Congestive heart failure and outpatient risk of venous thromboembolism: A retrospective, case-control study

Although CHF has been considered a risk factor for venous thromboembolism, this has not been directly studied. We hypothesized that congestive heart f ailure would increase the risk of venous thromboembolism in an outpatient p opulation. and that this risk would increase as patients' ventricular funct ion worsened. We conducted a case-control study to examine whether CHF due to left ventricular dysfunction was an independent risk factor for acute ve nous thromboembolism in outpatients, once established risk factors such as recent surgery and prior venous thromboembolism are taken into account. We reviewed 106 cases of DVT and 603 controls, admitted for diabetes mellitus or infection, matched for month of admission at a VA hospital. Assignment o f a diagnosis of venous thromboembolism required a definitive test, as did classification as CHF. In a logistic regression model CHF was an independen t predictor of venous thromboembolism. A second logistic regression model s howed that the risk of venous thromboembolism increased as the ejection fra ction (EF) decreased, with an EF < 20 associated with a venous thromboembol ism OR of 38.3 (95% CI 9.6. 152.5). CHF is an independent risk factor for v enous thromboembolism, and the risk increases markedly as the EF decreases. These results support the use of anticoagulation in selected patients with CHF. (C) 2001 Elsevier Science Inc. All rights reserved.