Pulmonary vascular remodeling and right ventricular adaptation in precapillary pulmonary hypertension

Background: In precapillary pulmonary hypertension (PH) as pulmonary arterial hypertension (PAH), chronic thromboembolic PH (CTPEH) and PH due to hypoxia and lung disease (HPH) the different pathomechanisms of vascular remodeling result in different right ventricular (RV) adaptation. Routine clinical factors which could predict vascular remodeling are lacking. Purpose: Our aim was to investigate the differences in parameters of pulmonary vascular remodeling and RV adaptation in subgroups of precapillary PH and to correlate the severity of PH with these parameters. Methods: Fifty-one patients (age 57±15 years) with precapillary PH (PAH N=18, CTEPH N=15, HPH N=18;) underwent right heart catheterization (RHC) and results of RHC, echocardiography and laboratory tests were analyzed retrospectively. Results: The majority of parameters did not show difference among PH groups, but diastolic PAP was higher in PAH than in CTEPH and HPH (p<0.05) and RV outflow tract velocity time integral (RVOT VTI) and RV stroke work index were increased in PAH compared to HPH (p<0.05). Pulmonary vascular resistance (PVR) showed a significant relation to pulmonary arterial compliance (PAC) in the total cohort (p<0.05, r=–0.661) and in all subgroups (PAH p<0.05, r=–0.70; CTEPH p<0.05, r=–0.525; HPH p<0.05, r=–0.793). In PAH, all parameters including RVOT VTI and acceleration time (AT), tricuspid annular plane systolic excursion, RV diameter and right atrial area showed correlations with PVR. In the HPH group, only RVOT AT had a correlation with PVR, but no parameters in the CTEPH group showed a relationship to other factors. Conclusion: In precapillary PH the different degree of RV adaptation in the subgroups is shown by RVSWI as an invasive parameter. The severity of PH is related to PAC in precapillary PH. Some parameters can better characterize the severity of vascular and cardiac changes in PAH than in CTEPH or HPH.