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Incidence of thromboembolic events in congestive heart failure. The V-HeFT VA Cooperative Studies Group
W B Dunkman1, G R Johnson, P E Carson
1Cardiology Section, Veterans Affairs Medical Center, Philadelphia, PA 19104.
Insights
Thromboembolism risk in heart failure patients is not high and warfarin may not significantly reduce events. Routine anticoagulant use in heart failure may not be justified.
Area of Science:
- Cardiology
- Clinical Medicine
- Pharmacology
Background:
- The role of anticoagulation in managing congestive heart failure (CHF) remains a subject of debate.
- Previous studies have yielded controversial results regarding the incidence of thromboembolism in CHF patients and the efficacy of anticoagulant therapy.
Purpose of the Study:
- To retrospectively analyze data from the Vasodilator-Heart Failure Trials (V-HeFT I and II) to evaluate the incidence of thromboembolism in patients with heart failure.
- To assess the potential benefit of warfarin in reducing thromboembolic events in this patient population.
Main Methods:
- Retrospective analysis of data from 1,446 men with heart failure across V-HeFT I and V-HeFT II trials.
- Evaluation of thromboembolic event rates in patients treated with and without warfarin.
- Correlation of thromboembolic events with clinical parameters such as ejection fraction and peak exercise oxygen consumption.
Main Results:
- The incidence of thromboembolic events was 2.7/100 patient-years in V-HeFT I and 2.1/100 patient-years in V-HeFT II, and was not reduced by warfarin treatment.
- Patients who experienced thromboembolic events had significantly lower peak exercise oxygen consumption and ejection fraction.
- Atrial fibrillation was not found to be associated with an increased risk of thromboembolic events.
Conclusions:
- The incidence of thromboembolism and stroke in patients with Class II or III heart failure is relatively low.
- Warfarin treatment did not demonstrate a significant reduction in thromboembolic events in this study population.
- Routine anticoagulation therapy may not be a justified approach for all patients with heart failure.
Background:
The incidence of thromboembolism and the benefit of anticoagulation in congestive heart failure are controversial.
Methods And Results:
The data base provided by the Veterans Affairs Vasodilator-Heart Failure Trials (V-HeFT I and II) was examined retrospectively to address these issues. In V-HeFT I, 642 men with heart failure were followed an average of 2.28 years, providing 1,464 patient-years of follow-up. 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 fraction 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 consumption of 14.7 mL.kg-1 x min-1 in V-HeFT I and 13.7 mL.kg-1 x min-1 in V-HeFT II: Warfarin and antiplatelet agents were administered at the discretion of individual investigators. The incidence of all thromboembolic events during 1,068 patient-years without warfarin in V-HeFT I was 2.7/100 patient-years and during 1,188 patient-years in V-HeFT 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 risk of thromboembolic events.
Conclusions:
The incidence of thromboembolism and stroke in class II or III congestive heart failure is not high and may not be significantly reduced with warfarin treatment. Routine use of anticoagulants in patients with heart failure may not be justified.