A 40-year-old woman has had increasing fatigue and shortness of breath for 6 months. Physical examination reveals normal vital signs and a resting O 2 saturation of 97%. Her lungs are clear without rales or wheezing. Cardiac examination shows a prominent pulmonary component of the second heart sound (P2 ) and a soft systolic murmur at the left sternal border that varies with respiration. Her neck veins show a prominent v wave. Chest x-ray shows right ventricular hypertrophy and enlargement of the central pulmonary arteries. What is the best next step in establishing a diagnosis in this patient?
A. EchocardiogramThis patient likely has primary pulmonary hypertension. Echocardiogram is a reliable noninvasive test to confirm the clinical suspicion. Once pulmonary hypertension is confirmed, secondary causes (pulmonary or congenital heart disease) should be ruled out. These are unlikely in this patient without clinical or radiographic evidence of chronic pulmonary disease. Once pulmonary hypertension is confirmed by echocardiography and secondary causes ruled out, patients often undergo right heart catheterization with measurement of pulmonary vascular resistance in response to various pulmonary vasodilators. Treatment choices have expanded in recent years; bosentan, sildenafil, and in severe cases, infused prostacyclin are effective treatments. In refractory cases, heart-lung transplantation (with its considerable risks) may be necessary. Spirometry is useful in defining obstructive or restrictive lung disease. Spirometry will be normal in pulmonary hypertension. Exercise stress testing in this patient will show a nonspecific decline in exercise tolerance; it is diagnostically useful when ischemic heart disease is a consideration. Measurement of alpha-1 antitrypsin would be indicated if this young woman had obstructive lung disease, but none of her clinical features point in this direction. If COPD were causing her symptoms, O2 desaturation or radiographic evidence of hyperexpansion would be expected.