Right heart dimensions and pulmonary arterial wedge pressure in pulmonary arterial hypertension: exploring a controversial relationship

Abstract The potential for progressive right ventricular (RV) enlargement in pulmonary hypertension (PH) to disproportionately elevate left ventricular end-diastolic pressure (LVEDP) remains controversial. This diagnostic uncertainty may complicate accurate classification between Group 1 and Group 2 PH, particularly in patients with advanced disease. This study investigates the relationship between right and left ventricular dimensions, and their association with LVEDP, estimated via pulmonary capillary wedge pressure (PCWP), in a large, multicenter cohort of patients with pulmonary arterial hypertension (PAH). Methods A post-hoc analysis was performed on 401 patients with idiopathic, heritable, or connective tissue disease-associated PAH, prospectively enrolled in the ULTRAsound RIGHt venTricular eVALUation (ULTRA RIGHT VALUE) registry. This represents the first multicenter, observational registry involving 8 European expert PAH referral centers, distinguished by centralized echocardiographic interpretation and high-quality imaging data. Each patient underwent a comprehensive clinical, echocardiographic, and hemodynamic assessment. Correlations between PCWP and ventricular dimensions were analyzed at baseline and after fluid challenge test. Results A total of 401 prevalent patients with PAH were enrolled. The mean age was 52±17 years. Idiopathic PAH was the most common subtype (244, 61%). At enrollment, 357 patients (89%) were classified as functional class (WHO-FC) II or III. ESC/ERS risk stratification revealed a relatively balanced distribution across low, intermediate, and high-risk categories, with a smaller subset of high-risk patients (8.5%). The REVEAL 2.0 risk score distribution is closely aligned with the ESC/ERS model. There were no significant correlations observed between RV end-diastolic area (RVEDA) (r=0.07, p=ns), LV end-diastolic eccentricity index (LVEId) (r=-0.06, p=ns), and LV end-diastolic area (LVEDA)(r=-0.004, p=ns) with PCWP at baseline. No correlation was found between ∆PCWP and ∆PVR (r=-0.06, p=ns) in 150 patients (37%) from baseline to follow-up. The fluid challenge test was available in 17 patients with severe RV dilatation and dysfunction. We found no significant correlation between PCWP and PVR at the end of the fluid challenge test (r=0.005, p=ns). No significant correlation was observed after fluid challenge test between changes in PCWP and baseline RVEDA and LVEI-d (respectively, r=0.224, p=ns; r=0.529, p=ns). The ratio between the peak early diastolic mitral inflow velocity and early diastolic mitral annular velocity (E/E’) value after fluid challenge was not significantly correlated with the delta PCWP (r= 0.237, p=ns). Conclusions In patients with severe PAH, no significant correlations were found between PVR, RVEDA, LVEId, or LVEDA and PCWP at baseline and after fluid challenge test. A markedly elevated PCWP should be considered as a non–Group 1 PH.Plot between PCWP and LVEI-d.