• coronary artery surgery
• risk assessment
• high risk patients

Quality assurance and league tables are part of the contemporary medical scene. During the 1980s, the revolt of the payers of health care, both private and public, led to the mantra that the cost of treatment must be taken into consideration in decisions about the provision of health care. In cardiac surgery the difference between success and failure is transparent and obvious to all, from the porter to the chief executive. It has come to be accepted that operative or hospital mortality is an indicator of the quality of care. For hospital mortality to remain a valid measure of quality, it must be related to the risk profile of the individual patient. Therefore much effort has been expended on the development of a robust and reliable risk stratification model.

It is inevitable that within the climate of transparency, the availability of results and public accountability will influence decision making. Without risk stratification, surgeons and hospitals treating high risk patients will appear to have worse results than others. This may prejudice referral patterns, affect the allocation of resources, and discourage the treatment of high risk patients. This is undesirable, because it is precisely this group of patients which stand to gain most from operation.¹ Risk stratification should help to eliminate the bias against high risk patients.