Blood flow in the internal mammary artery after the administration of papaverine during coronary artery bypass grafting.

Between January 1993 and February 1994, 106 patients whose internal mammary arteries were to be used for revascularization to treat coronary artery disease were examined for a prospective study of papaverine administration. The mean blood flow in the internal mammary artery was 59.9 mL/min +/- 7.3 mL/min before papaverine administration. The patients were divided into 3 groups: in Group I papaverine was administered intraluminally, retrograde in the internal mammary artery; in Group II, it was administered topically; and in Group III, it was administered perivascularly, in the pedicle. After papaverine administration, the mean blood flow in Group I was 135.7 mL/min +/- 10.1 mL/min; in Group II, it was 84.8 mL/min +/- 8.3 mL/min; and in Group III, it was 136.3 mL/min +/- 9.7 mL/min. The highest increases in blood flow were observed in Group I (105.3%) and in Group III (112.6%). On the basis of our results, we recommend that papaverine be injected perivascularly into the pedicle of the internal mammary artery, since retrograde injection can cause dissection.