MD Conference Express ISC 2013 - (Page 28)
SELECTED UPDATES ON IMS III
IMS III: Results and Perspective
Written by Phill Vinall
Peer-Reviewed
Highlights From
28
April 2013
Joseph P. Broderick, MD, University of Cincinnati, Cincinnati, Ohio, USA, presented data from
the randomized Interventional Management of Stroke III Trial [IMS III] study designed to test
whether endovascular therapy following IV tPA was more efficacious than IV tissue plasminogen
activator (tPA) alone [Broderick JP et al. N Engl J Med 2013].
IMS III was planned to enroll 900 subjects aged 18 to 82 years with an National Institutes of
Health Stroke Scale (NIHSS) ≥10, or an NIHSS 8 to 9 with computed tomography angiography (CTA)
evidence of internal carotid artery (ICA), M1, or basilar occlusion, prior to administration of IV tPA.
Subjects were randomized 2:1 to endovascular therapy following IV tPA (n=434) or standard IV tPA
alone (n=222). In the endovascular therapy group, tPA (~0.6 mg/kg) was to be administered within
3 hours of stroke onset, followed by angiography to determine if a treatable thrombus was present.
If present, endovascular therapy proceeded using intra-arterial of administration of tPA at the site
of the vessel occlusion or a thrombectomy device cleared for use by the FDA. The endovascular
treatment began within 5 hours and had to be completed within 7 hours of stroke onset. The
control arm received standard full dose tPA (0.9 mg/kg over one hour). The primary outcome was a
modified Rankin Scale (mRS) score of 0 to 2, or functional independence at 3 months. The primary
safety measure was mortality at 3 months and symptomatic intracerebral hemorrhage (ICH) within
30 hours of randomization.
IMS III was stopped for futility after enrolling 656 patients; there were no significant
safety concerns. Time from onset to start of endovascular therapy was 249 minutes. There
was no significant difference in the primary outcome between treatment arms even
when accounting for onset to IV tPA, Alberta Stroke Program Early CT score, or a positive
pretreatment CTA showing occlusion of the internal carotid artery, middle cerebral artery trunk, or
basilar artery. There was a trend toward significance (p=0.06) in patients with a baseline NIHSS ≥20
favoring endovascular treatment. Within 90 days, 19.1% of the patients in the endovascular group
died versus 21.6% in the IV tPA group. Asymptomatic ICH (p=0.01) and subarachnoid hemorrhage
(p=0.02) within 30 hours of IV tPA initiation were significantly higher in the endovascular group.
Andrew M. Demchuk, MD, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta,
Canada, discussed the impact of CT and magnetic resonance angiography (MRA) in the IMS III trial
based on location of occlusion. Of the 656 subjects in the trial, 292 had baseline CTAs and 14 had
baseline MRAs (total 47%). Results presented at the conference were limited to ICA, M1, M2, and
basilar segments of the IA circulation. Grade 1 (complete occlusion) and Grade 2 (hairline lumen)
were considered occlusion of that segment.
In the endovascular arm, recanalization was achieved in 85.71% of subjects with 24 hour CTA
versus 60.87% in the IV tPA-only (p<0.0001) group. The 24-hour recanalization rates were high in
both arms for middle cerebral artery occlusions. The 90-day clinical outcomes with mRS 0 to 2 for
isolated M1 occlusions were similar. Low 24-hour recanalization rates were seen in IV tPA arm for
ICA occlusions. A post hoc analysis of carotid T/L occlusions and tandem ICA plus M1 showed
greater recanalization and better outcomes with combined (IV tPA + endovascular) treatment
compared with IV tPA alone. Future endovascular/thrombolytic trial design should include baseline
vascular imaging given the wide differences in clinical effects by occlusion site seen in IMS III.
Stroke is becoming a global burden in the developing world, which has little access to modern
endovascular treatment resources. Stephen M. Davis, MD, Royal Melbourne Hospital, University
of Melbourne, Victoria, Australia, outlined the challenges many low-income regions face regarding
stroke treatment.
Stroke is the second leading cause of death with 16 million strokes occurring worldwide each year.
Between 1990 and 2010, stroke increased by 26% worldwide—mostly in developing countries [Lozano R
et al. Lancet 2012]. At the same time, there has been more than a 100% increase in low- to middleincome countries, there has been a 42% decrease in high-income countries (Figure 1) [Feigin VL et al.
Lancet Neurol 2009].
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Table of Contents for the Digital Edition of MD Conference Express ISC 2013
MD Conference Express ISC 2013
Contents
Defending the Stroke Guidelines
Stroke Update: An Overview of What Is Going on in the Area of Stroke
Brain Imaging Does Not Help Identify Patients Who May Benefit From Endovascular Treatments for Acute Ischemic Stroke
MISTIE II Trial: 365-Day Results Demonstrate Improved Outcomes and Cost Benefit
Addition of AMPLATZER PFO Occluder to Medical Therapy Is Beneficial in Patients With Cryptogenic Stroke and PFO
Intraoperative CT-Guided Endoscopic Surgery for ICH [ICES]
The EMBRACE Trial: Prolonged Ambulatory Cardiac Monitoring Improves the Detection and Treatment of Atrial Fibrillation in Patients With Cryptogenic Stroke
DP-b99 Does Not Improve Recovery Following Acute Ischemic Stroke
The Secondary Prevention of Small Subcortical Strokes Trial: Blood Pressure Intervention Results
Final Results of the Solitaire FR Thrombectomy for Acute Revascularization: The STAR Trial
Clopidogrel Plus Aspirin Reduces Risk of Recurrent Stroke: The CHANCE Trial
Reversal of Chronic Hypoperfusion to Improve Cognitive Function: The RECON Trial
Cardioembolic Stroke
IMS III
Novel Anticoagulants in Vascular Neurology Practice
Wake-Up Stroke
Virtual Reality in Stroke Rehabilitation
Reward Improves Long-Term Retention of a Motor Memory Through Induction of Offline Memory Gains
MD Conference Express ISC 2013
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