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Heng et al. Vessel Plus 2023;7:31 https://dx.doi.org/10.20517/2574-1209.2023.97 Page 11 of 14

SVG side branches and the use of suture in some cases to secure the study device to the graft. With these
findings in mind, the VEST II trial was designed to investigate if avoiding suture fixation and metal clips
[51]
could improve the early patency of externally stented SVGs in the right coronary territory . In total, 30
patients undergoing CABG were assigned to have external stenting of an SVG to the right coronary artery
specifically, and were found to have an improvement of graft patency to 86.2% during the 3 to 6-month
follow-up. Long-term outcomes of 21 patients from the original VEST I trial were reported in the extended
follow-up VEST IV study . While vein graft failure rates did not differ significantly at 4.5 years between
[52]
stented and control grafts (30% vs. 23%, P = 0.42), Fitzgibbon grade I patency reflecting no luminal
irregularities was higher in stented than non-stented grafts (81% vs. 48%, P = 0.42), suggesting improved
remodeling associated with external stenting. Extended outcomes from a larger cohort of 184 patients
undergoing CABG with the VEST sheath have also been reported in the VEST III European multicenter
randomized within-patient control trial . Consistent with the findings of VEST IV, 2-year follow-up
[53]
angiography and intravascular ultrasound demonstrated similar overall patency between groups
(78.3% vs. 82.2%, P = 0.43), and improved Fitzgibbon patency scale I rate (66.7% vs. 54.9%, P = 0.03). In the
USA, 224 patients have been recruited into the VEST Pivotal trial examining study endpoints of graft
patency and intimal hyperplasia at 1 year, as well as major adverse cardiac and cerebrovascular events
annually over 5 years. Though early graft patency did not differ significantly with the VEST, potential long-
term benefits associated with improved luminal geometry in patent vein grafts are yet to be seen .
[54]
CONCLUSION
The study and prevention of vein graft failure after coronary bypass surgery has seen significant
advancements that have paved the way for the development of novel devices and treatment strategies. While
existing therapies translated to human application have not yet demonstrated clinical benefit, long-term
follow-up and continued investigation in these trials are needed. With continued innovation in biomaterials
and fabrication technologies, next-generation devices of external vein graft support hold promise for
providing patient-specific and targeted biological solutions to reduce neointimal hyperplasia and achieve
long-term vein graft patency. Integrating these advancements into future translational efforts will be pivotal
in enhancing current approaches to prevent vein graft failure, and ultimately improve patient outcomes
after CABG.

DECLARATIONS
Authors’ contributions
These authors have made substantial contributions to the conception and design of the study and
performed data analysis and interpretation: Heng EE, Wang H, Obafemi O, Marsden A, Woo YJ, Boyd JH

Availability of data and materials
Not applicable.

Financial support and sponsorship
Publication of this work was supported in part by the National Institutes of Health (R38HL14361504 to
Heng EE; R01HL089315-11 to Woo YJ; R01HL159954-01’ to Marsden A).

Conflicts of interest
All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
Not applicable.