The Interventional Management of Stroke II (IMS II) trial supports a promising new treatment for victims of ischemic stroke. The trial demonstrated that intra-arterial (IA) drug delivery combined with more traditional intravenous (IV) approach results in a trend toward better outcomes than treatment with IV alone in ischemic stroke patients. The EKOS^® NeuroWave^TM Catheter was used in 41% of the patients in the 73 patient trial to deliver the thrombolytic drugs directly to the clot. The principal investigators of the trial were Joseph Broderick M.D. and Thomas Tomsick M.D. of the University of Cincinnati.

Higher Rate of Reopening of Blocked Brain Arteries

The IMS II study demonstrated a higher rate of reopening of the blocked brain arteries than Phase I of the IMS study, which did not use ultrasound catheters for patients treated with the IV/IA approach (69% in IMS II vs. 55.6% in IMS I).

Patients More Independent at Three Months

IMS II showed that the likelihood of patients to be independent at three months – a key measure of stroke recovery – was 1.65-fold higher than that of patients of similar age and stroke severity who were treated with IV alone in the benchmark NIH/NINDS t-PA Stroke Trial. Mortality rates were identical in both studies (16%) despite a difference in symptomatic intracranial hemorrhage rate (11% in IMS II vs. 6.3% in IMS I). 

Phase III Trial Upcoming

As a result of the positive findings of IMS II, NIH will commence a 40-center Phase III trial later this year to further study the efficacy of combined IA and IV treatment for ischemic stroke using the EKOS^® NeuroWave^TM Catheter.  

Additional Information About IMS II

IMS II follows the IMS I trial, which had the same parameters (patient selection, drug dosage and timing, and centers). However, IMS II utilized the EKOS^® NeuroWave^TM Catheter, while IMS I utilized non-ultrasound microcatheter technology. 

• In the IMS II trial, the EKOS^® NeuroWave^TM Catheter was used whenever possible to deliver low-energy ultrasound as well as Activase^® (recombinant tissue plasminogen activator [rt-PA]) at the site of the clot blocking the artery.
• 60% of the patients in the trial who received IA rt-PA had the drug delivered using the EKOS^® microcatheter^TM.
• 73 patients were enrolled into the IMS II trial with a media baseline NIHSS score of 19, indicating very severe stroke. These are the most severe stroke patients and generally have the most risk for a poor outcome even with the standard treatment.
• The median time-to-initiation of IV rt-PA was 141 minutes.

About Ischemic Stroke

An ischemic stroke refers to a blockage of a blood vessel and is caused by lack of blood flow and oxygen to the brain tissue. If the blockage lasts long enough, brain cells die and a stroke results.  Ischemic strokes account for nearly 88 percent of all strokes. 

Ischemic stroke is further divided into thrombotic stroke, where complete occlusion, or blockage, develops at the site of an atherosclerotic lesion (plaque build-up in the walls of a blood vessel), or embolic stroke, where the developing thrombus (blood clot) dislodges from the lesion and travels downstream to cause an occlusion elsewhere in the vasculature.  Thrombotic stroke accounts for more than 50 percent of all ischemic strokes. 

Treatments available for ischemic stroke

Ischemic strokes are caused by blood clots that block normal flow in brain blood vessels. If a person can be treated within three hours of the first symptoms, he or she may benefit from the intravenous (IV) administration of a clot-dissolving substance called tPA. It has been shown that the chances of complete or a near-complete recovery improve when tPA is used soon enough on the correct type of stroke.

Findings of a recent trial co-sponsored by the National Institutes of Health –Interventional Management of Stroke (IMS) II – demonstrated the feasibility and safety of a combined IV and intra-arterial (IA) approach to reopening blocked brain arteries in patients with ischemic stroke.  Based on the positive results, a 40-center randomized trial, also co-sponsored by the NIH, will commence later this year to further investigate the efficacy of a combined IV and IA approach compared to the standard IV approach for the treatment of ischemic stroke patients.

If a stroke is caused by accumulated plaque in the neck, the patient may need surgery (carotid endarterectomy) or stenting to open it.  If the plaque is in the brain, then the patient is placed on medical management such as an antiplatelet or an anticoagulant.  Plaque buildup in the brain is known as Intracranial Atherosclerotic Disease.