Both endothelium-dependent and -independent vasomotion of an infarct-related artery (IRA) were more evident with bioresorbable vascular scaffolds (BVS) compared with everolimus-eluting stents (EES) at three years, while functional microcirculatory parameters were mostly adequate and similar, according to results from the TROF II trial presented on May 24 at EuroPCR in Paris and published in JACC: Cardiovascular Interventions.

Using data from the randomized, controlled, multicenter study, Josep Gomez-Lara, MD, PhD, et al., screened 63 consecutive event-free patients to undergo coronary angiography with vasomotor, microcirculatory and optical coherence tomography examination to compare the IRA function between BVS and EES at three years. Vasomotion was defined as more than a four percent change in mean lumen diameter to acetylcholine and nitroglycerin as assessed by quantitative angiography, and microcirculatory examination was performed with pressure or thermodilution techniques.

Results showed that of the 38 patients included (20 BVS and 18 EES), over 60 percent exhibited paradoxical vasoconstriction to acetylcholine in the periscaffold or stent segments at three years. Vasoconstriction to acetylcholine and vasodilatation to nitroglycerin were found to be more often observed in the scaffold or stent segment with BVS than with EES (77.8 percent vs. 25.0 percent; p=0.008, and 61.1 percent vs. 18.8 percent; p=0.018).

For IRA-dependent microcirculation, the findings showed similar index of resistance (23.8 vs. 22.4; p=0.781), coronary flow reserve (2.4 vs. 1.9; p=0.523), fractional flow reserve (0.91 vs. 0.93; p=0.317) and absolute flow (135.5 ml/min vs. 147.3 ml/min; p=0.791). Optical coherence tomography showed remaining strut footprints and larger number of intraluminal scaffold dismantling (26.3 percent vs. 0 percent; p=0.049) in the BVS group.

The clinical implications of these findings require further investigations note the authors.

In an accompanying editorial comment, Hiroyuki Jinnouchi, MD, et al., note that these data are “valuable because they enhance our knowledge of the long-term vascular responses to this technology and might serve to temper enthusiasm.” However, they add, “the promise of BVS remains more fiction than fact, and if its future is to be realized, long-term responses such as vasomotion and compensatory dilation will need to be conclusively shown.”

Keywords: Coronary Angiography, Tomography, Optical Coherence, Nitroglycerin, Microcirculation, Acetylcholine, Vasodilation, Drug-Eluting Stents, Vasoconstriction, Absorbable Implants, Dilatation, Thermodilution, Stents, Arteries, Pressure, Endothelium

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