title: Absence of a 'smoker's paradox' in field triaged ST-elevation myocardial infarction patients undergoing percutaneous coronary intervention.
abstract: OBJECTIVE
  The 'smoker's paradox' refers to the observation of favorable prognosis in current smokers following an acute myocardial infarction (AMI). Initial positive findings were in the era of fibrinolysis, with more contemporary studies finding conflicting results. We sought to determine the presence of a 'smoker's paradox' in a cohort of ST Elevation Myocardial Infarction (STEMI) patients identified via field triage, treated with primary percutaneous coronary intervention (pPCI).
  
  
  METHODS
  This was a single center retrospective cohort study identifying consecutive STEMI patients presenting for pPCI via field triage. The primary end points were all cause mortality, major adverse cardiac events (MACE), major bleeding, in-hospital cardiac arrest and length of stay (LOS).
  
  
  RESULTS
  A total of 382 patients were included in the study. Current smokers were more likely to be younger (p<0.00001), male (p<0.001) and have fewer comorbidities, including renal impairment (p<0.01) and a history of AMI (p<0.05). Current smokers also had a shorter ischemic time (p<0.05), were less likely to have collateral circulation (p<0.05), and more likely to have signs of pulmonary edema at presentation (p<0.05). There was no difference between smoking groups and all cause mortality (p=0.67), MACE (p=0.49), major bleeding (p=0.49) or in-hospital cardiac arrest (p=0.43). Current smokers had a shorter LOS (p<0.05). In multivariate analysis smoking status did not correlate with primary outcomes.
  
  
  CONCLUSIONS
  The 'smoker's paradox' does not appear to be relevant among STEMI patients undergoing pPCI, identified via field triage. The previously documented 'smoker's paradox' may have been an indication of patient characteristics and the historical treatment of STEMI with thrombolysis. Further studies with larger numbers may be warranted.
authors.affiliation: Department of Cardiology, Royal North Shore Hospital, Sydney, Australia. usaid.allahwala@gmail.com
authors.forename: Usaid K
authors.initials: UK
authors.lastname: Allahwala
authors.forename: John C
authors.initials: JC
authors.lastname: Murphy
authors.forename: Gregory I C
authors.initials: GI
authors.lastname: Nelson
authors.forename: Ravinay
authors.initials: R
authors.lastname: Bhindi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006470:Hemorrhage / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000601:surgery*; D062645:Percutaneous Coronary Intervention / Q000379:methods; D011654:Pulmonary Edema / Q000601:surgery; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult
keywords: Early Field Triage; ST Elevation Myocardial Infarction; Smoker's paradox