Meta-Analysis of Transthoracic Echocardiography Versus Cardiac Magnetic Resonance for the Assessment of Aortic Regurgitation After Transcatheter Aortic Valve Implantation.

Residual aortic regurgitation (AR) is a major complication after transcatheter aortic valve implantation (TAVI). Although the echocardiographic assessment of post-TAVI AR remains challenging, cardiac magnetic resonance (CMR) allows direct quantification of AR. The aim of this study was to review the level of agreement between 2-dimensional transthoracic echocardiography (2D TTE) and CMR on grading the severity of AR after TAVI, and determine the accuracy of TTE in detecting moderate or severe AR. Electronic databases were searched in order to identify studies comparing 2D TTE to CMR for post-TAVI AR assessment. Kappa coefficient was used to determine the level of agreement between the 2 imaging modalities. CMR was used as the reference standard in order to assess the diagnostic accuracy of 2D TTE. Seven studies were included in this systematic review. Six studies reported a low correlation between 2D TTE and CMR (kappa coefficient ranging from -0.02 to 0.41), whereas one study showed good agreement with a kappa coefficient of 0.72. Given the heterogeneity in the included studies the diagnostic accuracy of TTE was evaluated by estimating the hierarchical summary receiver operator characteristic curve. The area under the curve for detection of moderate or severe AR with TTE was 0.83 (95% confidence interval 0.79 to 0.86). In conclusion, despite the reported significant disconcordance between TTE and CMR grading of AR, TTE has sufficient ability to discriminate moderate or severe AR from mild or none AR after TAVI in the clinical setting. CMR should be considered when TTE results are equivocal.