Stent implantation in the superficial femoral artery: Short thrombelastometry-derived coagulation times identify patients with late in-stent restenosis

article Introduction: 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. Materials and Methods: We aimed to examine in this retrospective study whether patients with high-degree reste- nosis (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 (b 50% lumen diameter reduction, n = 14). Results: The coagulation tests calibrated automated thrombography, activated partial thromboplastin time, plate- let aggregation, platelet adhesion, fibrinogen, and microparticles' procoagulant activity did not indicate a differ- ent 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 444.5 s iden- tify 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.