eComment. Is adventitial dissection enough as a simple and effective way to reduce radial artery spasm?

We read with great interest the article by Sandker et al. on the effectiveness of reduced radial artery (RA) spasm in coronary bypass surgery by dissecting the adventitia [1]. The authors conclude that the RA is less susceptible to vasoconstriction and more prone to vasorelaxation ex vivo after adventitial dissection and results in an increase in free blood flow through the RA before anastomosis. The tunica intima includes a single layer of endothelial cells lining the vessel lumen and the internal elastic lamina membrane. The tunica media comprises the muscular portion of the blood vessel, whereas the tunica adventitia includes the external elastic lamina, terminal nerve fibres, and surrounding connective tissue, which contains fibroblasts and tissue macrophages. A preserved adventitia provides structural support to the vessel, which may limit flow-related vascular enlargement and modulation of the vascular tone. Endothelium factors: Receptor-mediated (acetylcholine-induced) and receptor-independent (calcium ionophore-induced) factors modulate endothelium relaxation. These responses could be prevented through mechanical removal of the endothelium, guanylyl cyclase inhibition, or NO (nitric oxide) scavenging with oxyhaemoglobin. Pearson and coworkers [2] confirmed these observations and demonstrated that internal mammary artery relaxation to acetylcholine was attenuated by the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA). Age, gender, hormone influence: Joannides et al. [3] reported the influence of gender difference on RA dimension in flow-dependent dilatation. Men have a higher diameter of the RA compared with women. Herman and coworkers [4] have shown a deleterious effect of physiological levels of androgen hormone in men and a decrease of androgen levels related to age as a benefit in coronary artery disease and endothelium function. Majmudar and colleagues [5] showed the effects of oestrogen in increasing NO release in the arterial vasculature and maintaining the vasculature tone. Oestrogen hormone in the premenopausal woman plays a positive role in the modulation of endothelium flow-mediated dilatation of the RA. Men who receive RA conduits should have better results when they are over 60 years of age because of diminishing androgen hormone and its deleterious effect on the arterial wall [4]. Complex gender-/age-/hormone-related specific considerations play an important role in endothelium-dependent relaxation. We suggest that the authors consider the age and gender of the patients in their analysis, in short- and long-term follow-up. We are not sure whether adventitial dissection, rather than other modulating endothelium factors, influences vasculature tone. Conflict of interest: none declared