P2270Clinical characteristics and outcomes after TAVI in patients reclassified to moderate aortic stenosis by integration of multimodality imaging and pressure recovery
Authors: Holy E W , Nguyen-Kim D L , Hoffelner L , Stocker D L , Stadler T , Staehli B , Kebernik J , Maisano F , Ruschitzka F , Frauenfelder T , Nietlispach F , Tanner F 
Published: October 2019

Abstract

Background
Accurate assessment of aortic stenosis (AS) severity is critical for the correct management of patients. This has become particularly important because the introduction of transcatheter aortic valve implantation (TAVI) has markedly increased the number of patients eligible for aortic valve replacement

Aims
To assess whether reclassification of aortic stenosis (AS) grading by integration of fusion imaging using data from transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) under consideration of the energy loss index (ELI) predicts outcome in patients undergoing transcatheter aortic valve implantation (TAVI).

Methods
197 consecutive patients with symptomatic severe AS undergoing TAVI at our University Heart Center were included in this study. AS severity was determined according to current guidelines.

Results
Left ventricular outflow tract (LVOT) area derived from TTE was smaller than the planimetric area in MDCT due the ovoid shape of the LVOT (3.4±0.12 cm2 vs. 4.5±0.23 cm2; p<0.01). The sinotubular junction (ST-junction) diameter measured in TTE was similar to maximal, minimal, and mean diameters determined by MDCT. The sphericity index confirmed an almost circular anatomy of ST-junction, and its area derived from TTE was similar to the planimetric area in MDCT. Fusion aortic valve area index (fusion AVAi) assessed by inserting MDCT derived planimetric LVOT area in the continuity equation was significantly higher in all patients compared to conventional AVAi. 62 patients were reclassified from severe to moderate AS because fusion AVAi was >0.6 cm2/m2. ELI was calculated for conventional AVAi and fusion AVAi each with ST-junction area determined by both TTE and MDCT. Calculating ELI with fusion AVAi resulted in significantly larger effective orifice area, with values >0.6 cm2/m2 in 83 patients (ST-junction area from echo) and 85 patients (ST-junction area from MDCT). Similarly, calculating ELI with conventional AVAi resulted in significantly larger effective orifice area as compared to AVAi alone. Reclassified patients had lower mean transvalvular pressure gradients, lower myocardial mass, less symptoms according to NYHA classification, and lower proBNP levels at baseline. While both groups exhibited improvement of functional status at 1 year of follow-up, the survival rate at 3 years after TAVI was higher in patients reclassified to moderate AS (81% versus 66%; p=0.02).

Conclusion
Integration of TTE and MDCT derived values for calculation of ELI reclassifies the severity of AS in 43% of patients initially diagnosed with severe AS.Although reclassified patients display less advanced valve disease at baseline, TAVI results in functional improvement in all patients. Furthermore, patients reclassified to moderate AS exhibit higher survival rates at 3 years after aortic valve replacement.