Which echocardiographic parameters improve the risk prediction for peri-operative outcomes in patients undergoing coronary bypass surgery: a prospective study.

OBJECTIVE: To assess the performance of transthoracic echocardiographic parameters to predict operative mortality and morbidity in patients undergoing coronary artery bypass grafting, and to assess its incremental prognostic value as compared to the Society of Thoracic Surgeons (STS) score.

MATERIALS AND METHODS: We prospectively collected the clinical and biological data required to calculate the STS score in patients hospitalised for coronary artery bypass grafting. Preoperative transthoracic echocardiography was performed for each patient. The primary endpoint was 30-day mortality or major morbidity (i.e. stroke, renal failure, prolonged ventilation, deep sternal wound infection, reoperation) as defined by the STS. The secondary endpoint was prolonged hospitalisation for over 14 days.

RESULTS: A total of 172 patients was included (mean age 66.1±10.2 years, 12.2% were women). The primary endpoint occurred in 33 patients (19.2%), and 28 patients (16.3%) had a prolonged hospital stay. Independent predictive factors for the primary endpoint were an increased left atrial volume (>31 mL/m²; odds ratio (OR) 3.55, 95% confidence interval (CI) 1.38-9.12; P=0.004) and a decreased tricuspid annular plane systolic excursion (<20 mm; OR 3.45, 95% CI 1.47-8.21; P=0.008). The predictive value of the multivariate model increased when the two echocardiographic parameters were added to the STS score (area under the curve 0.598 vs. 0.695, P=0.001; integrated discrimination improvement 7.44%).

CONCLUSION: In patients undergoing coronary artery bypass grafting, preoperative assessment of left atrial size and tricuspid annular plane systolic excursion should be performed systematically, as it provides additional prognostic information to the STS score.