Anticoagulation in pulmonary arterial hypertension: a qualitative systematic review.

Thrombotic arteriopathy has been implicated in the pathophysiology of pulmonary arterial hypertension (PAH). However, the role of anticoagulants in the treatment of PAH is uncertain. Through a qualitative systematic review of epidemiological studies, the effectiveness of anticoagulation therapy with warfarin on survival was evaluated in patients with PAH. MEDLINE (1966 to November 2005), EMBASE (1966 to November 2005), bibliographies of included studies and published reviews were searched without language restriction. Epidemiological studies evaluating the effectiveness of warfarin in PAH were included. Studies had to report mortality as an outcome. Seven observational studies evaluating the effectiveness of warfarin comprising 488 patients were identified. Five studies support the effectiveness of anticoagulation therapy, whereas two do not. Data from observational studies suggest that anticoagulation therapy may be an effective intervention in pulmonary arterial hypertension. However, given the methodological limitations and the small number of existing observational studies, a randomised controlled trial is needed in order to definitively address this important clinical issue.