Increased right ventricular diastolic stiffness and reduced ejection fraction in pulmonary hypertension

Background: Right ventricular (RV) enlargement and systolic dysfunction have been reported in pulmonary hypertension (PH). However, few studies have focused on RV diastolic stiffness and its association with RV morphology and systolic function. Aims: To compare RV diastolic stiffness between PH patients and non-PH subjects and to examine its association with RV size and function in PH Methods: Consecutive 88 PH patients and 14 non-PH subjects (controls) who underwent magnetic resonance imaging (MRI) and right heart catheterization (RHC) within two weeks were enrolled. RV stiffness coefficient (β) and ejection fraction (RVEF) were calculated using MRI-derived RV begin-diastolic volume and end-diastolic volume (RVEDV) and RHC-derived begin-diastolic pressure and end-diastolic pressure. The correlation of β with RVEDV, RVEF and cardiac index (CI) was analyzed. Results: The subtypes of the PH patients were Group 1 (n = 39), Group 2 (n = 1), Group 3 (n = 20), and Group 4 (n = 28). The mean pulmonary arterial pressure of the PH patients was 36.6 ± 10.2 mmHg. When compared with the controls, the PH patients exhibited increased β (0.034 ± 0.015 vs 0.023 ± 0.009, p = 0.01) and decreased RVEF (42.1 ± 12.5 vs 50.1 ± 8.2, p = 0.02). In the PH patients, β significantly correlated with RVEDV (r = -0.25) and RVEF (r = -0.51). Also, β significantly correlated with CI with equivalent correlation coefficient (r = -0.33) compared with that of RVEF (r = 0.30). Conclusions: RV diastolic stiffness increased in PH patients and was inversely correlated with RV size, RVEF and CI. The clinical relevance of the comprehensive assessment of RV morphology and function needs to be further investigated.