title: Association between Intraoperative Hypotension and Myocardial Injury after Vascular Surgery.
abstract: BACKGROUND
  Postoperative myocardial injury occurs frequently after noncardiac surgery and is strongly associated with mortality. Intraoperative hypotension (IOH) is hypothesized to be a possible cause. The aim of this study was to determine the association between IOH and postoperative myocardial injury.
  
  
  METHODS
  This cohort study included 890 consecutive patients aged 60 yr or older undergoing vascular surgery from two university centers. The occurrence of myocardial injury was assessed by troponin measurements as part of a postoperative care protocol. IOH was defined by four different thresholds using either relative or absolute values of the mean arterial blood pressure based on previous studies. Either invasive or noninvasive blood pressure measurements were used. Poisson regression analysis was used to determine the association between IOH and postoperative myocardial injury, adjusted for potential clinical confounders and multiple comparisons.
  
  
  RESULTS
  Depending on the definition used, IOH occurred in 12 to 81% of the patients. Postoperative myocardial injury occurred in 131 (29%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 87 (20%) patients without IOH (P = 0.001). After adjustment for potential confounding factors including mean heart rates, a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury (relative risk, 1.8; 99% CI, 1.2 to 2.6, P < 0.001). Shorter cumulative durations (less than 30 min) were not associated with myocardial injury. Postoperative myocardial infarction and death within 30 days occurred in 26 (6%) and 17 (4%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 12 (3%; P = 0.08) and 15 (3%; P = 0.77) patients without IOH, respectively.
  
  
  CONCLUSIONS
  In elderly vascular surgery patients, IOH defined as a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury.
authors.affiliation: From the Department of Anesthesiology, University Medical Center Utrecht, Utrecht, The Netherlands (J.A.R.v.W., W.A.v.K., L.v.W.); Department of Anesthesia, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (D.N.W., W.S.B.); Department of Health Policy Management and Evaluation; Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (D.N.W.); and Division of Vascular Surgery, Toronto General Hospital and University of Toronto, Toronto, Ontario, Canada (T.F.L.).
authors.forename: Judith A R
authors.initials: JA
authors.lastname: van Waes
authors.forename: Wilton A
authors.initials: WA
authors.lastname: van Klei
authors.forename: Duminda N
authors.initials: DN
authors.lastname: Wijeysundera
authors.forename: Leo
authors.initials: L
authors.lastname: van Wolfswinkel
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lindsay
authors.forename: W Scott
authors.initials: WS
authors.lastname: Beattie
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D007022:Hypotension / Q000097:blood / Q000453:epidemiology*; D007431:Intraoperative Complications / Q000097:blood / Q000453:epidemiology*; D008297:Male; D016343:Monitoring, Intraoperative; D009203:Myocardial Infarction / Q000097:blood / Q000453:epidemiology*; D009864:Ontario / Q000453:epidemiology; D011183:Postoperative Complications / Q000097:blood / Q000453:epidemiology*; D014336:Troponin / Q000097:blood; D014656:Vascular Surgical Procedures / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D014336:Troponin