Assessment of sternal vascularity with single photon emission computed tomography after harvesting of the internal thoracic artery

Objective: This study prospectively evaluates the effect on sternal vascula rity of harvesting the left internal thoracic artery. Methods: Twenty-four consecutive patients undergoing primary coronary artery bypass grafting wer e studied. One patient's procedure tvas altered during the operation, and h e was eliminated from the study, The patients were prospectively randomized to receive a skeletonized internal thoracic artery (group I, n = 11) or a pedicled internal thoracic artery (group IT, n = 12) graft, Each patient un derwent a preoperative technetium 99 methylene diphosphonate bone scan usin g single photon emission computed tomography, The ratio of the mean counts per pixel on the left side of the sternum was compared with the mean counts per pixel on the right side. Postoperatively, all patients had a second sc an, and sternal uptake was compared with the preoperative uptake, Results: No significant differences in preoperative and operative variables were? ob served between the groups, A statistically significant reduction in blood f low to the left side of the sternum was shown postoperatively in group IT c ompared with group I (0.61 +/- 0.11 vs 0.85 +/- 0.09; P < .001). Multivaria ble logistic regression analysis of preoperative and operative variables re vealed only a pedicled left internal thoracic artery to be associated with a 20% or more reduction in left-to-right sternal activity ratio (odds ratio , 100; 70% confidence limits, 22-465; P = .002). Conclusion: A pedicled lef t internal thoracic artery graft to the left anterior descending artery red uces blood now to the left side of the sternum during the acute postoperati ve period, This does not occur when the left internal thoracic artery is sk eletonized.