VH-IVUS Study on Vascular Response at the Edge Segments of Abbott Vascular's Absorb Bioresorbable Scaffold Published

June 20, 2012—A virtual histology intravascular ultrasound (VH-IVUS) study from the first-in-man ABSORB Cohort B trial sought to investigate in vivo the vascular response at the proximal and distal edges of Abbott Vascular's (Santa, Clara, CA) second-generation Absorb everolimus-eluting bioresorbable vascular scaffold (BVS), which has not been previously investigated. Bill D. Gogas, MD, et al published the 6-month and 1-year follow-up findings in the Journal of the American Cardiovascular Cardiology: Cardiovascular Interventions (2012;5:656–665).

The investigators reported that the ABSORB Cohort B trial enrolled 101 patients and was divided into two subgroups: B1 (n = 45) and B2 (n = 56). The adjacent (5-mm) proximal and distal vessel segments to the implanted Absorb BVS were investigated at either 6 months (B1) or 1 year (B2) with VH-IVUS imaging.

As detailed in Journal of the American Cardiovascular Cardiology: Cardiovascular Interventions, at the 5-mm proximal edge, the only significant change was modest constrictive remodeling at 6 months (Δ vessel cross-sectional area: –1.8% [–3.18; 1.3]; P < .05), with a tendency to regress at 1 year (Δ vessel cross-sectional area: –1.53% [–7.74; 2.48]; P = .06). The relative change of the fibrotic and fibrofatty (FF) tissue areas at this segment was not statistically significant at either time point. At the 5-mm distal edge, a significant increase in the FF tissue of 43.32% (–19.9; 244.28; P < .05) 1 year after implantation was evident. The changes in dense calcium need to be interpreted with caution because the polymeric struts are detected as “pseudo” dense calcium structures with the VH-IVUS imaging modality.

The investigators concluded that the vascular response up to 1 year after implantation of the ABSORB BVS demonstrated some degree of proximal edge constrictive remodeling and distal edge increase in FF tissue resulting in nonsignificant plaque progression with adaptive expansive remodeling. This morphological and tissue composition behavior appears to not significantly differ from the behavior of metallic drug-eluting stents at the same observational time points, stated the investigators in the Journal of the American Cardiovascular Cardiology: Cardiovascular Interventions.