Effect of flow competition on internal thoracic artery graft: postoperative velocimetric and angiographic study

Area of Science:

• Cardiovascular Surgery
• Vascular Biology
• Interventional Cardiology

Background:

• Internal thoracic artery (ITA) grafts are crucial for coronary artery bypass grafting (CABG).
• Competitive blood flow from native coronary arteries can influence graft performance.
• Understanding the impact of native coronary artery stenosis on ITA graft hemodynamics is essential for optimizing surgical outcomes.

Purpose of the Study:

• To evaluate the effect of competitive blood flow on ITA graft hemodynamics and morphology.
• To investigate the relationship between the degree of native coronary artery stenosis and ITA graft flow velocity and diameter.
• To determine the implications of these findings for long-term graft patency and patient outcomes.

Main Methods:

• Fifty patients undergoing CABG with an ITA to the left anterior descending artery graft were studied.
• Intravascular Doppler graft velocimetry was performed during postoperative angiography.
• Patients were stratified into three groups based on native coronary artery stenosis severity (≥80%, 60-79%, 40-59%).

Main Results:

• Significant differences in average peak velocity, distal graft diameter, and calculated graft flow volume were observed across stenosis groups.
• Higher degrees of stenosis correlated with increased ITA graft peak velocity, diameter, and flow volume.
• Diastolic and systolic graft flow patterns varied significantly with the grade of native coronary artery stenosis.

Conclusions:

• Competitive blood flow significantly reduces ITA graft flow and diameter in a manner dependent on the native coronary artery stenosis grade.
• Grafting the ITA to coronary arteries with low-grade stenosis may predispose to graft atrophy and eventual failure.
• Careful consideration of native coronary artery stenosis is warranted when selecting ITA graft targets to ensure optimal long-term graft function.