Incremental prognostic value of regurgitant fraction in patients with secondary mitral regurgitation

Abstract Background Quantitative parameters of mitral regurgitation (MR), such as effective regurgitant orifice area (EROA), regurgitant volume (RegVol) and regurgitant fraction (RF), assessed by the proximal isovelocity surface area (PISA) method, are recommended measures of MR severity. Although studies have demonstrated that EROA is a predictor of outcome, comparative studies are limited. Purpose The aim of the study was to compare the prognostic value of parameters of MR severity derived from the PISA method in patients with secondary MR. Methods We retrospectively analysed 186 patients who consecutively underwent a comprehensive echocardiographic examination at out department in 2019 and had been diagnosed with more than mild secondary MR. Quantitative parameters of MR severity were separately reported: EROA, RegVol and RF by the PISA method. The clinical outcome was a composite of all-cause death or hospitalisation due to heart failure between the echocardiographic examination and the end of 2023. Results During the median follow-up of 769 (106-1584) days, 107 patients reached the composite endpoint. By univariate Cox regression, EROA ≥40mm2 and RF ≥50% were strongly associated with the combined clinical endpoint, while RegVol ≥60 ml showed no significant association. Adding either EROA≥40mm2 or RF≥50% to the baseline model (including age, left ventricular end-systolic volume index, stroke volume index, right ventricular diameter and pulmonary systolic pressure) enhanced the model’s association with the combined clinical outcome (Pannel A). Including both EROA and RF in the same model significantly improved its performance compared to using either EROA ≥40mm2 or RF ≥50% alone (Panel A). Kaplan-Meier curve showed that patients with both EROA