Abstract： Objective To explore the value of neutrophil-to-lymphocyte ratio in prognostic prediction of acute Stanford type B aortic dissection patients treated with thoracic endovascular aortic repair (TEVAR).Methods Clinical data of 120 acute Stanford type B aortic dissection patients admitted in Affiliated Hospital of Chengde Medical University from January to December 2016 were retrospectively analyzed.All patients had TEVAR in 1-3 d.According to NLR at admission,they were divided into low NLR group (NLR ＜ 5.0,n =62)and high NLR group(NLR≥5.0,n =58).General information,laboratory indicators,in-hospital mortality and adverse events were analyzed.Risk factors of in-hospital mortality were analyzed by COX model.Results Systolic blood pressure,diastolic blood pressure and heart rate in the high NLR group were higher and platelet count was lower than those in the low NLR group(P ＜0.001).In-hospital mortality rate in the high NLR group was higher than that in the low NLR group[17.2％ (10/58) vs 1.6％ (1/62)] (P =0.003).Incidences of coma neurological symptoms,hypotension,acute renal impairment and limb ischemia in the high NLR group were higher than those in the low NLR group[20.7％ (12/58) vs 3.2％ (2/62),20.7％ (12/58) vs 1.6％ (1/62),24.1％ (14/58) vs 4.8％ (3/62),20.7％ (12/58) vs 1.6％ (1/62)] (P ＜ 0.01).Single factor COX analysis showed that age,atherosclerosis history,platelet count and serum albumin were related to in-hospital mortality (all P ＜ 0.01).Multi-factor COX analysis showed that NLR≥ 5.0 (hazard ratio =3.127,95％ confidence interval:1.192-10.892,P =0.018),platelet count(hazard ratio =0.978,95％ confidence interval:0.945-0.996,P =0.012)and serum albumin(hazard ratio =0.882,95％ confidence interval:0.809-0.977,P =0.005) were independent predictors of in-hospital mortality.Conclusion NLR can be a prognostic predictor of mortality risk in acute Stanford type B aortic dissection treated with TEVAR.