Abstract 296: Comparison of Aortic Root Dimensions and Geometries Pre- and Post-Transcatheter Aortic Valve Implantation by 2- and 3-Dimensional Transesophageal Echocardiography and Multislice Computed Tomography
Background: Currently, aortic annular and left ventricular outflow tract (LVOT) sizing before transcatheter aortic valve implantation (TAVI) rely on 2-dimensional (2D) transesophageal echocardiography (TEE) measurements. 3-dimensional (3D) TEE may provide more accurate results with important clinical implications. We assessed agreements between 2D-, 3D-TEE measurements with multi-slice computed tomography (MSCT), and examined changes in annular and LVOT areas and geometries before and after TAVI.
Methods: 2D circular (calculated by π × r2), 3D circular and 3D planimetered annular and LVOT areas by TEE were compared to “gold standard” MSCT planimetered areas in 53 patients before TAVI. Changes in planimetered annular and LVOT areas after TAVI (as compared to baseline) were also assessed.
Results: Mean MSCT planimetered annular area was 4.65±0.82cm2 before TAVI. Annular areas were underestimated by 2D TEE circular (3.89±0.74cm2, p<0.001), 3D TEE circular (4.06±0.79cm2, p<0.001), and 3D TEE planimetered annular areas (4.22±0.77cm2, p<0.001). Mean MSCT planimetered LVOT area was 4.61±1.20cm2 before TAVI. LVOT areas were underestimated by 2D TEE circular (3.41±0.89cm2, p<0.001), 3D TEE circular (3.89±0.94cm2, p<0.001), and 3D TEE planimetered LVOT areas (4.31±1.15cm2, p<0.001). 3D TEE planimetered annular and LVOT areas had narrowest limits of agreement and least bias compared to respective MSCT gold standard. After TAVI, MSCT planimetered (4.65±0.82 vs. 4.20±0.46cm2, p<0.001) and 3D TEE planimetered (4.22±0.77 vs. 3.62±0.43cm2, p<0.001) annular areas decreased, whereas MSCT planimetered (4.61±1.20 vs. 4.84±1.17cm2, p=0.002) and 3D TEE planimetered (4.31±1.15 vs. 4.55±1.21cm2, p<0.001) LVOT areas increased compared to baseline. The annulus and LVOT became less elliptical after TAVI.
Conclusions: Before TAVI, the aortic annular and LVOT circular geometric assumption (by 2D or 3D TEE) significantly underestimated the respective MSCT planimetered areas. After TAVI, 3D TEE and MSCT planimetered aortic annular areas decreased as the “new effective” annulus assumes the internal dimensions of the prosthetic valve. However, planimetered LVOT areas increased due to a more circular geometry and “splinting” by the prosthetic valve.