Comparison of the effects on the flow in the left internal thoracic artery using nimodipine and papaverine as vasodilators

Objective: To compare the flow of the left internal thoracic artery under a local pharmacological effect caused by the topical action on the arterial pedicle and the intraluminal effect of a calcium channel blocker with a control group using papaverine. Methods: Over a period from July to November 2004, a prospective study was performed involving 73 patients who were submitted to coronary artery bypass surgery utilizing the left internal thoracic artery as one of a group of grafts. A comparative analysis of the flow was made when using two different pharmacological agents. The patients were randomized to receive either nimodipine or papaverine as vasodilators. Two types of flow were determined: the flow at Time 1 representing the period of topical action of the drug on the arterial pedicle (extraluminal) and the flow at Time 2 representing the intraluminal action of the drug. A comparison of the means of the two types of flow between the two groups of pharmacological agents was carried out using the non-parametric Mann-Whitney test. Results: There is no evidence that the mean flow using the two pharmacological agents is different at Time 1 (p = 0.534) or at Time 2 (p = 0.063). Conclusions: There is no evidence that the mean flow varies due to the topical action of one or other drug or that the mean flow is different due to the intraluminal action, proving that nimodipine as a locally acting vasodilator is similar to papaverine. Descriptors: Papaverine. Nimodipine. Mammary arteries. Vasodilator agents.