.56 years, with 2,061 patient-years of follow-up. Mean left ventricular ejection fract ion was 30% in V-HeFT I and 29% in V-HeFT II. Functional capacity was at the interface of classes II and III with a peak exercise oxygen con sumption of 14.7 mL . kg-1 . min-1 in V-HeFT I and 13.7 mL . kg-1 . mi n-1 in V-HeFT II. Warfarin and antiplatelet agents were administered a t the discretion of individual investigators. The incidence of all thr omboembolic events during 1,068 patient-years without warfarin in V-He FT I was 2.7/100 patient-years and during 1,188 patient-years in V-HeF T II was 2.1/100 patient-years and was not reduced in patients treated with warfarin. Patients experiencing events had a lower peak exercise oxygen consumption (p < 0.03 in V-HeFT I and p < 0.001 in V-HeFT II) and a lower mean ejection fraction (p=0.10 in V-HeFT I and p=0.07 in V -HeFT II). Atrial fibrillation was not associated with an increased ri sk of thromboembolic events. Conclusions. The incidence of thromboembo lism and stroke in class II or III congestive heart failure is not hig h and may not be significantly reduced with warfarin treatment. Routin e use of anticoagulants in patients with heart failure may not be just ified.