Abstract Body: Background: Surgical mitral valve repair is a cornerstone of care for patients with significant mitral valve disease, particularly in acute presentations. The “weekend effect,” describing differences in care delivery and outcomes between weekend and weekday admissions, remains poorly characterized in this population.

Research Question: This study evaluated whether weekend admission for surgical mitral valve repair is associated with differences in clinical outcomes, resource utilization, and hospital charges compared with weekday admissions.

Goals: The goal of this study was to assess the impact of weekend versus weekday admission on in-hospital mortality, length of stay (LOS), resource utilization, and hospital charges among patients undergoing surgical mitral valve repair.

Methods: Patients undergoing surgical mitral valve repair in 2021 were identified using the National Inpatient Sample. Admissions were categorized as weekend or weekday. Multivariable logistic and linear regression models assessed associations between weekend admission and clinical outcomes, including mortality, LOS, resource utilization, and hospital charges. Models were adjusted for demographics and comorbidity burden using the Charlson Comorbidity Index. A two-sided p-value <0.05 was considered statistically significant.

Results: In 2021, 92.2% of surgical mitral valve repair admissions occurred on weekdays and 7.8% on weekends. Weekend admission was not associated with increased in-hospital mortality or vasopressor use. However, weekend admission remained independently associated with prolonged LOS (adjusted β 11.89 days, 95% CI 1.23–22.54, p<0.05).

Among payer groups, Medicare patients had significantly greater total hospital charges compared with privately insured patients (adjusted β $112,138, 95% CI $30,791–$193,485). Medicare patients also had higher odds of mechanical ventilation (aOR 2.49, 95% CI 1.21–5.11), with a similar trend observed among self-pay patients (aOR 4.10, 95% CI 0.98–12.09). Increasing age was associated with greater intra-aortic balloon pump use (aOR 1.04 per year, 95% CI 1.01–1.06).

Conclusion: Weekend admission for surgical mitral valve repair was not associated with increased mortality, suggesting consistent access to life-saving surgical care regardless of admission timing. However, significant differences in LOS, hospital charges, and resource utilization indicate persistent system-level variation in resource utilization, particularly across payer groups.