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Perioperative Stroke in Noncardiac, Nonneurosurgical Surgery. Ng et al, Anesthesiology 2011; 115:879-90 Presented by Paul Larsen. Stroke Definitions. Stroke - Focal or global neurologic deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours
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Perioperative Stroke in Noncardiac, Nonneurosurgical Surgery • Ng et al, Anesthesiology 2011; 115:879-90 • Presented by Paul Larsen
Stroke Definitions • Stroke - Focal or global neurologic deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours • TIA - <24 hours • Covert Stroke - Asymptomatic ischemic event detected with imaging
Stroke Incidence • In cardiac, neurologic, and carotid surgery, the incidence is 2.2-5.2% • Other procedures have a range of 0.05-4.4% • Differences in patient population, changing clinical practice over 40 year study design, diagnostic tests, and duration of follow up may account for the large variance in reported stroke rates
Outcomes • 12.6% mortality rate in non-surgical strokes • Perioperative stroke mortality ranges from 26% in general surgery to 87% in patients with a previous stroke
Pathophys • The majority of perioperative strokes occur after the second postoperative day • Only 5.8% of strokes are thought to have occured during surgery • Cardiothoracic surgery related strokes are 60% embolic • Other surgeries have a 68% thrombotic etiology of the stroke
Why Thrombosis? • Post-op endothelial dysfunction? • General anesthetics impair endothelial function • Withholding antiplatelet/anticoagulant agents may aggrevate surgically induced hypercoaguability
Who is at risk? • Comorbidities: • Age, history of stroke, atrial fibrillation are among the most important risk factors • Others include COPD, PVD, DM
Who is at risk? • Type of Surgery • Hip arthoplasty, peripheral vascular surgery have a higher incidence of stroke than knee arthroplasty or general surgery • Head and neck surgery increases risk by 0.2-5%
Who is at risk? • B-blockers - increase in non-fatal stroke, hypotension, and bradycardia in patients undergoing noncardiac surgery • It is unclear if there is causation, and no temporal relationship between the stroke and hypotension has been defined.
Risk modification • Timing elective surgery after a recent stroke • Acute stroke impairs cerebral autoregulation so blood flow becomes passively dependent on perfusion pressure • Occurs within 8 hours of a stroke, can last 2-6 months • Recommend delaying nonurgent surgery for at least 1-3 months
Risk modification • A fib: • If pre-existing, continue antiarrhythmic or rate-controling agent perioperatively • Correct post-op electrolyte imbalances and fluid volume
Risk modification • Anticoagulants:
Perioperative stroke management • ID at risk patients and make an early diagnosis • Non-contrast CT within 25 minutes, consider thrombolysis, correct hypotension, fever • ASA is the only oral antiplatelet agent found to be beneficial