Year : 2014 | Volume
: 17 | Issue : 4 | Page : 271--272
Predicting mortality after congenital heart surgeries: Evaluation of the Aristotle and risk adjustment in congenital heart surgery-1 risk prediction scoring systems: A retrospective single center analysis of 1150 patients
Krishna S Iyer1, Parvathi U Iyer2,
1 Executive Director, Pediatric and Congenital Heart Surgery, New Delhi, India
2 Director, Pediatric Cardiac Intensive Care Fortis Escorts Heart Institute, New Delhi, India
Krishna S Iyer
Fortis Escorts Heart Institute, Okhla Road, New Delhi 110 025
|How to cite this article:|
Iyer KS, Iyer PU. Predicting mortality after congenital heart surgeries: Evaluation of the Aristotle and risk adjustment in congenital heart surgery-1 risk prediction scoring systems: A retrospective single center analysis of 1150 patients.Ann Card Anaesth 2014;17:271-272
|How to cite this URL:|
Iyer KS, Iyer PU. Predicting mortality after congenital heart surgeries: Evaluation of the Aristotle and risk adjustment in congenital heart surgery-1 risk prediction scoring systems: A retrospective single center analysis of 1150 patients. Ann Card Anaesth [serial online] 2014 [cited 2020 Jun 5 ];17:271-272
Available from: http://www.annals.in/text.asp?2014/17/4/271/142058
In this issue of Annals of Cardiac Anaesthesia, Joshi et al.  have attempted to validate the now well established risk prediction scoring systems - Aristotle score and the risk adjustment in congenital heart surgery (RACHS-1) score, using data from their own single unit experience spanning 6 years. They have concluded that for their cohort of patients the Aristotle comprehensive score provided more reliable prediction of outcomes than the RACHS-1 score. The authors need to be congratulated for documenting and comparing their surgical outcomes with available international standards. Whether or not their study validates, the reliability of risk prediction of both these scoring systems is debatable.
The Aristotle and RACHS-1 scoring systems were born out of a long felt need for a way to compare outcomes between various institutions in a balanced manner that accounted for variability in case mix as well as to some extent individual patient variables. The scores also served as a documented risk profile which could be used for presurgical patient and or parent counseling and for planning peri-operative care. What the scores presuppose is that those institutions providing care for patients with congenital heart disease (CHD) especially complex CHD are adequately equipped and are appropriately trained for providing such care. Institutions in the developed world where these scores were evolved have very stringent guidelines and regulations for units providing care for CHD. Unfortunately, no such regulatory controls exist in most developing countries. Most units in our country that provide care for CHD have evolved from the physicians desire rather than a planned healthcare initiative to address the plight if children born with CHD. Most units do not have the full complement of trained staff that would constitute a comprehensive pediatric cardiac unit. Clinical staff members are also likely to occupy crucial positions in the team without the necessary training or certification. This is more likely to happen in government institutions where seniority takes precedence over merit. There would, therefore, understandably be significant differences in patient outcomes when different institutions due to wide variations in infrastructure, manpower and financial resources. The developers of the Aristotle and RACHS-1 scores certainly did not take this into account. Awori and Ogendo from Kenya  and Nina et al.  from Brazil concluded in their study that the RACHS-1 may not be a useful benchmark to compare surgical results in developing countries. Other studies from resource-limited countries have found both scoring systems somewhat useful for risk stratification. 
There are other confounding factors that complicate pediatric cardiac care in developing countries. Late presentation (in the natural history of the lesion) is norm rather than an exception. A 10-year-old boy with a large ventricular septal defect (VSD) and borderline operability, an 18-year-old tetralogy of Fallot (TOF) with severe polycythemia and thrombocytopenia or a 2-month-old transposition with intact septum and regressed left ventricle - all pose surgical and postoperative challenges that are not adequately quantitated in either of the two scoring systems. Units that take on such cases may fare adversely when compared to those who refuse such cases even though their surgical complexity scores as calculated by the above two systems may be comparable.
These may be some of the reasons for the higher than internationally accepted mortality rates in the present study. A relatively high proportion of simple cases - 89.8% RACHS-1 category 1or 2, mean ABC score of 6.44, indicates relative inexperience of the team or a lack of adequate resources. The surgical volume is also low - 1150 patients in 6 years, which translates to about 190 patients/year. Compared with western data the mean age and weight at surgery [Table 1] are considerably higher indicating very low volume of infant surgery. What is a bit puzzling though is that the patients in the mortality group are younger in age (2.23 vs. 4.92 years), understandably, but heavier (13.99 vs. 12.78 kg)! [Table 3] lists the diagnosis wise mortality. However the scoring systems are based on surgical procedures. VSD, TOF, atrial septal defect and patent ductus arteriosus form the bulk of the patients. What is perplexing is the very small number of patients with single ventricle (0.3%). What is apparent though from the table is that the mortality rates for total anomalous pulmonary venous return - 26%, thermogravimetric analysis - 19.4% and atrioventricular canal defect - 22.2% are rather high but two patients of hypoplastic left heart syndrome seem to have survived without mortality in the group! Given the rather skewed nature of the data it may not be fair to use it to validate established risk prediction scoring systems.
The risk scoring systems are of great help however for units to track their own performance over the course of time and to monitor effects of alteration of management strategies of improvements in care pathways. This was well-documented in the Gautemalan experience.  Improved performance would be indicated by an improvement in survival rates along with an increase in mean ABS. Analysis of the performance in the individual sub-groups would help identify areas of care that require strengthening.
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|2||Awori MN, Ogendo SW. Rachs-1 system in risk stratification for congenital heart disease surgery outcome. East Afr Med J 2008;85:36-8.|
|3||Nina RV, Gama ME, Santos AM, Nina VJ, Figueiredo Neto JA, Mendes VG, et al. Is the RACHS-1 (risk adjustment in congenital heart surgery) a useful tool in our scenario? Rev Bras Cir Cardiovasc 2007;22:425-31.|
|4||Vijarnsorn C, Laohaprasitiporn D, Durongpisitkul K, Chantong P, Soongswang J, Cheungsomprasong P, et al. Surveillance of pediatric cardiac surgical outcome using risk stratifications at a tertiary care center in Thailand. Cardiol Res Pract 2011;2011:254321.|
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