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Stroke treatment to widen time window to 8 hours
How many times have you carefully assessed a stroke patient in your ED to determine time of symptom onset, only to find out that this individual is not eligible to receive thrombolytics? New treatment options on the horizon will give you other potentially lifesaving interventions for these patients.
Catheter-based treatments for acute ischemic stroke, such as local thromboplasty and angioplasty, have been shown in small studies to be safe, feasible, and efficacious, says Lauren Brandt, RN, MSN, CNRN, clinical director of the Neurosciences, Brain, & Spine Center at Brackenridge Hospital in Austin, TX.1,2
When researchers tracked long-term outcomes of 16 stroke patients who were ineligible for thrombolytics and underwent catheter-based treatments, they found the patients had significantly improved.1
"Although there need to be additional large scale studies done to confirm this, it opens up another option to the patient experiencing an ischemic stroke," says Brandt.
Currently, the only treatment approved by the Food and Drug Administration (FDA) for acute ischemic stroke is the administration of intravenous (IV) tPA within three hours of symptom onset, but only 2%-4% of patients are eligible for this intervention. "Many limitations, including the patient’s delay in reaching the ED and potential risk of bleeding, make patients ineligible for this life-saving drug," says Dawn K. Beland, RN, MSN, CCRN, CS, CNRN, stroke center coordinator at the Stroke Center at Hartford (CT) Hospital.
Time limitations for treatment is the primary reason why less than 5% of ischemic stroke patients are being treated with standard IV thrombolysis, according to Brandt. As the catheter-based treatment options become available, the number of patients who can receive life-saving treatment in the ED will increase dramatically, she predicts.
As an ED nurse, you play a pivotal role not only in recognizing stroke symptoms, but also in determining whether this patient is treated or not, emphasizes Brandt. "The ED nurse is in a unique position to impact care of the stroke patient population," she says.
You must be knowledgeable of what other options are available and what the criteria for those options are, says Brandt. "As these options are continually being refined and changed, review or update of protocols will be necessary," she adds.
New options on the way
For patients with a middle cerebral artery occlusion noted on computed tomography angiogram, promising results are being seen from device trials or catheter-based treatments, says Beland.
Beland’s ED participated in the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial. The MERCI device (developed by Mountain View, CA-based Concentric Medical) is a helical-shaped coil that ensnares the clot, removing it through a catheter in the femoral artery. A proximal balloon catheter situated in the femoral artery is inflated as the clot is being removed to prevent normal blood flow from fragmenting the snared clot.
All patients who were treated with the device originated in the ED, since treatment needs to be done within eight hours of symptom onset, says Beland. "The sooner the cerebral vessels are opened, the smaller the stroke will be, hopefully translating to decreased dependency and death," she says.
Results for 114 patients treated in 20 centers showed a 53.2% success rate for reopening of the occluded blood vessel.3
Since the MERCI device can be offered up to eight hours from symptom onset with less risk for bleeding, more patients were eligible for this treatment than for thrombolytics.
"One drawback to this device is that it requires highly specialized physicians and imaging techniques in order to use it effectively, making it less than accessible to small, rural communities," notes Beland. "This is one of many reasons why smaller hospitals are partnering with larger regional stroke centers for rapid transport and care of acute ischemic stroke patients."
Overall, the success rate of IV tPA administration has been reported to be between 15%-33% while the preliminary results of the MERCI trial have shown a 56% success rate for clot retrieval, reports Beland. "As we wait for the FDA ruling on this new device, a second trial is under way, named Multi-MERCI," she says.
The Multi-MERCI trial is using the same device with and without additional procedures such as IA tPA, angioplasty, or stenting if needed. "Employing a variety of options is often necessary in patients with significant cerebrovascular disease," says Beland.
The current study is expected to take less than a year to complete, with several months for data analysis, and it then can go through the FDA approval process. "So if everything goes well, we’re looking at 18 to 24 months before the device becomes only the second FDA-approved treatment for acute ischemic stroke," says Beland. "We are very excited about this."
1. Ramee SR, Subramanian R, Felberg RA, et al. Catheter-based treatment for patients with acute ischemic stroke ineligible for intravenous thrombolysis. Stroke 2004; 35:109-111.
2. Nesbit C, Luh G, Tien R, et al. New and future endovascular treatment strategies for acute ischemic stroke. J Vascular Interventional Radiology 2004; 15:S103-S110.
3. Duckwiler G. An overview of the device design and clinical results for the MERCI stroke treatment system. Endovascular Today 2004; 69-71.
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