Superiority of bilateral internal thoracic artery grafting in long-term survival after coronary artery bypass through the lenses of a bedside risk score.

OBJECTIVE: Risk algorithms for the prediction of long-term survival after coronary artery bypass grafting (CABG) do not include the use of bilateral internal thoracic artery (BITA) grafting among the independent predictors. We sought to reveal the superiority of BITA grafting in the long-term outcome through the lenses of an existing bedside risk score (BRS). METHODS: This study analyzed data from 5,666 consecutive patients undergoing isolated (n = 4,715 - BITA = 2,792) and combined (n = 951 - BITA = 246) CABG. The mean follow-up period was 10.3 years (interquartile range, 9.9 years). All the predictors of an existing BRS were available for analysis (age, body mass index, ejection fraction, unstable hemodynamic state, left main disease, cerebrovascular disease, peripheral arterial disease, congestive heart failure, malignant ventricular arrhythmia, chronic obstructive pulmonary disease, diabetes, and previous heart surgery). Furthermore, a modified BRS was constructed taking into account the use of BITA grafting and combined CABG. RESULTS: The good discriminatory ability and satisfactory calibration of the BRS was confirmed in the isolated CABG subgroup. The modified BRS showed improved discriminatory ability and similar calibration. It showed a time-varying coefficient, and accordingly, we calculated the adjusted survival predictions up to 20 years after isolated and combined CABG with or without BITA grafting. Patients with BITA grafting in the low-risk quartile showed 68.4% and 65.5% predicted survival rates at 20 years in the isolated and combined CABG subgroups, respectively, versus the survival rates of 56.4% and 52.8% observed among patients without BITA grafting. CONCLUSION: The modified BRS is a useful simplified algorithm for clinicians in choosing treatment intervention for severe isolated or combined coronary artery disease. We clearly demonstrated the superiority of BITA grafting in long-term survival throughout the entire range of the modified BRS.

Prediction of Long-Term Survival after Coronary Artery Bypass with Bilateral Internal Thoracic Artery Grafting: External Validation of A Contemporary Nomogram.

Background: This study aimed to verify the external validation of a contemporary nomogram in predicting long-term survival after an isolated coronary artery bypass with bilateral internal thoracic artery grafting (CABG-BITA). Methods: Consecutive patients who underwent CABG-BITA at a single center were included in the study. All the predictors of the original risk score (age, diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, chronic renal failure, old myocardial infarction, ejection fraction, intra-aortic balloon pump and peripheral arterial disease) were available for analysis. Results: Among the 2846 consecutive patients, a total of 1176 (41.3%) deaths were recorded during the 31,383 patient years of follow-up. The median EuroSCORE II was 2.35, and the median follow-up was 11.1 years. The risk score showed 72.7% overall discriminatory ability as measured by Harrell's concordance statistic. It showed satisfactory calibration at 10, 15 and 20 years of follow-up. The risk score showed a time-varying nonlinear effect, and accordingly, adjusted long-term survival predictions were calculated. There were subgroups (scores < 50 points) with favorable 20-year survival rates ranging from 77% to 60%. Higher risk subgroups (scores > 90 points) showed poor 20-year survival rates ranging from 22% to 4%. Conclusions: The validated risk score represents a useful algorithm for the detection of patients who could benefit after CABG-BITA with respect to long-term survival. Although further multi-center studies are required worldwide to reveal the usefulness of this score in the clinical setting, its wide adoption may act as a motivation for cardiac surgeons resulting in higher numbers of CABG-BITA procedures.