title: Clinical presentation of acute coronary syndrome in patients previously treated with nitrates.
abstract: OBJECTIVE
  Several reports have suggested that nitrates limit acute ischaemic damage by a mechanism similar to preconditioning. This study aims to evaluate the effect of chronic oral nitrates on the clinical presentation and short-term outcomes of patients admitted with acute coronary syndrome (ACS).
  
  
  METHODS
  A retrospective cohort study was conducted in patients with ACS admitted to 62 acute care units from 2010 to 2011. A propensity score-matched samples analysis was performed.
  
  
  RESULTS
  We analysed 3171 consecutive patients, of whom 298 (9.4%) were chronically treated with nitrates. Patients previously treated with nitrates had higher comorbidity and disease severity at admission, lower prevalence of ACS with ST elevation, lower troponin elevation, higher prevalence of initial Killip class 2-4 and higher hospital mortality. The propensity score-matched analysis confirmed that previous use of nitrates is independently associated with a lower prevalence of ST-elevation ACS [odds ratio (OR) 0.53, 95% confidence interval (CI) 0.36-0.78; P = 0.0014] and a lower troponin elevation (OR 0.61, 95% CI 0.41-0.92) but not with Killip class on admission (OR 1.18, 95% CI 0.83-1.67, P = 0.3697) or mortality (OR 0.71, 95% CI 0.37-1.38, P = 0.3196).
  
  
  CONCLUSIONS
  The results support the hypothesis that nitrates have a protective effect on acute ischaemic injury.
authors: aHospital General Universitario de Elche, Elche bHospital Moncloa, Madrid cHospital Universitario La Fe, Valencia dHospital Severo Ochoa, Leganés, Madrid eHospital General de Ciudad Real, Ciudad Real fHospital San Pedro, Logroño gHospital General Yagüe, Burgos, Spain.
authors: Jaime
authors: J
authors: Latour-Pérez
authors: Vicente
authors: V
authors: Gómez-Tello
authors: María Paz
authors: MP
authors: Fuset-Cabanes
authors: Eva de Miguel
authors: Ede M
authors: Balsa
authors: Frutos Del Nogal
authors: Fdel N
authors: Sáez
authors: Francisco Javier Coves
authors: FJ
authors: Orts
authors: Carmen Martín
authors: CM
authors: Rodríguez
authors: Karel
authors: K
authors: Pino-Izquierdo
authors: María de la Concepción Pavía
authors: Mde L
authors: Pesquera
authors: Antonio José Montón
authors: AJ
authors: Rodríguez
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy* / Q000453:epidemiology; D000368:Aged; D000369:Aged, 80 and over; D000725:Andorra / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D019194:Ischemic Preconditioning; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000008:administration & dosage*; D057216:Propensity Score; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D014336:Troponin / Q000097:blood
chemical_list: D009566:Nitrates; D014336:Troponin