Serial global and longitudinal RV functional assessment in symptomatic, severe aortic stenosis undergoing AVR

Abstract

Abstract Background Right ventricular (RV) dysfunction is currently regarded as an end-stage marker of of cardiac damage in patients with severe aortic stenosis (AS). However, global RV assessment prior to and after aortic valve replacement (AVR) has largely been neglected and little is known about RV response after AVR. Aims to describe the prevalence of RV dysfunction in a group of patients with severe AS referred to surgical AVR, and to evaluate post-operative evolution, as assessed by both CMR and echocardiography. Methodology Single-center prospective cohort study of patients with isolated severe symptomatic high-gradient AS submitted to surgical AVR. Those with previous known cardiomyopathy were excluded. All patients performed same day transthoracic echocardiogram (TTE) and CMR both before surgery and at the 3rd to 6th post-operative month. Global RV dysfunction was defined by an RVEF <45% at CMR. Echocardiographic evidence of RV dysfunction was defined by: tricuspid annular plane excursion (TAPSE) <17mm, free wall longitudinal strain (FWLS) >- 21% or RV S’ wave by tissue Doppler imaging <12 cm/s. Results A total of 112 patients were included (mean age 71 ± 8 years; mean valvular transaortic gradient 61 ± 18 mmHg; mean indexed aortic valve area 0.4 ± 0.1 cm2/m2; mean indexed systolic volume 48 ± 11mL/m2,mean LV ejection fraction by CMR pre and post-AVR: 60 ± 10% and 59 ± 8%; mean pulmonary artery systolic pressure pre-AVR: 35 ± 10mmHg). Only four of the patients (3.4%) had pre-operative stage 4 cardiac damage (RV dysfunction) as assessed by CMR. Moreover, only FWLS at TTE was significantly related to CMR RVEF at both pre-operative (Spearmen R= -0.337, p<0.001) and post-operative evaluation (Spearmen R = -0.217, p=0.026). Contrary to CMR RVEF (58 ± 15% vs. 57 ± 8%, p=0.461), there was a significant worsening of all TTE parameters at post-operative evaluation – overall, 32%, 20% and 25% of patients met one, two or three echocardiographic parameters of RV dysfunction - Figure 1. Conclusion RV dysfunction is common after AVR is patients with severe AS as assessed by common TTE parameters, but this is not accompanied by significant impairment of RVEF. Overall, only FWLS showed a consistent, albeit only moderate, correlation with RVEF at pre and post-AVR. These results highlight the limitations of longitudinal function indexes in evaluating post-surgical global RV function.