Abstract 18221: Flow Characteristics of CoreValve Transcatheter Aortic Valve: Implications for Calculation of Stroke Volume and Effective Orifice Area

Abstract

Background: The hour-glass shape of the CoreValve THV used for TAVR has raised questions assessing stroke volume (SV) and effective orifice area. Objective: To determine the optimal location of diameter for calculating SV for the CoreValve THV. Methods: 98 TAVR patients with CoreValve THV had intra-procedural TEE analyzed at 3 levels in a mid-systolic frame: the outer-to-outer border of the inflow region (outer level), the inner-to-inner border just within the inflow (inner level), and the inner-to-inner border at the level of neo-aortic leaflets (mid level). Patients with ≥mild paravalvular or pulmonary regurgitation were excluded. THV area was directly planimetered at these levels using 3D TEE. SV was calculated using pulsed Doppler VTIs obtained at these levels, paired with the respective THV area by 2D (SV2D-OUT, SV2D-IN and SV2D-MID) and by 3D (SV3D-OUT, SV3D-IN and SV3D-MID). Right ventricular outflow tract (RVOT) area was calculated from 2D or planimetered directly from CT to calculate SV2D-RVOT and SV3D-RVOT. Results: TEE 2D measurements were performed in 53 patients with 3D measurements in a subset of 27 patients. There was a significant difference between SV2D-RVOT and SV3D-RVOT (p = 0.002) (Table 1). There were no significant differences between the SV2D-RVOT and left-sided SV at all 3 levels. There was a significant difference in SV3D-RVOT and SV3D-MID but not SV3D-OUT or SV3D-IN. For 2D SV measurements, a strong correlation to SV2D-RVOT was observed at all levels (r = 0.94-0.97, p < 0.0001)). For 3D measurements, correlation to SV3D-RVOT was significant although modest (r = 0.46-0.63, p > 0.01). For the subgroup with SV3D-RVOT, there were significant differences in SV2D-OUT (53.7±15.1, p = 0.002), SV2D-IN (53.5±15.0, p = 0.001), and SV2D-MID (53.8±14.2, p = 0.002). Conclusions: This study suggests that consistent SV can be calculated using 2D THV diameters with matching VTI at multiple locations and there is no significant flow acceleration within this valve.