Blood flow characteristics of the bilateral internal thoracic artery: implications of optimal graft configuration for coronary artery bypass grafting to maximize blood supply.

Purpose: There is controversy regarding which internal thoracic artery (ITA) should be anastomosed to the left anterior descending artery (LAD). Here, we propose an optimal graft design based on measurement of blood flow in the ITA.
Methods: Sixty-one patients (53 men, median age 68 [62-75] years) undergoing first elective coronary artery bypass grafting were enrolled. Fifty-seven left ITAs (LITAs) and 28 right ITAs (RITAs) were harvested in either a semi-skeletonized manner using a harmonic scalpel covered with papaverine-soaked gauze (group-A, n = 45) or a fully skeletonized manner using electrocautery with intraluminal papaverine injection (group-B, n = 41). Free flow of 33 ITAs was measured after pharmacological dilatation and in situ ITA-LAD flow was measured in 59 patients by transit-time flowmetry.
Results: RITA and LITA free flow were 147.0 [87.8-213.0] mL/min and 108.0 [90.0-144.0] mL/min, respectively (P = 0.199). The group-B had significantly higher ITA free flow (135.0 [102.0-171.0] mL/min) than group-A (63.0 [36.0-96.0] mL/min, P = 0.009). In 13 patients with bilateral ITA harvesting, free flow of the RITA (138.0 [79.5-204.0] mL/min) was also significantly higher than the LITA (102.0 [81.0-138.0] mL/min, P = 0.046). There was no significant difference between RITA and LITA flow anastomosed to the LAD. The group-B had significantly higher ITA-LAD flow (56.5 [32.3-73.6] mL/min) than group-A (40.9 [20.1-53.7] mL/min, P = 0.023).
Conclusion: RITA provides significantly higher free flow than LITA but similar blood flow to the LAD. Full skeletonization with intraluminal papaverine injection maximizes both free flow and ITA-LAD flow.
(© 2023. The Author(s), under exclusive licence to The Japanese Association for Thoracic Surgery.)