Comparative Analysis of Vizient and The Society of Thoracic Surgeons (STS) Performance Ratings in Cardiac Surgery: A Qualitative Review.

Abstract

STS and Vizient each produce rating systems for cardiac surgery performance. At our institution, during a similar timeframe and for nominally similar cohorts, STS ratings indicated exemplary performance while Vizient suggested worse than expected performance. We hypothesized that these discordant quality signals were driven by methodological differences in how each platform defines cohorts, captures data, adjusts risk, and measures outcomes. We conducted a single-institution, 12-month retrospective comparison of procedures categorized as isolated coronary artery bypass grafting (CABG) by either STS or Vizient. We compared data sources, patient cohort definitions, observation periods, risk modeling, and outcome definitions, and performed chart review of cases unique to either database. STS identified 414 and Vizient 407 patients in their isolated CABG cohorts. Of these, 398 patients were shared, while 16 were unique to STS and 9 to Vizient. STS and Vizient recorded discrepant mortality counts (9 vs 8 deaths, respectively). Chart reviews revealed discordant operative procedure classifications and inconsistent capture of perioperative events between systems. STS relies on audited clinical registry data, clinically-defined patient cohorts and risk factors, peer-reviewed risk models and measures, and multi-year rolling data windows. Vizient uses administrative claims data and associated risk-adjustment variables and outcomes, proprietary methodologies, and shorter reporting cycles. Discordant assessments of cardiac surgery performance by STS and Vizient quality ratings reflect multiple methodological differences. Understanding these differences is essential for assessing the credibility of these two performance rating systems, reconciling conflicting reports, educating hospital leadership and the public, and guiding evidence-based quality improvement.