Cardiac complications during waiting for elective coronary artery bypass graft surgery: incidence, temporal distribution and predictive factors.

OBJECTIVES: Since waiting lists for coronary artery bypass graft surgery are common and carry a risk of severe events, the purposes of this study were: (1) to analyse the incidence and temporal distribution of cardiac complications during waiting for elective coronary artery bypass grafting; (2) to identify predictive factors of such complications.
METHODS: Data were collected from 574 patients referred to surgery from 1 January 1998 to 12 July 2001. Two types of complications were defined: (1) a composite end-point, which included cardiac death, myocardial infarction, unstable angina or hospital admission due to cardiac cause; (2) sudden or any cardiac death. Previous cardiac events, risk factors, clinical features, laboratory exams, non-invasive tests for myocardial ischemia, left ventricular function and coronary anatomy were analysed. Kaplan-Meier method, multivariate Cox regression and Student's t-test were used for statistical analyses.
RESULTS: Median time to surgery was 126 days (5-1022). Among 516 patients consecutively referred to the surgery from 1 January 1998 to 31 December 2000, sudden or cardiac death occurred in 2.5% and the composite end-point in 22.9%. Most complications (72.1%) were observed within 120 days. The main factors predictive of sudden or cardiac death were severe left ventricular dysfunction and heart failure (univariate analysis). Independent predictive factors of the composite end-point were angina, heart failure functional classes and high triglyceride levels.
CONCLUSIONS: During long delay for coronary artery bypass surgery, cardiac events are frequent and tend to occur early. Severe left ventricular dysfunction, advanced angina, heart failure functional classes and high triglyceride level must be considered when selection is necessary, in order to diminish morbidity and mortality during the waiting period.