One-Year Graft Patency for Elective CABG Affected by Baseline Glycemic Control

A year after coronary artery bypass grafting (CABG), the graft patency rate was higher among patients with lower baseline glycated hemoglobin (HbA_1C). These findings were published in JACC: Asia.

The Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Graft Surgery (DACAB; ClinicalTrials.gov identifier: NCT02201771) trial was a multicenter, open-label, randomized trial conducted at 6 hospitals in China. Patients (N=500) scheduled to undergo elective CABG were randomly assigned in a 1:1:1 ratio to receive 90 mg twice daily ticagrelor with 100 mg once daily aspirin, ticagrelor monotherapy, or aspirin monotherapy for 1 year. This post-hoc analysis evaluated 1-year outcomes on the basis of glycemic control. Graft outcomes were evaluated by computed tomography angiography or coronary angiography. Patency was defined as FitzGibbon grade A and nonocclusion as FitzGibbon grade A+B.

Patients with low HbA_1C (defined as <6.5%; n=233) and high HbA_1C (³6.5%; n=172) were aged mean 63.8±8.1 and 64.2±8.0 years; 85.0% and 76.7% were men (P =.035); 62.7% and 55.2% had unstable angina; and 98.3% and 93.0% used statins within 1 year of the procedure (P =.007), respectively. Patients in both groups received 3.8 grafts during the procedure.

The rate of FitzGibbon grade A was 86.1% and 77.9% and the rate of FitzGibbon grade A+B was 88.9% and 81.6% among the low and high HbA_1C cohorts, respectively.

Higher HbA_1C was associated with worse patency per graft (adjusted hazard ratio [aHR], 1.69; 95% CI, 1.08-2.64; P =.021) and per patient (aHR, 1.62; 95% CI, 1.01-2.60; P =.048) and worse nonocclusion per graft (aHR, 1.70; 95% CI, 1.04-2.79; P =.034).

Similarly, when HbA_1C was treated as a continuous variable, increased HbA_1C associated with worse patency per graft (aOR, 1.25; 95% CI, 1.08-1.45; P =.003) and per patient (aOR, 1.29; 95% CI, 1.10-1.52; P =.002) and worse nonocclusion per graft (aOR, 1.25; 95% CI, 1.07-1.46; P =.004) and per patient (aOR, 1.26; 95% CI, 1.07-1.48; P =.007).

Stratified by treatment, for both glycemic control cohorts the dual therapy recipients were associated with higher patency rates followed by the ticagrelor and aspirin monotherapies. However, no significant interactions for graft patency outcomes were observed on the basis of treatment received.

Bleeding events occurred among 19.8% and 17.5% of the low and high HbA_1C cohorts, respectively. Among the low HbA_1C group, those who were randomized to receive the ticagrelor and aspirin combinatorial therapy were associated with higher bleeding events overall (P <.001) which were attributed to higher minimum events (P <.001). No other group differences were observed for safety outcomes.

This study was limited by the proportion of patients in the trial with missing baseline HbA_1C data.

The study authors noted, “In the DACAB trial, higher baseline HbA1c was associated with lower vein graft patency 1 year after CABG. T+A improved 1-year vein graft patency vs aspirin, irrespective of baseline HbA1c. Overall, multiple artery grafts might be a more appropriate choice for these patients with poor glycemic control.”

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Zhu Y, Hu J, Zhang M, et al. Influence of baseline HbA1c and antiplatelet therapy on 1-year vein graft outcome. JACC Asia. Published online March 15, 2022. doi:10.1016/j.jacasi.2021.11.009