1. Ischemic Posterior Circulation Stroke Christopher Lewandowski, M. D
Ischemic Posterior Circulation Stroke Christopher Lewandowski, M.D. Residency Program Director Department of Emergency Medicine Henry Ford Hospital, Detroit, MI Sunitha Santhakumar, M.D. Department of Emergency Medicine Henry Ford Hospital, Detroit, MI 54 1 54

2. Case Study
HPI:
The patient is 41 y.o. male, with a past history of alcohol abuse, hypertension who presents to the ED with a chief complaint of right -sided weakness, slurred speech, and loss of balance.
The symptoms began 90 minutes prior to arrival.

3. Case Study PMHx: Medications Social Hx
Alcohol Abuse, quit for 3 years
Hypertension
Seizures, Generalized, none for past 7 years
Medications
Dyazide
Social Hx
Smoking- 2 pack per day
ROS: Mild dizzy spells for the past 2 weeks, each lasting 5-10 minutes

4. Case Study Physical Exam: BP- 149/79, P-100, RR-18, T-36.9
A&Ox3 on presentation, later became stuporous
CN: dysarthria, pupils: R 3.5/ L 3.0 reactive
L facial droop, gaze palsy to the L
Motor: R arm and R leg weakness (3/5)
Sensory: Decreased to light touch and pinprick on R
Coordination: dysmetria on R (not out of proportion to weakness)
NIH Stroke Scale score = 14

5. Epidemiology 20% of all strokes
The posterior circulation – 20% of the CBF
Basilar artery occlusion – 8% - 14% of posterior circulation strokes
Mortality: 90% for BAO
4% other posterior strokes
Unfavorable outcome 20%-60%

6. Posterior Circulation Stroke: Anatomy

7. Posterior Circulation Stroke: Anatomy

8. Posterior Circulation Stroke Characteristics
Clinical Findings:
The 5 Ds: Dizziness, Diplopia, Dysarthria, Dysphagia, Dystaxia
Hallmarks: Crossed findings
Cranial nerve deficits - Ipsilateral
Motor / Sensory deficits - Contralateral

9. Posterior Circulation Stroke Prodrome
Prodrome very common
Occurs in 60% of patients with Basilar artery thrombosis
Common Prodomal Symptoms (in order of frequency)
Vertigo and Nausea (30%)
Headache, Neckache (20%)
Hemiparesis (10%)
Dysarthria, Diplopia (10%)
Hemianopia ( 6%)
Ferbert, Stroke 1990

10. Was this Patient’s Dizziness Central or Peripheral
Central Peripheral
Intensity Mild Severe
Tinnitis Rare Common
CN findings Frequent None
Nystagmus:
Visual fixation No inhibition Inhibits
Horizontorotary Rare Common
Latency None sec
Fatigue None yes

11. Posterior Circulation Stroke: Syndromes
VBI, brainstem TIAs:
Occur over days-weeks
Intermittent fluctuating brainstem sx
Dizziness plus cranial nerve symptoms
Rarely dizziness alone

12. Posterior Circulation Stroke: Syndromes

13. Posterior Circulation Stroke: Syndromes
Locked-in Syndrome
Basilar Artery or bilat. vertebral art. Occlusion
Progressive awake quadriplegia
Bilateral facial and oropharyngeal palsy
Preservation of cortical function and vertical gaze
Patient is awake and alert until RAS involved
>90% in hospital mortality

14. How do you evaluate this patient?
Confirm the Diagnosis (Emergent)
CT Scan
MRI
Blood studies
Evaluation of Stroke Etiology (Inpatient)
MRA / Angiography
Echo / TEE
TCD
Carotid Doppler

15. Case Study: CT Scan

16. Baseline CT scan

17. What is the prognosis for this patient ?
All Posterior Circulation Strokes
New England Medical Center Posterior Circulation Stroke Registry:
Mortality = 4%
Minor or no Disability = 79%
Locked In Syndrome (Basilar artery occlusion)
Mortality > 90%
How do you know if a patient will progress to locked-in syndrome ? Observation

18. What are your treatment options?
Conservative Treatment
Antiplatelet and Antithrombotic
Thrombolytic Treatment
Intravenous: within 3 hours symptom onset and the patient meets all treatment criteria
Intra-Arterial Therapy: infusion of thrombolytic agent into vessel or clot within 24 hours of onset of symptoms

19. Posterior Circulation Stroke: Treatment
Conservative Treatment
Antiplatelet and Anti thrombotic Therapy
Uncontrolled, Retrospective Studies , 1950s & 1960s
Compared to historical controls, patients treated with heparin had lower mortality (8-15% vs %)
Stopped progression of VBI to infarction
TOAST Trial
No evidence to support LMWH in acute stroke

20. Posterior Circulation Stroke: Treatment
Intravenous Thrombolysis
NINDS rt-PA Acute Stroke Trial
t-PA approved within 3 hours of symptom onset
Few posterior circulation strokes

21. Posterior Circulation Stroke: Treatment
Intra-arterial Thrombolysis
No randomized controlled trials completed
Multiple small series and reports
Results (Over 200 patients treated)
Mortality % , assoc. with lack of recanalization
Favorable outcomes in 25%-60%
ICH rate low, 0-15%

22. Posterior Circulation Stroke Future Treatment
Intra-arterial Thrombolysis
Superselective approach, micro-catheters
Angioplasty
Angio-jet

23. Case Study: Outcome
The patient mental status deteriorated, repeat NIH-SS score was 22
He received intravenous thrombolysis
He had significant early improvement but without complete resolution of symptoms
On day 4, the NIH - SS score was 10
MRA : L sup. cerebellar art. and R&L Ant-Inf cerebellar arteries were non-visualized,
Cardiac evaluation was negative
He was discharged on Coumadin to Rehab

24. Case Study: MRI - DWI <12 Hours 4 Days

25. Summary
Posterior Circulation Strokes are characterized by the 5D’s and crossed findings
Maintain a high index of suspicion for prodromal symptoms - vertigo with CN sx
The locked-in syndrome consists of quadriplegia, bilateral facial and oropharyngeal palsy; but preservation of cortical function and vertical gaze

26. Summary
The prognosis for vertebrobasilar ischemia is generally good, except for locked-in syndrome (basilar artery occlusion)
Treatment consists of conservative therapy (aspirin and heparin) or IV thrombolysis (<3 hrs) or IA thrombolysis (up to 24 hours)