Operative Details and Clinical Outcomes of Chordal Preservation in Mitral Valve Replacement Surgery

BACKGROUND Chordal preservation in mitral valve replacement (MVR) has been historically associated with favorable postoperative left ventricular remodeling. We evaluated the outcomes of chordal preservation in a contemporary MVR cohort. METHODS Consecutive MVR patients at a single institution (2015-2024) were divided into chordal preservation and non-preservation groups. Baseline differences were balanced by inverse probability of treatment weighting. Primary outcome was survival. Secondary outcomes included change in left ventricular ejection fraction and end-diastolic diameter between pre- and postoperative echocardiography. Subgroup analyses by mitral valve disease etiology were performed. RESULTS Of 320 patients, 244 (76.3%) underwent chordal preservation and 76 (23.7%) did not. Adjusted Kaplan-Meier analysis demonstrated similar postoperative four-year survival between chordal preservation and non-preservation patients (79.0% vs. 75.3%, p=0.31), confirmed by multivariable Cox regression adjusting for concomitant tricuspid surgery and prosthesis type (aHR 0.67 [0.33-1.35], p=0.26). Percent change in left ventricular ejection fraction (-1.2% vs. -1.5%, p=0.94) and end-diastolic diameter (-13.5% vs. -6.5%, p=0.12) were similar. In adjusted subgroup analyses, chordal preservation was associated with improved survival in myxomatous disease (aHR 0.23 [0.09-0.59], p=0.002) but not rheumatic disease (aHR 0.55 [0.20-1.52], p=0.25); however, formal interaction analysis showed no evidence that the effect of preservation differed by etiology (Wald p=0.44). CONCLUSIONS After adjustment, chordal preservation was not associated with differences in overall survival or early left ventricular function in contemporary MVR. We found no evidence that mitral valve disease etiology modifies this association.