Different Patterns of Adaptation of the Right Ventricle to Pressure Overload: A Comparison between Pulmonary Hypertension and Pulmonary Stenosis

Background The study was designed to compare RV morphological and functional parameters derived from conventional and myocardial deformation echocardiography in two instances of right heart pressure overload: pulmonary arterial hypertension (PAH) and pulmonary stenosis (PS). Methods Sixty-two individuals were included: 22 patients with pulmonary arterial hypertension (PAH), 19 patients with PS and 21 healthy individuals who served as a control group. All patients had clinical evaluation with 6-minute walking test, standard and two-dimensional strain echocardiography and B-type natriuretic peptide evaluation. Results At similar levels of pressure overload (RV systolic pressure, 88.2 ± 31.5 vs 73.4 ± 34.9 mm Hg; P = NS) the right ventricles of patients with PS were less dilated (RV end-diastolic diameter, 31.7 ± 3.7 vs 43.7 ± 10.5 mm; P < .001) and performed significantly better than those of patients with PAH (RV strain, −27.4 ± 5.8% vs 16.2 ± 7.9%; RV fractional area change, 51.1 ± 9.2% vs 29.1 ± 11.3%; P < .001). Although some of the RV functional parameters were comparable with those in healthy individuals, strain rate showed lower values, suggesting subclinical longitudinal dysfunction in patients with PS. Myocardial stress biomarkers were correlated with RV systolic pressure only in patients with PAH ( r = 0.64, P = .03), not in those with PS ( r = 0.22, P = .50). Conclusions At similar levels of pressure overload, the right ventricle is less dilated and performs better in patients with PS compared with those with PAH.