CRT-700.10 Aortic Valve Area and Prosthesis-Patient Mismatch Estimated by Echocardiography Versus Computed Tomography for Transcatheter Aortic Valve Replacement

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Conference Proceeding

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Background: Patient prosthesis mismatch (PPM) is a size discrepancy between the implanted valve’s orifice area and the patient’s native valve orifice area, and is associated with poor patient outcomes. Echocardiography is the standard modality used in pre-procedural transcatheter aortic valve replacement (TAVR) planning, valve sizing, and evaluation of PPM, yet it is limited by inaccuracies inherent to aortic valve area (AVA) assessment derived from the measured left ventricular outflow tract (LVOT) diameter. Computed tomography angiography (CTA) has become a core element of pre-TAVR planning, as it offers a three-dimensional and more accurate assessment of the LVOT and AVA compared to transthoracic echocardiography (TTE). We sought to compare CTA and TTE on their assessment of AVA and incidence of PPM post-TAVR. Methods: This is a retrospective single-center study of patients who underwent TAVR. Pre- and post-TAVR TTE, and pre-procedural CTA data were analyzed. The continuity equation was used to calculate AVA. TTE AVA was calculated using the post-TAVR TTE LVOT area derived from the measured LVOT diameter. CTA AVA was calculated using measured pre-TAVR CTA LVOT area and post-TAVR velocity indices. Rates of PPM were analyzed by post-TAVR TTE and CTA by dividing respective calculated AVA by the patient’s body surface area. Results: A total of 65 patients with routine post-TAVR follow-up TTE were included in this study (mean age: 79 years; 40% male). On average, post-TAVR AVA determined by CTA was 0.537 cm2/m2 larger (p <0.0001) than post-TAVR AVA determined by TTE, indicating TTE has a higher incidence of AVA under-sizing compared to CTA. Indexed effective orifice area (iEOA) determined by CT was on average 0.2755 cm2/m2 larger (p <0.0001) than iEOA determined by TTE, indicating higher rates of false positive PPM by TTE. With TTE, moderate PPM was detected in 29% of patients and severe PPM in 4.6% of patients. With CTA, moderate PPM was detected in 6.2% of patients and severe PPM in 1.5% of patients. All patients were clinically asymptomatic for heart failure post-TAVR. Conclusion: There is a significant difference in AVA determined by TTE versus CTA. TTE predicts higher incidence of PPM compared to CTA, therefore resulting in higher incidence of false positive PPM detected by TTE. Larger studies are necessary to define appropriate post-TAVR evaluation workflows.

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