Neutrophil extracellular traps-related markers in chronic limb threatening ischemia - a relation with progression and prognosis.

Background: Neutrophil extracellular traps (NETs) formation is involved in atherothrombosis, though little is known about this phenomenon in peripheral artery disease (PAD). We investigated whether NETs-associated markers are related with the PAD severity and long-term outcomes after endovascular treatment and if they affect fibrin properties and thrombin generation.

Methods: We studied 85 patients with chronic limb threatening ischemia (CLTI) and restenosis within one year after endovascular treatment and 47 age-sex-matched PAD controls without restenosis. NETs-associated markers, i.e. circulating citrullinated histone H3 (H3cit), myeloperoxidase (MPO), protein arginine deaminase 4 (PAD4), cell-free DNA (cfDNA) along with DNAse-I, together with fibrin clot permeability (Ks), clot lysis time (CLT), thrombin generation and fibrinolysis markers were determined. During follow-up a composite endpoint including re-intervention, amputation and death was assessed.

Results: Compared with the control group, patients with CLTI and restenosis had higher H3cit (59.8 %), MPO (58.4 %) and cfDNA (35.3 %; all p < 0.01). Rutherford class positively correlated with H3cit, MPO, PAD4 and cfDNA in the restenosis group and with H3cit in controls (all p < 0.05). In the restenosis group Ks negatively correlated with H3cit and cfDNA while CLT positively correlated solely with H3cit (all p < 0.05). At a median follow-up of 66 months, 56 patients who died (65.9 %) had higher H3cit, MPO and cfDNA concentrations than survivors (all p < 0.05). On multivariable analysis H3cit, ETP, α2-antiplasmin and Ks were independent predictors of combined re-intervention, amputation and death.

Conclusions: Higher levels of NETs-associated markers in relation to prothrombotic fibrin clot properties characterize endovascularly treated PAD patients at risk of 1-year restenosis and worse long-term outcomes.