title: Local determinants of thrombus formation following sirolimus-eluting stent implantation assessed by optical coherence tomography.
abstract: OBJECTIVE
  We conducted this study to assess the prevalence and determinants of subclinical thrombus after sirolimus-eluting stent (SES) implantation.
  
  
  BACKGROUND
  Angioscopic analyses have demonstrated the presence of thrombus is more common than the clinical incidence of SES thrombosis.
  
  
  METHODS
  Fifty-three patients (53 lesions) underwent 6-month follow-up optical coherence tomography. A stent eccentricity index ([SEI] minimum/maximum stent diameter) was determined in each cross section. To evaluate unevenness of neointimal thickness, a neointimal unevenness score ([NUS] maximum neointimal thickness in the cross section/average neointimal thickness of the same cross section) was calculated for each cross section. Average SEI and NUS were calculated for each stent. Major adverse cardiac events were defined as a composite of death, myocardial infarction, and target vessel revascularization.
  
  
  RESULTS
  Fourteen cases of thrombus (26%) were detected by optical coherence tomography (thrombus: n = 14 vs. nonthrombus: n = 39). The percentage of thrombus was associated with longer stents (36.4 +/- 20.2 mm vs. 25.1 +/- 9.8 mm; p = 0.008), a larger number of uncovered struts (17 +/- 16 vs. 8 +/- 11; p = 0.03), smaller average SEI (0.89 +/- 0.04 vs. 0.92 +/- 0.03; p = 0.001), and greater average NUS (2.22 +/- 0.24 vs. 2.00 +/- 0.33; p = 0.03). A significant relationship existed between average SEI and average NUS (p < 0.0001, R = 0.68), and between average SEI and the number of uncovered struts (p < 0.0006, R = 0.46). There was no significant difference in major adverse cardiac events during follow-up (median: 485 days, 7.1% vs. 12.8%; p > 0.99).
  
  
  CONCLUSIONS
  Longer stents and greater asymmetric stent expansion may be important determinants of thrombus formation after SES implantation. In this small cohort, the presence of thrombus did not increase the risk of major adverse cardiac events.
authors.affiliation: Department of Internal Medicine, Division of Cardiovascular and Respiratory Medicine, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Otake
authors.forename: Junya
authors.initials: J
authors.lastname: Shite
authors.forename: Junya
authors.initials: J
authors.lastname: Ako
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shinke
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tanino
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ogasawara
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sawada
authors.forename: Naoki
authors.initials: N
authors.lastname: Miyoshi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Honda
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Fitzgerald
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D023903:Coronary Restenosis / Q000209:etiology / Q000517:prevention & control; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D054855:Drug-Eluting Stents; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007564:Japan; D008297:Male; D015999:Multivariate Analysis; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D020123:Sirolimus / Q000008:administration & dosage / Q000627:therapeutic use*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D041623:Tomography, Optical Coherence; D018084:Ultrasonography, Interventional
chemical_list: D007166:Immunosuppressive Agents; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin; D020123:Sirolimus