Patients with long standing mitral valve disease are at risk of developing pulmonary hypertension, which may present a formidable challenge for the cardiac anesthetist (perioperatively) during cardiac surgery. Pulmonary hypertension is an important risk factor for the development of acute right sided heart failure during cardiac surgery. Even with early and adequate therapy, right ventricular (RV) failure is associated with increased morbidity and mortality. Adequate treatment of RV failure consists of different strategies. The main goal is to decrease RV afterload by using vasodilating agents .