Abstract 4925: Noninvasive Angiographic Follow-Up 18 Months after Bioabsorbable Everolimus-Eluting Stent Implantation Using 64-Slice Computed Tomography (ABSORB)

While assessment of metal stents by CT angiography is complicated by blooming artifacts, noninvasive follow-up should be possible after implantation of non-metal, radiolucent, bioabsorbable stents. In a multicenter, prospective, open-label study (ABSORB) 30 patients underwent implantation of a 3.0 ×12-mm (N=28) or 3.0 × 18-mm(N=2) bioabsorbable everolimus-eluting stent made of polylactic acid (Abbott Vascular, Santa Clara, CA). At 19.2 ±1.1 months 64-slice CT angiography (Siemens Somatom Definition, Germany; Philips Brilliance 64, The Netherlands; GE LightSpeed VCT, WI) was performed in 25 patients (65 ±11 years, 15 male). Five patients were lost due to target-lesion re-intervention (N=1), contrast allergy (N=1), withdrawn consent (N=3). Cross-sectional, in-stent lumen areas were measured at submillimeter intervals using quantitative CT software (Circulation®, Siemens). Minimal in-stent lumen area was compared to the reference lumen area, based on adjacent proximal and distal lumen areas. Motion artifacts excluded one CT study. Radiopaque indicators (figure ) at the egdes of the absorbed stent were the only visible remains: distance 11.4 ±0.5 mm (12-mm stents). All stents were patent. Mean lumen area 5.2 ±1.3 mm 2 (range 3.2 – 7.4 mm 2 ). Minimal lumen area 3.6 ±0.9 mm 2 (range 2.2 – 5.7 mm 2 ), compared to a reference lumen area of 5.5 ±1.0 mm 2 (range 3.3 – 7.6 mm 2 ), resulting in a lumen area stenosis of 31 ±15% (range -2 - 51%). One case showed local lumen enlargement (12.0 mm 2 ). CT angiography was feasible and demonstrated moderate in-stent lumen loss without significant obstruction after bioabsorbable stent implantation.