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Royse et al. Vessel Plus 2020;4:5 I http://dx.doi.org/10.20517/2574-1209.2019.34 Page 15 of 22

independent stress for the surgeon. It is far better to become familiar with the technique under ideal or
optimal circumstances, so that under urgent or non-optimal circumstances the methods are well practiced.

Alternative combinations of graft reconstructions
Many variants are described but these may be summarised as “mini-Y” grafts. Specifically, short lengths
of conduits that may have been redundant from a previous aorta-coronary graft can be effectively utilised
by creating a Y graft and using the conduit to graft a coronary artery with a more ideal lie. For example, a
short length of IMA or RA could be sutured to the LIMA as a Y graft and used to graft a diagonal artery
that was adopting a course widely divergent from the LAD, making a conventional sequential anastomosis
with the main LIMA more difficult. Generally, more complex iterations of this technique do not facilitate
ease of grafting.

Relatively common grafting configurations are depicted in Figure 8.

Alternative conduits
Second internal mammary artery
Use of a second internal mammary artery in composite grafting is discussed above. The alternative is the
use of an in situ or RIMA. The key limitation of the in situ graft is the frequent inability to reach distal
coronary targets. Devotees of the use of in situ graft usually claim that the PDA and sometimes the left
ventricular branch, distal LAD or more distal marginal arteries can be reached; however, this is often not
the case in the hands of many surgeons. The trajectory to the right coronary territory may be at risk of
tension with excessive inflation of the lungs. Additionally, for circumflex territory targets, the trajectory of
the RIMA may limit grafting by being constrained to passage through the transverse sinus or anterior to
the ascending aorta to reach the LAD. For these left coronary vessel targets, the presence of a patent IMA
graft in close proximity to the ascending aorta results poses a significant risk of inadvertent injury during
redo surgery. Additionally, the meta-analysis data would suggest that, on balance, the risk of deep sternal
wound infection with bilateral compared to unilateral IMA harvest roughly doubles [53-56] . The free graft
is commonly believed to confer a lower patency compared to the in situ graft. However, this may be an
anomaly of grafting strategy, as it is most commonly grafted to the RCA targets, or to circumflex targets of
secondary importance. Therefore, when compared to LIMA-LAD grafts, the patency is lower, yet similar
to other arterial grafts [100,101] . However, when a free IMA is grafted to the LAD, the survival is similar [102] . It
is likely therefore that the higher patency of the LAD graft principally reflects the larger “run-off” of this
vascular bed, compared to the conduit.

Gastroepiploic artery
The proponents are predominantly Japanese surgeons and advocate a pedicled over a free graft
configuration [87,103-107] . The reported complication rate of harvesting this conduit is low, but it is rarely used
outside of Japan. The popular view internationally is that the harvest of this conduit is a major additional
step to surgery and that the complication rate would be higher than for either SVG or RA harvest.
Logically, this appears likely, especially with the higher obesity rates in Western countries, but there is very
little direct evidence. The artery itself would be expected to behave in a similar manner to IMA or RA, by
being resistant to the development of conduit atherosclerosis over the long term [103,108] .

Degree of coronary stenosis and graft selection
This topic is beyond the scope of this article. Competitive flow may affect all conduits and is present in all
coronary territories. General observations are that the effects are greatest in the RCA territory and least in
the LAD territory. For the surgeon early in their experience with multiple arterial grafting, it is wise to be
conservative and graft lesions of high severity (e.g., ≥ 80% stenosis). The alternative to grafting should be
not to graft, rather than grafting with SVG.