title: Temporal variation in inhospital mortality with percutaneous coronary intervention: a report from the National Heart, Lung and Blood Institute Dynamic Registry.
abstract: BACKGROUND
  Cardiovascular morbidity and mortality display a distinct time dependence also known as circadian variation. Whether such time dependence extends to the risk of procedural-related mortality after percutaneous coronary intervention (PCI) is presently unknown.
  
  
  METHODS
  Inhospital mortality was analyzed in 6,347 patients with PCI start times from 8:00 am to 6:59 pm ("usual" workday). The sample was divided into 3 evenly populated groups (morning start 8:00-10:59 AM, midday start 11:00 AM-1:59 PM, afternoon start 2:00-6:59 PM). The association between procedural start time and mortality was assessed using multivariable analysis including a propensity score accounting for factors associated with procedural start time.
  
  
  RESULTS
  There was a significant, nonlinear relationship between procedural-related mortality and start time (P = .03). Afternoon start patients were at higher adjusted risk of mortality compared with midday start patients (OR 2.03, 95% CI 1.07-3.83, P = .03 ). Morning start patients were also at higher risk compared with midday start patients although the association was not statistically significant (OR 1.73, 95% CI 0.89-3.39, P = .11).
  
  
  CONCLUSIONS
  There is a significant time-dependent variation in the risk of inhospital PCI-related mortality during usual working hours. The highest risk period, taking into account numerous factors that confound this association, is the latter part of the workday. A second period of apparent greater risk occurs during the early part of the workday and is consistent with our present understanding of circadian variation in cardiovascular disease processes.
authors.affiliation: Division of Cardiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA. warrenlaskey@earthlink.net
authors.forename: Warren K
authors.initials: WK
authors.lastname: Laskey
authors.forename: Faith
authors.initials: F
authors.lastname: Selzer
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.forename: Robert L
authors.initials: RL
authors.lastname: Wilensky
authors.forename: Howard A
authors.initials: HA
authors.lastname: Cohen
authors.forename: David O
authors.initials: DO
authors.lastname: Williams
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Kip
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Detre
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000401:mortality*; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology