Evolution of case-mix in heart surgery: from mortality risk to complication risk

During the last two decades despite an increase of the average preoperative mortality risk of patients referred to heart surgery a decrease of hospital mortality has been observed in many surgical institutions. The ratio between the increase of risk and the decrease of mortality could be defined as the 'risk paradox' for coronary surgery. Meanwhile an increase of the incidence of postoperative complications is leading to a longer stay in intensive care that involves a remarkable cost increase per single hospitalisation and a disproportionally long-term use of reanimation beds in those patients who survive the operation but have comorbidities complicating the postoperative course. This progressive change of the epidemiology of patients undergoing heart surgery is coupled with a progressive increase of costs. In the present review a comparison of stratification models developed to predict hospital mortality with those developed to predict prolonged stay in intensive care is discussed. Such predictions are not obviously aimed at deciding whether to operate a patient or not, but can be looked in managing high risk patients, e.g. by a daily monitoring and revision of their prognosis and relevant therapeutic choices, as well as in discussing with their relatives about whether to continue or not implacable treatments. After identifying the models, it is desirable that they are spread into professional Societies in order to sensitise field operators' awareness on the issue of proper intervention indications and on the opportunity of identifying those patients for whom an intervention is not to be advised and to whom propose medical or intervention treatments.