Vasoreactivity and histology of the radial artery: comparison of open versus endoscopic approaches

Objective: Radial artery harvesting using the less invasive endoscopic technique involves dissection in a narrow tunnel and may cause an injury or induce vasospasm to the conduit. To assess this hypothesis, radial artery segments harvested endoscopically or conventionally were studied for reactivity and integrity. Methods: Rings of radial arteries from 80 CABG patients who had their radial artery harvested either open (n = 40) or endoscopic (n = 40), were attached to a force transducer then subjected to norepinephrine (NE, 10^-6 M), acetylcholine (ACh, 10^-5 M), followed by sodium nitroprusside (SNP, 10^-7 to 10^-5 M) to test endothelial dependant and non-dependant relaxation. Vessels' integrity was assessed by microscopic staining with hematoxylin-eosin for muscle layers, Masson trichrome for collagen content and von Gieson for elastica layers. Results: Contraction and relaxation in response to NE, ACh and SNP were similar in both techniques. Arterial layers, collagen content and elastic lamina were preserved in all radial rings. Both techniques were found to be equally efficient in physiological and microscopic tests. Conclusions: The similar reactivity and integrity of the radial artery in both techniques should encourage the less invasive endoscopic approach.