Differences in clinical and echocardiographic features and outcomes between atrial functional mitral regurgitation patients with and without posterior mitral leaflet bending

Posterior mitral leaflet (PML) bending is a cause of atrial functional mitral regurgitation (AFMR). We aimed to investigate differences in clinical and echocardiographic features and outcomes between AFMR patients with and without PML bending. We retrospectively examined 118 AFMR patients with atrial fibrillation (AF), mild or greater MR without degenerative mitral valve changes, and left ventricular ejection fraction ≥50 %. Patients were classified by the presence of PML bending: PML bending (n=24) and no PML bending (n=94). PML bending was defined as PML-to-anterior mitral leaflet angle ratio ≥3.1 calculated using receiver operating characteristics analysis for eccentric MR jet toward left atrial posterior wall. The study endpoint was a composite of cardiac death, admission for heart failure, and mitral valve surgery. Overall, a total of 88 patients (75 %) had mild MR. There were no between-group differences in clinical and echocardiographic characteristics including AF duration and cardiac cavities size except for the length of inward bending of the left ventricular posterobasal wall and the mitral annular area. The 36-month event-free survival for the composite endpoint was significantly lower in the PML bending group (63 % vs. 78 %; Log-rank p=0.047). In multivariate analysis, PML bending was also associated with the composite outcome. AFMR patients with PML bending may have worse outcomes than those without PML bending despite similar clinical features. PML bending in AFMR. PML bending has attracted attention because of the distinctive morphology of the mitral valve complex, characterized by flattened anterior mitral leaflet and tethered PML resulting in eccentric mitral regurgitation jet toward the left atrial posterior wall. Patients with PML bending might have worse outcomes than those without PML bending. AFMR, atrial functional mitral regurgitation; PML, posterior mitral leaflet. [Display omitted] •Posterior mitral leaflet (PML)-to-anterior mitral leaflet angle ratio ≥3.1 was the determinant of eccentric jet.•PML bending was present in 20 % of atrial functional mitral regurgitation (AFMR) patients.•Duration of atrial fibrillation and left atrial size did not differ between patients with and without PML bending.•PML bending was associated with adverse events in AFMR patients.