Does heart failure confer a hypercoagulable state? Virchow's triad revisited

It is well-recognized that patients with congestive heart failure are at an increased risk of stroke and venous thromboembolism. Nevertheless, stroke, thromboembolism and myocardial infarction have generally been regarded to be end points of secondary importance in large heart failure trials, when c ompared with mortality or hospital readmissions. It may well have been that the incidence of thrombotic events are underestimated. The problem of thro mbus formation (thrombogenesis) in heart failure may therefore: be a much m ore significant problem than is currently recognized. The pathophysiology of thrombogenesis in heart failure could well be explai ned in the context of Virchow's original triad. In addition to "abnormal fl ow" through low cardiac output, dilated cardiac chambers and poor contracti lity, patients with heart failure also demonstrate abnormalities of hemosta sis and platelets (that is "abnormal blood constituents") and endothelial d ysfunction ("vessel wail abnormalities"). These abnormalities contribute to a prothrombotic or hypercoagulable state, which increases the risk of thro mbosis in heart failure and impaired left ventricular systolic function. Some observational data are available on the role of anticoagulants in hear t failure, and there is sound evidence to support the use of antithrombotic therapy in patients with heart failure and atrial fibrillation. However, t here are no large-scale prospective randomized controlled trials of antithr ombotic therapy in patients with heart failure who remain in sinus rhythm a lthough important studies are in progress. Although the results of these st udies are awaited, measurement of suitable markers of thrombogenesis might prove to be valuable in identifying "high risk" patients and in determining the nature, duration and intensity of such treatment. Further information is also needed on the predictive value of various markers of hypercoagulabi lity in patients with heart failure, the association between hemostatic var iables and the severity of heart failure, and the effects of different trea tments. (C) 1999 by the American College of Cardiology.