Factors Associated with Operative Mortality in Medium Volume Congenital Heart Surgery Centers: A Mixed-Methods Analysis.

Abstract

An inverse relationship exists between congenital heart surgery center volume and mortality. However, mortality rates are heterogeneous within volume strata, and intra-stratum variability has not been studied. We studied medium volume centers (MVC, 75-200 annualized index cases/year) to identify factors associated with center-level mortality. We identified MVC from The STS Congenital Heart Surgery Public Reporting website (7/2019-6/2023). Surgical leaders were asked to complete a survey and a semi-structured interview. Topics included hospital demographics, organizational structure, resources, partner relationships, and multidisciplinary collaboration. A codebook was developed using a combined deductive-inductive approach. Interview transcripts were analyzed using reflexive thematic analysis. Centers were then stratified by overall O/E mortality ratios (> or < 1.0). Stratified data were reviewed, code summaries generated, and overarching patterns and themes identified. Forty-two MVC were identified. Surgeon leaders from 36 centers (86%) completed the survey and 32 the interview (76%). Regardless of observed-to-expected (O/E) mortality ratios, team cohesion, technical skill, and experience, as well as accessible, supportive hospital administrations were considered critical. Leaders from centers with O/E<1 had stronger administrative support, funding, and dedicated resources, whereas leaders of programs with O/E>1 reported more communication challenges and administrative disconnects. Staffing shortages and inexperienced personnel were common challenges for both groups. Alignment with and support from hospital administration and provider team composition are associated with center-level mortality in MVC, yet these factors are not in databases used to evaluate performance. Understanding these factors is essential for defining program quality and guiding strategies to enhance performance.