Purpose: Evaluations of patients with pulmonary hypertension (PH) commonly include chest computed tomography (CT). We hypothesized that cardiac chamber volumes calculated from the same CT scans can yield additional information to distinguish left heart disease-related PH (WHO Group 2) from other PH subtypes.
Methods: Patients with right heart catheterization (RHC)-confirmed PH and contrast-enhanced chest CT studies were enrolled in this retrospective multicenter study. Cardiac chamber volumes were calculated using automated segmentation software and compared between Group 2 and non-Group 2 PH patients.
Results: This study included 114 PH patients, of whom 27 (24%) were classified as Group 2 based on their pulmonary capillary wedge pressure. Group 2 PH patients exhibited significantly larger median left atrial (LA) volumes (118 vs. 63 mL, P < 0.001), larger median left ventricular (LV) volumes (90 vs. 76 mL, P = 0.02), and smaller median right ventricular (RV) volumes (173 vs. 210 mL, P = 0.005) than non-Group 2 patients. On multivariate analysis adjusted to age, gender, and mean pulmonary arterial pressure, Group 2 PH was significantly associated with larger median LA and LV volumes (P < 0.001 and P = 0.008, respectively), and decreased volume ratios of RA/LA, RV/LV and RV/LA (P = 0.001, P = 0.004, and P < 0.001, respectively). Enlarged LA volumes demonstrated high discriminatory ability for Group 2 PH (AUC=0.92; 95%CI, 0.870-0.968).
Conclusions: Volumetric analysis of the cardiac chambers from non-gated chest CTs, particularly with findings of an enlarged LA, exhibited high discriminatory ability for identifying patients with PH due to left heart disease.
