• Cardiac Surgery
• QUality of Care and Outcomes

The decision to recommend surgical treatment for patients with cardiac surgical disease is based on a multidisciplinary approach of the evaluation of the intended benefits and inherent risks of the proposed treatment.1 This is particularly important for patients of advancing age, with multiple comorbidities and who receive complex interventions. Such patients have higher operative risk and, increasingly, form the routine referral base for cardiothoracic operations. Subjective assessment of a patient's clinical risk, undertaken in isolation, is no longer acceptable—objective evaluation is highly recommended, allowing patients and surgeons a more informed decision and commissioners, regulators and researchers a mechanism to benchmark standards of access to and outcomes of care.2

It is, therefore, essential that reliable and valid tools are established which predict outcomes after surgery. Higher risk may then be quantified and, where appropriate, patients offered alternative evidence-based therapies. This is relevant to coronary artery and aortic valve disease interventions where, in parallel with established cardiothoracic operations provider volume-outcome associations are under close scrutiny and some cardiac devices may, in future, be ‘commissioned through evaluation’. Specifically, between and within centre surgical outcomes are regularly monitored and compared, as part of institutional, national and international quality improvement programmes.2 ,3 Thus, case-mix adjustment that carefully models the full spectrum of baseline patient risk is central to the identification of ‘outlier’ status and the evaluation of the quality of care of operative interventions.4

Siregar et al5 use clinical and administrative data from the majority of hospitals in The Netherlands performing cardiac surgery to report the differences in data quality and model performance indices with and without model recalibration. Clinical data are sourced from their National Cardiac Surgical Registry, analogous to the UK Society for Cardiothoracic Surgery (SCTS) in Great Britain and Ireland registry, and administrative data from the …