ABSTRACT
The purpose of this study was to assess the sternal osteoblastic activity and perfusion in the early period after a coronary artery bypass graft (CABG) using single-photon emission computed tomography (SPECT) and three-phasic dynamic scintigraphy (3PDS) with 99mTc methylene diphosphonate (MDP). METHODS: The study group consisted of 57 male patients that were 57.3 ± 6.6 years of age. Thirty-six of them were randomized into two groups: in group I (n = 18), the internal thoracic artery (ITA) was skeletonized, and in group II (n = 18), the ITA was pedicled. All the patients in groups I and II underwent an off-pump CABG using 1.7 ± 0.3 grafts, including one anastomosis of the ITA to the left anterior descending coronary artery. The control group III (n = 21) consisted of patients that underwent mitral valve repair surgery, in whom the sternotomy without the ITA harvesting was performed. The 3PDS and SPECT of the thorax with 99mTc MDP were performed 2 weeks after surgery. RESULTS: The sternal phosphates uptake in group I was approximately twice as high as in group II and approximately 1.5 times higher than in group III (p < 0.05). The MDP uptake asymmetry after the ITA skeletonization was the same as in the group with both intact ITAs. In contrast, after the pedicled ITA harvesting, the osteoblastic activity of the ipsilateral side of the sternum was lower than in the contralateral one. There was no statistically significant difference in scintillation count in the xiphoid process between groups I and II (p > 0.05); however, we observed a significant difference in the manubrium and body (p < 0.05). CONCLUSION: The main factor that improved the sternal perfusion after a CABG was the preservation of branches supplying the sternum using the skeletonization technique of ITA harvesting.
ABSTRACT
The objective of the study was to estimate the internal thoracic arteries (ITA) and radial arteries (RA) micromorphologic features by light microscopy after harvesting them using the skeletonization and pedicled methods in patients undergoing coronary artery bypass grafting. The micromorphologic characteristics of ITA and RA were studied by luminous microscopy in 61 patients undergoing coronary artery bypass grafting. A total of 122 ITA and RA segments harvested during surgery, fixed in formalin, and stained with hematoxiline and eosin were evaluated. The mean intima-media thickness of ITA was 9.2 and 134.7 µm and that of RA was 9.1 and 334.2 µm, respectively. In the distal segment of ITA the media-intima relation was 1.5 times bigger than in the proximal segment. None of ITA specimens contained atherosclerotic plaques or lipid inclusions. Atherosclerotic plaques were found in 3 (5%) RA specimens. Other degenerative changes were detected in 30%-74.2% of the specimens: splitting of internal elastic lamina, reduced tortuosity of the internal elastic lamina, and thickening and detachment of the intima; their incidence was associated with the skeletonization of the vessels. In conclusion, the incidence of ITA and RA degenerative changes varies from 30%-74.2% and its increase is associated with the skeletonization of the vessels, which is statistically significant. The media of the RA is 2.5 times thicker than that of the ITA (P < 0.01). This fact shows that RA has higher spasmogenic potential than that of ITA. The distal segment of the ITA has 1.5 times bigger media-intima relation than the proximal segment. Therefore, in case of enough graft length, it is recommended to avoid the distal segment and cut it off.
