The effects of different techniques of internal mammary artery harvesting on sternal blood flow

We investigated chest wall blood flow in a canine model to determine if the technique used to harvest the mammary artery has a differential effect on residual chest wall blood flow. Eight dogs underwent bilateral internal mammary artery mobilization; one artery was harvested as a pedicle and the other was harvested as a skeletonized vessel. Residual blood flow to the chest wall distribution of each artery was measured with radioactive microspheres. Chest wall blood flow was significantly decreased from preharvest levels after internal mammary artery mobilization regardless of the technique used. Tissue blood flows decreased to 46.9%, 22.1%, and 41.2% of baseline values for the manubrium (p < 0.01), sternum (p < 0.001), and ribs (p < 0.05), respectively. Residual sternal blood flow on the side of the skeletonized vessel was significantly greater than on the side of the pedicle graft (2.60 +/- 0.68 versus 1.27 +/- 0.27 cm3/min/100 gm, p < 0.001). We conclude that minimization of tissue mobilization during internal mammary artery harvesting may reduce sternal devascularization. This finding may have clinical significance with respect to lowering the incidence of sternal wound complications in coronary bypass surgery using the internal mammary artery as a bypass conduit.