Comparing Arterial Response to Scaffolds and Stents
What are patterns of arterial remodeling among patients receiving bioresorbable vascular scaffolds (BVS) and drug-eluting stents (DES)?
Data from the ABSORB II randomized trial were used to identify patients who underwent intravascular ultrasound (IVUS) assessment pre- and post-procedure and at 3-year follow-up. A total of 383 lesions (247 BVS; 136 DES) were evaluated. Using lumen, plaque, and vessel area, nine patterns of vessel remodeling were identified. Expansive remodeling was defined as increase in lumen (>15%) and vessel (>12%) area. Patterns of remodeling were compared between vessels treated by BVS and by DES. Multivariate analysis was performed to identify independent predictors of expansive remodeling.
Overall, relative change in mean vessel area (6.7 ± 12.6% vs. 2.9 ± 11.5%; p = 0.003) and mean lumen area (1.4 ± 19.1% vs. -1.9 ± 10.5%, p = 0.031) was significantly greater with BVS compared with DES, respectively. A substantial (78%) proportion of patients who received DES had no change in either vessel or lumen area. Predictors of expansive remodeling included use of BVS, female sex, balloon-artery ratio >1.25, among others.
The authors concluded that use of BVS is associated with greater gains in lumen and vessel area over time compared with DES. Expansive remodeling is more likely to occur with BVS, although clinical and procedural factors may play a role.
The study is an IVUS-based comprehensive evaluation and comparison of the effect of BVS and DES on vessel remodeling. Expansive remodeling (Glagov principle) is thought to be a compensatory response in vessels with <40% plaque burden. Although only a few patients in the current study had plaque burden <40%, the authors were able to show evidence of expansive remodeling based on IVUS, and that this phenomenon was more evident in patients receiving BVS compared with DES. Interestingly, BVS was also associated with more plaque/media increase with late lumen reduction (19% vs. 4%), and >75% of DES lesions did not exhibit any change on IVUS follow-up. This study adds to our understanding of vessel response to currently available treatments, but given recent concerns about stent thrombosis related to BVS, clinical implications of the findings remain to be determined.
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