6 Stroke, part 3 Flashcards
Definition of “Onset of Stroke symptoms”
The time the patient was last known well or last known to be at their neurologic baseline
Remarks on NIHSS in administration of thrombolytics
A score between 4 and 22 is commonly used.
However, there is no upper or lower limit of NIHSS score for thrombolytics administration as benefit may be seen with both mild but disabling (e.g., aphasia, hemianopia, gait disturbance) a well as in very severe strokes
Criteria for rtPA administration for those with onset of symptoms from 3 to 4.5 hours
Age 80 y or below
No history of diabetes mellitus and prior stroke
NIHSS ≤25
Not taking oral anticoagulants
No brain imaging evidence of ischemi injury involving > 1/3 of the MCA territory
Some exclusion criteria form thrombolysis in acute ischemic stroke (AIS)
S/s suggestive of SAH
Suspected aortic dissection
Prior ischemic stroke or severe head trauma within 3 months
GI malignancy or GI bleeding within 21 days
—
Platelet <100,000/mm3
INR >1.7 or APTT >40s, or PT >15s
Use of LMWH, direct thrombin inhibitors, or direct factor Xa inh within preceding 48 hours
—
Pretreatment SBP >185 or DBP >110 DESPITE therapy
Myocardial infarction and thrombolysis
Acute myocardial infaction is not a contraindication to rtPA
Unruptured intracranial aneurysm
An aneurysm <10 mm is NOT a contraindication to rtPA.
rtPA administration with an aneurysm ≥10 mm is controversial
As per the WAKE UP trial, these patients may benefit from IV thrombolysis despite the onset time being uncertain
Diffusion-weighted imaging-fluid attenuated inversion recovery mismatch
- acute infarct in diffusion-weighted MRI, but no parenchymal hyperintensity on fluid-attenuated inversion recovery
Dosage of IV alteplase in acute ischemic stroke
0.9 mg/kg,
max dose of 90 mg.
administer 10% of the dose as bolus over 1 minute,
with the remaining infused over 60 minutes
Dosage of IV alteplase in STEMI
BW >67:
15 mg initial IV bolus, 50 mg infused over next 30 minutes, 35 mg infused over next 60 minutes
(max dose of 100 mg)
BW <67 kg
15 mg initial IV bolus, 0.75 mg/kg infused over next 30 mins, 0.5 mg/kg infused over next 60 mins
Dose of tenecteplase
<60 kg: 30 mg
≥60 but <70 kg: 35 mg
≥70 but <80 kg: 40 mg
≥80 but <90 kg: 45 mg
≥90 kg: 50 mg
Max dose of 50 mg
Tenecteplase is given as a single IV bolus over 5-10 seconds.
Nicardipine infusion in thrombolysis
Start at 5 mg/hour
titrate up by 2.5 mg/hour at 5- to 15-min intervals
max dose of 15 mg/hour
when desired BP is attained, reduce to 3 mg/hour
Nitroprusside infusion in thrombolysis
0.5-10 mcg/kg/min
Continuous arterial monitoring advised
Use with caution in patients with hepatic or renal insufficiency
Increases intracranial pressure
Pregnancy category C
Frequency of BP monitoring in thrombolysis
Time after rtPA infusion
0-2 h: every 15 min
3-8 h: every 30 min
9-24 h: every 60 min
Risk of orolingual angioedema after alteplase is increased in
Patients taking ACE inhibotrs.
Treat angioedema similarly to other causes of angioedema
Endovascular therapy is feasible up to ______ of symptom onset
6 hours
AHA/ASA indications for endovascular therapy with a stent retriever
Prestroke mRS score 0 to 1
Acute ischemic stroke receiving IV rtPA within 4.5 hours of onset
Causative occlusion of the ICA or proximal MCA (M1)
Age ≥18 y
NIHSS ≥6
ASPECTS ≥6
Treatment can be initiated (groin puncture) within 6 hours of symptom onset
All 7 criteria need to be met for stent retriever endovascular therapy to be indicated
Trials that showed improved functional outcome with thrombectomy even if done for late presenting stroke (>6 hours)
DAWN trial (6 to 24 hours)
Evidence of potentially reversible ischemia via mismatch between clinical symptoms and infarct size
DEFUSE 3 trial (6 to 16 hours)
Evidence of potentially reversible ischemia via penumbra of ≥15 mL
Remarks on transient ischemic attack (TIA)
analogous to unstable angina - that is, an ominous harbinger of a potential future vascular event
Diagnostics for TIA
Noncontrasted head CT is still the initial imaging study of choice (primarily to rule out stroke mimics)
although it cannot reliably predict risk of subsequent stroke
Treatment of TIA primarily focuses on
Prevention of subsequent stroke
CHANCE trial: Aspirin + Clopidogrel = reduces risk of stroke in the first 90 days
POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke, 2018):
A+C = confirmed less recurrent stroke, but higher risk of major hemorrhage at 90 days
The risk of hemorrhagic transformation of an acute stroke is greatest when?
in the first 48 hours
Anticoagulation in acute ischemic stroke
In the setting of acute atrial fibrillation, anticoaguation is typically should NOT be started in the ED but should be initiated in the inpatient setting
The use of unfractionated heparin, LMWH, or heparinoids for emergent treatment of a specific stroke subset or TIA CANNOT be recommended based on available evidence, even in the presence of atrial fibrillation.
Risk stratification scoring system for TIA
ABCD2
Age ≥60 +1
BP ≥140/90 +1
Clinical features (unilateral weakness +2, speech disturbance only +1)
Duration of symptoms (10-59 mins +1, ≥60 mins +2)
Diabetes history +1
Interpretation of ABCD2
7-day stroke risk
0-3: low-risk (1%)
4-5: moderate-risk (6%)
6-7: high-risk (12%)
However, “The ABCD2 does not sufficiently identify the short-term risk for stroke to use alone *as a risk-stratification instrument
Remarks on MI + AIS
For patients presenting with concurrent AIS and acute MI, treatment with IV alteplase at the dose appropriate for cerebral ischemia, followed by percutaneous coronary angioplasty and stenting if indicated is reasonable.
Do not delay thrombolysis for stroke if the patient qualifies
Most common cause of ischemic stroke in children
Sickle cell disease
Treatment includes oxygen, hydration, pain control, and emergent exchange PRBC transfusion with the goal of reducing hemoglobin S levels to <30% and achieve a total hemoglobin level of 10 g/dL (but no higher in order to avoid hyperviscosity)
Remarks on strokes in the young adults
age 18 to 50 years
Younger stroke victims have more favorable morbidity and mortality rates after IV thrombolysis, thrombectomy, and decompressive surgery for large MCA strokes.
Therefore, treat these patients aggressively.
