Emergency Medicine

HOT OFF THE PRESS

Thrombectomy in Ischemic Stroke

mrclean1

Previous studies on intra-arterial treatment for ischemic stroke were not that encouraging, BUT many used non-contrast CT’s instead of CTA and many used alteplase instead of or in addition to mechanical thrombectomy.

Recent studies from the NEJM suggest that in patients with a proximal vessel occlusion, thrombectomy has better results than usual care, AKA IV alteplase. All of the studies were randomized, open-label, multicenter trials.

Let’s take a look at the studies…

Inclusion criteria

Endovascular therapy within Occluded arteries Infarct Core Waited for alteplase response
MR CLEAN 6 hours ICA, M1, M2 N/A Yes
EXTEND-IA 6 hours ICA, M1, M2 No large ischemic core No
ESCAPE 12 hours M1, M2, +/- ICA Small infarct core No
SWIFT PRIME 6 hours ICA, M1 Small-moderate infarct core No
REVASCAT 8 hours M1, +/- ICA Small infarct core Yes

ICA= internal carotid artery, MCA= middle cerebral artery, M1/M2= branches of MCA

downloadHyperdense MCA on CT

(Talluri et al, IJCRI 2011)

Results

Percentage of patients with modified Rankin scores of 0-2 (which indicates functional independence) compared to conventional therapy

Thrombectomy Conventional Therapy OR or p value          N
MR CLEAN

32.6%

19.1%

OR= 2.16

500

EXTEND-IA

71%

40%

p= 0.01

70

ESCAPE

53.0%

29.3%

OR= 2.6

316

SWIFT PRIME

60%

35%

p< 0.001

196

REVASCAT

43.7%

28.2%

OR= 2.1

206

Safety Outcomes

Mortality at 90 days

  Thrombectomy Conventional Therapy p value
MR CLEAN

18.9%

18.4%

p= NA (30 day mortality)
EXTEND-IA

9%

20%

p= 0.31
ESCAPE

10.4%

19.0%

p= 0.04
SWIFT PRIME

9%

12%

p= 0.50
REVASCAT

18.4%

15.5%

p= 0.60

Symptomatic intracranial hemorrhage

  Thrombectomy Conventional Therapy p value
MR CLEAN

7.7%

6.4%

p= NA
EXTEND-IA

0%

6%

p= NA
ESCAPE

3.6%

2.7%

p= 0.75
SWIFT PRIME

0%

3%

p= 0.12
REVASCAT

1.9%

1.9%

p= 1.00

Caveats

-all the studies were funded by Covidien

-in MR CLEAN, both thrombectomy and intra-arterial thrombolysis were used; 83.7% had mechanical treatment and 10.3% had intra-arterial thrombolytics given

Bottom line:

These studies suggest that thrombectomy results in improved functional scores compared with IV alteplase alone. The therapeutic window for treatment is longer, up to 6-12 hours. All of the studies but one showed no difference in mortality. Although non-funded studies would be preferable, all the trials seem well done. The next step is likely a meta-analysis combining these studies to see the overall effect.

So, for your next patient in whom you are worried about an acute ischemic stroke, make sure you order a CTA. If there’s a visualized occlusion of the internal carotid artery or M1 or M2 branch of the middle cerebral artery, get neurosurgery or IR on the phone to discuss performing thrombectomy in your patient.

References

-MR CLEAN: N Engl J Med. 2015 Jan 1;372(1):11-20.

-EXTEND-IA: N Engl J Med. 2015 Mar 12;372(11):1009-18

-ESCAPE: N Engl J Med. 2015 Mar 12;372(11):1019-30.

-SWIFT PRIME: N Engl J Med. 2015 Apr 17. [Epub ahead of print]

-REVASCAT: N Engl J Med. 2015 Apr 17. [Epub ahead of print]

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