Effect of papaverine applications on blood flow of the internal mammary artery.

The aim of this prospective study was to compare the effect of different papaverine applications on the free blood flow in the internal mammary artery (IMA) prepared for coronary artery bypass grafting (CABG). The patients were divided into three groups: group I (n=50; intraluminal papaverine application), group II (n=50; topical papaverine application), and group III (n=50; periarterial papaverine application). The free flow from the distal cut end of the IMA was measured under controlled hemodynamic conditions (Flow 1). Just before the establishment of cardiopulmonary bypass, the flows of the IMA were measured again (Flow 2). The mean blood flow in the IMA was 60.7+/-6.0 ml/min before papaverine application. After papaverine application, the mean blood flow in group I was 129.3+/-10.0 ml/min, in group II, it was 87.7+/-3.8 ml/min, and in group III, it was 130.6+/-9.2 ml/min (p<0.0001). Proportional increases in blood flow observed in group I (106.3%) and group III (116.2%) were higher than in group II (44.2%) (p<0.0001). Consequently, to relieve perioperative spasm of the IMA, application of papaverine injected into the periarterial tissues of its pedicle was considered to be a safe and effective alternative to topical or intraluminal application.