Functional integrity and aging of the left internal thoracic artery after coronary artery bypass surgery

Objective: To study the endothelial function in the left internal thoracic artery after coronary artery bypass surgery and to identify predictors of e arly dysfunction, we performed a provocative test with acetylcholine in 23 male patients who underwent routine postoperative coronary angiography. Methods: The change in mean diameter of the proximal thoracic artery was as sessed by quantitative angiography after selective injections of acetylchol ine and nitroglycerin. Results: The thoracic artery showed a 6.8% (P <.001) and 9.0% (P <.001) inc rease in mean diameter after acetylcholine and nitroglycerin administration , respectively. Vasodilative responses to acetylcholine and nitroglycerin a dministration were strongly correlated (R: 0.88; P <.001). Among the common risk factors, only age was associated with an impairment in the vasodilati ve response of the arterial graft (P =.001), and acetylcholine-induced vaso dilation was inversely correlated to the age of the patient (R: 0.69; P<.00 1). Conclusions: Endothelium-dependent vasodilative response to acetylcholine a dministration seems well preserved in the left internal thoracic artery aft er surgery. Common risk factors, except for age, do not affect the function al integrity of the arterial graft. The vasodilative properties of the graf t depend on the age of the patient and do not deteriorate over time after o peration.