Abstract 19074: Relationship Between Hospital Procedure Volume and Complications Following Congenital Cardiac Catheterization: a Report from the IMPACT® Registry

Background: The association between institutional procedural volume and outcomes has been demonstrated for many procedures within the field of cardiology, but whether this relationship pertains to congenital cardiac catheterization is unknown. Methods: Using the IMPACT® (Improving Pediatric and Adult Congenital Treatment) Registry, we identified all catheterizations between 2011 and 2013 at 64 U.S. centers. Programs were categorized as small (<150 cases/year), medium (150 to 300 cases/year), large (300-500 cases/ year), and very large (>500 cases/ year). Hierarchical logistic regression, adjusted for patient and procedural characteristics, was used to determine the association between annual procedural volume and occurrence of a major adverse event (cardiac arrest; arrhythmia requiring permanent pacemaker; tamponade; air embolus; embolic stroke; device malposition, thrombus, or embolization; new requirement for dialysis; event requiring extracorporeal membrane oxygenation or left ventricular assist device; unplanned cardiac, vascular, or other surgery; or subsequent cardiac catheterization). Results: Among 64 hospitals, there were 19 small, 15 medium, 19 large, and 11 very large programs. Among 33,825 catheterizations, a major adverse event occurred in 711 (2.1%). In unadjusted analysis, major adverse events differed based upon annual volume, with a major adverse event occurring in 79 (2.8%) cases at small, 145 (2.3%) cases at medium, 234 (2.1%) cases at large, and 253 (1.9%) cases at very-large programs (p=0.01). After adjusting for patient and procedural risk factors, there was no association between annual procedure volume and occurrence of a major adverse event (odds ratio 0.96 [95% Confidence Interval=0.90, 1.04] per increase in annual volume of 100, p=0.32). There was no interaction between procedure-type risk group and volume on outcomes (p=0.49). Conclusions: Although the unadjusted risk of adverse events was lower in centers performing more catheterizations for congenital heart disease, this association between center volume and outcomes did not persist after adjustment for patient and procedural case-mix. The hospital sample size and low event rate may have limited our ability to detect significant differences.