Impact of bilateral internal mammary artery grafting in patients with mildly decreased renal function.

BACKGROUND

The effectiveness of bilateral internal mammary artery (BIMA) grafting during multivessel coronary artery bypass grafting (CABG) is uncertain in patients with mildly decreased renal function (glomerular filtration rate 60-89 ml/min/1.73 m). We compared outcomes of bilateral versus single IMA (SIMA) grafting in this population.

METHODS

We analyzed 933 patients with mildly decreased renal function who underwent isolated primary CABG using BIMA (n = 454) or SIMA (n = 479) at our center. Patients receiving radial artery grafts or no IMA grafts were excluded. Inverse probability treatment weighting was used to create a well-balanced cohort. 6-year survival and the cumulative incidence of major adverse cardiac or cerebrovascular events (MACCE)-including death, stroke, myocardial infarction, revascularization, and rehospitalization-were assessed.

RESULTS

The median age of the entire cohort was 68.0 years (IQR 61.5-74.0). Median follow-up time was 4.63 years (IQR 4.46-4.82). In well-balanced cohort, BIMA group had a higher number of total distal anastomoses (P < 0.001), with similar rate of complete revascularization (P = 0.101). BIMA group had significantly higher 6-year survival compared to SIMA group (91.9% [87.7-96.3%]; 85.9% [81.7-90.2%]; P = 0.046), which was reconfirmed on multivariable Cox regression analysis (Hazard ratio: 0.505 [0.268-0.953], P = 0.035). MACCE incidence was significantly lower with BIMA (23.5% vs. 40.5%, P < 0.001).

CONCLUSION

Among patients with mildly decreased renal function, the BIMA group was associated with longer survival and lower major adverse cardiac or cerebrovascular events after multivessel CABG.