Purpose: To assess vancomycin paste effect on poststernotomy healing in high-risk coronary artery bypass grafting (CABG) patients compared to bone wax using the 6-point computed tomography (CT) score. Additionally assessed the reliability of this score and its relationship to the occurrence of infection. Patients and Methods: A prospective comparative analysis included 126 high-risk CABG patients. The patients were randomly assigned into bone wax or vancomycin paste for sternal haemostasis. All patients were submitted to CT examinations 6-months postoperative. Two radiologists independently reviewed all CT scans to assess sternal healing using the 6-point CT score. The CT healing score of the two groups was compared. The kappa statistics were used to calculate the inter-reader agreement (IRA) of the 6-point CT score. Results: The final analysis included 61 patients in each group. The main CT score for sternal healing was 3.9±0.4 in the vancomycin group and 3.3±0.8 in the bone wax group. Patients in the vancomycin group had a higher statistically significant improvement in CT healing score than those in the bone wax group (p<0.001). There was no statistically significant relationship (p = 0.79) between the occurrence of infection and the 6-point CT score in the vancomycin group. The overall IRA of the 6-point CT score was good in two groups (κ = 0.79 in the vancomycin group and = 0.78 in the bone wax group). Conclusion: Vancomycin paste had a better CT healing score and can be used as a sternal haemostatic material instead of bone wax. The 6-point CT healing score is a reliable diagnostic tool for evaluating sternal healing