The European System for Cardiac Operation Risk Evaluation (EuroSCORE) has been a remarkably successful and widely adopted tool to predict early postoperative mortality in patients undergoing cardiac surgery. Why has it been so ubiquitous, when there have been many other surgical risk scoring systems developed?1 2 Its authors, Nashef, Roques and Michel, set out in the mid-1990s to generate a surgical risk assessment tool that could be used at the bedside, that had relatively objective criteria for risk factor measurement, and was based on a large and heterogeneous group of patients for whom a very “clean” dataset existed.3 At a time when easy access to computing on the ward was rare, the ability to generate a score without recourse to solving exponential equations was a big bonus. At that time the other major scoring system in the United States was based on the Society of Thoracic Surgeons database. This was kept secret because of intellectual property issues, and so was unavailable for critical analysis.

Perhaps as a result of this combination of factors, the EuroSCORE went on to be tested in widely differing populations both in Europe,4 Scandinavia,5 Japan,6 and in the USA.7 Despite the very different patient demographics and operation types represented, the score worked well. In the USA, for example, the patients were older, more often had isolated coronary bypass operations, diabetes (30% vs 17%) and prior cardiac surgery (11% vs 7%).7 Nevertheless EuroSCORE performed better than the Society of Thoracic Surgeons risk assessment model. Across Europe there were particularly large differences in valve surgery (ranging from 18.6% in Finland to 51.5% in Spain).4 Thus despite a number of potential hurdles, the EuroSCORE was found to be an easy and acceptable way to evaluate perioperative mortality across the world.

One …