Stroke in Surgical Patients: A Narrative Review

Phillip E. Vlisides, M.D.; Laurel E. Moore, M.D.

Disclosures

Anesthesiology. 2021;134(3):480-492. 

In This Article

Postoperative Management

Screening and Diagnostic Considerations

Stroke detection is challenging postoperatively. The signs and symptoms of stroke can be masked in the setting of opioid and sedative administration, pain, and delayed neurocognitive recovery after surgery and anesthesia. In fact, perioperative stroke is associated with delayed recognition, diagnosis, and neuroimaging compared to out-of-hospital stroke.[1,2] Various clinical screening tools are available for stroke detection,[35] but these assessments have not been validated in the perioperative setting. Furthermore, perioperative changes in cognition and physical exam findings can trigger false-positive results. A recent prospective cohort study of noncardiac surgery patients revealed that modified National Institutes of Health (Bethesda, Maryland) stroke scale changes were common postoperatively.[71] Increased scores, compared with preoperative baseline, were found in 20% of low-risk patients and more than 30% of high-risk patients. Such tools may thus have a low positive predictive value in the immediate postoperative setting. In the absence of reliable physical examination findings or clinical assessment tools, serum biomarkers may serve in a complementary role to assist with disease screening and diagnosis. However, currently, there are no clinically validated, reliable biomarkers for detecting cerebral ischemia and infarction.[71] Thus, currently available clinical screening tools and serum biomarkers are not presently recommended for routine postoperative screening. A targeted examination that focuses on signs and symptoms of large-vessel occlusion (Table 3) may improve stroke detection.

In the event of suspected stroke, urgent noncontrast computed tomography or magnetic resonance imaging should be ordered to rule out intracranial hemorrhage. If large-vessel occlusion is suspected, concurrent computed tomography angiography and perfusion or diffusion-weighted magnetic resonance imaging should be performed. Such perfusion-guided imaging can assess for viable penumbra and eligibility for endovascular intervention. Recent trials have demonstrated improved functional outcomes in patients who underwent endovascular thrombectomy for large-vessel stroke, even with intervals of 16 to 24 h since the patient was last known to be well.[17] Thus, surgical patients with a large-vessel postoperative stroke may benefit from endovascular interventions even several hours after time last known well.

Stroke Management

Once acute ischemic stroke is identified, subsequent evaluation and clinical decision-making should occur within a multidisciplinary framework that includes neurology, interventional neuroradiology, and the primary surgical service. Intravenous recombinant tissue plasminogen activator remains standard therapy for acute thromboembolic stroke; however, the decision to administer recombinant tissue plasminogen activator should occur carefully in the postoperative patient and in close collaboration with neurologic and surgical services. The thrombolytic potential of rtPA should be weighed against the documented risk of postoperative hemorrhage.[72] Although recent intracranial or major spinal surgery is a contraindication to intravenous recombinant tissue plasminogen activator, other types of major surgery are relative, rather than absolute, contraindications.[73]

Endovascular interventions may be appealing for large-vessel occlusion given the targeted anatomical approach without need for systemic thrombolytic therapy. Within the past 5 years, multiple clinical trials have demonstrated improved functional outcomes in patients who underwent endovascular mechanical thrombectomy with retrievable stent devices,[14–16] with a pooled number needed to treat of 2.6 for reducing major disability.[74] Guidelines are available for anesthetic management of endovascular treatment for acute ischemic stroke by the Society for Neuroscience in Anesthesiology and Critical Care.[75] These guidelines include optimal strategies for preoperative evaluation, intraoperative management, and postoperative disposition. To review key recommendations, general anesthesia is usually elected for patients with profoundly decreased levels of consciousness or difficulty with protecting the airway. Outcomes otherwise appear to be similar between general anesthesia and conscious sedation techniques.[76–78] In fact, pooled meta-analytical data suggest that patients who undergo general anesthesia may demonstrate improved functional outcomes and recanalization rates compared to conscious sedation techniques.[79,80] Additionally, implementation of hemodynamic protocols during general anesthesia, with targeted thresholds for blood pressure treatment, may further mitigate risk of poor outcomes.[81] Patients should then be admitted to dedicated intensive care units specializing in stroke care after the procedure.

Last, optimal physiologic management during stroke is imperative, both in conjunction with interventional treatments and in the absence of interventions (i.e., if ineligible, for example). The American Heart Association/American Stroke Association published guidelines for such supportive management in the acute stroke setting.[22] Intubation and mechanical ventilation are recommended for those with severely decreased consciousness or brainstem dysfunction that compromises the airway. Systolic blood pressure (SBP) should be lowered to less than 185 mmHg, and diastolic blood pressure should be lowered to less than 110 mmHg, if IV alteplase and/or mechanical thrombectomy are being considered. For patients ineligible for such therapies, SBP should be maintained at less than 220 mmHg, and diastolic blood pressure should be less than 120 mmHg. Epidemiologic data reveal an association between increased mortality and SBP of less than 130 mmHg during stroke presentation, although this association does not necessarily reflect causality.[82] Nonetheless, there appears to be a "U-shaped" relationship between stroke mortality and admission blood pressure, with extreme values of hypo- and hypertension most strongly associated with increased mortality. Hyperglycemia (greater than 180 mg/dl) is also associated with worse stroke outcomes,[83] although aggressive efforts to reduce hyperglycemia (less than 130 mg/dl) do not appear to improve outcomes and may increase risk of hypoglycemic events.[84] Reserving treatment for glucose more than 180 mg/dl thus appears reasonable. Hyperthermia within 24 h after stroke has been associated with increased mortality and should be treated.[85]

In summary, new studies support endovascular intervention for large-vessel occlusion, even with prolonged time between stroke onset and clinical recognition. This makes identification of new neurologic symptoms critical in surgical patients, who may be candidates for endovascular intervention. A coordinated, multispecialty response, careful blood pressure management, and determination of anesthetic technique (based on individual patient needs) are all essential to optimizing patient care in this setting.

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