The aim of this study was to develop a graphical method of risk-stratified outcome analysis in paediatric cardiac surgery to provide a means of continuous, prospective performance monitoring and allow real-time detection of change in outcomes.Methods:
Risk-adjusted survival following open-heart surgery was prospectively measured over a 15-month period (n = 460). Outcomes were charted using variable life-adjusted display (VLAD) charts, which indicate the cumulative difference in observed minus expected survival against the cumulative number of cases performed. Risk stratification was based on RACHS-1 (risk adjustment in congenital heart surgery) risk category and age at surgery, using our previously published risk model. The probability of deviation in performance from the expected baseline level was determined using a mathematical model.Results:
By the end of the series, observed survival (443/460 = 96.3%) exceeded that predicted by the risk model (434.5/460 = 94.5%), equivalent to a one-third reduction in expected mortality. Mathematical modelling indicated a 1-5% likelihood that this difference would have occurred by random variation alone, suggesting the outcomes represented genuine improvement.Conclusions:
VLAD charts provide an effective, easily visualised display of surgical performance and can be applied to paediatric cardiac surgery. Early detection of change, whether improvement or deterioration, is important for ongoing quality assurance within a cardiac surgery programme.