Very Late Scaffold Thrombosis

Fro De Tri ter Kin (33 Wi spe rec On gra Bio an Ma BACKGROUND Bioresorbable scaffolds provide transient lumen support followed by complete resorption. OBJECTIVES This study examined whether very late scaffold thrombosis (VLScT) occurs when resorption is presumed to be nearly complete. METHODS Patients with VLScT at 3 tertiary care centers underwent thrombus aspiration followed by optical coherence tomography (OCT). Thrombus aspirates were analyzed by histopathological and spectroscopic examination. RESULTS Between March 2014 and February 2015, 4 patients presented with VLScT at 44 (case 1), 19 (cases 2 and 4), and 21 (case 3) months, respectively, after implantation of an Absorb Bioresorbable Vascular Scaffold 1.1 (Abbott Laboratories, Abbott Park, Illinois). At the time of VLScT, all patients were taking low-dose aspirin, and 2 patients were also taking prasugrel. OCT showed malapposed scaffold struts surrounded by thrombus in 7.1%, 9.0%, and 8.9% of struts in cases 1, 2, and 4, respectively. Scaffold discontinuity with struts in the lumen center was the cause of malapposition in cases 2 and 4. Uncovered scaffold struts with superimposed thrombus were the predominant findings in case 3. OCT percent area stenosis at the time of VLScT was high in case 1 (74.8%) and case 2 (70.9%) without evidence of excessive neointimal hyperplasia. Spectroscopic thrombus aspirate analysis showed persistence of intracoronary polymer fragments in case 1. CONCLUSIONS VLScT may occur at advanced stages of scaffold resorption. Potential mechanisms specific for VLScT include scaffold discontinuity and restenosis during the resorption process, which appear delayed in humans; these findings suggest an extended period of vulnerability for thrombotic events. (J AmColl Cardiol 2015;66:1901–14) © 2015 by the American College of Cardiology Foundation. m the *Swiss Cardiovascular Center Bern, Department of Cardiology, Bern University Hospital, Bern, Switzerland; yCardiology partment, Thorax Institute, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain; zCardiology Department, emlispital, Zurich, Switzerland; xCvPath Institute, Gaithersburg, Maryland; kThoraxcenter, Erasmus University Hospital, Rotdam, the Netherlands; and the {International Centre for Cardiovascular Health, Imperial College London, London, United gdom. This study was supported by institutional grants and a grant from the Swiss National Science Foundation CM30_140336 I 1). Dr. Räber is on the advisory board of Abott Vascular; and received speaker fees from St. Jude Medical. Drs. ndecker, Sabaté, and Serruys have received research grants and speaker fees from Abbott Vascular. Dr. Windecker has received aker’s honoraria from AstraZeneca, Eli Lilly, Boston Scientific, Biosensors, Biotronik, Medtronic, and Edwards; and has eived grants to the institution from Abbott Vascular, Boston Scientific, Biosensors, Biotronik, Medtronic, and Edwards. Dr. uma is on the advisory board of Abbott Vascular. Dr. Freixa is a proctor for St. Jude Medical. Dr. Eberli has received institutional nts from Abbott Vascular, Biotronik, and Terumo. Dr. Joner has received institutional grants from Abbott Vascular, Biosensors, tronic, Boston Scientific, CeloNova, Medtronic, MicroPort, Stentys, OrbusNeich Medical, SINO Medical Technology, Terumo, d W.L. Gore. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. nuscript received July 15, 2015; revised manuscript received August 5, 2015, accepted August 11, 2015. ABBR EV I A T I ON S