New Guidelines Recommend Use of Endovascular Therapy in Acute Ischemic Stroke
Nearly 800,000 Americans experience a stroke each year (more than 8 in 10 of which are ischemic) and many are left with functional deficits. 71% of stroke survivors have long-term speech deficits, 20% have difficulties walking and 31% need help caring for themselves. These deficits are largely the result of treatment delays primarily caused by the distance to a stroke center, poor understanding of stroke symptoms and the requirement that patients arrive at the emergency department within 4.5 hours of stroke symptom onset to receive the current therapy, tissue plasminogen activator (tPA).
But things are changing. Recent clinical trials evaluating endovascular intervention in the management of acute ischemic stroke show benefit and provide patients with additional options and extended time to receive treatment. The American Heart Association recently released new guidelines detailing recommendations for its use. As a result of these much anticipated guidelines, many comprehensive stroke centers will see a strong increase in the number of endovascular procedures they do. However, they should also expect increasing competition, as primary stroke centers in many markets will want to add these capabilities to their stroke services.
Endovascular Therapy Added to Established Acute Stroke Management
The new guidelines released on June 29 in the journal Stroke build on the 2013 guidelines and incorporate results from 8 additional clinical trials that evaluated the use of endovascular therapy in acute ischemic stroke management. These results are expected to drive increases in the number of endovascular procedures performed for ischemic stroke, and Sg2 expects double-digit growth annually. The guidelines emphasize rapid assessment and early treatment with thrombolytic therapy (tPA). They also elevate the importance of developing stroke care networks to increase access to all interventions. The following are the foundational clinical elements for consideration of endovascular intervention in patients with acute ischemic stroke.
Treat With tPA First. Based on the clinical trial results, which included a limited number of patients who did not first receive tPA, the guidelines recommend that to be considered for endovascular therapy, a patient should first receive intravenous tPA therapy. The guidelines also state that patients who received tPA need not be observed before pursuing endovascular therapy. Finally, it is further recommended that patients who are considered ineligible for tPA treatment may still be considered for endovascular therapy, but need to be carefully selected.
Time to Treatment Remains Critical. The guidelines emphasize that tPA therapy needs to be initiated within 4.5 hours of stroke onset and endovascular therapy before 6 hours and that delays in treatment, even within these time windows, should be avoided. Treatment outside the 6-hour time frame should be used with caution.
Location of Ischemic Occlusion Guides Patient Selection. Evidence supports use of endovascular therapy in cases where the stroke-causing occlusion is in one of two locations: internal carotid artery or proximal location (M1) of the middle cerebral artery (MCA). Other locations such as anterior location, the M2 or M3 location of the MCA, vertebral arteries, basilar artery or posterior cerebral arteries may be reasonable in carefully selected patients, but benefits are still unknown.
Stroke Severity Linked to Demonstrated Outcomes. The guidelines emphasize the importance of stroke severity and the impact the stroke may have on patient function. For patients to be considered for endovascular therapy the guidelines recommend they must have had a higher level of function prior to the onset of the stroke with a prestroke modified Rankin Scale (mRS) score of a 0 or 1. Their National Institutes of Health Stroke Scale (NIHSS) score must be a 6 or greater. Finally, based on the CT scan, the Alberta Stroke Program Early CT score (ASPECTS) must be greater than 6. These parameters help select patients who are likely to see the greatest benefit from endovascular therapy. Patients outside these ranges may be considered for treatment but as with other deviations from the recommendations should be carefully considered because benefits are uncertain.
Consider Functional State Over Age. The guidelines set a lower age limit of 18 years but no upper limit. An upper age limit does not provide value when taken out of context of the patient’s current functional state. An 85-year-old who remains active and independent may still benefit from endovascular intervention when other parameters are met, but a 70-year-old who requires assistance with daily activities and is managing multiple chronic health conditions may not be as likely to realize that same benefit.
2015 Sg2 Forecast Accounts for Positive Clinical Results
Sg2’s 2015 Impact of Change® forecast includes the impact of growing adoption and demand for endovascular intervention for acute ischemic stroke. Study results presented at the International Stroke Conference in Nashville, TN, prompted us to accelerate adoption timings and increase the impact of clinical innovation on the forecast for this procedure. Over the next decade we expect that the number of patients treated with endovascular interventions for acute ischemic stroke will double nationally. Locally, the growth rates may vary significantly based on involvement in clinical trials and currently established baseline volumes. Organizations that have been participating in trials will likely experience dampened growth compared with national projections. Organizations in markets with limited access to endovascular services could see greater growth rates if new services are added to their stroke programs.
Inpatient Forecast: Endovascular Procedures, Ischemic Stroke
|Endovascular Procedure—Cerebral, With and Without tPA||2015||2020||2025||5-Year||10-Year|
Note: Excludes 0–17 age group. Includes Ischemic Stroke CARE Family only. Sources: Impact of Change® v15.0; NIS; Sg2 Analysis, 2015.
Guidelines Expand Importance of Stroke Care Networks
Time to treatment is still critical, even with expanding treatment options. The guideline authors emphasize that a local stroke care network needs to be established. The reality of access to endovascular-capable centers will be a challenge, but a coordinated effort between stroke-ready, primary and comprehensive stroke centers can get patients quickly to tPA treatment and then on to endovascular treatment where appropriate.
Sources: University of Calgary Faculty of Medicine. Understanding Alberta Stroke Program Early CT Score (ASPECTS); Internet Stroke Center. Modified Rankin Scale; HealthCarePoint. NIH Stroke Scale; Powers WJ et al. 2015 AHA/ASA focused update of the 2013 guidelines for the early management of patients with acute ischemic stroke regarding endovascular treatment. Stroke [Published online before print June 29, 2015]. All websites accessed July 10, 2015.