title: Relationship between low lymphocyte count and major cardiac events in patients with acute chest pain, a non-diagnostic electrocardiogram and normal troponin levels.
abstract: OBJECTIVE
  Risk stratification of patients with acute chest pain, non-diagnostic electrocardiogram and normal troponin (ACPneg) remains a challenge, partly because no standardized set of biomarkers with prognostic ability has been identified in this population. Lymphopenia has been associated with atherosclerosis progression and adverse outcomes in cardiovascular diseases; although its prognostic value in ACPneg is unknown. We sought to determine the relationship between the lymphocyte count obtained in the Emergency Department (ED) and the risk of the long-term all-cause mortality or myocardial infarction (MI) in patients with ACPneg.
  
  
  METHODS
  We analyzed 1030 consecutive patients admitted with ACPneg in our institution. Lymphocyte count was determined in the ED as a part of a routine diagnostic workup to rule out an acute coronary syndrome. Patients with inflammatory, infectious diseases, or active malignancy were excluded (final sample=975). The independent association between lymphocyte count and the composite endpoint (death/MI) was assessed by survival analysis for competing risk events (revascularization procedures).
  
  
  RESULTS
  During a median follow-up of 36 months, 139 (14.3%) patients achieved the combined endpoint, with rates increasing monotonically across lymphocyte quartiles (6.2%, 10%, 20.6% and 24.1% for Q4, Q3, Q2 and Q1 (p<0.001), respectively). In a multivariable analysis, patients in lymphocytes' Q1 and Q2 as compared with those in Q4 had an increased risk for the combined endpoint: HR=2.45 (CI 95% 1.25-4.79, p=0.008) and HR=2.56 (CI 95% 1.30-5.07, p=0.007), respectively.
  
  
  CONCLUSIONS
  In patients with ACPneg, low lymphocytes count was associated with an increased risk for developing the combined endpoint of death or MI.
authors.affiliation: Servicio de Cardiología, Hospital Clínico Universitario, Universitat de Valencia, Avda. Blasco Ibáñez 17, Valencia, Spain. yulnunez@gmail.com
authors.forename: Julio
authors.initials: J
authors.lastname: Núñez
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchis
authors.forename: Vicent
authors.initials: V
authors.lastname: Bodí
authors.forename: Eduardo
authors.initials: E
authors.lastname: Núñez
authors.forename: Luis
authors.initials: L
authors.lastname: Mainar
authors.forename: Anne M
authors.initials: AM
authors.lastname: Heatta
authors.forename: Oliver
authors.initials: O
authors.lastname: Husser
authors.forename: Gema
authors.initials: G
authors.lastname: Miñana
authors.forename: Pilar
authors.initials: P
authors.lastname: Merlos
authors.forename: Helene
authors.initials: H
authors.lastname: Darmofal
authors.forename: Mauricio
authors.initials: M
authors.lastname: Pellicer
authors.forename: Angel
authors.initials: A
authors.lastname: Llàcer
mesh_terms: D000368:Aged; D015415:Biomarkers; D002637:Chest Pain / Q000175:diagnosis / Q000209:etiology*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality; D014336:Troponin / Q000097:blood*
chemical_list: D015415:Biomarkers; D014336:Troponin