Phipps – ischemic stroke 6-22-17

Summary by Dr. Tony Basel

Stroke:  A clinical neurologic syndrome that occurs when blood flow to the brain is interrupted by either a blocked (Ischemic) or ruptured (Hemorrhagic) blood vessel.

• Per AHA, 800,000 strokes per year
  • A stroke occurs every 40 seconds!
  • A stroke KILLS someone every 4 minutes!
  • It’s the number 1 cause of disability in the United States
• Biggest Risk Factor: Hypertension

Prioritize:

• When a suspected stroke hits your unit, ask yourself these 3 questions
  • Is this a Stroke? (rule out mimickers)
  • Can I intervene? With either IV tPA or Mechanical Intervention
    • Take a good history: establish time of last known well (more on this below)
    • Get a NIHSS
  • Is this a Bleed? (Get the Non Contrast CT head)
    • Door to Reading of the CT = 30min (STANDARD OF CARE)
    • If Stroke is <6hr old… CT head will likely be NORMAL!
      • This is a good thing, we can still salvage brain

The Large Vessel Stroke

• Can we clinically tell the difference?
  • Not really but sometimes…
    • Patients have higher NIHSS
    • Cortical Signs: aphasia, neglect, visual field deficit, gaze deviation
• What do we mean by large vessel stroke?

Time is Brain!

• The ischemic punumbra
  • The area of salvageable brain tissue that surrounds the infarct core of the stroke
  • This area is maintained by collateral circulation: percolating blood/oxygen to the punumbra
    • Various branches from the Circle of Willis
    • Leptomeningeal circulation
  • Collaterals help by some time, but the brain is still dying!
    • Every 30min = 10% loss of neurons

APECTS Score

• What if our initial CT shows some evidence of Infarct? Are we too late?
• Does this affect the outcomes of our possible interventions like IV tPA?
• This is where the APECTS score comes from…
  • Alberta Stroke Program early CT score (APECTS)
    • A 10pt quantitative topographic CT score used in patients with MCA strokes
      • Best Score = 10 (no areas of infarct noted)
      • Each area of infarct à deduct 1 point
    • In the study done by R.I Aviv et al, ASPECTS scores <8 treated with IV tPA did not have good clinical outcomes!

Modified Rankin Score

• How we determine clinical outcomes in Neurology
• A quantitative assessment of dependence/disability

Thrombolysis

• IV tPA approved in 1996 from the basis of 2 randomized trials
  • Showing improved 3-month outcomes if given within 3 hours of symptom onset
  • Later showed to improve outcomes if given up to 4.5 hours
• Many providers are still fearful of the complications of IV tPA
  • Studies have shown if you follow the criteria, the Benefit > Risk

Brain Attack Evaluation

• Time of Onset = Last Known Well (LKW)
  • How were you/they
    • Yesterday? At bedtime?
    • What time were they up at night? In the morning?
  • Who saw them or spoke to them last?

IV rTPA Contraindications at UMMC
Time	Vitals	Symptoms	Rads	Comorbidities	Anticoagulants	Labs
Onset >4.5hrs Can’t give TPA in 4.5hrs	SBP > 185 DBP >110 Despite Treatment	TIA/Resolved Mimicker	ICH on CT Large Infarct; >1/3 MCA	Endocarditis Terminal illness Pt Refusal	DOAC within 48hrs LMWH within 24hrs Heparin within 48hrs and high PTT	PLT <100 INR >1.7 Elevated aPTT Glucose <50

IV rTPA warnings/precautions
Uncertain symptoms are due to strokeLP, Subclavian venous stickArterial stick in noncompressible site < 7 daysMajor surgery/biopsy/trauma < 14 daysPregnancy, Lactating women, delivery < 14 daysGI/GU Bleeding < 21 days Head trauma/surgery or spinal surgery < 3 months	Hx of stroke < 3 monthsAcute MI/Pericarditis < 3 monthsHx ICH, Neoplasm, AVM, AneurysmSeizure at onset of symptomsHemorrhagic ophthalmic conditionSeptic thrombophlebitis

TPA Limitations

• Lower recanalization rates for more PROXIMAL, Large vessel occlusions
• Large clot burdens (length >8mm) less likely to respond to IV TPA alone

Mechanical Therapies

• Intra-Arterial Fibrinolysis
  • Limited efficacy
  • NO RCT has shown a change in outcomes
  • Only used as adjunctive therapy
• Mechanical Thrombectomy
  • Many Types
    • Microguidewire fragmentation
    • MERCI retrieval device
    • Penumbra Suction devices
    • Stents
    • Stent Retrieval Devices (Solitaire and Trevo): now mostly used
    • Advanced Suction Catheters: coming into favor
• The Disappointment of 2013
  • IMS 3
    • Randomized trial of IV tPA + IA treatment vs. IV tPA alone (started within 3 hrs)
    • Stopped Early due to Futility
    • No difference in Outcomes (good or bad) between the two groups
    • The Hits just kept coming!
      • SYNTHESIS à no improvement in outcomes
      • MR RESCUE à no improvement in outcomes
• 2014 and 2015 ushered in a NEW ERA (all treatments given within 6 hrs)
  • MR CLEAN à Increased rates of Independence in those who got IAT (no diff in mortality)
  • SWIFT PRIME à Improved mRS
  • ESCAPE Trial à Improved mRS with Decrease in mortality!
  • EXTEND IA à Improved mRA with Trend in decreased mortality
  •  REVASCAT à Improved mRS and NIHSS

• Meta-Analysis

• Endovascular therapy reduced disability at 90days (OR 2.49)
  • Number needed to treat 2.6

NNTT = 3-4 to Improve 1 Person from Dependent/Dead à Alive and Independent

Coming Soon

• DAWN Trial:  May extend the window of IA therapy to 6-12 hours

Summary

• IV tPA is STILL the standard of care
• Offer IA Therapy
  • Acute, Large vessel Anterior Circulation by 6hrs
  • Posterior strokes (Basilar) considered within 12hrs
• Patient Eligibility
  • Age >18
  • NIHSS >6 or Occlusion of Large Artery (ICA, M1, M2)
  • Head CT
    • No ICH
    • Hypodensity < 1/3 MCA territory
    • ASPECTS > 6
  • Premorbid mRS 0-1
  • Groin puncture by 6 hours from LKW
  • Case by case
    • Ineligible for IV tPA
    • > 6hrs from LKW