# Single Versus Bilateral Internal Thoracic Artery Grafting in Patients on Chronic Dialysis

## TL;DR

This study compares the outcomes of single and bilateral internal thoracic artery grafting in patients on dialysis undergoing heart surgery, finding no clear long-term survival benefit for the more complex procedure.

## Contribution

The study provides the first detailed comparison of BITA and SITA grafting outcomes specifically in patients on chronic dialysis.

## Key findings

- BITA revascularization showed a trend toward better five-year survival in the unmatched cohort, but not in the matched cohort.
- Age and EuroSCORE II were significant predictors of survival, but BITA grafting was not.
- Early mortality and adverse events were similar between the SITA and BITA groups.

## Abstract

Objective: To evaluate the outcome of single vs. bilateral internal thoracic artery (SITA vs. BITA) revascularization in patients with multivessel coronary disease referred for coronary artery bypass graft (CABG) while on chronic dialysis. Methods: This retrospective analysis included all the patients with multivessel disease on chronic dialysis who underwent isolated CABG in our center during 1996–2021, utilizing SITA or BITA revascularization. We further matched the groups according to patient age and EuroSCORE II ±0.5. Results: Of the 7547 patients with multivessel disease who underwent CABG, 77 were on chronic dialysis. Of these, 2 had incomplete follow-up data, 58 underwent SITA, and 17 BITA revascularization. Comparing the SITA group with the BITA, the mean age was higher (67.8 vs. 58.6 years, standardized mean difference 1.035); the median (interquartile range) EuroSCORE II was higher (3.73 (1.78–6.23) vs. 1.78 (1.38–3.50), standardized mean difference 0.934); and comorbidities were more prevalent. Early mortality did not differ between the BITA and SITA groups in the unmatched cohort (11.8% vs. 15.5%, p > 0.999) or in the matched cohort (12.5% vs. 6.3%, p = 0.999). Other early adverse events such as early stroke, myocardial infarction, and bleeding requiring re-exploration were also similar. The median survival was 1.22 ± 0.5 years for the SITA and 5.64 ± 1.50 years for the BITA group. The respective five-year survival rates were 22.5 ± 5.9% and 58.35 ± 13.80%, p = 0.005. For the matched cohort, comprising 16 patient pairs, the five-year survival did not differ between the groups (27.8 ± 11.7% vs. 54.7 ± 14.7%, p = 0.258). In multivariable analysis, adjusted to EuroSCORE II and age, the hazard ratio (95% confidence interval) for BITA revascularization was insignificant, 0.638 (95% CI 0.25–1.62), p = 0.343. The hazard ratios for age and EuroSCORE II were 1.061 (95% CI 1.023–1.101), p = 0.002 and 1.155 (95% CI 1.070–1.246), p < 0.001. Conclusions: Despite a trend in favor of BITA utilization, no clear long-term survival benefit was demonstrated for BITA revascularization in patients on chronic dialysis after CABG.