145 AORTIC REGURGITATION AFTER COREVALVE TRANSCATHETER AORTIC VALVE IMPLANTATION (TAVI): ASSESSMENT BY ECHOCARDIOGRAPHY AND CARDIOVASCULAR MAGNETIC RESONANCE

Abstract

Background Transcatheter Aortic Valve Implantation (TAVI) is increasingly used to treat patients with severe aortic stenosis at high surgical risk. The severity of post-implantation valvular or paravalvular regurgitation has been shown to adversely affect patient outcome. The aim of the study was to assess the prevalence and severity of aortic regurgitation (AR) at 6 months post-TAVI using cardiovascular magnetic resonance (CMR).Methods 25 severe aortic stenosis patients underwent a 1.5T CMR (Intera, Philips Healthcare) scan at baseline and 6 months after CoreValve™ TAVI. LV function was assessed using cine imaging with a steady state free precession pulse sequence. The LV outflow tract was imaged in two planes and through-plane phase contrast velocity imaging was performed perpendicular to the aortic valve and transverse to the aorta at the sinotubular junction. Post-processing was performed using QMass 7.2 and QFlow 5.2 (Medis, The Netherlands). AR severity was defined using regurgitant fraction (RF) as: none to mild<8%, mild to moderate 8–19%, moderate to severe 20–29% and severe >30%. Transthoracic echocardiography (iE33, Philips Healthcare) was performed at baseline and 6 months follow-up. Aortic regurgitation was graded using a comprehensive integrated approach following the recent Valve Academic Research Consortium (VARC) guidelines.Results Mean age was 80.6±6.6 years, 44% were female, Logistic EuroSCORE 19.5±14.9 LV ejection fraction significantly improved post-TAVI (52.1±11.8% vs 55.9±9.6%, p<0.0001) and reduction in indexed end-systolic LV volume (46±18 ml/m2 vs 41±17 ml/m2, p=0.02). The end-diastolic volume (95±18 ml/m2 vs 91±20 ml/m2, p=ns) and stroke volume (48±10 ml/m2 vs 50±10 ml/m2, p=ns) did not change. There was a significant reduction in aortic RF 6 months post-TAVI (median RF 12.4%, IQR 5.6–16.8% vs 6.2% IQR 3.6 to 13.2%, p=0.034) (figure 1). There was no significant difference between the transthoracic echo grading and CMR grading of aortic regurgitation. (χ2=3.74 p=0.159) (figure 2). Echocardiography showed statistically significant reductions in peak forward flow velocity (4.87±0.57 ms−1 vs1.98±0.35 ms−1 p<0.05), peak pressure gradient (96.1±24.3 mm Hg vs17±5.7 mm Hg p<0.05) and mean pressure gradient (54.8±15.9 mm Hg vs8±3 mm Hg p<0.05) compared to baseline; the effective orifice area (EOA) was significantly larger compared to the baseline state (0.57±0.03 cm2 vs 1.63±0.3 cm2 p<0.05).Quantification of aortic regurgitation by CMR phase contrast velocity mapping before and 6 months after TAVI implantation.Comparison of aortic regurgitation grading by CMR and transthoracic echocardiograph.Conclusions There was an overall reduction in aortic regurgitant fraction post-TAVI even in the presence of pre-existing AR. CMR can be used in the TAVI population, pre- and post-procedure to quantify the degree of aortic regurgitation.Funding SP is funded by a British Heart Foundation fellowship (FS/10/62/28409). SP and JPG receive an educational research grant from Philips Healthcare.