Measurements of pulmonary artery (PA) distensibility were more effective to detect pulmonary hypertension (PH) due to left heart disease (LHD) than measurements of PA dilatation, in patients with severe heart failure with reduced ejection fraction (HFrEF), aortic stenosis, or primary mitral regurgitation, according to study findings published in European Radiology.
In this prospective, diagnostic and prognostic study, 100 patients (mean age, 63±17 years; 79% men) who were considered for heart transplant due to HFrEF, for transcatheter aortic valve implantation due to aortic stenosis, or for surgery due to primary mitral regurgitation at a single center in Belgium, were recruited between 2015 and 2019. All patients underwent right heart catheterization, ungated computed tomography (CT), electrocardiograph (ECG)-gated CT, and echocardiography.
The patients with vs without PH differed significantly in heart rate (76±13 vs 65±11, respectively; P <.001), rates of atrial fibrillation (32% vs 11%, respectively; P <.001), New York Heart Association functional class III or IV (41% vs 20%, respectively; P <.001), HFrEF (59% vs 41%, respectively; P<.001), aortic stenosis (65% vs 35%, respectively; P <.001), and mitral regurgitation (27% vs 73%, respectively; P <.001).
PA distensibility <18% was found to detect PH-LHD with 96% sensitivity, 73% specificity, an area under the receiving operator curve (AUC) of 0.92, which was significantly larger than the AUCs for tricuspid regurgitation gradient (0.83), or for the ratio of PA diameter to aorta diameter (0.82).
PA distensibility was found to correlate with the patient factors of age (r, -0.35; P <.001), heart rate (r, -0.40; P <.001), mean pulmonary artery pressure (r, -0.72; P <.001), pulmonary artery wedge pressure (r, -0.65; P <.001), pulmonary vascular resistance (r, -0.59; P <.001), right PA minimal cross-sectional area (r, -0.59; P <.001), right PA maximal cross-sectional area (r, -0.42; P <.001), cardiac index (r, 0.38; P <.001), and atrial fibrillation (r, -0.27; P =.006) in a univariate analysis. Detection of PA distensibility was reproducible both within (r, 0.96; P <.001) and between (r, 0.89; P <.001) observers.
Predictors for PA distensibility was independently associated, in a multivariate analysis, with mean PA pressure (ß, -0.41; P <.001), minimal right PA area (ß, -0.008; P =.019), and age (ß, -0.07; P =.019).
Limitations of this study include the fact that CT and right heart catheterization were conducted during separate procedures. In addition, CT was performed while the patient held their breath after a deep inspiration and PA pressure was recorded after a long expiration. These factors may have introduced some variation.
“[I]n patients with severe HFrEF, aortic stenosis, or mitral regurgitation, PA distensibility in ECG-gated CT can detect PH-LHD better than the parameters reflecting PA dilatation in ungated CT or TR gradient in echocardiography,” concluded the study authors.
Colin G C, Verlynde G, Pouleur A C, et al. Pulmonary hypertension due to left heart disease: diagnostic value of pulmonary artery distensibility. [Published online June 16, 2020] Eur Radiol. doi:10.1007/s00330-020-06959-7