Screening of Mechanical Complications of Dilated Pulmonary Artery to the Risk for Sudden Cardiac Death in Patients with Pulmonary Arterial Hypertension by Transthoracic Echocardiography

Background: In patients with pulmonary arterial hypertension (PAH), the mechanical complications of pulmonary artery (PA) enlargement are related to sudden cardiac death (SCD). The aim of this study was to investigate the prevalence of PA enlargement, the correlation of main PA (MPA) diameter with other echocardiographic parameters, and the role of transthoracic echocardiography in screening for such complications. Methods: Among 298 patients who were followed for PAH, patients with PA enlargement (>40 mm) by transthoracic echocardiography were consecutively enrolled in a prospective manner. The presence of left main and airway compression, PA dissection, or PA thrombus was determined with cardiac computed tomography. Results: Forty-six patients (15.4%; mean age, 49 +/- 14 years; 32.6% men) with dilated MPAs were enrolled. Mechanical complications were present in 16 patients (34.8%). Those with complications had more dilated MPAs compared with patients without (mean PA diameter, 55.6 +/- 12.2 vs 46.7 +/- 4.3 mm; P=.012). Other echocardiographic parameters of the right heart, such as right ventricular systolic pressure, showed no differences (P>.05 for all). The area under the receiver operating characteristic curve for MPA diameter was 0.750 (95% CI, 0.577-0.923; P=.009), with the highest sensitivity and specificity values for the presence of complications being 85.7% and 58.6%, respectively, according to an MPA diameter of 46.5 mm. Conclusions: Mechanical complications related to sudden cardiac death in patients with PAH with dilated PAs are common. The overall performance of transthoracic echocardiography as a screening tool for predicting such complications appears reasonable. Given the burden of sudden cardiac death, measurement of PA diameter should be routinely included over the course of follow-up, especially in patients with PAH.