Quality of Mitral Valve Surgery Does Not Differ by Hospital Volume in New Jersey

Background and Aim of the Study. To investigate if mitral valve (MV) surgery quality differs by hospital volume in New Jersey (NJ). Methods. Using the NJ State Inpatient Database, patients ≥18 years undergoing MV repair or replacement from 2016–2019 were identified. Centers were considered high-volume if they performed more than 50 mitral operations annually. Baseline characteristics and outcomes (in-hospital mortality, seven-day readmission, hospital length of stay (LOS), and postoperative complications) were evaluated for the population and by center volume. Subanalysis by center volume within each procedure was conducted. Results. Among 2,560 mitral operations, MV replacement (92.3% (n = 2,362)) was performed more often than repair. High- (4) and low-volume (15) centers performed 1,180 (46.1%) and 1,380 (53.9%) mitral surgeries, respectively. Charlson Comorbidity Indices did not differ by center volume, including in subgroup analyses. Low-volume centers had higher rates of Hispanic patients, low-income patients, and readmission rates. High-volume centers had more transfers, urgent/emergent admissions, higher rates of in-hospital mortality, and longer LOS. Postoperative complications did not differ by volume. The MV replacement cohort reflected many of the differences seen in the total population, in addition to seeing higher rates of heart failure at high-volume centers and stroke at low-volume centers. Within MV repairs, significantly more Hispanic patients presented to low-volume centers and high-volume centers had longer LOS. Multivariable analysis indicated that hospital volume was not correlated to in-hospital mortality for the total population and within each procedure. Conclusions. MV replacement is performed more frequently than repair. Hospital volume is not correlated with MV surgical quality, and more representative quality measures are needed.