Surgical management of congenital heart disease: evaluation according to the Aristotle score

Abstract

The Aristotle basic complexity (ABC) score (1.5-15 points) is the sum of potentials for early mortality, morbidity and anticipated surgical technique difficulty. The Aristotle comprehensive complexity (ACC) score (1.5-25 points) is the sum of ABC score and patient-adjusted complexity score; it comprises six complexity levels. We used the ACC score to evaluate quality in surgical management of congenital heart disease. Procedures performed in year 2002 and 2007 were analysed. Proportion of procedures requiring at least 1 week of stay in the intensive care unit was chosen as the marker of morbidity. We adopted threshold duration of 120 min for cardio-pulmonary bypass (CPB) cases and the same duration for operations without CPB as surrogate of surgical technical difficulty. The ACC scores were correlated to mortality, morbidity and technical difficulty. This study included 758 patients who underwent 787 primary procedures. The mean ABC and ACC scores amounted to 7.61+/-2.46 and 9.51+/-3.84. Early mortality was 3.05% (24/787), 95% confidence interval (CI): 1.97-4.51%. Zero at ACC levels 1 and 2, it increased from 1.2% (2/161) for level 3 up to 22.2% (2/9) for level 6. Morbidity index was evaluated at 25.9% (204/787), 95% CI: 22.9-29.1%. 1.9% at level 1, it escalated up to 77.8% at level 6. Index of technique difficulty was estimated at 35.2% (277/787), 95% CI: 31.8-38.6%, ranging from 4.8% for level 1 to 66.7% for level 6. A high correlation was found between the ACC scores and mortality, indices of morbidity and technique difficulty, Spearman's correlation coefficient r being 0.9856, 1 and 0.9429, respectively. Mortality (p=0.037) and morbidity (p=0.041) were lower in year 2007 than in 2002 with ABC (p=0.18) and ACC (p=0.37) surgical performance being not significantly different. The Aristotle score is still under development. Morbidity evaluation should be ideally based on observed postoperative complications; estimation of surgical technical difficulty chosen in this study may not be generalised. Nevertheless, the actual Aristotle comprehensive complexity score, as evaluated in its three components, accurately determined the outcome of surgical management of congenital heart disease. It appears to be an adequate tool to evaluate quality in paediatric cardiac surgery, over time.