Acute circulatory failure caused by primary pulmonary hypertension or pulmonary embolism

Patients with acute massive pulmonary embolism or primary pulmonary hypertension may develop acute circulatory failure and are therefore admitted in the intensive care. The mortality rate of patients with pulmonary embolism and shock varies between 25 and 35% whereas the corresponding figure in patients with submassive embolism is less than 10%. Spiral computed tomography may be the most convenient test for diagnosing pulmonary embolism in the setting of acute circulatory failure. In the few patients who remain unstable despite adequate symptomatic treatment, transthoracic echocardiography combined with clinical judgement is appropriate. Inotropic support and thrombolytic therapy are clearly indicated for patients with massive embolism and shock. The role of the latter is more controversial in patients with right ventricular distension and normal blood pressure. The optimal duration of anticoagulant therapy for pulmonary embolism remains to be defined. Most patients are adequately treated with a six-month course of oral anticoagulants. A shorter duration may be sufficient when a transient risk factor is the cause of the initial event whereas patients with cancer or antithrombin deficiency may require a life long treatment. Primary pulmonary hypertension is a much more uncommon disease which can also lead to right ventricular failure. Symptomatic treatment combines oxygen, inotropic drugs, as well as the optimisation of right ventricular filling pressure. Specific treatment includes inhaled nitric oxide or intravenous epoprostenol followed by anticoagulants with either calcium channel blockers in patients responding acutely to vasodilators or a continuous infusion of epoprostenol in those who do not respond to acute challenge or who are not improving with calcium channel blockers. Although the long term survival has markedly improved as a result of epoprostenol treatment, some patients with refractory primary pulmonary hypertension remain candidates for lung transplantation.