5942Clinical outcomes and prognostic implications of effective regurgitant orifice area. Defining severe mitral regurgitation

Background Previous studies showed that the effective regurgitant orifice area (EROA) is a strong predictor of clinical outcomes. However, there is controversy over the optimal threshold that identifies patients at high-risk, especially in secondary mitral regurgitation (MR). Purpose To determine the optimal EROA threshold that identifies a subgroup patients with an increased risk of cardiac death and hospitalization for heart failure (HF), in both, primary and secondary MR. Methods A total of 6022 consecutive transthoracic echocardiograpic studies were analysed. Patients with significant MR were prospectively included. The EROA was calculated by the PISA method. Each patient was followed up for three years. Cox regression was performed to study predictors of the combined end-point. ROC curve analysis was performed to determine the optimal cut-off values of EROA. Results Significant primary MR was found in 115 patients (62%), whereas significant secondary MR was described in 71 studies (38%). In primary MR, the optimal threshold of EROA for predicting the combined end-point was 45mm2 (Sn=85.7%; Sp=82.2%). After adjusting for NYHA class, ejection fraction and chronic kidney disease, an EROA ≥45mm2 was strongly associated with cardiac death and admissions due to HF (HR 15.65, 95% CI 4.34–56.47, p Sensitivity and specificity curves Conclusions Our study demonstrates that an EROA of at least 45mm2 in primary MR or of at least 21mm2 in secondary MR is independently associated with a significantly increased risk of cardiac death and hospitalization for HF.