Pulmonary hypertension: etiology and clinical evaluation.

Elevation of pulmonary arterial pressure may be secondary to many diseases of the lungs, chest wall, and heart. From a pathophysiologic viewpoint, pulmonary hypertension is secondary to vascular obstruction, vasoactivity, increased circulation, and passive forces. Clinically, the entities that result in secondary pulmonary hypertension present with a picture that identifies the primary disease. Patients with primary pulmonary hypertension may be difficult to identify. Pulmonary hypertension may present early with dyspnea and fatigue, while syncope and hemoptysis are late symptoms. In many instances, pulmonary hypertension can be diagnosed utilizing physical examination and noninvasive tests. Eventually, right heart catheterization is necessary to confirm the diagnosis and to monitor trials of therapy with vasodilators. Treatment may be specific (closure of a septal defect, thromboendarterectomy) or generic (vasodilators). These have been used recently for both secondary and primary pulmonary hypertension in an effort to reduce pulmonary vascular resistance, thereby decreasing right ventricular afterload and improving cardiac output and oxygen delivery. The success of these treatments has not been demonstrated.