Proportionality analyses based on EROA (COAPT 0.002 vs MITRA-FR 0.001 cm-1) differ from volume analyses (0.15 vs 0.18), casting doubt that EROA alone explains the differing trial outcomes.
Can differences in clinical outcomes between the MITRA-FR and COAPT trials be explained by the severity of regurgitant volume relative to end-diastolic volume?
Proportionality analyses based on regurgitant volume contradict those based on EROA, suggesting that EROA analysis alone cannot explain the disparate clinical outcomes between the COAPT and MITRA-FR trials.
Importance: Two randomized clinical trials of transcatheter edge-to-edge mitral valve repair in patients with secondary mitral regurgitation (the Multicentre Randomized Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation MITRA-FR and the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation COAPT) report clinical outcome disparities that are largely unexplained. This appraisal sought to provide insight and an explanation for the differences in clinical outcomes (survival and hospitalization rates) in the 2 clinical trials. The mean echocardiogram Doppler results (and derived volume parameters) from each of the 2 clinical trials were compared and examined relative to the clinical outcomes. Special emphasis was placed on the assessment of mitral regurgitation proportionality coefficients that were determined as the ratio of effective regurgitant orifice area (EROA) to end-diastolic volume and the ratio of mitral regurgitant volume to end-diastolic volume. Observations: In this analysis of the differences in the clinical outcomes of the MITRA-FR and COAPT clinical trials, the ratio of the EROA to the end-diastolic volume in the COAPT study was found to be twice that of the MITRA-FR study (0.002 cm-1 vs 0.001 cm-1, respectively). The finding of a larger proportional EROA in the COAPT study suggests more severe mitral regurgitation compared with the MITRA-FR study, thereby providing a potential explanation for the different outcomes in the 2 clinical trials. In contrast, the ratio of the mitral regurgitant volume to the end-diastolic volume in the COAPT study was similar to (but slightly lower than) that of the MITRA-FR study (0.15 vs 0.18, respectively), indicating that the proportional mitral regurgitant volume was comparable in the 2 clinical trials. This finding contradicts the conclusions of the EROA analysis. Conclusions and Relevance: The results of proportionality analyses based on EROA differ from those based on a volume analysis. This disparity casts doubt on the notion that an EROA analysis alone can explain the different results of the 2 randomized clinical trials.
Gaasch et al. (Wed,) conducted a review in Secondary mitral regurgitation. Transcatheter edge-to-edge mitral valve repair was evaluated on Ratio of effective regurgitant orifice area (EROA) to end-diastolic volume and ratio of mitral regurgitant volume to end-diastolic volume. Proportionality analyses based on EROA (COAPT 0.002 vs MITRA-FR 0.001 cm-1) differ from volume analyses (0.15 vs 0.18), casting doubt that EROA alone explains the differing trial outcomes.
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