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Page 6 of 22 Royse et al. Vessel Plus 2020;4:5 I http://dx.doi.org/10.20517/2574-1209.2019.34

Figure 3. Survival of propensity score matched radial artery Y graft versus total arterial revascularisation patients by any other
reconstruction technique, n = 332 pairs. Reproduced with permission, JACC 2018 [37] . LIMA-RA-Y: left internal mammary artery radial
artery Y graft; TAR: total arterial revascularisation

Is RAY or TAR survival significantly better than single internal mammary artery and saphenous vein graft?
We demonstrated that the survival of the “conventional CABG” of left internal mammary artery and
supplementary saphenous vein graft (LIMA + SVG) was significantly lower (HR 1.3 95%CI: 1.0-1.6, P =
[37]
0.043 , Figure 4).
Is multi-arterial grafting significantly better than single IMA + SVG?
The theoretical framework is that, if one arterial graft is better than SVG, then two or even three
arterial grafts should have incrementally greater survival, and this contention is supported by multiple
publications [38-40] . In our own national database analysis, we conducted a series of large-scale propensity
score matches using 17 variables. One arterial graft with supplementary SVG (1A + SVG) was compared to
2A + SVG (n = 7895 pairs) with a mortality hazard in favour of more arterial conduits of 1.21 (95%CI: 1.12-
1.30, P < 0.001). For the comparison of 3A + SVG (n = 3017 pairs), the mortality hazard in favour of more
arteries was 1.41 (95%CI: 1.24-1.60, P < 0.001). Our findings are consistent with the literature and with
greater sample size.

The 10-year Arterial Revascularisation Trial outcome remains highly controversial and variously claimed
to support the lack of evidence for two IMA leading to improved late survival as would otherwise be
[41]
predicted by the evidence presented earlier . Clarity of interpretation is gained by understanding the key
confounders and thereby discounting the “as randomised” (intention-to-treat) analysis in favour of the “as
treated” analysis. The all-cause mortality was not different for those randomised to one or two IMA (P =
0.62).

One key weakness of the study design was to allow use of RA without consequence - this was consistent
with the popular belief at the time of study design - that RA was perhaps “no better” than SVG. Although
this view remains commonplace to this day, the evidence is that RA has superior angiographic, clinical and