Late Stent Recoil of the Bioabsorbable Everolimus-Eluting Coronary Stent and its Relationship With Plaque Morphology

Objectives This study sought to evaluate late recoil of a novel bioabsorbable everolimus-eluting coronary stent (BVS), which is composed of a poly-L-lactic acid backbone, coated with a bioabsorbable polymer containing everolimus. Background Little is known about the mechanical behavior of bioabsorbable polymer stents after deployment in diseased human coronary arteries. Methods The study population consisted of 16 patients, who were treated with elective BVS implantation for single de novo native coronary artery lesions and were followed at 6 months. All patients underwent an intravascular ultrasound examination at post-procedure and follow-up. A total of 484 paired cross-sectional areas (CSAs) were acquired and analyzed. Late absolute stent recoil was defined as stent area at post-procedure ( X) - stent area at follow-up (Y). Late percent stent recoil was defined as (X - Y)/X X 100. In each CSA, plaque morphology was assessed qualitatively and classified as calcific, fibronecrotic, or fibrocellular plaque. Results Late absolute and percent recoil of the BVS was 0.65 +/- 1.71 mm(2) (95% confidence interval [CI]: 0.49 to 0.80 mm(2)) and 7.60 +/- 23.3% (95% CI: 5.52% to 9.68%). Calcified plaques resulted in significantly less late recoil (0.20 +/- 1.54 mm(2) and 1.97 +/- 22.2%) than fibronecrotic plaques (1.03 +/- 2.12 mm(2) and 12.4 +/- 28.0%, p = 0.001 and p = 0.001, respectively) or fibrocellular plaque (0.74 +/- 1.48 mm(2) and 8.90 +/- 19.8%, p = 0.001 and p = 0.001, respectively). Conclusions The BVS shrank in size during the follow-up period. The lesion morphology of stented segments might affect the degree of late recoil of the BVS. ( ABSORB Everolimus Eluting Coronary Stent System First in Man Clinical Investigation; NCT00300131) (J Am Coll Cardiol 2008; 52: 1616 - 20) (c) 2008 by the American College of Cardiology Foundation