Key factors influencing the RA patency
Besides the CB prescription, whose utility is still under investigation, there are other factors that might influence RA graft patency or at least ‘interact’ with the CB in order to contribute to RA longevity30. Briefly, those are:
a) appropriate coronary target selection b) meticulous and scrupulous harvesting technique (either open or endoscopic) and a c) a general ‘no touch technique’, avoiding hyperinflation of the conduits that can lead to potential for damage of the RA intima and internal elastic lamina.
With regard to target selection, rather than the location of the target vessel it seem far more important to consider the severity of the coronary stenosis; the reversal of one case of string sign concomitant with the progression of the coronary stenosis, although anecdotal, further underscore the influence of native, competitive flow on RA graft15. Royse and colleagues31defined 70% coronary stenosis as the ‘cut-off’ point; below this degree of stenosis the long-term patency of the RA was found to be significantly reduced. Desai and colleagues recommended the use of RA graft only for severely stenotic vessel (>90%)32.
The most common adopted vasodilators for intraoperative dilatation during RA harvesting are CB, papaverine, nitrates and phenoxybenzamine, without clear evidence of superiority of one of them33. To date, no significant advantages related to skeletonizaton of the conduit, endoscopic harvesting, or utilization of the harmonic scalpel during surgical harvesting have been reported33; yet it seem advisable during graft preparation, to avoid hyperinflation and distension of the conduit since would result in damage of the endothelium and the elastic laminae.