Emergent Management of Ischemic Stroke: Treatment ABCs

Dr. Page is an associate professorof clinical pharmacy and physicalmedicine at the University of Colorado,Denver, Schools of Pharmacy andMedicine.

Stroke has been defined as a"heterogeneous, neurologic syndromecharacterized by gradualor rapid, nonconvulsive onset of neurologicdeficits that fit a known vascularterritory and that lasts for 24 hours ormore."¹ In other words, this disease canbe characterized as a sudden impairmentof normal body functioning causedby a disruption in the supply of bloodto a specific area in the brain. Thisimpairment may be transient, lastingseveral days or even permanently. In theUnited States, an individual experiencesa stroke every 45 seconds. This statisticequates to approximately 700,000Americans annually. About 500,000 ofthese are first-time or primary strokes,while the remaining are recurrent or secondarystrokes. Each year, stroke claimsapproximately 155,000 lives, making itthe third leading killer in the UnitedStates behind cardiovascular disease and cancer.²

Table 1

Appropriate Candidates for Alteplase

• Diagnosis of ischemic stroke causing measurable neurologic deficit
• Neurologic signs should not be clearing spontaneously
• Neurologic signs should not be minor and isolated
• Caution should be exercised in treating a patient with major deficits
• Symptoms of stroke should not be suggestive of subarachnoid hemorrhage
• Onset of symptoms <3 hours before beginning treatment
• No head trauma or prior stroke in previous 3 months
• No myocardial infarction in previous 3 months
• No gastrointestinal or urinary tract hemorrhage in previous 21 days
• No major surgery in previous 14 days
• No arterial puncture at a noncompressible site in previous 7 days
• No history of previous intracranial hemorrhage
• BP not elevated (systolic <185 mm Hg and diastolic <110 mm Hg)
• No evidence of active bleeding or acute trauma (fracture) on examination
• Not taking an oral anticoagulant or, if anticoagulant being taken, INR <1.7
• If receiving heparin in previous 48 hours, aPTT must be in normal range
• Platelet count ≥100,000 mm3
• Blood glucose concentration ≥50 mg/dL (2.7 mmol/L)
• No seizure with postictal residual neurologic impairments
• CT scan does not show a multilobar infarction (hypodensity ≥1/3 cerebral hemisphere)
• The patient or family members understand the potential risks and benefits from treatment

Review of Stroke Pathophysiology

Stroke can be classified into 2 types: (1) ischemic, which iscaused by a blood clot within the brain, accounting for 75% to80% of all strokes, and (2) hemorrhagic, which occurs whenweakened cerebral arteries rupture, leading to subarachnoidor intracerebral bleeding.² Ischemic stroke is caused by emboli,thrombus, or systemic hypoperfusion. Forty-five percent of ischemicstrokes are due to embolic causes, which may be due toatrial fibrillation, patent foramen ovale, and low ejection fraction.Thrombus accounts for 30% of ischemic stroke and is associatedwith plaque buildup and atherosclerosis. The remaining 25%can be attributed to systemic hypoperfusion, hypercoagulablestates, and cryptogenic etiologies.²

The signs and symptoms most commonly reported bypatients suffering from an acute stroke are unilateral paralysisor weakness; difficulty with speech, gait, or coordination; andthe "worst" headache of the patient's life.³ Other symptomsinclude facial droop, altered vision, sensory impairment, orthought process interference.^4,5

ABCs for Acute Ischemic Stroke

As pharmacists, we have all beentaught the "ABCs" of basic life support,(airway, breathing, and circulation).While these definitely apply tothe emergent management of stroke,a more drug-focused set of ABCs aremore specific for the pharmacist.Once in the emergency department, the focus of managementshould be to determine if indeed the patient is having a stroke,treating the stroke with alteplase (a tissue plasminogen activator),when applicable&#8212;the "A" in the ABCs&#8212;and identifyingother conditions warranting immediate intervention. Table1 summarizes appropriate candidates for alteplase therapy.Guidelines for administering alteplase are listed in Table 2.Blood pressure (BP), the "B" in our ABCs, plays a crucial rolein ischemic stroke, as it can be a cause and/or complicationpoststroke. High BP can affect the patient outcome and alsomay delay alteplase administration. An excessively high BPalso can contribute to hemorrhagic transformation followingalteplase administration. Current guidelines recommend treatinga systolic BP >220 mm Hg or a diastolic BP >120 mm Hg.⁶Finally, the "C" in our mnemonic is controlling the patient'sblood glucose concentrations (BGCs). In the heat of themoment, practitioners may forget to closely monitor the BGC;however, an elevated BGC needs to be recognized and treatedimmediately. Evidence indicates that persistent hyperglycemia(>140 mg/dL) during the first 24 hours poststroke is associatedwith poor clinical outcomes. Whereas this concentration maynot seem elevated, recent stroke guidelines recommend thatthe BGC be maintained in the range of 80 to 140 mg/dL andthat the use of insulin be initiated in these cases.⁶

By remembering and using these 3 simple ABCs, pharmacistswithin any health system can play a significant role in theemergent management of a patient with an acute ischemicstroke.

Table 2

Administration of IV Alteplase

• Infuse 0.9 mg/kg (maximum dose 90 mg) over 60 minutes, with 10% of the dose given as a bolus over 1 minute
• Admit the patient to an intensive care or stroke unit for monitoring
• Perform neurologic assessments every 15 minutes during the infusion and every 30 minutes thereafter for the next 6 hours, then hourly until 24 hours after treatment
• If the patient develops severe headache, acute hypertension, nausea, or vomiting, discontinue the infusion (if alteplase is being administered) and obtain emergency CT scan
• Measure BP every 15 minutes for the first 2 hours and subsequently every 30 minutes for the next 6 hours, then hourly until 24 hours after treatment
• Increase the frequency of BP measurements if a systolic BP is ≥180 mm Hg or if a diastolic BP is ≥105 mm Hg; administer antihypertensive medications to maintain BP at or below these levels
• Delay placement of nasogastric tubes, indwelling bladder catheters, or intra-arterial pressure catheters
• Obtain a follow-up CT scan at 24 h before starting anticoagulants or antiplatelet agents

IV = intravenous; BP = blood pressure; INR = international normalized ratio; aPTT = activated partial thromboplastin time; CT = computed tomography.

Adapted from reference 6.

References

• Hickey JV, Hock NH. Stroke and other cerebrovascular diseases. In: Hickey JV, ed. Clinical Practice of neurological and neurosurgical nursing. Philadelphia, PA: Lippincott, Williams & Wilkins; 2003.
• Heart Disease and Stroke 2008 Update At-a-Glance Statistics. American Heart Association Web site. www.americanheart.org/downloadable/heart/1200078608862HS_Stats%202008.final.pdf. Accessed July 3, 2008.
• Suwanwela N, Koroshetz WJ. Acute ischemic stroke: overview of recent therapeutic developments. Annu Rev Med. 2007;58:89-106.
• Rathore SS, Hinn AR, Cooper LS, Tyroler HA, Rosamond WD. Characterization of incident stroke signs and symptoms: findings from the atherosclerosis risk in communities study. Stroke. 2002;33:2718-2721.
• Toole JF, Lefkowitz DS, Chambless LE, Wijnberg L, Paton CC, Heiss G. Self-reported transient ischemic attack and stroke symptoms: methods and baseline prevalence. The ARIC Study, 1987-1989. Am J Epidemiol. 1996;144:849-856.
• Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists. Stroke. 2007;38(5):1655-1711.