IMS 3 article

Endovascular Therapy after Intravenous
t-PA versus t-PA Alone for Stroke
Joseph P. Broderick, M.D., Yuko Y. Palesch, Ph.D., Andrew M. Demchuk, M.D., et al NEJM 2013

 

BACKGROUND
Endovascular therapy is increasingly used after the administration of intravenous tissue
plasminogen activator (t-PA) for patients with moderate-to-severe acute ischemic
stroke, but whether a combined approach is more effective than intravenous t-PA
alone is uncertain.
METHODS
We randomly assigned eligible patients who had received intravenous t-PA within
3 hours after symptom onset to receive additional endovascular therapy or intravenous
t-PA alone, in a 2:1 ratio. The primary outcome measure was a modified
Rankin scale score of 2 or less (indicating functional independence) at 90 days
(scores range from 0 to 6, with higher scores indicating greater disability).
RESULTS
The study was stopped early because of futility after 656 participants had undergone
randomization (434 patients to endovascular therapy and 222 to intravenous t-PA
alone). The proportion of participants with a modified Rankin score of 2 or less at
90 days did not differ significantly according to treatment (40.8% with endovascular
therapy and 38.7% with intravenous t-PA; absolute adjusted difference, 1.5 percentage
points; 95% confidence interval [CI], −6.1 to 9.1, with adjustment for the National
Institutes of Health Stroke Scale [NIHSS] score [8–19, indicating moderately severe
stroke, or ≥20, indicating severe stroke]), nor were there significant differences for
the predefined subgroups of patients with an NIHSS score of 20 or higher (6.8
percentage points; 95% CI, −4.4 to 18.1) and those with a score of 19 or lower (−1.0
percentage point; 95% CI, −10.8 to 8.8). Findings in the endovascular-therapy and
intravenous t-PA groups were similar for mortality at 90 days (19.1% and 21.6%, respectively;
P = 0.52) and the proportion of patients with symptomatic intracerebral hemorrhage
within 30 hours after initiation of t-PA (6.2% and 5.9%, respectively; P = 0.83).
CONCLUSIONS
The trial showed similar safety outcomes and no significant difference in functional
independence with endovascular therapy after intravenous t-PA, as compared with
intravenous t-PA alone. (Funded by the National Institutes of Health and others;
ClinicalTrials.gov number, NCT00359424.)

 

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There's a lot of issues with the studies:

IMS III:

1) IMS III only included patients that arrived in <3 hours and could get IV tPA.

2) Patients that are not candidates for IV tPA (recent surgery, coumadin, etc) undergo endovascular mechanical thrombectomy.

3) 5197 patients were screened for IMS III, but only 656 patients randomized, which typically means the confined scope of a PRCT does not generalize to the real world.

4) For most of IMS III, noncontrast CT was the only imaging (CTA was only added later) which means there were likely a significant number of patients withOUT an occlusion that were randomized in the study (in the Ciccone study, 10% of patients did not have an occlusion!).

5) IMS III included a hodge-podge of endovascular treatments including EKOS, which no one uses, and IA tPA, which is rarely used now that we have mechanical thrombectomy devices.

6) The study was halted because of futility, thus the number of patients studied was not enough for the study to be adequately powered to demonstrate a difference.

7) IMS III was a comparison of IV tPA versus IV tPA plus endovascular therapy. What the study shows is maybe IV tPA is our best treatment. However, the way we practice, and most high-volume stroke centers are the same, is we give IV tPA to eligible candidates and only perform endovascular therapy in patients that are not eligible for IV tPA, or who receive IV tPA and the IV tPA does not work.

8)  Current devices in past year are much more effective and current protocols stress earlier door to needle.