Bedside estimation of risk as an aid for decision-making in cardiac surgery

Background. Evaluations of the cardiac-surgery mortality rates of hospitals and surgeons can be fair and realistic only when the observed mortality ra tes are compared with expected rates with preoperative risk factors taken i nto account. Risk-approximation calculations also can assist patients and p hysicians in discussing the risk of cardiac surgery, especially if the esti mation of surgical mortality takes all of the important risk factors into a ccount. Methods. A logistic regression model was developed in which 47 potential ri sk factors were considered, and a method requiring only simple addition and graphic interpretation was designed for approximating the estimated risk e asily and quickly, with Raper and pencil alone. Results. The estimates provided by the simplified model correlated well wit h the observed mortality rates. Conclusions. A simple approximation of a logistic regression model has been found to be helpful in discussions between physicians and patients contemp lating aortocoronary bypass or valve-related surgery. (C) 2000 by The Society of Thoracic Surgeons.