title: Stent implantation in the superficial femoral artery: short thrombelastometry-derived coagulation times identify patients with late in-stent restenosis.
abstract: BACKGROUND
  The mechanisms of restenosis, the recurrence of luminal narrowing, are complex and incompletely understood to date. Thrombin, the pivotal enzyme in haemostasis, presumably contributes to the formation of in-stent restenosis (ISR). It was therefore the aim of our study to investigate whether blood coagulation/thrombin generation plays a critical role in the formation of ISR in peripheral artery disease patients with stent angioplasty in the superficial femoral artery.
  
  
  METHODS
  We aimed to examine in this retrospective study whether patients with high-degree restenosis (50-75% lumen diameter reduction, n=20) are in a hypercoaguable state implying enhanced readiness to generate thrombin compared to patients with low-degree restenosis (<50% lumen diameter reduction, n=14).
  
  
  RESULTS
  The coagulation tests calibrated automated thrombography, activated partial thromboplastin time, platelet aggregation, platelet adhesion, fibrinogen, and microparticles' procoagulant activity did not indicate a different coagulation status in the two patient groups. However, the thrombelastometry-derived value Coagulation Time (CT) was significantly shorter in the high-degree restenosis group (p=0.012), indicating a hypercoagulable state of patients with high-degree restenosis. Under our experimental conditions, CTs shorter than 444.5s identify patients at high risk (sensitivity=95%) for luminal narrowing.
  
  
  CONCLUSIONS
  Our study supports the assumption that blood coagulation/thrombin generation plays a critical role in the development of ISR in peripheral arteries after stent insertion and that the thrombelastometry-derived CT might be a suitable value to identify peripheral artery disease patients at risk for development of high-degree in-stent restenosis in the superficial femoral artery.
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Austria. gerhard.cvirn@medunigraz.at
authors.forename: Gerhard
authors.initials: G
authors.lastname: Cvirn
authors.forename: Gerd
authors.initials: G
authors.lastname: Hoerl
authors.forename: Axel
authors.initials: A
authors.lastname: Schlagenhauf
authors.forename: Erwin
authors.initials: E
authors.lastname: Tafeit
authors.forename: Marianne
authors.initials: M
authors.lastname: Brodmann
authors.forename: Guenther
authors.initials: G
authors.lastname: Juergens
authors.forename: Martin
authors.initials: M
authors.lastname: Koestenberger
authors.forename: Thomas
authors.initials: T
authors.lastname: Gary
mesh_terms: D000368:Aged; D005260:Female; D005263:Femoral Artery / Q000601:surgery*; D006083:Graft Occlusion, Vascular / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D058729:Peripheral Arterial Disease / Q000097:blood* / Q000601:surgery*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents / Q000009:adverse effects*; D013916:Thrombelastography; D016896:Treatment Outcome; D014914:Whole Blood Coagulation Time