Lateral costal artery assessment in patients undergoing Mini-CABG procedure. Exploratory assessment of the potential clinical significance of LCA in Mini-CABG patients.

PURPOSE: The left internal mammary artery (IMA) is the gold standard in coronary artery bypass grafting (CABG) to the left anterior descending (LAD) coronary artery. The presence of the lateral costal artery (LCA) has been identified as the culprit for post-operative steal phenomenon in some patients. Direct ligation of LCA in minimally invasive CABG (mini-CABG) may be challenging due to limited surgical access. This study aims to evaluate the presence, length, and size of the LCA and to determine whether it plays a role in LAD territory ischemia after mini-CABG. MATERIAL AND METHODS: All patients who underwent contrast-enhanced chest imaging (CTA, cardiac CTA) prior to CABG from January 1, 2015 to September 30, 2021 were included. CTA studies were analyzed for image quality, LCA presence, diameter, LCA/IMA ratio and length. Operative reports were reviewed for intraoperative LCA ligation. Postoperative follow-up was performed up to 8 years after CABG procedure by chart review for symptoms of LAD territory ischemia suggestive of steal phenomenon. RESULTS: The cohort consisted of 126 patients (64.5 ± 10y). LCA was present in 13 patients (10.3 %), unilateral in 5 (38 %) patients and bilateral in 8 patients (62 %). 62 (49 %) patients underwent mini-CABG where 5 (8 %) were positive for LCA. The mean LCA diameter was 1.4 ± 0.2 mm and the average IMA diameter measured 3.5 ± 0.3 mm. The mean LCA/IMA ratio was 0.4 ± 0.06 , and the average LCA length was 79 ± 20.6 mm. No LCA positive mini-CABG patients had documented symptoms of postoperative LAD-territory ischemia or symptoms suggestive of coronary steal phenomenon during follow-up. Two patients after regular CABG presented with angina within the first month after CABG, but this was attributed to non-coronary causes. CONCLUSION: The LCA was visualized with CTA in patients before undergoing CABG including mini-CABG. LCA positive patients after mini-CABG showed no documented symptomatic LAD-territory ischemia in electronic patient records. The analysis was underpowered to detect an association between presence of LCA and potential postoperative LAD territory ischemia. The clinical significance of LCA remains uncertain and requires further studies with larger cohorts to clarify the clinical implications of LCA in patients undergoing mini-CABG.