Can we safely discharge TIA patients?

Louis MullerEM RegistrarJanuary 2010

Objectives

• Define TIA. Change in Definition.• How is TIA dx?• How should TIA be evaluated in the ED?• How should these patients be treated in ED?• What is their correct disposition?

Discharging TIA patients

• Challenges the EP face in the ED.

1. Which patients are at highest short term risk of stroke?

2. Who do we admit?

TIA – Background

• Common – 68 per 100 000• Over 2.5 million cases EDs/year• Estimated 800 000 stroke/yr in US– 15 – 30% preceded by TIA

• How do we measure outcome?– stroke– other cardiovascular events (MI and sudden

death)

New definition - TIA

• Tissue-based rather than time-based• Recognises TIA as a pathophysiological entity• TIA defined by symptomatic ischaemia, with no

evidence of infarction.

• Pt’s with brief Sx duration, but do not receive a detailed diagnostic evaluation – TIA or Stroke??

ACUTE NEUROVASCULAR SYNDROME

Why change in def?

• Studies from many groups have shown

The arbitrary time threshold was too broad, because 30 – 50 % of classically def. TIA’s shows brain injury on DW (MRI)

TIA is to stroke as . . .

• DVT is to PE• Unstable Angina is to myocardial infarction• Near syncope is to syncope

• TIA and stroke are different manifestations of the same disease

How do we Dx TIA• History

– Abrupt onset – Deficits fall within a vascular territory (Ant vs Post) – Different body part symptoms occur simultaneously – Duration of symptoms

Positive vs. Negative– TIA usually is a negative symptom - something that is absent –weakness, aphasia, numbness– Seizure (and migraine) is usually a positive symptom - something

that is abnormally present –tingling, “pins & needles”, involuntary movements

Dx TIA

• Physical examination– Fundi– Neck – bruit– Cardiac – murmurs, rhythm– Full neurological exam

Symptomsnot acceptable for diagnosis of TIA

• Non-focal symptoms– LOC– Dizziness– Generalized weakness– Mental confusion– Loss of vision if associated with reduced LOC– Sphincter incontinence

Symptomsnot acceptable as evidence of TIA

• Any of following IF ISOLATED findings:– Vertigo (usually) or loss of balance– Diplopia, dysphagia or tinnitus– Sensory Sx confined to part of one limb or the

face– Amnesia– Drop attacks– Isolated dysarthria

Differential diagnoses - TIA

• Stroke• Migraine• Cranial artery dissection• Seizure• Mass lesion (SDH, abscess, tumor)• Transient global amnesia• Metabolic abnormalities• Rare – vasculitis, AVM• Children – either a heart or vascular problem

TIA Dx – What now?

• What is short term risk of stroke?• Do we admit the pt?• How quickly out pt – work up?• How reliable is pt?• Does Pt have PCP?• What Rx can we initiate in ED?

TIA – Risk of Stroke?

• What is the short-term likelihood of stroke & can we risk stratify patients?

1. When will these strokes occur?2. Who will it occur in?

When will these strokes occur?

• 25-30% will stroke within 5 years

• ~ 10% will stroke within 3 months

• ~ 5% will stroke within 2 days (125,000 of them will have a stroke in the

next 48hours)

Who will these strokes occur in?

• We need to identify risk factors for stroke after TIA.

• 3 Broad strategies been studied as predictors.– Clinical risk scores (pt charac.+ neurology)– DW (MRI)– Vascular imaging (id stenosis)

Clinical risk scores• California (2000 Johnstone et al)

– 16 hospitals over 1year (1707 pt’s)– 5 variables independently predictive– 90 day stroke risk

• ABCD (2005 Rothwell et al)– 209 pt’s ( validated 190pts)– 5 predictive variables– 7 day stroke risk

• ABCD2 (authors combined their data)– to derive a unified optimal risk score– validation was done in 4 indep. populations (2893 pt)– 2, 7, 90 day stroke risk

Clinical risk scores - limitation

• The ability to ID – “treatment-urgent” patients, ie– Carotid stenosis requiring revascularization– Cardioembolism needs anticoag

not been established.• One study (Cucchiara et al 2006) 117 pts the ABCD score performed poorly in ID “high risk”

patients• Risk scores supplement but don’t replace clinical

judgment.

Can imaging help with risk stratification?

Can imaging help with risk stratification?

• Benefit in patients with low ABCD2?• Limitations to MRI use– Availability– Cost– Patient tolerance– Time

• CUS and echo use in risk stratification – limited data.

Acute Management of TIA• Goal – to optimize potentially compromised cerebral

blood flow– Positioning head of bed flat– Permissive hypertension– IV fluids – Antiplatelet therapy

• IST and CAST – aspirin reduce recurrent ischemic stroke by 7 per 1000 and mortality by a further 4 per 1000 pts treated

– Anticoagulation early in TIA – limited data– Early initiation of statin therapy during hospitalization has

been shown to increase long-term compliance and may have a potential neuroprotectant effect

AHA/ASA Guidelines for antiplatelet Tx for stroke prevention

• Both recommend the use of antiplatelet therapy for patients who have a noncardioembolic TIA

• Aspirin at a dosage of 50 to 325 mg/d; the combination of aspirin, 25 mg, and ER-DP, 200 mg twice daily; and clopidogrel at a dose of 75 mg/d are all considered acceptable

• Initial therapy with aspirin and ER-DP is suggested instead of aspirin alone

• clopidogrel may be considered instead of aspirin alone

• The combination of aspirin and clopidogrel is not routinely recommended

• The AHA/ASA guidelines emphasize that the selection of antiplatelet agents should be individualized on the basis of patient characteristics,such as risk profile and tolerance of side effects

TIA – Who do we admit?

• Options

Admit (medicine/neurology) vs Urgent-access specialized TIA clinics vs ED observation unit (EDOU) vs Outpatient

TIA – Who do we admit?

• Potential benefits of admission– If stroke develops, could lyse faster– Work-up can often be accomplished faster – Initiate treatment sooner Carotid intervention for stenosis Heparin for atrial fibrillation– Observation if there is diagnostic uncertainty– Medico-legal issues– PREVENT A STROKE

TIA – Who do we admit?• Most patients with TIA will not stroke in short term• Benefit of hospitalization uncertain (limited clinical

data)– Poisson et al (2007)– Prospective surveillance study– 5yr/ 552pts – 69% admitted– Risk of stroke at 30d

• 2% hospitalized• 7% discharged

• Considerable expense and resource consumption ( vs long term care of stroke pt)

Urgent access TIA clinic

• Outpatient evaluation <24 -48hrs in specialized TIA clinic.

• EXPRESS study (Rothwell et al)– Rapid-access TIA clinic vs std outpatient eval.– This included IMMEDIATE Dx testing and Rx initiation (1278

pts)– 2 phases (Before vs After)– Stroke rate at 90d decreased from 10.3% to 2.1%

• SOS- TIA Trial

ED observation units• Accelerated diagnostic protocol applied• Idea very similar to Mx of low-intermediate risk Chest pain

pts. (Chest pain unit )• 2007 Ross et al –

– Prospective randomized study– Inpatient(control) vs EDOU(TIA ADP)– CT,ECG,bloods,serial clinical exams– Neurology consult, CUS, Echo, cardiac monitoring– Length of stay 61 vs 26hrs– Lower 90d total direct costs– Comparable 90d clinical outcomes

• Promising alternative, but requires commitment of resources.

Admission recommendation 2006 – National Stroke Association

• Consider – 1st TIA <24-48hrs• Generally recommended– crescendo TIA’s– duration Sx > 1hr– Sx Carotid stenosis > 50%– known cardiac source of embolus– known hypercoagulable state– Appropriate ABCD2 score

Diagnostic Recommendations

Diagnostic recommendations

Diagnostic recommendations

Current practice at UCT/US?• GSH

– C15 -stroke team via medicine (?GFJ & NSH) ABCD2 >4 admit (pending bed availability,6 or more definitely) CUS + imaging <24hrs

ABCD2 <2 Workup as outpt <48hrs At least CUS

– Neurology• Used to give ASA / simvastatin/ control DM, BP Out pt workup• Now ABCD2 (high – stroke bed low – workup within 1-2 weeks• Attitude changed over last year. They want to know about all pts. More

urgent management

Current practice at UCT/US?

• Tygerberg– Neurology• Admit all patients• Do not really use risk stratification• Same day CUS• CTA/MRA on ind. Cases• Obs 2-3 days• Very few as out patients

Summary

• Neuroimaging studies altered the understanding of TIA pathophysiology

• Change in definition• TIA = high short-term risk of early stroke• Risk stratify• New recommendations – greater urgency(same urgency as pts with Unstable Angina?)• Further research needed to optimize risk

stratification (+- neuroimaging)

References• Stroke 2009;40;2276-2293 – May 2009• Rothwell et al, Express study.Lancet.2007;370:1432 – 1442• Cucchiara BL et al,Is the ABCD score useful for risk stratification op

patients with acute TIA? Stroke 2006;37:1710-1714• Ross,M et al . Management of TIA in the Twenty-First Century. Emerg med

Clin N Am 27( 2009)51-69• Edlow,JA. Current cotroversies in the Management of TIA, Chicago

Scientific Assembly• Cucchiara BL et al. Transient Ischemic Attack: risk stratification and

Treatment.Annals of Emergency Medicine vol 52 no2 (August 2008)• Edlow, JA. Rapid TIA patient evaluation and treatment. www.ferne.org• Stead,L. Suspected TIA patients in the Emergency department: The Mayo

Clinic appearance. www.ferne.org