Bilateral vs. Single Internal Mammary Artery Use in Patients with Chronic Kidney Disease

Y. Hohri¹, Y. Zhao², I. Feng³, C. Yang³, G. Dardik¹, K. Rajesh⁴, H. Takayama⁴, K. Takeda^1
1Columbia University Medical Center, New York, New York ²Columbia University Irving Medical Center, New York, New York ³New York-Presbyterian/Columbia University Medical Center, New York, New York ⁴Columbia University, New York, New York

Purpose: Benefits of bilateral intermammary artery (IMA) usage are uncertain in patients with chronic kidney disease (CKD). We compare outcomes of bilateral IMA (BIMA) versus single IMA (SIMA) for CKD patients.

Methods: All patients undergoing isolated CABG at our center between 2015 and 2022 were reviewed. Patients with CKD undergoing isolated multivessel CABG were included in this study. We defined CKD according to current guidelines (glomerular filtration rate < 60 ml/min per 1.73 m2). Patients with radial artery grafts, no IMA graft, or with fewer than 2 anastomoses were excluded. Outcomes were compared between the BIMA (BIMA with additional saphenous veins) and SIMA (SIMA with additional saphenous veins) groups. Prior surgical history, baseline characteristics, hospital courses, and outcomes were reviewed from the medical record. Inverse probability treatment weighting (IPTW) was used to balance baseline characteristics. The primary endpoint was long-term survival and secondary outcome was cumulative incidence of major adverse cardiac or cerebrovascular event (MACCE): including all-cause mortality, stroke, myocardial infraction, revascularization, and re-hospitalization for heart failure. Multivariable Cox regression identified independent factors associated with long-term mortality and incidence of MACCE.

Results: A total of 1129 patients who underwent isolated multivessel CABG with BIMA (n=480) or SIMA (n=649) were analyzed. The median age of the cohort was 69.0 (IQR 52.0–74.0). IPTW yielded well-balanced groups with standardized mean differences < 0.10 for all baseline characteristics. BIMA group was likely to have more distal anastomosis (BIMA: 4.0 (IQR3.0-4.0) vs. SIMA: 3.0(IQR 3.0-4.0), P< 0.001) and to have more frequent complete revascularization (BIMA: 87.1% vs. SIMA: 81.3%, P=0.02) compared to SIMA group. The incidence of postoperative complications was similar between the two groups. However, long-term survival was significantly difference at 6 years (BIMA: 95.5% [92.6%-98.6%] vs. SIMA: 85.3% [80.4%-90.6%], P=0.006) (Figure 1A). Furthermore, the incidence of MACCE in BIMA group was significantly lower at 6 years (BIMA: 22.9% [16.4%-28.8%] vs. SIMA: 45.0% [36.8%-52.1%], P< 0.001) (Figure 1B). Multivariable Cox regression showed that BIMA usage was associated with better long-term survival (HR 0.384, [0.158-0.934], P=0.035), and lower MACCE (HR: 0.518, [0.357-0.754], P=0.001).

Conclusion: Among patients with CKD requiring multivessel CABG, BIMA grafting may be associated with better long-term survival and lower incidence of MACCE.

Identify the source of the funding for this research project: none