Echocardiographic recognition of pulmonary arterial disease and determination of Its cause

Abstract

Echocardiography provided the initial diagnosis of significant pulmonary hypertension, unrelated to left heart pathologic conditions, in 10 patients: four with acute pulmonary embolism; five with chronic pulmonary hypertension, primary in three patients and secondary to tumor emboli in the other two patients; and one with Eisenmenger's syndrome due to previously unsuspected atrial septal defects. Referral diagnoses were pericardial disease in five patients (including three with suspected tamponade), and right ventricular infarction versus pericarditis, atrial septal defect, dyspnea, inferoposterior infarction (by electrocardiography), and Ebstein's malformation in one patient each. The echocardiographic diagnoses were confirmed by lung scan (ventilation/perfusion mismatches were interpreted as high probability for pulmonary emboli in all four patients considered to have acute pulmonary emboli by echocardiographic study), pulmonary angiography (one patient), cardiac catheterization (four patients), and autopsy (three patients). No patient had evident aortic or mitral valvular, myocardial, or other left heart pathologic condition. In acute pulmonary embolism, mean right ventricular diameter was increased at 4.2 cm (range 3.2 to 6 cm) and right ventricular wall thickness was normal (mean 4.5 mm, range 3 to 5 mm). Moderate or marked right ventricular hypokinesis was noted in two patients each. Doppler examination, performed in three patients, revealed tricuspid regurgitation in all, with an increased flow velocity suggestive of mild to moderate systolic pulmonary hypertension (right ventricular minus right atrial pressures of 28 to 36 mm Hg). Patients with chronic pulmonary hypertension also had right ventricular dilatation (mean 4.4 cm diameter, range 3 to 5.4 cm) and hypokinesis (marked in four and moderate in one patient), but wall thickness was increased in all (mean of 9 mm, range 6 to 14 mm) and the flow velocities in the tricuspid regurgitant jets, detected by Doppler in all patients, suggested higher right ventricular minus right atrial pressures of 44 to 104 mm Hg (mean 64 mm Hg). The single patient with Eisenmenger's syndrome had right ventricular dilatation (3.2 cm), hypertrophy (10 mm), and hypokinesis (mild). Only the patient with Eisenmenger's syndrome had Doppler or contrast echocardiographic evidence for an intracardiac or extracardiac shunt. In the absence of left heart pathologic conditions, right ventricular dilatation and hypokinesis strongly suggest pulmonary arterial or primary right ventricular disease. An increase in the right ventricular to right atrial pressure gradient, determined from the tricuspid regurgitant jet, favors pulmonary hypertension and may help to differentiate acute pulmonary embolism, in which only mild to moderate pulmonary hypertension causes right ventricular failure, from chronic pulmonary hypertension. Right ventricular wall thickness is generally normal in acute emboli. Imaging, contrast, and Doppler echocardiography may identify shunts causative of pulmonary hypertension.