Early and late mortality after surgery for unstable angina in relation to Braunwald class

Background The prognostic value of the preoperative Braunwald class of unstable angina to predict early and long-term outcome after urgent coronary artery bypass grafting (CABG) has not been studied previously. Methods Deaths were recorded after all primary isolated CABG performed for unstable (n = 992) and stable (n = 5376) angina pectoris during 1980-1995. Severity of symptoms in the unstable patients was classified according to Braunwald. Results Death within 30 days of surgery occurred in 4.6% of the patients having unstable angina and in 1.6% of those with stable angina. Early mortality was 2.5% in Braunwald class II, 4.9% in class IIIB, and 6.2% in class IIIC unstable patients. The risk of early death, after adjustment for risk factors, was about four times higher in Braunwald class IIIB (odds ratio [OR] 4.3, 95% confidence interval [CI] 2.4-7.7) and IIIC (OR 4.7, 95% CI 2.2-10.3) patients than in stable patients. The risk of death during postoperative months 1 to 6 tended to be higher (relative risk 2.4, 95% CI 0.8-7.1) in Braunwald class IIIC patients than in stable patients. After the first 6 months up to 5 years, survival rates in all Braunwald classes were similar to those in patients operated on for stable angina. Conclusions There was a higher risk of early death after urgent bypass surgery in patients with Braunwald class III unstable angina than after elective CABG. The long-term survival rates after the first 6 postoperative months was similar in stable and unstable patients, regardless of preoperative Braunwald class. (Am Heart J 2001;141:9-14.)