Preoperative ultrasound evaluation of the internal thoracic artery in coronary artery bypass grafting planning

Objective

The internal thoracic artery (ITA) is the preferred conduit for coronary artery bypass grafting (CABG) due to its superior long-term patency, so preoperative meticulous evaluation of ITA quality is crucial to optimize surgical outcomes and ensure graft patency. This study employs ultrasound to assess ITA anatomical and functional characteristics, specifically investigating the relationship between ultrasound-derived ITA diameter, peak systolic velocity (PSV), and intraoperative graft flow.

Methods

In this prospective observational study conducted between March 2024 and March 2025, 199 patients scheduled for CABG underwent preoperative ITA ultrasound evaluation and 148 patients undergoing CABG with ITA grafting were included in the final analysis. Preoperative ultrasound measurements of ITA diameter and PSV were recorded at the third, fourth, and fifth intercostal spaces. Multivariable linear regression models were constructed to assess the associations between preoperative ITA ultrasound parameters and intraoperative graft flow, which was measured using the transit-time flow measurement method with a flowmeter.

Results

Examination of the ITA revealed that 98.0% showed no stenosis, whereas mild abnormalities (plaque or mild stenosis) were observed in 1.0%, and 0.8% had a tortuous course. Similarly, 96.7% of subclavian arteries exhibited no stenosis, with moderate stenosis in 2.0% and severe stenosis or occlusion in 1.3%. Among vertebral arteries, only 3.5% displayed severe stenosis or occlusion. After adjusting for various confounding factors, PSV at the fourth intercostal space was significantly associated with intraoperative ITA graft flow (β = .399, 95% CI 0.109-0.689; P = .007). Furthermore, after adjusting for age, PSV ≥65.0 cm/s seemed significantly predicted better ITA grafts flow (β = 10.527; P = .040), with a significant linear trend observed (P for trend = .039).

Conclusions

Preoperative ITA ultrasound, as a convenient, cost-effective, and noninvasive method, can be used for evaluating the ITA before surgery, thereby improving surgical outcomes in CABG.