title: Stent-related defects in patients presenting with stent thrombosis: differences at optical coherence tomography between subacute and late/very late thrombosis in the Mechanism Of Stent Thrombosis (MOST) study.
abstract: OBJECTIVE
  Subacute, late, and very late stent thrombosis (ST) may occur after stent implantation, but they are characterised by different underlying pathophysiological mechanisms. We sought to appraise differences between subacute and late/very late ST at the thrombus site by optical coherence tomography (OCT). The Mechanism Of Stent Thrombosis (MOST) study was a prospective multicentre non-randomised registry which enrolled six subacute ST and six controls (subacute ST study), and 17 late/very late ST and 17 controls (late/very late ST study).
  
  
  RESULTS
  Patients with subacute ST had a minimum stent area at the thrombus site of 2.1 mm² (1st-3rd quartile 1.3-4.5) vs. 2.9 mm² (2.4-5.0) in the matched control (p=0.05). Uncovered struts were 26.2% (16.5-35.9) vs. 13.9% (8.9-18.9), p=0.001. Malapposed struts were 18.8% (13.1-24.5) vs. 15.2% (12.8-17.6), p=0.001. In patients with late/very late ST, uncovered struts were 23.6% (13.9-33.3) vs. 5.2% (0.5-10.2), p=0.001. Malapposed struts were 12.1% (6.4-17.8) vs. 2.8% (0.4-5.2), p=0.001, and maximum malapposition distance was 0.45 mm (0.32-0.62) vs. 0.12 mm (0-0.25), p=0.01. Notably, all patients with ST had previously discontinued dual antiplatelet therapy (n=14) or showed high residual platelet reactivity on clopidogrel therapy.
  
  
  CONCLUSIONS
  Subacute ST had a significant stent underexpansion while late/very late ST had a greater stent strut malapposition distance at the thrombus site. These findings explain how procedure-related complications and vessel remodelling have a specific impact on the segment characterised by thrombus. High platelet reactivity also seems a necessary cofactor for both subacute and late/very late ST.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov unique identifier NCT01410539.
authors.affiliation: Department of Cardiology, Careggi Hospital, Florence, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Parodi
authors.forename: Alessio
authors.initials: A
authors.lastname: La Manna
authors.forename: Luca
authors.initials: L
authors.lastname: Di Vito
authors.forename: Marco
authors.initials: M
authors.lastname: Valgimigli
authors.forename: Massimo
authors.initials: M
authors.lastname: Fineschi
authors.forename: Benedetta
authors.initials: B
authors.lastname: Bellandi
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Niccoli
authors.forename: Betti
authors.initials: B
authors.lastname: Giusti
authors.forename: Renato
authors.initials: R
authors.lastname: Valenti
authors.forename: Alberto
authors.initials: A
authors.lastname: Cremonesi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Biondi-Zoccai
authors.forename: Francesco
authors.initials: F
authors.lastname: Prati
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015607:Stents / Q000009:adverse effects*; D013927:Thrombosis / Q000175:diagnosis / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome