Abstract 4911: Quantitative Assessment of Strut Absorption of a Poly-L-Lactic-Acid (PLLA) Bioabsorbable Stent Design Using Intracoronary Ultrasound (ICUS) Derived Compositional Parameters: A Feasibility Study
Bioabsorbable stents could overcome current clinical problems of conventional stent designs but preserve their benefits. ICUS is the imaging modality used in the first-in-man studies of these new stent designs evaluating several properties as luminal dimensions, late malapposition and strut coverage. Dedicated tissue composition software quantified the relative fraction of hypo- and hyperechogenic components of plaque+media+struts in the stented segments using the adventitia grey-level intensity as discriminator. Stent struts appear as bright hyperechogenic structures on ICUS and partially absorbed struts are showing a lower intensity (less hyperechogenic) over time due to the polymer degradation process (Fig.). This study investigated the feasibility to use ICUS derived quantitative echogenicity to study the absorption process of bioabsorbable stents. Thirty patients enrolled in the ABSORB trial, treated with a single bioabsorbable stent (BVS; Abbott vascular, Santa Clara, CA, USA), were imaged by ICUS directly after implantation and at 6 months follow-up (FUP). Five patients could not be analyzed due to: no baseline ICUS (2), no 6 months ICUS (1) and insufficient ICUS recordings (2). In the remaining 25 patients a significant decrease of %hyperechogenicity was measured: 18.4±9.5% at post-stent implantation and 9.3±6.5% at 6 months, p<0.001, respectively. Quantitative assessment of the absorption process by ICUS derived compositional parameters appears feasible. A 24 months ICUS follow-up is currently in progress and could confirm if the proposed method could be applied as a surrogate to quantify strut absorption.