Cardiac Computed Tomography and Echocardiography Integration for Chronic Secondary Mitral Regurgitation Quantification

Objectives: This study aimed to determine whether it would be possible to reclassify the severity of secondary mitral regurgitation (MR) using an integrated mitral regurgitant volume (RVol) derived from computed tomography (CT) and echocardiography data. Methods: This cross-sectional study was conducted at Ibn al-Bitar Specialized Center for Cardiac Surgery, Baghdad, Iraq. Systolic CT data of patients with isolated secondary MR were evaluated from June 2023 to December 2025. The image with the highest regurgitant orifice area (ROA) and the smallest left ventricular volume was chosen from the CT systolic phase. To calculate the integrated RVol (iRVol), the velocity time integral obtained by echocardiography was multiplied by the mitral anatomic ROA (AROA) that was obtained using planimetry. Results: A total of 113 patients were included in this study. While the mean AROA and iRVol measured by CT were 0.143 ± 0.090 cm2 and 26.47 ± 10.61 mL, respectively, the mean effective ROA and RVol of MR measured by echocardiography were 0.175 ± 0.095 cm2 and 27.57 ± 8.82 mL, respectively. A total of 62% of patients were reclassified from severe to non-severe MR and 21% from non-severe to severe MR when iRVol grading was used instead of only echocardiography. Conclusion: By integrating the real cross-sectional mitral ROA measured by CT with Doppler mitral haemodynamics, a quantitative metric for MR severity (called mitral iRVol) was developed, leading to a clinically important reclassification of secondary MR grade.