In-Hospital Management of Stroke and Early Prevention of Secondary Stroke

Educational Objectives

The goal of this lecture is to improve the management of stroke. After hearing and assimilating this lecture, the clinician will be better able to:

1. Differentiate a transient ischemic attack from a stroke.

2. Choose appropriate patients to receive anticoagulation therapy following a stroke.

3. Diagnose and treat venous system stroke.

Summary

Transient ischemic attack (TIA): defined as transient episode of neurologic dysfunction; as of 2009, negative magnetic resonance imaging (MRI) required for diagnosis (rather than resolution of symptoms within 24 hr; patients with stroke have evidence on MRI whether or not symptoms present); workup for TIA must be addressed with same sense of urgency as workup for stroke

ABCD² score: clinical score to determine risk for stroke within first 2 days following TIA; factors include age, blood pressure, clinical features, duration, and diabetes; although patients with score of ≤3 may not require hospitalization, any risk factor warrants additional investigation; 10% to 15% of all patients with TIA experience stroke within 3 mo, with 50% of those patients developing stroke within 48 hr; workup — all patients screened with same laboratory studies and tests regardless of medical comorbidities

Imaging: CT — may be used to rule out hemorrhage and visualize extent of infarct; accessible; can be performed rapidly; acceptable choice if MRI unavailable; drawbacks include decreased ability to visualize posterior fossa (and, hence, infarcts of cerebellum and brainstem), increased exposure to radiation, and possibility of age-indeterminate infarct; MRI — helps differentiate stroke from TIA, allows better visualization of tissue, can identify old injury, and may identify stroke mimics; use may be precluded in patients with pacemaker or implantable cardiac defibrillator, patients with claustrophobia, or patients unable to lie flat

Cardiovascular assessment: all patients undergo EKG to rule out atrial fibrillation (AF) and/or other abnormalities, and are placed on continuous telemetry for duration of hospitalization; surface echocardiography — performed in all patients to evaluate ejection fraction, wall motion abnormalities, vegetations, and source of thrombus; patent foramen ovale (PFO) or atrial septal defect may be detected in subset of patients (usually <50 yr of age with no strict risk factors; Doppler studies of all extremities and imaging of pelvic veins performed if found); advanced cardiac imaging — usually warranted if multiterritory infarcts with normal blood vessels seen on MRI; atrial enlargement (evidence of paroxysmal AF) warrants consultation with cardiologist, with additional imaging if necessary; long-term monitor — use of implantable loop monitor vs 30-day event monitor generally provider specific and dependent on patient presentation

Imaging of blood vessels: posterior circulation, aortic arch, proximal blood vessels, and vessels in brain possible sources of emboli in addition to carotid arteries; intracranial atherosclerosis leading cause of stroke worldwide; carotid ultrasound — not equivalent to CT angiography or MR angiography for workup of stroke; noninvasive; useful for distinguishing stenosis from occlusion and characterization of plaque; does not visualize arch, posterior circulation, or intracranial blood vessels; may overcall critical stenosis as occlusion; transcranial Doppler — probe in bony windows to assess blood vessels; useful for intracranial stenosis or occlusion and vasospasm in subarachnoid hemorrhage; can reveal microemboli; however, requires trained technicians and experience in interpretation; conventional cerebral angiography — used for increasingly complicated causes of stroke; imaging blood vessels in totality allows visualization of proximal sources as well as extra- and intracranial vessels with possible multiple abnormalities; total view needed for risk stratification

Laboratory studies: basic blood work includes complete blood count and comprehensive metabolic panel; all patients should receive lipid panel, hemoglobin (Hg) A1c, and urine drug screen regardless of age; disease-specific studies include B12 level, homocysteine, hypercoagulable panels, rheumatologic panels, and thyroid-stimulating hormone

Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria: large-artery atherosclerosis — usually extracranial but occasionally intracranial; thrombus at site of stenosis can embolize distally; small-vessel disease — lacunar infarcts due to diabetes, hypertension, cholesterol, or smoking; cardioembolism — structural and electrical problems with heart; other — less common causes (sickle cell, vasculitis) considered after other causes ruled out; cryptogenic — diagnosed if no cause found after workup

Standard acute secondary prevention: patient in hospital for 24 hr post tPA therapy; should select antiplatelet medication (anticoagulation medication if indicated) by end of day 1; all patients treated with high-dose statin therapy on admission; blood pressure medication started after acute phase; treat for control of blood sugar

Antiplatelet therapy: all patients treated after stroke (unless anticoagulant indicated); options include aspirin, clopidogrel (Plavix), and aspirin plus dipyridamole; patients need only 1 antiplatelet agent for long-term stroke therapy (long-term dual therapy increases risk of bleeding); may use 1 agent (eg, clopidogrel preferable) if patient has concomitant coronary artery disease; defer to cardiology if believed two agents needed; choose medications based on safety, cost, patient experience, and preference; patients commonly on antiplatelet agent when stroke occurs; no evidence that changing to another antiplatelet agent reduces risk for subsequent events; anticoagulation therapy — clear indications include AF, thrombus of left ventricle or left atrial appendage, identified hypercoagulable states, pulmonary embolism or deep venous thrombosis, and mechanical heart valves; heparin drip not indicated in acute stroke patient unless identified reason for anticoagulation therapy

Anticoagulation therapy: hemorrhagic conversion of large territory infarct in patient with AF most worrisome possibility; current hemorrhagic transformation or hematoma additionally concerning; Heparin in Acute Embolic Stroke Trial (HAEST) study — risk of recurrent ischemic stroke at 14 days only ≈6% to 8% in patients with AF treated with aspirin or low-molecular-weight heparin; allows patient to stay on aspirin pending follow-up imaging to rule out expanding hematoma; guidelines support initiation of anticoagulation therapy within 14 days of stroke onset; however, risk-benefit discussion with patient should occur if stroke due to other conditions

Acute management of statins: guidelines revised; all stroke patients treated; statin benefit groups — patients with clinical atherosclerotic cardiovascular or cerebrovascular disease placed on high-dose statin regardless of lipid profile; treat patients >75 yr of age with moderate-intensity therapy; individualize treatment for patients who do not tolerate medication; goal to lower low-density lipoproteins, stabilize plaque, and increase benefit from neuroprotective component of statins

Acute management of blood pressure: permissive hypertension — goal to prevent infarction in ischemic brain fed by vessel with critical stenosis or occlusion; recruits collateral circulation to perfuse brain; optimal range not established; reasonable not to lower blood pressure in first 24 hr unless level >220/120; most patients become symptomatic when pressure inadequate; supine position, fluids (if cardiac status permits), or Trendelenburg position used to maintain brain perfusion; most patients normalize and can restart antihypertensives within 24 hr; do not abruptly discontinue β blockers; consider halving dose to avoid exacerbation of heart failure; adjust treatment to patient and comorbidities; goal <140/90, or <130/80 in patients with diabetes or recent lacunar infarct

Acute management of blood glucose: outcomes worse in patients with persistent in-hospital hyperglycemia than in patients with normoglycemia; treat to range of 140 to 180 mg/dL; long-term goal to maintain HgA1c at <7%

Etiology-specific treatment: extracranial carotid stenosis — treatment depends on symptoms; carotid endarterectomy (CEA) recommended for symptomatic stenosis of 70% to 99%, and recommended depending on patient-specific factors if 50% to 69%; intervention not recommended for stenosis <50%; reasonable to perform CEA within 2 wk of TIA or stroke; urgent surgery not recommended due to increased risk for morbidity and mortality; currently unclear whether medical or surgical therapy superior for asymptomatic stenosis; intracranial atherosclerosis — aggressive medical therapy superior to medical therapy plus stenting for symptomatic stenosis of 70% to 99%; treat with aspirin and clopidogrel for 90 days followed by monotherapy with aspirin (patients in study also treated with high-dose statin, aggressive control of blood pressure, and exercise); dual antiplatelet therapy reduces stroke recurrence in these patients; warfarin effective option in patients who also have AF; large-artery dissection — Cervical Artery Dissection in Stroke Study (CADISS) showed no difference between aspirin and warfarin therapy; consider high risk for subarachnoid hemorrhage in dissection that extends intracranially, particularly in posterior circulation; nondisabling stroke or high-risk TIA — load with clopidogrel 300 mg, plus aspirin, followed by dual therapy with aspirin plus clopidogrel for next 20 days, then monotherapy

Additional etiologies: AF — anticoagulation therapy recommended if stroke occurs; no evidence that ablation therapy reduces risk of stroke, and these patients should also remain on anticoagulation therapy; venous system stroke — uncommon cause of stroke; usually seen in younger obese women; associated with oral contraceptives and smoking; patients can present with altered headache, vision changes, or seizure; patients undergo hypercoagulable workup; screen for dehydration, hormonal therapy, and tobacco use; anticoagulation therapy recommended, even if hemorrhage present; PFO — not risk factor for stroke; occurs in 15% to 25% of general population; allows venous embolism to enter arterial system; perform Doppler studies in all extremities; image pelvic veins; determine hypercoagulable status; anticoagulate for DVT or hypercoagulable state

Cryptogenic stroke: no clear etiology for stroke after full workup; ≈25% of all strokes cryptogenic; all patients require long-term cardiac monitoring and treatment with antiplatelet therapy; no current data support empiric anticoagulation therapy without identified cause; rheumatologic studies would include antinuclear antibodies (further testing depending on results); consider if patient on hormonal therapy; estrogen risk factor for stroke (discontinue if present); prescription nonsteroidal anti-inflammatory agents may increase stroke risk in patient with history of stroke and myocardial infarction

Readings

Adams HP Jr et al: Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment. Stroke 1993 Jan;24(1):35-41; Derdeyn CP et al: Aggressive medical treatment with or without stenting in high-risk patients with intracranial artery stenosis (SAMMPRIS): the final results of a randomised trial. Lancet 2014 Jan 25;383(9914):333-41; Douglas V et al: Should CT Angiography be a Routine Component of Acute Stroke Imaging? Neurohospitalist 2015 Jul;5(3):97-8; Easton JD et al: Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. Stroke 2009 Jun;40(6):2276-93; Johnston SC et al: Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007 Jan 27;369(9558):283-92; Kernan WN et al: Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2014 Jul;45(7):2160-236; Homma S, Di Tullio MR: Patent foramen ovale and stroke. J Cardiol 2010 Sep;56(2):134-141; Markus HS et al: Antiplatelet treatment compared with anticoagulation treatment for cervical artery dissection (CADISS): a randomised trial. Lancet Neurol 2015 Apr;14(4):361-7; Mehndiratta P et al: Etiologic stroke subtypes: updated definition and efficient workup strategies. Curr Treat Options Cardiovasc 2015 Jan;17(1):357; Stone NJ et al: Treatment of blood cholesterol to reduce atherosclerotic cardiovascular disease risk in adults: synopsis of the 2013 American College of Cardiology/American Heart Association cholesterol guideline. Ann Intern Med 2014 Mar 4;160(5):339-43; Wang Y et al: Clopidogrel with aspirin in acute minor stroke or transient ischemic attack. N Eng J Med 2013 Jul 4;369(1):11-9; Wintermark M et al: Imaging recommendations for acute stroke and transient ischemic attack patients: a joint statement by the American Society of Neuroradiology, the American College of Radiology and the Society of NeuroInterventional Surgery. J Am Coll Radiol 2013 Nov;10(11):828-32.

Disclosures

For this lecture, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Smock was recorded at the 2nd Annual Comprehensive Stroke and Cerebrovascular Update, held November 14, 2015, in Charleston, SC, and sponsored by the Medical University of South Carolina Department of Neurology and Office of Continuing Education. For information about upcoming CME activities from the Medical University of South Carolina, please visit cme.musc.edu. The Audio Digest Foundation thanks the speakers and the Medical University of South Carolina for their cooperation in the production of this lecture.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

NE070402

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.