Mathematical modeling for predicting the optimal size of ring annuloplasty in the repair of degenerative mitral valves

Background: During mitral valve repair (MVRe), the sizing of the prosthetic ring/band often depends more on the surgeon's experience than objective methodology. The study aims to validate a mathematical approach based on transthoracic echocardiography to predict the optimal ring size in a surgical cohort. Methods: Patients who underwent MVRe between July 2021 and July 2023 were retrospectively evaluated. Pre-operative echocardiography data were collected [including pre-operative coaptation length (CL0), anteroposterior (AP) diameter, anterior mitral leaflet (AML) length, posterior mitral leaflet (PML) length]. A dedicated formula was developed to predict the postoperative AP (pAP) diameter, ensuring a CL of 8 mm, according to the literature. Based on the calculated pAP, the optimal ring size was selected using the manufacturer's ring charts. A linear regression study tested the consistency between the predicted and implanted sizes. Results: Fifty-four patients were included; six implanted a Flexible Band, 17 a Semirigid Band, and 31 a Semirigid Ring. In linear regression, there was an acceptable correlation between predicted/implanted sizes (r=0.589; P