title: Neutrophil-lymphocyte ratio as a prognostic marker of outcome in infrapopliteal percutaneous interventions for critical limb ischemia.
abstract: BACKGROUND
  Endovascular intervention has become a frequently used treatment of critical limb ischemia (CLI) in recent times. The recent Bypass vs Angioplasty in Severe Ischaemia of the Leg (BASIL) trial consensus recommended endovascular treatment as a first-line treatment in patients who have a life expectancy that was limited to <2 years. Despite these recommendations, there still remains limited data available to clinicians when seeking to risk stratify patients who present with CLI. The neutrophil-lymphocyte ratio (NLR) has been suggested to be a marker for predicting mortality and patency. This study aimed to investigate the use of the NLR as a prognostic marker for primary patency and mortality after an infrapopliteal endovascular intervention in patients with CLI.
  
  
  METHODS
  All patients who underwent tibial angioplasty for CLI were retrospectively analyzed. Demographics, degrees of stenosis, vessel patency rates, mortality, and comorbidities were recorded. NLRs were calculated from preoperative blood samples. Primary end points were all-cause mortality, primary patency, and amputation-free survival (AFS) within the follow-up period of 12 months. Multivariate Cox proportional hazard models were used to identify independent predictors. Overall survival, AFS, and the probability of a vessel remaining patent were evaluated by standard Kaplan-Meier survival curves and groups compared by the log-rank test.
  
  
  RESULTS
  Eighty-three patients were monitored for 12 months. Ninety limbs were identified, with 104 procedural events and 127 vessels undergoing successful angioplasty. The technical success rate was 86%, and patency at 1 year was 19%. Survival at 1 year was 76% and AFS was 61%. Patients with a NLR ≥5.25 had an increased risk of death (hazard ratio, 1.97; 95% confidence interval, 1.08-3.62; P = .03) compared with those with a NLR of <5.25. Furthermore, those with lymphocytes counts of <1.5 × 10(9)/L had higher mortality (hazard ratio, 1.88; 95% confidence interval, 1.02-3.70; P = .045) than those with lymphocyte counts >1.5 × 10(9)/L.
  
  
  CONCLUSIONS
  The NLR and absolute lymphocyte counts are potentially valuable prognostic indicators for risk stratification of patient's presenting with CLI undergoing infrapopliteal angioplasty.
authors.affiliation: Department of Vascular Surgery, Flinders Medical Centre and Flinders University, Adelaide, South Australia, Australia.
authors.forename: Chun
authors.initials: C
authors.lastname: Chan
authors.affiliation: Department of Vascular Surgery, Flinders Medical Centre and Flinders University, Adelaide, South Australia, Australia.
authors.forename: Phillip
authors.initials: P
authors.lastname: Puckridge
authors.affiliation: Flinders Centre for Epidemiology and Biostatistics, School of Medicine, Faculty of Health Sciences, Flinders University, Adelaide, South Australia, Australia.
authors.forename: Shahid
authors.initials: S
authors.lastname: Ullah
authors.affiliation: Department of Vascular Surgery, Flinders Medical Centre and Flinders University, Adelaide, South Australia, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Delaney
authors.affiliation: Department of Vascular Surgery, Flinders Medical Centre and Flinders University, Adelaide, South Australia, Australia. Electronic address: ian.spark@health.sa.gov.au.
authors.forename: J Ian
authors.initials: JI
authors.lastname: Spark
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D017130:Angioplasty / Q000009:adverse effects / Q000401:mortality; D016009:Chi-Square Distribution; D016638:Critical Illness; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007511:Ischemia / Q000097:blood / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D053208:Kaplan-Meier Estimate; D023821:Limb Salvage; D035002:Lower Extremity / Q000098:blood supply*; D018655:Lymphocyte Count; D008214:Lymphocytes; D008297:Male; D015999:Multivariate Analysis; D009504:Neutrophils; D011150:Popliteal Artery / Q000503:physiopathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency