David A, Miller, MD Interventions in Acute Ischemic Stroke: Strategies for the New Millennium...

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David A, Miller, MD

Interventions in Interventions in Acute Ischemic Stroke:Acute Ischemic Stroke:

Strategies for the Strategies for the New Millennium New Millennium

David A, Miller, MD

Clinical Decisions in Clinical Decisions in Emergency MedicineEmergency Medicine

Ponte Vedra, FLPonte Vedra, FLJune 22-23, 2007June 22-23, 2007

David A, Miller, MD

David A. Miller M.D.David A. Miller M.D.Assistant Professor of RadiologyAssistant Professor of Radiology

Endovascular and Therapeutic Endovascular and Therapeutic NeuroradiologyNeuroradiology

Mayo Clinic Mayo Clinic Jacksonville, FLJacksonville, FL

David A. Miller, MD

The Rationale For The Rationale For Acute Stroke Treatment Acute Stroke Treatment

• Stroke is a very common disorder. Estimates there between 700,000 and 750,000 strokes each year in the U.S. Mortality is now over 150,000/year.

• A large percentage of these are ischemic.• The lifetime cost of an ischemic stroke is

100,000 or more.

David A. Miller, MD

The Rationale For The Rationale For Acute Stroke TreatmentAcute Stroke Treatment

• Despite improvements in conventional medical therapy the morbidity and mortality rates are close to 17% at 30 days and 40% at 5 years.

• In patients with acute MCA occlusion the rate of death or severe disability has been reported at 40 -78%.

David A. Miller, MD

• The treatment of acute ischemic stroke has undergone a tremendous evolution over the past decade or so with the introduction of techniques for early intervention.

• This, coupled with advances in diagnostic capability, has allowed for much more aggressive treatment of these patients

David A. Miller, MD

• More than 60% of hospitals in a recent survey did not have stroke protocols in place, and even more did not provide for the rapid identification of stroke patients.

• Nationally, less than 5% of patients with ischemic stroke are receiving tPA.

David A. Miller, MD

DiagnosticsDiagnostics• The availability of high quality CT

or MRI imaging and immediate quality interpretation is essential for acute stroke care.

• Aside from the initial neurologic examination, this is the most important piece of information that you can get.

David A. Miller, MD

DiagnosticsDiagnostics

• The CT scan remains the mainstay of diagnostic evaluation of acute stroke.

• A non contrast CT scan of the brain is the fastest and most effective way of making the initial evaluation of acute stroke patients.

David A. Miller, MD

Principles of Acute Stroke CarePrinciples of Acute Stroke Care• It can quickly exclude patients

(parenchymal hemorrhage, large infarct, mass) from treatment paradigms and can occasionally quickly include patients (dense artery sign).

• Unfortunately, the non contrast CT is relatively insensitive in detecting thrombus.

David A. Miller, MD

DiagnosticsDiagnostics• Non contrast CT is also unable to give much information about

the size of the acute lesion or status of the affected tissue.

• Newer high speed (spiral) CT scanners can, however, provide this type of information through perfusion imaging and CT angiography.

David A. Miller, MD

• With time as a primary issue, we follow the non contrast CT with CT perfusion and CTA.

• This allows us to get most of the imaging information we need to make treatment decisions in a few minutes.

David A. Miller, MD

Principles of Acute Stroke CarePrinciples of Acute Stroke Care• A recent study of 62 patients found

that CT angiography failed to show a lesion seen on conventional angiography in only one instance.

• These capabilities allow very rapid stratification of the patient into a treatment group.

David A. Miller, MD

DiagnosticsDiagnostics• MRI

• Tremendous potential for both anatomic and physiologic evaluation of acute stroke.

• Diffusion weighted imaging probably the most sensitive measure of ischemia.

David A. Miller, MD

DiagnosticsDiagnostics• Diffusion/Perfusion mismatch

offers the promise of extending the window for treatment.

• Problems of cost, availability, and longer time will need to be addressed before this will become widely used in acute stroke.

David A. Miller, MD

DWI MTTEDWI

David A. Miller, MD

MRA Brain 8:25 PM 4.5 hours out from witnessed stroke. Pt. had anaphylaxis to prior iodine injection

David A. Miller, MD

• Tissue Plasminogen Activator (tPA) has been approved by the FDA for the treatment of acute stroke. Approval has been for intravenous administration within 3 hours of onset of symptoms.

• This drug (and others) have been used in several large scale trials of intravenous and intra-arterial thrombolysis in acute stroke.

David A. Miller, MD

IA tPA Therapy for Acute StrokeIA tPA Therapy for Acute Stroke• The delivery of thrombolytic agents

locally to the site of intracranial thrombus has been used effectively in the treatment of acute stroke.

• The method has the advantages of achieving higher local concentration of drug at a lower dose, potentially increasing effectiveness while lowering systemic concentration.

David A. Miller, MD

IA tPA Therapy for Acute StrokeIA tPA Therapy for Acute Stroke• Other advantages include:

• the possibility of mechanical manipulation of the clot.

• the ability to follow the progress of therapy and adjust drug dose to effect.

• a greater window for initiating treatment.

David A. Miller, MD

IA tPA Therapy for Acute StrokeIA tPA Therapy for Acute Stroke• The method does have some

disadvantages as well:• Angiography is required for drug

delivery, with the increased risk for complication associated with the procedure (though complication rates for angiography even in this setting are low)

• There is an inherent delay in delivering medication.

David A. Miller, MD

• The Studies

David A. Miller, MD

NINDS tPA Stroke Study NINDS tPA Stroke Study (the IV tPA study)(the IV tPA study)

• tPA given intravenously at a dose of 0.9 mg/kg (10% as bolus with the remainder infused over 60 minutes).

• Initial results showed early improvement in 47% of the treated group vs. 39% of the placebo group.

• Good outcomes with tPA were 11-13% higher

David A. Miller, MD

NINDS tPA Stroke StudyNINDS tPA Stroke Study

• Symptomatic hemorrhage was 6.4% for the treated group vs. 0.6% for the placebo group.

• Still mortality at 3 months was 17% for the treated group vs. 21% for the placebo group.

David A. Miller, MD

IA tPA Therapy for Acute Stroke IA tPA Therapy for Acute Stroke (Proact II)(Proact II)

• Multicenter Randomized Trial (180pts).

• Stroke in the MCA distribution, onset <6hrs.

• Angiogram demonstrating M1 or M2 occlusion.

• 9mg IA pro-urokinase with heparin vs. heparin alone.

David A. Miller, MD

IA tPA Therapy for Acute StrokeIA tPA Therapy for Acute Stroke• Pts generally had severe strokes (NIHSS>17).• recanalization rate with pro-UK was 66%.• recanalization rate with heparin alone was

18%.• proportion of patients achieving

independence at 90 days (mRS<2) was 40% in UK group vs. 25% in the heparin only group.

• Symptomatic ICH 10.9% with UK vs. 3.1% with heparin.

David A. Miller, MD

Proact (II)Proact (II)• Randomized multicenter trial with 180

patients treated within 6 hours of onset (this required screening over 12,000 patients).

• Recanalization rate was 66% (18% control).• Good clinical outcomes at 90 days

(mRS<2) were seen in 40% of treated patients vs. 25% of controls. (a 15% absolute benefit and 58% relative benefit)

David A. Miller, MD

Combined TrialsCombined Trials• Several randomized trials comparing i.v.

therapy alone v.s. i.v. and i.a. therapy have been conducted. These include the EMS bridging trial(Lewandowski), the IMS trial( Tomsick), and the IA/IV trial (Keris).

• These trials generally showed increased rates of recanalization with combined therapy (without significant increased morbidity) and improved outcomes for combined therapy in 2 of the 3 trials.

David A. Miller, MD

Intracranial Hemorrhage after tPAIntracranial Hemorrhage after tPA

• Major acute complication of either IV or IA therapy.

• Severity of initial deficit, initial CT findings of ischemia, increased dose of thrombolytic, age and increased BP have been suggested as potential risk factors.

David A. Miller, MD

Intracranial Hemorrhage after tPAIntracranial Hemorrhage after tPA

• In NINDS, pts with a NIHSS of >20 (severe deficit) were 11 times more likely to develop a symptomatic ICH than pts with a NIHSS of <5 (mild deficit).

• The presence of early ischemic changes (hypodensity, gyral edema) on CT, mass effect or brain edema increased the risk of ICH.

David A. Miller, MD

Intracranial Hemorrhage after tPAIntracranial Hemorrhage after tPA• Time is also a factor in ICH. The later

treatment is instituted, either with IV or IA therapy, the more likely that ICH will occur.

• With IA therapy, increasing dose also increases the ICH risk, though different trials have reported varying rates of increase. Interestingly, ICH is not always symptomatic, and many studies show increased overall benefit despite increased symptomatic hemorrhage.

David A. Miller, MD

Combined IV and IA TherapyCombined IV and IA Therapy• EMS / IMS• Studies looking at combined therapy with

an initial (lower) dose of of iv tPA (0.6 mg/kg) followed by cerebral angiography and IA therapy of any identified thrombus (M1 or M2)

• recanalization was achieved in 67% of pts receiving iv and IA tPA and in 60% of pts receiving placebo and IA tPA

David A. Miller, MD

MERCIMERCI• 80 patients with acute ICA thrombus.

• 53% had recanalization with MERCI alone.

• 63% had recanalization with MERCI and adjunctive endovascular therapy.

• Good clinical outcome @ 90 days:– 39% with recanalization – 3% without recanalization

David A. Miller, MD

Thrombolysis In The Thrombolysis In The Vertebral Basilar SystemVertebral Basilar System

• Several small series of patients with posterior circulation occlusions have been reported.

• In general, the series are not randomized. The majority of patients presented and were treated outside the 3 hr. or even 6 hr. window.

• They were almost all treated with pro-UK. • Mortality was high and efficacy is

unclear.

David A. Miller, MD

Principles Of Acute Stroke CarePrinciples Of Acute Stroke Care

• Designation of appropriate centers and clear plans for delivery of patients will also greatly improve the available population for acute treatment.

• The establishment of stroke centers may aid in reducing the time to treatment.

David A. Miller, MD

Mayo Clinic Jacksonville Mayo Clinic Jacksonville Stroke TreatmentStroke Treatment

• Mayo Clinic Jacksonville has recently achieved certification by the JCAHO as a Primary Stroke Center.

David A. Miller, MD

• Stroke Team consisting of the ER Physician, ER charge nurse, Neurologist on call, CT tech, Neuroradiologist on call, Angiography tech on call, and Radiology nurse on call.

• Pharmacy, Laboratory services, and Critical Care Physician all notified ASAP and standing by

David A. Miller, MD

• Identification of an acute stroke with potential for intervention triggers a Brain Attack alert.

• ER and CT cleared for rapid assessment and imaging.

• Patient arrives in ER, is immediately assessed, and blood work is drawn. Large bore iv placed.

• If patient meets criteria for brain attack treatment, they are transferred to CT ASAP

David A. Miller, MD

• At this point the “Brain attack” team is called.

• This includes the ER physician, the Neurology resident on call, and the Neuroradiologist on call.

• The idea is that they will meet in the CT scan room (if possible) to review the scan and plan Tx

David A. Miller, MD

• Non contrast head CT is performed.• If no hemorrhage (or other exclusion

criteria) contrast is injected for CT perfusion and CT angiogram.

• Evaluation of imaging performed by Neuroradiology with stroke team, and plan of action is formed.

David A. Miller, MD

• In general, the patient is treated with IV tPA, IA tPA, or combination therapy according to the guidelines outlined by recent studies.

• Patients may be enrolled in other protocols if eligible.

• If patient does not meet criteria for inclusion or if family refuses acute thrombolysis, patient is admitted for conservative care.

David A. Miller, MD

Acute StrokeAcute Stroke

• Timing of Therapy:

–1-3 hours – systemic (intravenous tPA) therapy

–1-6 hours – local (intracranial micro catheter) therapy

–1-24 (or more) hours local therapy in the posterior fossa.

David A. Miller, MD

• Advantages to Mayo Clinic model in developing a stroke team and center:

• Institutional support.• no competing groups.• no financial disincentives or

disagreements.

David A. Miller, MD

The FutureThe Future• Improved medications (more

thrombolytic, more selective, less systemic effects).

• Ultrasound assisted IA thrombolysis.• New and improved mechanical extraction

devices.• Increased awareness leading to more

eligible patients, increased centers able to treat acute stroke, improved facilities and imaging.

David A. Miller, MD

Take Home MessagesTake Home Messages

•TIME = BRAIN

• There is no substitute for decreasing the time to initiation of treatment

David A. Miller, MD

• You do not need a big center to treat stroke. You do need a core of staff willing to mobilize and act as a team.

David A. Miller, MD

• Acute stroke treatment is where acute MI treatment was when the Seattle CPR project started. When people become aware that there is urgent treatment for this disease, they will seek it out and it will become standard of care.

David A. Miller, MD

• If you treat an acute stroke and watch a patient’s speech return, or watch a hemiparetic patient start moving and get up off your ER bed or angiography table you will never feel anything quite like it in your medical career.

David A, Miller, MD

Questions?Questions?

www.FERNE.org

adm1@yahoo.com (904) 613-4462

ferne_pv_2007_miller_interventions_080607_finalcd04/19/23 19:42

David A, Miller, MD Interventions in Acute Ischemic Stroke: Strategies for the New Millennium...

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