Very Late Scaffold Thrombosis: Intracoronary Imaging and Histopathological and Spectroscopic Findings.
BACKGROUND
Bioresorbable scaffolds provide transient lumen support followed by complete resorption.


OBJECTIVE
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.
Swiss Cardiovascular Center Bern, Department of Cardiology, Bern University Hospital, Bern, Switzerland.
Lorenz
L
Räber
Cardiology Department, Thorax Institute, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Salvatore
S
Brugaletta
Swiss Cardiovascular Center Bern, Department of Cardiology, Bern University Hospital, Bern, Switzerland.
Kyohei
K
Yamaji
Cardiology Department, Triemlispital, Zurich, Switzerland.
Crochan J
CJ
O'Sullivan
Cardiology Department, Thorax Institute, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Shuji
S
Otsuki
CvPath Institute, Gaithersburg, Maryland.
Tobias
T
Koppara
Swiss Cardiovascular Center Bern, Department of Cardiology, Bern University Hospital, Bern, Switzerland.
Masanori
M
Taniwaki
Thoraxcenter, Erasmus University Hospital, Rotterdam, the Netherlands.
Yoshinobu
Y
Onuma
Cardiology Department, Thorax Institute, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Xavier
X
Freixa
Cardiology Department, Triemlispital, Zurich, Switzerland.
Franz R
FR
Eberli
International Centre for Cardiovascular Health, Imperial College London, London, United Kingdom.
Patrick W
PW
Serruys
CvPath Institute, Gaithersburg, Maryland.
Michael
M
Joner
Cardiology Department, Thorax Institute, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Manel
M
Sabaté
Swiss Cardiovascular Center Bern, Department of Cardiology, Bern University Hospital, Bern, Switzerland. Electronic address: stephan.windecker@insel.ch.
Stephan
S
Windecker
D000368:Aged; D003324:Coronary Artery Disease / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology*; D013997:Time Factors; D054457:Tissue Scaffolds / Q000009:adverse effects; D041623:Tomography, Optical Coherence
bioresorbable scaffold; coronary artery disease; optical coherence tomography; thrombosis