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.