Chapter 90 - Pulmonary Hypertension

Abstract

Pulmonary hypertension (PH) is the existence of sustained elevations in blood pressure within the pulmonary arteries and is defined as a mean pulmonary arterial pressure >25 mm Hg. PH is classified into five groups determined by the World Health Organization (WHO) based on etiology of disease. Physiologically, PH develops in the setting of remodeling of the low-pressure high-flow pulmonary vasculature system that results in right ventricular failure and clinical manifestations of PH. The hallmark symptoms of PH are exertional dyspnea, fatigue, and decreased exercise tolerance. These symptoms manifest physically as elevated jugular venous pressure, right ventricular heave, and a tricuspid regurgitation murmur. Echocardiography with Doppler evaluation is the most appropriate initial screening study, with right heart catheterization being reserved for subsequent diagnostic testing for the measurement of pulmonary capillary wedge pressure (PCWP). As a prognostic measure, 6-minute walk testing assists with determining exercise tolerance. Therapies for PH focus on symptomatic relief of dyspnea and improving right ventricular function. Nonpharmacological therapies include pulmonary rehabilitation and exercise training. Pharmacological therapies include calcium channel blockers, prostacyclin pathway agonists in various formulations, phosphodiesterase type V inhibitors, soluble guanylate cyclase stimulators, and endothelin receptor antagonists. When medical management proves insufficient, surgical management includes pulmonary endarterectomy, balloon atrial septostomy, or bilateral lung or heart-lung transplantation.