Does Bilateral Internal Mammary Artery Grafting Better Suit Patients With Diabetes? - Two Different Ways to Explore Outcomes

Meta-analysis of BITA versus SITA grafting in diabetic patients: evidence from propensity score-matched studies

BACKGROUND

It has been demonstrated that the use of bilateral internal thoracic artery (BITA) grafting in coronary artery bypass grafting (CABG) improves long-term survival in comparison to the use of a single internal thoracic artery (SITA) graft. However, the optimal transplantation technique for diabetic patients remains undetermined. The purpose of this meta-analysis was to compare the effectiveness and safety of BITA and SITA CABG in diabetic patients.

METHODS

A comprehensive search of Google Scholar, Science Direct, and PubMed was conducted for studies with propensity score-matched comparing between BITA and SITA grafting in diabetic patients. The main goal was to know mid- to long-term mortality, and the supplementary results included incidence of deep sternal wound infection, 30-day mortality, and incidence of reoperation due to hemorrhage.

RESULTS

The meta-analysis included 11 studies involving 3762 diabetic patients with matched propensity scores. Compared to SITA grafting, BITA grafting was associated with a significant reduction in long-term mortality (HR 0.78; 95% CI 0.67-0.91), P = 0.03, I2 = 54%. There were no significant differences between the two groups in terms of 30-day mortality, reoperation for bleeding, cerebrovascular accident, or renal failure.

CONCLUSIONS

BITA grafting appears to provide better overall survival than SITA grafting in patients with diabetes. However, using BITA grafting is associated with a greater risk of deep sternal wound infection. These findings may help guide the choice of grafting technique in diabetic patients undergoing CABG.

Association of HbA1c and utilization of internal mammary arteries with wound infections in CABG

Background

Deep sternal wound infection (DSWI) remains a serious complication after coronary artery bypass grafting (CABG). We herein aimed to stratify diabetic patients who underwent CABG using bilateral internal mammary artery (BIMA) for levels of glycated hemoglobin A1C (HbA1c) and compare postoperative outcomes.

Methods

Between January 2010 and August 2020, 4,186 consecutive patients underwent isolated CABG at our center. In 3,229 patients, preoperative HbA1c levels were available. Primary endpoints were wound healing disorder (WHD), DSWI, and 30-day mortality. Patients were stratified according to preoperative HbA1c levels. Patients were further divided into subgroups according to utilization of BIMA.

Results

After adjustment, no differences in mortality and stroke rates were seen between group 1 (HbA1c < 6.5%) vs. group 2 (HbA1c ≥ 6.5%). WHD was more frequent in group 2 [2.8 vs. 5.6%; adjusted p = 0.002; adjusted odds ratio (OR), 1.853 (1.243-2.711)] but not DSWI [1.0 vs. 1.5%; adjusted p = 0.543; adjusted OR, 1.247 (0.612-2.5409)]. BIMA use showed a higher rate of WHD [no BIMA: 3.0%; BIMA: 7.7%; adjusted p = 0.002; adjusted OR, 4.766 (1.747-13.002)] but not DSWI [no BIMA: 1.1%; BIMA: 1.8%; adjusted p = 0.615; adjusted OR, 1.591 (0.260-9.749)] in patients with HbA1c ≥ 6.5%.

Conclusions

Intraoperative utilization of BIMA is not connected with an increase of DSWI but higher rates of WHD in patients with poor diabetic status and HbA1c ≥ 6.5%. Therefore, application of BIMA should be taken into consideration even in patients with poor diabetic status, while identification of special subsets of patients who are at particular high risk for DSWI is of paramount importance to prevent this serious complication.

Bilateral vs Single Internal Mammary Artery Grafts for Coronary Artery Bypass in the United States

BACKGROUND

The use of the bilateral internal mammary artery (BIMA) in coronary artery bypass grafting remains controversial. The objective of this study was to investigate the long-term outcomes using the BIMA vs the single internal mammary artery (SIMA) in the United States.

METHODS

Medicare beneficiaries who underwent primary isolated coronary artery bypass surgery using the SIMA or BIMA from 1999 to 2010 were included in this retrospective study, with follow-up through 2014. Greedy matching algorithms were used for 1:4 matching on propensity score based on age, gender, year of surgery, and comorbidities. Kaplan-Meier survival analyses were performed. The primary outcome was death from any cause.

RESULTS

A total of 1,156,339 and 25,005 patients who were 72 ± 7.6 years of age and 70.3 ± 7.9 years of age underwent primary isolated coronary artery bypass surgery using SIMA and BIMA, respectively. Matching created comparable groups with 95,780 SIMA and 24,160 BIMA patients. Matched median survival using SIMA vs BIMA was 11.8 vs 12.4 years (P < .001) and 9.6 vs 10 years in diabetic patients (P = .006), respectively. At 10 years of follow-up, the respective survival rates of using SIMA vs BIMA were 58.3% vs 61.1%, respectively. The stratified matched median survival using SIMA vs BIMA with 1, 2, 3, and 4 or more aortocoronary bypasses were 11.8 vs 12.3 years (P = .005), 11.7 vs 12.5 years (P < .001), 11.9 vs 12.3 years (P = .01), and 11.4 vs 12 years (P = .02), respectively.

CONCLUSIONS

Primary isolated coronary artery bypass surgery using the BIMA rather than the SIMA was associated with improved long-term survival. This survival advantage was independent of aortocoronary bypass grafts or patient diabetes status.