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Page 10 of 22 Royse et al. Vessel Plus 2020;4:5 I http://dx.doi.org/10.20517/2574-1209.2019.34

The key perioperative risks relate to end-organ dysfunction due to iatrogenic systemic hypotension leading
to end organ hypoperfusion. Acar first advanced the hypothesis that RA was prone to spasm that could
[63]
be managed by intravenous vasodilators . The media of RA is thicker than for IMA, and the logic that
RA appeared likely to be prone to spasm gained momentum, resulting in a widespread use of vasodilators
only when RA was used. This continues in most centres today, resulting in early abandonment of RA use.
Remarkably, there has been no large-scale study undertaken to date. Two small randomised controlled trials
(RCT) failed to show benefit for vasodilators, but they were criticised for lack of power [64,65] . In a meta-
[67]
[66]
analysis of six RA RCTs, benefit for vasodilators was found , but caution in interpretation was advised .
This author has used vasoconstrictors in the majority of patients since 1996, and 100% of patients since
2008 including all patients where RA was used. The author observes that RA spasm is less severe and less
frequent than for IMA.

A theoretical risk for composite grafting is a poorly constructed Y anastomosis, which could compromise
one or both of the conduit limbs distal to the Y graft. However, there are no reports that relate specifically
to this risk. It is assumed that the patency of both limbs is primarily dependent on the integrity of the
conduits and flow dynamics affecting the distal anastomoses. The influence of competitive flow has been
suggested to influence composite grafts to a greater extent than aorta-coronary grafts [68-70] ; however, the
bulk of the literature would suggest that the outcomes are similar [71-76] .

The relationship between surgeon or institutional operative volume and mortality or other outcomes is
generally strongly held. There is some evidence from the surgical literature (often not relating to CABG)
that lower volume equates with higher mortality or adverse outcome [77-80] , whereas other studies found no
such relationship [81,82] . For the Royal Melbourne experience, the mortality of CABG when routine TAR was
[83]
adopted was lower , and mortality is lower or similar in many reports [52,84-89] .

However, this argument misses the point of change in CABG practice. In the examples above, mostly the
analysis relates to performance of a procedure in sufficient volume (or not performing the procedure -
insufficient volume). In the case of CABG using more arterial conduits, there is usually no change to the
number of cases performed or the reconstruction methods used. Thus, the central consideration relates
to a minor change in practice rather than a consideration of the volume of cases. Specifically, the number
of CABG cases for each surgeon or institution, the number and distribution of grafts, the management of
cardiopulmonary bypass, and for the most part the postoperative management of the patient will all remain
the same. The differences in operative technique for the harvest of arterial rather than venous conduit, the
anastomosis suture technique and any other aspect of the surgical procedure are minor. It is a common
view, therefore, that that differences between non-complex arterial reconstructions and conventional
surgery are greatly exaggerated. The adoption of TAR represents a relatively small and easily managed
alteration to the operative technique.

PSYCHOLOGICAL BARRIERS TO ACHIEVING TOTAL ARTERIAL REVASCULARISATION - THE
KEY BARRIERS
The conformist pressure
A remarkably powerful force in medicine is the desire of a group to be homogenous or at least in
conformity with the leader of the group. In addition, since the cardiac surgeon is dependent on the
cardiologist for patient referrals (but the cardiologist is not dependent on the surgeon for referrals), many
surgeons are conscious of the need to ensure that their referring cardiologists prefers greater use of arterial
grafts - before the surgeon changes their technique. In practice, there is often a misalignment between
cardiologist and surgeon which results in maintenance of the status quo.