Cardiac surgery risk scoring systems: In quest for the best.

Abstract

Over the last 3 decades, there has been a profusion in the number of cardiac surgery risk score systems available (approximately 20 in current adult cardiac surgery literature).1 One common factor in these scoring systems is that they have all been proposed from either North America or Europe.1 The field of cardiac surgery is continuously evolving with changes in surgical indications, spectrum of diseases, surgical expertise, perioperative management and extensiveness of surgical audit. Consequently, newer scoring systems have been regularly published with the common objective of predicting surgical mortality and more recently,  surgical morbidity. Search of literature reveals no scoring system from large population subgroups like Japan, South-east Asia or Africa. Several reports from these populations have employed the commonly used ‘western’ risk scoring systems like the European System for Cardiac Operative Risk Evaluation (Euroscore) I, Euroscore II, Parsonnet or the Society of Thoracic Surgeons (STS) systems to their population. There are numerous studies which compare the performance of two or more different scoring systems on some subset of cardiac surgery patients (eg, low risk vs high risk coronary artery bypass grafting (CABG), single/multivalve surgery, CABG+ valve surgery, aortic surgery and so on2 3). The conclusions commonly drawn indicate that Euroscore II and STS scores are most widely used; however, even these two scores give different predictions in different groups. Thus, these ‘western’ scores are seen to be relatively ‘off-the-mark’ in correctly predicting the operative mortality in eastern population, thus essentially being inaccurate to a variable extent4. The common ‘inaccuracies’ reported include variations between the subgroups of elective/semiurgent/emergency surgical procedures and low-risk/ high-risk surgical groups. These ‘discrepancies’ raise the following questions: 1. What is the utility of scoring systems? Should all cardiac surgeries at …