Decreasing sternum microcirculation after harvesting the internal thoracic artery

Objective: The effect of harvesting the internal thoracic artery (ITA) on blood supply to the sternum is not completely understood. Using a novel laser Doppler flow meter, we evaluated changes in sternum microcirculation prior to and after ITA harvesting.

Methods: Forty-six patients (37 males, 69.4 ± 7.9 years) scheduled for coronary artery bypass grafting were enrolled into the study and divided into skeletonized (n = 23) and pedicled (n = 23) groups of patients with a left ITA. All right ITA were harvested using the skeletonized method. Sternal blood flow was measured presternally and retrosternally in the upper, middle, and lower sternal parts with a novel laser Doppler flow meter that measures blood flow at 1-mm depth using a 780-nm laser. Following median sternotomy, blood flow was measured before and after ITA harvesting.

Results: In all patients (46 left and 16 right ITA cases), the middle part of the retrosternal microcirculation deteriorated (middle: pre- 2.71 ± 1.49, post- 2.43 ± 1.01 ml min(-1)100 g(-1); p < 0.05), while blood flow of other parts did not change. In patients with left ITA divided into skeletonized and pedicled groups, although middle retrosternal blood flow decreased after harvesting in both groups, there was no difference in deterioration between the groups. In patients with right ITA, the middle and lower retrosternal blood flow also deteriorated.

Conclusions: The degree of sternal microcirculation damage after ITA harvesting is not different between skeletonized and pedicled group patients, suggesting that skeletonization is not advantageous for maintaining sternal microcirculation.