P960 Response of alveolo-capillar membrane diffusion to mitral regurgitation in heart failure with reduced ejection fraction

Abstract

Abstract Background In HFrEF patients, high pulmonary vascular resistances (PVR) imply a combined increase of both pre- and post-capillary pressures, associated with worse outcome. Mitral regurgitation (MR) may play a role in this complex physiopathology. We sought to investigate MR impact on lung DLCO and pulmonary vascular hemodynamic in HFrEF patient. Methods 27 HFrEF patients (age 69 ± 9; LV EF 34 ± 6) underwent right heart catheterization, rest and exercise echocardiography, right ventricle 3D assessment and lung alveolo-capillary membrane DLCO. We identified 2 subgroups divided by normal (<3 WU, n= 20) or abnormal (>3 WU, n = 7) PVR. Results Abnormal PVR patients showed increased pulmonary artery pressures and TPG, reduced CO and pulmonary artery compliance. Total DLCO was not significantly different between groups. The membrane component (Dm) and the alveolar volume (Va) were significantly reduced in abnormal PVR group, while the capillary volume (VC) showed a strong trend toward higher values. Abnormal PVR group had a very high percentage of moderate-to-severe MR. The TASPE/SPAP ratio and the circumferential component of RV systolic function were significantly reduced in abnormal PVR group. Conclusion The presence of severe MR is associated with alveolar-capillary membrane remodeling (lower Dm), worse hemodynamic profile (higher PA pressures, lower PA compliance and higher PA resistance) and worse right ventricle to pulmonary circulation coupling (lower TAPSE/SPAP and lower 3D RV circumferential EF) in this cohort of HFrEF patients. These results confirm the adequacy of using therapeutic strategies aimed to solve valvular disease.