Newly Published
Perioperative Medicine  |   June 2018
Defining an Intraoperative Hypotension Threshold in Association with Stroke in Cardiac Surgery
Author Notes
  • From the Division of Cardiac Anesthesiology (L.Y.S., A.M.C., M.B.) and the Division of Cardiac Surgery (M.R.), University of Ottawa Heart Institute, Ottawa, Ontario, Canada; the School of Epidemiology and Public Health (L.Y.S.), University of Ottawa, Ottawa, Ontario, Canada; Cardiovascular Research Program, Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada (L.Y.S.); Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (M.E.F.); the Heart and Stroke Richard Lewar Centre, University of Toronto, Toronto, Ontario, Canada (M.E.F.); the Department of Critical Care and Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada (S.v.D.); and the Department of Neurology, The Icahn School of Medicine at Mount Sinai, New York, New York (J.W.).
  • Submitted for publication August 7, 2017. Accepted for publication May 8, 2018.
    Submitted for publication August 7, 2017. Accepted for publication May 8, 2018.×
  • Research Support: Supported in part by the Research Funds of the Division of Cardiac Anesthesiology of the University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Dr. Chung was supported by the Heart and Stroke Foundation (Ontario, Canada) Hannah Pherril Scholarship.
    Research Support: Supported in part by the Research Funds of the Division of Cardiac Anesthesiology of the University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Dr. Chung was supported by the Heart and Stroke Foundation (Ontario, Canada) Hannah Pherril Scholarship.×
  • Competing Interests: Dr. Farkouh receives research support from Amgen (Mississauga, Ontario, Canada). The other authors declare no competing interests.
    Competing Interests: Dr. Farkouh receives research support from Amgen (Mississauga, Ontario, Canada). The other authors declare no competing interests.×
  • Correspondence: Address correspondence to Dr. Sun: Room H2410, 40 Ruskin Street, Ottawa, Ontario K1Y 4W7, Canada. lsun@ottawaheart.ca. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Cardiovascular Anesthesia / Central and Peripheral Nervous Systems
Perioperative Medicine   |   June 2018
Defining an Intraoperative Hypotension Threshold in Association with Stroke in Cardiac Surgery
Anesthesiology Newly Published on June 7, 2018. doi:10.1097/ALN.0000000000002298
Anesthesiology Newly Published on June 7, 2018. doi:10.1097/ALN.0000000000002298
Abstract

Background: Stroke is a leading cause of morbidity, mortality, and disability in patients undergoing cardiac surgery. Identifying modifiable perioperative stroke risk factors may lead to improved patient outcomes. The association between the severity and duration of intraoperative hypotension and postoperative stroke in patients undergoing cardiac surgery was evaluated.

Methods: A retrospective cohort study was conducted of adult patients who underwent cardiac surgery requiring cardiopulmonary bypass at a tertiary center between November 1, 2009, and March 31, 2015. The primary outcome was postoperative ischemic stroke. Intraoperative hypotension was defined as the number of minutes spent within mean arterial pressure bands of less than 55, 55 to 64, and 65 to 74 mmHg before, during, and after cardiopulmonary bypass. The association between stroke and hypotension was examined by using logistic regression with propensity score adjustment.

Results: Among the 7,457 patients included in this analysis, 111 (1.5%) had a confirmed postoperative diagnosis of stroke. Stroke was strongly associated with sustained mean arterial pressure of less than 64 mmHg during cardiopulmonary bypass (adjusted odds ratio 1.13; 95% CI, 1.05 to 1.21 for every 10 min of mean arterial pressure between 55 and 64 mmHg; adjusted odds ratio 1.16; 95% CI, 1.08 to 1.23 for every 10 min of mean arterial pressure less than 55 mmHg). Other factors that were independently associated with stroke were older age, hypertension, combined coronary artery bypass graft/valve surgery, emergent operative status, prolonged cardiopulmonary bypass duration, and postoperative new-onset atrial fibrillation.

Conclusions: Hypotension is a potentially modifiable risk factor for perioperative stroke. The study’s findings suggest that mean arterial pressure may be an important intraoperative therapeutic hemodynamic target to reduce the incidence of stroke in patients undergoing cardiopulmonary bypass.