Aristotle Comprehensive Complexity Score Research Articles

The Aristotle Comprehensive Complexity Score Predicts Mortality and Morbidity After Congenital Heart Surgery

The Aristotle Comprehensive Complexity (ACC) score has been proposed for complexity adjustment in the analysis of outcome after congenital heart surgery. The score is the sum of the Aristotle Basic Complexity score, largely used but poorly related to mortality and morbidity, and of the Comprehensive Complexity items accounting for comorbidities and procedure-specific and anatomic variability. This study aims to demonstrate the ability of the ACC score to predict 30-day mortality and morbidity assessed by the length of the intensive care unit (ICU) stay. We retrospectively enrolled patients undergoing congenital heart surgery in our institution. We modeled the ACC score as a continuous variable, mortality as a binary variable, and length of ICU stay as a censored variable. For each mortality and morbidity model we performed internal validation by bootstrapping and assessed overall performance by R(2), calibration by the calibration slope, and discrimination by the c index. Among all 1,454 patients enrolled, 30-day mortality rate was 3.4% and median length of ICU stay was 3 days. The ACC score strongly related to mortality, but related to length of ICU stay only during the first postoperative week. For the mortality model, R(2) = 0.24, calibration slope = 0.98, c index = 0.86, and 95% confidence interval was 0.82 to 0.91. For the morbidity model, R(2) = 0.094, calibration slope = 0.94, c index = 0.64, and 95% confidence interval was 0.62 to 0.66. The ACC score predicts 30-day mortality and length of ICU stay during the first postoperative week. The score is an adequate tool for complexity adjustment in the analysis of outcome after congenital heart surgery.

Congenital Heart Surgery: Applicability of Hospital Reimbursement According to German Diagnosis-Related Groups System in Conformity with the Aristotle Complexity Score

Scores of Aristotle comprehensive complexity (ACC) levels have been demonstrated to correlate with the case-mix index (CMI) (cost-weights) generated by the German Diagnosis-Related Groups (DRG) 2009 version (G-DRG 2009). The equation used was "y = 0.5591 + 0.939 x" whereby y stands for cost-weight and x for ACC score. We hypothesised that each ACC level could be assigned a DRG (ACC DRG) and be used to determine hospital reimbursement. 185 patients underwent cardiac surgery between January and June 2009. The ACC scores of these 185 patients were grouped in ACC levels, based on the basic cost-weight value of their DRG. One ACC DRG was assigned to each group and a corresponding cost-weight calculated based on the aforementioned equation. The resulting ACC CMI was compared with the CMI generated by the G-DRG 2009 (G-DRG 2009 CMI). Finally, the ACC surgical performance (complexity x hospital survival) was used to calculate the cost-weight; the obtained CMI was called "effective ACC CMI". Mean ACC score was 9.515 +/- 3.611 points. Derived ACC CMI and related G-DRG 2009 CMI were 9.494 and 8.438, respectively. Hospital survival was 97.8 % (181/184). Therefore ACC surgical performance and "effective ACC CMI" were 9.306 and 9.297, respectively. For each ACC level, the number of patients (n), mean ACC score, ACC CMI and related G-DRG 2009 CMI were as follows: Level 1: n = 25, 4.024 +/- 0.879, 4.338 and 5.911; Level 2: n = 30, 6.563 +/- 0.574, 6.722 and 6.602; Level 3: n = 43, 8.665 +/- 0.540, 8.695 and 8.088; Level 4: n = 73, 11.730 +/- 1.690, 11.574 and 9.612; Level 5: n = 14, 16.710 +/- 1.380, 16.249 and 11.843, respectively. The Aristotle score can be used to adjust hospital reimbursement by assigning a DRG and cost-weight value to each ACC level. Missing figures for level 6 can be obtained from a previous study which showed a mean score of 22.11 +/- 1.24: the ACC CMI would be 21.320. The 6 ACC DRGs indicate the correct compensation based on the complexity of the procedure. Reimbursement using the German DRG 2009 appears to favour less complex cases, while procedures with a higher complexity are penalised. Reimbursement according to "effective ACC CMIs" would have a strong impact by supporting units providing high-quality care.

Surgical Management of Congenital Heart Disease: Correlation between Hospital Costs and the Aristotle Complexity Score

Hospital costs are expected to correlate with clinical complexity. Do costs for congenital heart surgery correlate with Aristotle complexity scores? 442 inpatient stays in 2008 were evaluated. Aristotle scores and levels were determined. Costs were estimated according to the German Institute for Hospital Reimbursement system. Pearson and Spearman R correlation coefficients and corresponding goodness-of-fit regression coefficients R2 were calculated. Mean basic and comprehensive Aristotle scores were 7.60 +/- 2.74 and 9.23 +/- 2.94 points, respectively. Mean expenses per hospital stay amounted to 29,369 +/- 30,823 Euros. Aristotle basic and comprehensive scores and levels were positively correlated with hospital costs. With a Spearman R of 1 and related R2 of 0.9436, scores of the 6 Aristotle comprehensive levels correlated best. Mean hospital reimbursement was 26,412 +/- 17,962 Euros. Compensation was higher than expenses for patients in comprehensive levels 1 to 3, but much lower for those in levels 4 to 6. Aristotle comprehensive complexity scores were highly correlated with hospital costs. The Aristotle score could be used as a scale to establish the correct reimbursement after congenital heart surgery.

Poor outcome for patients with totally anomalous pulmonary venous connection and functionally single ventricle

Totally anomalous pulmonary venous connection, when also associated with a functionally univentricular connection, is known to have a poor outcome. We retrospectively analysed results for 19 patients undergoing surgery for this combination of lesions between 1995 and February 2009.Of the patients, 12 were neonates, with 11 presenting with signs of pulmonary venous obstruction. In 3 patients, a modified Blalock-Taussig shunt had been constructed. The dominant ventricle was of right ventricular morphology in 17 of the 19 patients, and double inlet was present in all bar 1. Pulmonary atresia or stenosis was found in 14 patients, a common atrioventricular junction in 14 patients, and isomerism of the right atrial appendages in 12 patients, respectively. Comprehensive Aristotle scores ranged from 14 to 23.50. The mean was 16.55, with a standard deviation of 2.19. Pulmonary venous rerouting was combined in 6 patients with construction of a modified Blalock-Taussig, in 4 with banding of the pulmonary trunk, in another 4 with a bidirectional Glenn anastomosis, in 3 with creation of a total cavo-pulmonary connection, and in 1 each with enlargement of the right ventricular outflow tract and the Norwood procedure. Of the cohort, 8 patients died early due to pulmonary hypertension, with all patients having Aristotle scores of at least 18 points dying. Among the 11 early survivors, 5 needed mechanical ventilation for over a week, but 5 patients died later, 3 due to pulmonary hypertension and 2 due to infection. Actuarial survival stabilized at 31.6%, with standard error of 10.7%, from one year onwards. Conversion to the Fontan circulation was successful in 5 patients.Our experience confirms that totally anomalous pulmonary venous connection, when associated with the functionally univentricular arrangement, carries one of the worst outcomes in current surgical practice. Use of the Aristotle comprehensive complexity scores effectively discriminates those patients with this condition at particularly high risk.

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

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.

Birth Weight and Complexity Are Significant Factors for the Management of Hypoplastic Left Heart Syndrome

Classic options for treatment of hypoplastic left heart syndrome include the Norwood procedure (NW) and heart transplantation (HT). Recently off-pump palliative procedures were introduced in the management of these patients. Risk factors influencing the decision between the NW with staged reconstruction or off-pump palliation and HT were assessed. Between January 2002 and January 2006, 69 patients with hypoplastic left heart syndrome were referred for either a NW (n = 33) or HT (n = 36). Patients referred for HT underwent off-pump palliation (catheter-based, n = 20, or surgical hybrid procedures, n = 7) until a donor organ became available: including patent ductus arteriosus stenting (80.6%), atrial septostomy (41.7%), and branch pulmonary artery banding (55.6%). Heart transplantation patients were more complex, based on a higher Aristotle Comprehensive Complexity score calculated at birth (HT 18.8 +/- 2.4 versus NW 17.7 +/- 1.7; p < 0.05). Presurgical death was significantly greater for HT referrals (HT 27.8% versus NW 3.0%; p < 0.01); however, there was no difference between the two groups in operative (HT 11.5% versus NW 21.9%; not significant) or overall mortality (HT 36.1% versus NW 24.2%; not significant). No independent risk factors for death were identified with HT; however, a lower birth weight (<2.5 kg) and a higher Aristotle score (>20) correlated with surgical death with NW (p < 0.01). Noticeably, surgical survival was 85.7% for infants with birth weight of 2.5 kg or greater undergoing NW. Overall survival is similar for hypoplastic left heart syndrome patients referred for the NW or HT. Lower birth weight and higher complexity are risk factors for patients undergoing NW. Off-pump palliation followed by HT or further staged palliation should be considered for these high-risk hypoplastic left heart syndrome patients.