Predictive value of the National Institutes of Health Stroke Scale and the Mini-Mental State Examination for neurologic outcome after coronary artery bypass graft surgery
Received 19 August 2008; received in revised form 2 June 2009; accepted 22 July 2009. published online 11 September 2009.
Objective
We intended to define the role of the National Institutes of Health Stroke Scale and the Mini-Mental State Examination in identifying adverse neurologic outcomes in a large international sample of patients undergoing cardiac surgery.
Methods
We evaluated 4707 patients undergoing cardiac surgery with cardiopulmonary bypass at 72 centers in 17 countries between November 1996 and June 2000. Prespecified overt neurologic outcomes were categorized as type I (clinically diagnosed stroke, transient ischemic attack, encephalopathy, or coma) or type II (deterioration of intellectual function). The National Institutes of Health Stroke Scale and Mini-Mental State Examination were administered preoperatively and on postoperative day 3, 4, or 5. Receiver operating characteristic curves were plotted to determine the predictive value of worsening in National Institutes of Health Stroke Scale and Mini-Mental State Examination scores with respect to type I and II outcomes.
Results
The receiver operating characteristic area under the curve for changes in National Institutes of Health Stroke Scale score (n = 4620) was 0.89 for type I outcomes and 0.66 for type II outcomes. A 1-point worsening in National Institutes of Health Stroke Scale score provided excellent discrimination (86% specificity; 84% sensitivity) of type I outcomes. The receiver operating characteristic area under the curve for changes in Mini-Mental State Examination score (n = 4707) was 0.75 for type I outcomes and 0.71 for type II outcomes. A 2-point worsening in Mini-Mental State Examination score provided only fair discrimination (73% specificity; 62% sensitivity) of type II outcomes.
Conclusion
We used baseline controls and postoperative worsening in National Institutes of Health Stroke Scale and Mini-Mental State Examination scores to predict both serious adverse neurologic outcome and deterioration of intellectual function. Our findings provide the only reference for evaluating these tests that are used in cardiac surgical clinical trials.
aDepartment of Anesthesiology, SUNY Upstate Medical University, Syracuse, NY
bIschemia Research and Education Foundation, San Bruno, Calif
cCardiovascular Anesthesia Group, Kaiser-Permanente, and the University of California, San Francisco, Calif
dDepartment of Anesthesiology, University of Wisconsin Hospital and Clinics, Madison, Wis
eDepartment of Anesthesia, Stanford University School of Medicine, Stanford, Calif
fDepartment of Anaesthesia, The Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
gDepartment of Anesthesia, Gottsegen György Hungarian Institute of Cardiology, Budapest, Hungry
hInstitute of Anesthesiology and Intensive Care, San Raffaele Hospital, and San Paolo University Hospital, Milan, Italy
iDepartment of Anesthesiology, Lehigh Valley Hospital and Health Network, Allentown, Pa
Address for reprints: Nancy A. Nussmeier, MD, SUNY Upstate Medical University (Syracuse, New York), c/o Editorial Office, Ischemia Research and Education Foundation, 1111 Bayhill Drive, Suite 480, San Bruno, CA 94066.
Disclosures: None.
∗ A complete list of the investigators and participating centers of the Ischemia Research and Education Foundation and the Multicenter Study of Perioperative Ischemia Research Group is at the end of this article.
ABSTRACT