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Comparative histological and biometric study of the coronary, radial and left internal thoracic arteries
M M Barry1, P Foulon, G Touati
1Service de Chirurgie Cardiaque, CHU Amiens, Amiens, France. misbarry@voila.fr
Insights
Radial arteries, unlike internal thoracic arteries, are muscular and prone to intimal changes and atheromatous plaque, impacting coronary artery bypass graft patency. Understanding their histology is crucial for improving graft outcomes.
Area of Science:
- Vascular Biology
- Cardiovascular Surgery
- Histopathology
Background:
- Coronary artery bypass grafting (CABG) outcomes are influenced by graft choice.
- Radial artery (RA) and left internal thoracic artery (LITA) are common CABG conduits.
- Understanding arterial histology is key to preventing graft occlusion.
Purpose of the Study:
- To investigate the biometric and histologic differences between coronary arteries, RAs, and LITAs.
- To elucidate the causes of occlusion in RAs used for CABG.
- To identify factors influencing CABG graft patency.
Main Methods:
- Harvesting of coronary, radial, and left internal thoracic arteries from 20 cadavers.
- Biometric calibration of arterial specimens to bypass graft sites.
- Histological examination of vessel wall structure and innervation.
Main Results:
- No consistent correlation between internal calibers of coronary, radial, and LITA, except for specific coronary branches.
- Intimal changes and atheromatous plaque observed in coronary and radial arteries, but absent in LITA.
- Radial and coronary arteries are muscular, exhibiting age-related intimal thickening and medial changes; LITA is elastic.
- Radial and coronary arteries possess adventitial nerves; LITA lacks them.
Conclusions:
- Radial arteries, being muscular, undergo histologic changes similar to coronary arteries, potentially affecting graft patency.
- Left internal thoracic artery, an elastic artery, shows distinct aging patterns and lacks atheromatous changes, suggesting superior graft suitability.
- Histological characteristics, not just caliber, dictate graft patency in coronary artery bypass procedures.
Abstract:
In an attempt to elucidate the causes of occlusion of radial arteries used for coronary artery bypass grafts and to improve the results of these procedures, we studied the biometry and histology of the coronary, radial and left internal thoracic arteries. These arteries were harvested from 20 cadavers (13 males, 7 females). The specimens were calibrated to the various bypass graft sites using coronary calibrators, and were then submitted to histological examination to determine the structure and innervation of the vessel wall. No correlation was observed between the internal calibers of these various arteries, with the exception of the anterior interventricular and right coronary arteries. Intimal changes and the presence of atheromatous plaque were observed in coronary and radial arteries, but never in the internal thoracic artery. Like the coronary arteries and their branches, the radial artery is a muscular artery. Aging of muscular arteries results in thickening of the intima, which becomes fibrotic due to migration of myocytes from the media and duplication of the internal elastic lamina. The media becomes fibrous, hypertrophic or atrophic. The walls of the radial and coronary arteries contain several adventitial nerves (sympathetic and parasympathetic nerve fibers), but these nerve fibers were not observed in the wall of the left internal thoracic artery. In contrast, the internal thoracic artery, like the aorta, is an elastic artery. Aging of elastic arteries is first observed between the ages of 20 and 29 years and is characterized by loss of one or several elastic laminae of the media and more marked intimal thickening, over a variable length. Even if a radial artery's caliber is similar to that of the coronary artery, histological evolution and graft patency depend on its muscular identity.