Time is Tissue: Intraarterial Treatment for Acute Ischemic Stroke

Ellie Kamarjian, PharmD Candidate 2015 Mercer University College of Pharmacy 

According to the American Heart Association and American Stroke Association (AHA/ASA), the first line therapy in patients that present with confirmed acute ischemic stroke should be intravenous fibrinolytics such as alteplase within 4.5 hours after symptom onset.1 The effectiveness and safety of additional treatments such as the use of intraarterial therapy has conflicting evidence to support its use.

A Randomized Trial of Intraarterial Treatment for Acute Ischemic Stroke 2
Design A pragmatic, phase III, multicenter clinical trial with randomized treatment-group assignments, open-label treatment, and blinded end point evaluation
Objective To assess whether intraarterial treatment plus usual care would be more effective than usual care alone in patients with a proximal arterial occlusion in the anterior cerebral circulation that could be treated intraarterially within 6 hours after symptom onset.
Study groups Intraarterial treatment (intraarterial thrombolysis, mechanical treatment, or both) plus usual care (which could include intravenous administration of alteplase) was compared with usual care alone (control group) in patients with acute ischemic stroke and a proximal intracranial arterial occlusion of the anterior circulation that was confirmed on vessel imaging.
Methods Patients were 18 years of age or older (no upper age limit) with acute ischemic stroke caused by an intracranial occlusion in the anterior circulation artery. Initiation of intraarterial treatment had to be possible within 6 hours after stroke onset. Eligible patients had an occlusion of the distal intracranial carotid artery, middle cerebral artery (M1 or M2), or anterior cerebral artery (A1 or A2), established with computed tomographic (CT) angiography (CTA), magnetic resonance angiography (MRA), or digital subtraction angiography (DSA), and a score of 2 or higher on the National Institutes of Health Stroke Scale (NIHSS).

All patients underwent clinical assessment (including determination of the NIHSS score) at baseline, after 24 hours, and at 5 to 7 days or at discharge if earlier. A single experienced trial investigator, who was unaware of the treatment group assignments, conducted the follow-up interviews at 90 days by telephone with the patient, proxy, or health care provider. This interview provided reports for the assessment of the modified Rankin score by reviewers who remained unaware of the treatment-group assignments.

Duration December 2010 to March 2014
Primary Outcome Measure The primary outcome was the score on the modified Rankin scale at 90 days.
Baseline Characteristics The mean age of the 500 study participants was 65 years (range, 23 to 96); 292 participants (58.4%) were men. Risk factors for a poor outcome, clinical risk factors for stroke, and aspects of prerandomization treatment were evenly distributed between the two treatment groups. In total, 233 patients (46.6%) were assigned to the intervention group and 267 patients (53.4%) were assigned to the control group.
Results In total, 233 patients (46.6%) were assigned to the intervention group and 267 patients (53.4%) were assigned to the control group. One patient received intraarterial treatment after being assigned to the control group. Intraarterial treatment was never initiated in 17 patients (7.3%) assigned to the intervention group. The distribution of the primary-outcome scores was an adjusted common odds ratio of 1.67 (95% confidence interval [CI], 1.21 to 2.30). The outcomes in favor of the intervention was consistent for all categories of the modified Rankin scale, except for death. The absolute between-group difference in the proportion of patients who were functionally independent (modified Rankin score, 0 to 2) was 13.5 percentage points (95% CI, 5.9 to 21.2) in favor of the intervention (32.6% vs. 19.1%), with an adjusted odds ratio of 2.16 (95% CI, 1.39 to 3.38).
Adverse Events Common Adverse Events: Not available
Serious Adverse Events: Any serious adverse event in the intervention group 110 (47.2%) versus 113 (42.3%) in the control group
Percentage that Discontinued due to Adverse Evens: Not available
Study Author Conclusions Intraarterial treatment in patients with acute ischemic stroke caused by a proximal intracranial occlusion of the anterior circulation was effective and safe when administered within 6 hours after stroke onset.

The window of opportunity to treat an ischemic stroke is already very narrow and time sensitive. Therefore, the consideration of an additional treatment should be valuable, in addition to safe and effective. Although this study did show a slight increase in functional patient outcome, there’s not enough evidence to show that intraarterial treatment for all ischemic stroke patients is beneficial. Until further, more extensive and inclusive studies can be conducted, it is difficult to make this a practice standard.

References:
1. Jauch EC, Saver JL, Adams HP, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2013; 44(3):870-947.
2. Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015; 372(1):11-20.

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