EFFECT OF CARDIAC-SURGERY PATIENT CHARACTERISTICS ON PATIENT OUTCOMESFROM 1981 THROUGH 1995

Background Previous studies have demonstrated increased risk in patien ts undergoing coronary artery bypass surgery (CABG), but the effect of this increasing risk on outcomes has not been well documented. The pu rposes of this study were (1) to evaluate patients who had CABG from 1 993 to 1995 (group III) and compare them with patients from 1981 throu gh 1987 (group I) and 1988 through 1992 (group II) to determine if the trend toward higher-risk patients continued and (2) to evaluate what effect risk had on in-hospital outcomes. Methods and Results Data were collected prospectively on patients undergoing CABG. Patients from th e three time periods were compared by use of univariate and multivaria te statistics. Risk models for mortality were developed by use of logi stic regression. Significant changes were noted in the three time peri ods, with risk increasing over time. Increased risk was associated wit h increased mortality in group II, but mortality declined in group III despite the continued increase in patient risk. Group II had an incre ase in complications, with little change in group III. The actual mort ality rate was lower than predicted in group III. Conclusions Patients undergoing CABG are increasingly high risk. In-hospital mortality rat es declined during the period from 1993 through 1995 and were lower th an predicted despite the increase in risk. This decreased mortality ra te may reflect greater experience in providing care to high-risk patie nts and improved myocardial protection and surgical and anesthetic tec hniques. Although continued analysis of patient risk and benefit is ne eded, researchers must be cognizant of the rapid changes in technology and knowledge and should correlate changes in the process of care wit h outcomes.