Incremental Value of the Preoperative Echocardiogram to Predict Mortality and Major Morbidity in Coronary Artery Bypass Surgery

Jonathan Afilalo; Aidan W. Flynn; Avi Shimony; Lawrence G. Rudski; Arvind K. Agnihotri; Jean-Francois Morin; Cristina Castrillo; David M. Shahian; Michael H. Picard

CIRCULATIONAHA.112.127639 Published online before print December 12, 2012,

Abstract

Background—Although echocardiography is commonly performed before coronary artery bypass surgery (CABG), there has yet to be a study examining the incremental prognostic value of a complete echocardiogram.

Methods and Results—Patients undergoing isolated CABG at two hospitals were divided into derivation and validation cohorts. A panel of quantitative echocardiographic parameters was measured. Clinical variables were extracted from the STS database. The primary outcome was in-hospital mortality or major morbidity, and the secondary outcome was long-term all-cause mortality. The derivation cohort consisted of 667 patients with a mean age of 67.2±11.1 years and 22.8% females. The following echocardiographic parameters were found to be optimal predictors of mortality or major morbidity: severe diastolic dysfunction as evidenced by restrictive filling (OR 2.96; 95% CI 1.59,5.49), RV dysfunction as evidenced by fractional area change <35% (OR 3.03; 95% CI 1.28,7.20) or myocardial performance index >0.40 (OR 1.89; 95% CI 1.13,3.15). These results were confirmed in the validation cohort of 187 patients. When added to the STS risk score, the echocardiographic parameters resulted in a net improvement in model discrimination and reclassification with a change in c-statistic from 0.68 to 0.73 and an integrated discrimination improvement of 5.9% (95% CI 2.8%, 8.9%). In the Cox proportional hazards model, RV dysfunction and pulmonary hypertension were independently predictive of mortality over 3.2 years of follow-up.

Conclusions—Preoperative echocardiography, in particular RV dysfunction and restrictive LV filling, provides incremental prognostic value in identifying patients at higher risk of mortality or major morbidity after CABG.