Abstract
AIMS: Pre-capillary pulmonary hypertension (PH(pre-cap) ) has a poor prognosis, especially when caused by pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-PAH). Whether cardiac magnetic resonance (CMR)-based quantification of atrial volumes in PH(pre-cap) is beneficial in risk assessment is unknown. The aims were to investigate if (i) atrial volumes using CMR are associated with death or lung transplantation in PH(pre-cap) , (ii) atrial volumes differ among four unmatched major PH(pre-cap) subgroups, and (iii) atrial volumes differ between SSc-PAH and idiopathic/familial PAH (IPAH/FPAH) when matched for pulmonary vascular resistance (PVR). METHODS AND RESULTS: Seventy-five PH(pre-cap) patients (57 ± 19 years, 53 female, 43 de novo) with CMR and right heart catheterization were retrospectively included. Short-axis stacks of cine images were analysed, and right and left atrial maximum (RAV(max) and LAV(max) ) and minimum volume (RAV(min) and LAV(min) ) were indexed for body surface area. Increased (mean + 2 SD) and reduced (mean - 2 SD) volumes were predefined from CMR normal values. Transplantation-free survival was lower in patients with increased RAV(max) than in those with normal [hazard ratio (HR) = 2.1, 95% confidence interval (CI) 1.1-4.0] but did not differ between those with reduced LAV(max) and normal (HR 2.0, 95% CI 0.8-5.1). RAV(max) and RAV(min) showed no differences among unmatched or matched groups (P = ns). When matched for PVR, LAV(max) , LAV(min) , and pulmonary artery wedge pressure were reduced in SSc-PAH compared with IPAH/FPAH (95% CI 0.3-21.4, 95% CI 0.8-19.6, and 95% CI 2-7, respectively). CONCLUSIONS: Patients with PH(pre-cap) and increased right atrial volume measured with CMR had worse clinical outcome. When matched for PVR, left atrial volume was lower in SSc-PAH than in IPAH/FPAH, consistent with left-sided underfilling, indicating a potential differentiator between the groups.