Anticoagulation in patients with heart failure: Who, when, and why?

The mortality rate associated with advanced heart failure (HF) remains high. Although pharmacological and device therapy have improved survival in patients with HF or depressed systolic function, antithrombotic therapy is controversial. Autopsy studies demonstrated a high incidence of arterial and venous thrombo-embolism in patients with HF, but secondary analyses of clinical trials have suggested lower rates of stroke and clinical thrombo-embolic events, perhaps because a relatively high percentage of patients had atrial fibrillation (AF) and were treated with anticoagulants. Although anticoagulation is recommended for patients with AF who have HF or reduced left ventricular ejection fraction (EF), guidelines vary regarding antithrombotic therapy for patients without AF. Those with ischaemic heart disease are typically treated with a platelet inhibitor such as aspirin. Further studies are needed to define the incidence of venous or right-sided intracardiac source of thrombo-embolism in patients with HF or reduced EF, as this may be an under-recognized cause of morbidity and mortality. Ongoing studies will provide more insight into the selection of optimum antithrombotic therapy and better assess the net impact of such therapy on event-free survival in patients with advanced HF.