Endothelial-dependent vasomotion in a coronary segment treated by ABSORB everolimus-eluting bioresorbable vascular scaffold system is related to plaque composition at the time of bioresorption of the polymer: indirect finding of vascular reparative therapy?

To analyse the vasoreactivity of a coronary segment, previously scaffolded by the ABSORB bioresorbable vascular scaffold (BVS) device, in relationship to its intravascular ultrasoundvirtual histology (IVUSVH) composition and reduction in greyscale echogenicity of the struts. Coronary segments, transiently scaffolded by a polymeric device, may in the long-term recover a normal vasomotor tone. Recovery of a normal endothelial-dependent vasomotion may be enabled by scaffold bioresorption, composition of the underlying tissue, or a combination of both mechanisms. All patients from the ABSORB Cohort A and B trials, who underwent a vasomotion test and IVUSVH investigation at 12 and 24 months, were included. Acetylcholine (Ach) and nitroglycerin were used to test either the endothelial-dependent or -independent vasomotion of the treated segment. Changes in polymeric strut echogenicitya surrogate for bioresorptionIVUSVH composition of the tissue underneath the scaffold and their relationship with the pharmacologically induced vasomotion were all evaluated. Overall, 26 patients underwent the vasomotion test (18 at 12 and 8 at 24 months). Vasodilatory response to Ach was quantitatively associated with larger reductions over time in polymeric strut echogenicity (y 0.159x 6.85; r 0.781, P 0.001). Scaffolded segments with vasoconstriction to Ach had larger vessel areas (14.37 2.50 vs. 11.85 2.54 mm(2), P 0.030), larger plaque burden (57.31 5.96 vs. 49.09 9.10, P 0.018), and larger necrotic core (NC) areas [1.39 (1.14, 1.74) vs. 0.78 mm(2) (0.20, 0.98), P 0.006] compared with those with vasodilation. Vasodilatory response to Ach, in coronary segments scaffolded by the ABSORB BVS device, is associated with a reduction in echogenicity of the scaffold over time, and a low amount of NC. In particular, the latter finding resembles the behaviour of a native coronary artery not caged by an intracoronary device.