Tag Archives: stroke

Atrial Fibrillation: anticoagulate or not?

Interesting analysis from Annals of Internal Medicine.  The decision to start anticoagulation in atrial fibrillation, using CHADSVASC score is not so clear cut.  See tables below.

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Reference:

Shah, S., Eckman, M., Aspberg, S., Go, A. and Singer, D. (2018). Effect of Variation in Published Stroke Rates on the Net Clinical Benefit of Anticoagulation for Atrial Fibrillation. Annals of Internal Medicine.

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TIA Management

Low-risk TIA

  • ABCD scores 0-3
  • out patient work-up in the next 1-2 days
  • alternative is to admit
  • begin ASA 81mg or plavix 75 or ASA 25/ER dipyridamole 200mg BID
  • perform carotid imaging: US, CTA, MRA
  • consider TTE (if bilateral infarcts on CT, high suspicion of cardioembolic source and TTE normal – obtain TEE)
  • consider 30d ambulatory cardiac monitor to document cryptogenic Afib
  • smoking cessation
  • Statins:
    • start high-dose statin (atorvastatin 40-80; rosuvastatin 20-40)
    • consider mod intensity statin if >75 y/o (atorvastatin 10-20, rosuvastatin 5-10, simvastatin 20-40, pravastatin 40-80)
  • consider anticoagulation if ECG (+) Afib, calculate CHADS or CHADSVASC and HAS-BLED scores
  • ? Referral to vascular neurologist or cardiologist

 

High-Risk TIA:

  • admit
  • permissive HTN
  • gradually lower BP limits over 24-48h

 

 

Reference:

Gross, H. and Grose, N. (2017). Emergency Neurological Life Support: Acute Ischemic Stroke. Neurocritical Care, 27(S1), pp.102-115.

Criteria for Thrombectomy / Endovascular Treatment of Stroke

Patients eligible for intravenous alteplase should receive intravenous alteplase even if endovascular treatments are being considered

Patients should receive endovascular therapy with a stent retriever if they meet all the following criteria:

  1. prestroke mRS score 0–1,
  2. acute ischemic stroke receiving intravenous alteplase within 4.5 h of onset
  3. causative occlusion of the internal carotid artery or proximal MCA (M1),
  4. age >18 years, (note: there is no upper age limit),
  5. NIHSS score of C6,
  6. ASPECTS of C6
  7. treatment can be initiated (groin puncture) within 6 h of symptom onset

As with intravenous alteplase, reduced time from symptom onset to reperfusion with endovascular therapies is highly associated with better clinical outcomes

When treatment is initiated beyond 6 h from symptom onset, the effectiveness of endovascular therapy is uncertain for patients with acute ischemic stroke who havecausative occlusion of the internal carotid artery or proximal MCA (M1)

In carefully selected patients with anterior circulation occlusion who have contraindications to intravenous alteplase, endovascular therapy with stent retrievers completed within 6 h of stroke onset is reasonable

Although the benefits are uncertain, use of endovascular therapy with stent retrievers may be reasonable for carefully selected patients with acute ischemic stroke in whom treatment can be initiated (groin puncture) within 6 h of symptom onset and who have causative occlusion of the M2 or M3 portion of the MCAs, anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries

Endovascular therapy with stent retrievers may be reasonable for some patients <18 years of age with acute ischemic stroke who have demonstrated large vessel occlusion in whom treatment can be initiated (groin puncture) within 6 h of symptom onset, but the benefits are not established in this age group

Observing patients after intravenous alteplase to assess for clinical response before pursuing endovascular therapy is not required to achieve beneficial outcomes and is not recommended

Endovascular therapy with stent retrievers is recommended over intra-arterial fibrinolysis as first-line therapy

It might be reasonable to favor conscious sedation over general anesthesia during endovascular therapy for acute ischemic stroke. However, the ultimate selection of anesthetic technique during endovascular therapy for acute ischemic stroke should be individualized based on patient risk factors, tolerance of the procedure, and other clinical characteristics

Reference:

Gross, H. and Grose, N. (2017). Emergency Neurological Life Support: Acute Ischemic Stroke. Neurocritical Care, 27(S1), pp.102-115.

Checklist: Bleed post TPA

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Half life of TPA is ~5 minutes and only 20% is present and active 10 mins after completion of infusion, but PT and PTT prolongation and fibrinogen levels are decreased x 24 hours or more.

Checklist:

  • STOP alteplase
  • VS q15h, GCS, pupil response, treat BP, increased ICP
  • Neurosurgery consult
  • DIAGNOSTICS: STAT CT head, PT/PTT, platelets, fibrinogen, type and cross 2-4 unit pRBC
  • THERAPEUTICS:
  1. Transfuse cryoprecipitate 6-8 units IV
    1. If fibrinogen 50-100mg/dL transfuse 10 bags
    1. If fibrinogen <50 mg/dL transfuse 20 bags
  2. Check fibrinogen level 30-60 mins post transfusion, goal fibrinogen level >100 mg/dL
  3. ALTERNATIVE: transfuse single donor platelets or 6-8 bags of random donor platelets

*each bag of cryoprecipitate contains 200-250 mg of fibrinogen, increases fibrinogen levels by 6-8 mg/dL (in a 70 Kg adult)

*half life of fibrinogen is 3-5 days

Reference:

Gross, H. and Grose, N. (2017). Emergency Neurological Life Support: Acute Ischemic Stroke. Neurocritical Care, 27(S1), pp.102-115.

Abciximab for Reocclusion after tPA

Platelet-mediated thrombotic mechanisms may play a key role in rethrombosis after tPA lysis.  Rersidual thrombus provides a nidus for rethrombosis.  vWF is activated, which mediates platelet adhesion and formation of thrombus.

A thrombus which is platelet-rich can be dissolved rapidly by abciximub.  Abciximab-induced disaggregation of preformed platelet-rich thrombus is time-dependent.

In a prospective study, 4 patients with reocclusion after tPA clot lysis were treated with abciximab.  a 0.2mg/Kg bolus was given, followed by a maintenance infusion of 0.125 ug/kg/min x 12 hours.  

Dose for abciximab in UpToDate (for PCI):

Percutaneous coronary intervention (PCI): IV: 0.25 mg/kg bolus administered 10 to 60 minutes prior to start of PCI followed by an infusion of 0.125 mcg/kg/minute (maximum: 10 mcg/minute) for 12 hours

Reference:

Heo, J., Lee, K., Kim, S. and Kim, D. (2003). Immediate reocclusion following a successful thrombolysis in acute stroke: A pilot study. Neurology, 60(10), pp.1684-1687.

Uptodate. Abciximab: Drug information. Accessed 09/11/2017.

ABCD2 Score

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Table: ABCD2 Score

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TIA Prognosis and Key Mx Considerations by National Stroke Association

ABCD2 Score:

  • Discharge low risk scores (ABCD 0-3)
    • outpatient work-up within 1-2 days (alternate option: admit for work-up)
    • DIAGNOSTICS:
      • carotid imaging (US, CTA, MRA)
      • Consider TTE; if high suspicion for cardioembolic source / bilateral infarcts, obtain TEE
      • Consider 30-d ambulatory cardiac monitor to detect cryptogenic Afib
    • smoking cessation
    • THERAPEUTICS:
      • Start antiplatelet therapy:
        • ASA 81mg/day or
        • Clopidogrel 75mg/day or
        • ASA 25mg/ER dipyridamole 200mg BID
      • start high-intensity statins
        • Atorvastatin 40-80mg/d or
        • Rosuvastatin 20-40mg/day
      • *consider moderate intensity statins if >75y/o
        • Atorvastatin 10-20mg/d or
        • Rosuvastatin 5-10mg/d or
        • Simvastatin 20-40mg/d or
        • Pravastatin 40-80mg/d
      • Consider OAC or LMWH if rhythm shows atrial fibrillation – calculate CHADSVASC and HAS BLED score to guide therapy

    Admit high risk TIAs (ABCD2 scores >3)

    • Admit to hospital
    • Permissive hypertension (up to 220/120mm Hg) and gradually lower over 24-48h

Reference:

Stroke.org. (2017). [online] Available at: http://www.stroke.org/sites/default/files/resources/tia-abcd2-tool.pdf?docID [Accessed 31 Jul. 2017].

Gross, Hartmut, and Noah Grose. 2017. “Emergency Neurological Life Support: Acute Ischemic Stroke”. Neurocritical Care 27 (S1): 102-115. doi:10.1007/s12028-017-0449-9.

Heads up Maneuver

Clinical scenario:  Patient with stroke comes in with large vessel occlusion and neuro deficits; he was placed supine for CT scan and NIHSS improved.  Vascular imaging still shows clot, but deficits are now nondisabling and NIHSS is low.  Should you proceed with thrombectomy?

Small study from UCLA used the Heads Up maneuver to select patients who should proceed to thrombectomy.

 

Patients included:

  1. stroke within 7.5h onset
  2. disabling neuro deficit on presentation
  3. improved while on CT to nondisabling deficit
  4. evidence (in MRA) of persisting large vessel occlusion

 

Heads up Maneuver: (performed in angio suite)

  1. position 90 degrees upright x 30 minutes, monitor BP/HR q5-10mins
  2. if worsened –> lower to supine, proceed with angio
  3. if remained stable –> lower to supine or 30 deg HOB; transfer to stroke unit

 

Pathophysiology of Delayed Collateral Failure:

STROKE –> increased CO / SVR –> improved flow to peri-infarct regions –> MI / CHF / dysrhythmias / sepsis / dysautonomia / drugs –> reduced CPP –> delayed collateral failure –> expansion of core infarct

 

Heads Up:

Head position influences collateral flow by increasing flow velocity in affected MCA. Impaired autoregulation allows perfusion to collateral channels to become passive-pressure dependent.  Head flat position increases CPP by 20%, improves neurologic function in 15% of patients.  Risk of aspiration PNA with head flat position is <5%.

 

Outcome:

The study found that heads up maneuver can be used to stress collateral systems and identify those patients who are vulnerable to hemodynamic failure.

  1. Only 5 patients included in the series – all had high NIHSS on arrival, improved during MRI scanning.
  2. Two patients tolerated 30 minutes, no thrombectomy performed, had excellent outcome with just medical therapy.
    1. *Spontaneous recanalization occurred within 72h (assumed that vigorous collaterals promoted recanalization).
  3. Three patients worsened with manuever and had successful recanalization and excellent outcomes as well.

 

Reference:

Ali, L., Weng, J., Starkman, S., Saver, J., Kim, D., Ovbiagele, B., Buck, B., Sanossian, N., Vespa, P., Bang, O., Jahan, R., Duckwiler, G., Viñuela, F. and Liebeskind, D. (2016). Heads Up! A Novel Provocative Maneuver to Guide Acute Ischemic Stroke Management. Interventional Neurology, 6(1-2), pp.8-15.