Multimodality imaging derived energy loss index and outcome after transcatheter aortic valve replacement.

AIMS: To assess whether the combination of transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) data affects the grading of aortic stenosis (AS) severity under consideration of the energy loss index (ELI) in patients undergoing transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: Multimodality imaging was performed in 197 patients with symptomatic severe AS undergoing TAVR at the University Hospital Zurich, Switzerland. Fusion aortic valve area index (fusion AVAi) assessed by integrating MDCT derived planimetric left ventricular outflow tract area into the continuity equation was significantly larger as compared to conventional AVAi (0.41 ± 0.1 vs. 0.51 ± 0.1 cm2/m2; P < 0.01). A total of 62 patients (31.4%) were reclassified from severe to moderate AS with fusion AVAi being >0.6 cm2/m2. ELI was obtained for conventional AVAi and fusion AVAi based on sinotubular junction area determined by TTE (ELILTL 0.47 ± 0.1 cm2/m2; fusion ELILTL 0.60 ± 0.1 cm2/m2) and MDCT (ELIMDCT 0.48 ± 0.1 cm2/m2; fusion ELIMDCT 0.61 ± 0.05 cm2/m2). When ELI was calculated with fusion AVAi the effective orifice area was >0.6 cm2/m2 in 85 patients (43.1%). Survival rate 3 years after TAVR was higher in patients reclassified to moderate AS according to multimodality imaging derived ELI (78.8% vs. 67%; P = 0.01). CONCLUSION: Multimodality imaging derived ELI reclassifies AS severity in 43% undergoing TAVR and predicts mid-term outcome.

Impact of stroke volume assessment by integrating multi-detector computed tomography and Doppler data on the classification of aortic stenosis.

BACKGROUND: The prevalence of low flow low gradient (LFLG) severe aortic stenosis (AS) may be overrated due to underestimation of stroke volume in two-dimensional (2D) echocardiography. The implications of 3D imaging on stroke volume calculation for AS classification have not been elucidated. Integrating multi-detector computed tomography (MDCT) and Doppler data may improve diagnostic accuracy in patients with LFLG AS. METHODS: A total of 186 patients with severe AS evaluated for transcatheter aortic valve replacement were classified according to indexed stroke volume (SVI, cut-off 35mL/m2) and mean transaortic pressure gradient (cut-off 40mmHg). SVI was calculated using a) the biplane Simpson's method, b) left ventricular outflow tract (LVOT) velocity time integral (VTI) and LVOT diameter determined by 2D echocardiography, or c) LVOT VTI and LVOT area planimetered by MDCT. RESULTS: SVI assessed by the biplane Simpson's method was smaller than that obtained from 2D echocardiography LVOT diameter (29.5±0.6 vs 34.9±0.8mL/m2, p<0.001). The latter was smaller than SVI calculated by integrating MDCT and Doppler data (47.5±1.4mL/m2, p<0.001). LFLG and paradoxical LFLG severe AS were diagnosed in 42.5% and 27.4% of patients using the biplane Simpson's method, in 30.1% and 16.7% using 2D echocardiography LVOT diameter, and in 17.2% and 8.1% when integrating MDCT and Doppler data. CONCLUSIONS: The prevalence of LFLG and paradoxical LFLG severe AS was overestimated by 2.5- and 3.4-fold based on 2D echocardiography alone. Integration of MDCT and Doppler data should be considered for stroke volume assessment in the classification of severe AS.