Integrated imaging of echocardiography and computed tomography to grade mitral regurgitation severity in patients undergoing transcatheter aortic valve implantation.

Aims: Quantitative mitral regurgitation (MR) grading remains challenging. This study evaluated the concept of integrating echocardiography and computed tomography for grading MR severity. Specifically, an integrated parameter was developed that combines the true cross-sectional mitral regurgitant orifice area (ROA) assessed with multi-detector row computed tomography (MDCT) with flow data from echocardiography.
Methods and Results: Systolic MDCT data of 73 patients, referred for transcatheter aortic valve implantation (TAVI) who also had MR, were evaluated. The MDCT systolic phase with the smaller left ventricular volume and the largest mitral regurgitant orifice was selected. Using planimetry, the mitral ROA was measured. The mitral ROA was multiplied with the velocity time integral of the MR jet on echocardiography for the calculation of the integrated regurgitant volume (RVol). MDCT analysis showed a mean mitral ROA of 11.3 ± 7.4 mm2 and a mean integrated RVol of 21.4 ± 14.7 mL/beat, whereas echocardiography showed a mean effective ROA and RVol of MR of 13.3 ± 8.2 mm2 and 23.9 ± 13.6 mL/beat, respectively. Compared with echocardiography, grading based on integrated mitral RVol resulted in reclassification of 10% of the patients from severe to non-severe MR and 14% of the patients from non-severe to severe MR.
Conclusions: Integrated mitral RVol is a quantitative parameter of MR severity by combining the true cross-sectional mitral ROA assessed with MDCT and Doppler mitral haemodynamics which resulted in a significant reclassification of MR grade in patients with severe aortic stenosis undergoing TAVR.
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