Expanding the Stroke Toolkit: Emerging Interventions in Prehospital, Acute and Rehab Care
With nearly 800,000 Americans experiencing a stroke each year (more than 80% of which are ischemic), stroke remains a leading cause of disability in the US. Total direct medical stroke-related costs are expected to triple from 2012 to 2030. While as many as half of ischemic stroke patients may be eligible for tissue plasminogen activator (tPA) or endovascular interventions, treatment underuse remains an issue due primarily to proximity to designated stroke centers.
With this in mind, it was no surprise that a recent Sg2 member survey reported improving access, timeliness and continuity in stroke care remains top of mind in 2015. When asking survey respondents to share with us their biggest neurosciences accomplishments in 2014, as well as their concerns and plans for this year, initiatives included reduction in door-to-needle time, telestroke, comprehensive stroke center certification, education, and adoption and management of interventional procedures. Endovascular procedures (which in ischemic stroke include mechanical clot removal) were noted as a topic of renewed interest, due in part to the success of recent acute stroke therapy trials presented at the 2015 International Stroke Conference (ISC).
Sg2 joined 4,000+ stroke experts from around the world this February at the ISC, where new evidence supporting endovascular procedures, as well as prehospital and post-acute interventions, was discussed.
Initiating Early Acute Endovascular Treatment
Endovascular revascularization for acute ischemic stroke was the main topic of discussion at the ISC.
Clinical Trial Results
Results from the ESCAPE, EXTEND-IA and SWIFT PRIME trials, and new analyses of the 2014 MR CLEAN trial were presented. Following a period in which acute stroke therapy trials had yielded a dearth of positive results, the overwhelmingly positive outcomes of these studies showed that, with proper emphasis on workflow and careful patient selection, mechanical clot removal can reduce mortality and disability, and increase the rate of functional independence following ischemic stroke.
In MR CLEAN, results indicated that for patients treated within 6 hours of onset, good outcomes (as defined by a Modified Rankin Scale score of 0–2) increased to 1 in 3 patients vs 1 in 5 treated with standard care. In SWIFT PRIME, data show that for every 2.5 patients treated, 1 more patient had a better disability outcome, and 1 more patient for every 4 treated was independent at long-term follow-up. Unsurprisingly, time was a crucial factor: benefit of treatment declined by about 7% for every hour of treatment delay in the MR CLEAN trial.
Additional data from the REVASCAT, THERAPY and THRACE trials presented in April at the European Stroke Organisation Conference support utility of endovascular approaches in acute ischemic stroke.
Placement in the Care Continuum
Although recent endovascular trials have shown overwhelming benefit in the appropriate patient populations, there are still questions about how and where endovascular therapy will fit into the care continuum in relation to tPA. Future research opportunities include improving recovery, reducing time to treatment and minimizing reperfusion injury (for which various neuroprotection strategies such as hypothermia and adjunctive catheter-delivered agents were discussed).
Improving Access and Timeliness Through Prehospital Interventions
The number of tools aimed at increasing early access is growing, with each market evolving differently based upon local resources and needs. Though significant work has been done to reduce door-to-needle time in thrombolysis, onset-to-treatment times have remained a challenge, often because patients don’t arrive to the ED in time.
Mobile Stroke Units
One promising strategy aimed at addressing this is the mobile stroke unit, which cuts prehospital delays by leveraging telemedicine to diagnose stroke and begin tPA treatment in the ambulance. While the model varies slightly among sites, the unit consists of an ambulance outfitted with a CT scanner, a larger-than-normal generator (to keep the CT unit cool) and a mobile telemedicine system through which the diagnosing neurologist can read the CT image and see the patient. Investigators with the University of Saarland in Homburg, Germany (who created the first mobile unit of this kind), the University of Texas Medical School at Houston with Memorial Hermann-Texas Medical Center, and the Cleveland Clinic presented at the conference.
Both US sites are conducting ongoing trials and presented encouraging early results showing feasibility and efficacy in improving treatment times. They noted that hemorrhagic stroke can be treated in the unit and that patients who require endovascular treatment could derive benefit through crucial time savings achieved by proper triage; however, data on financial viability of the model are not yet available.
Other research leveraging telemedicine to improve prehospital care included a pilot feasibility study from the University of Virginia. Results indicate that National Institutes of Health Stroke Scale (NIHSS) scores (a stroke-specific measure of dysfunction at the neurological level) obtained from an ambulance using an iPad-based telestroke system were well-correlated with in-person assessments. This suggests that a mobile telestroke system (using relatively inexpensive off-shelf equipment in this case) is feasible. If successful, this model could speed up processes by starting the initial physician assessment prior to arrival to the ED.
Pursuing Improvements in Stroke Recovery
Though novel acute treatments that have been shown to reduce stroke disability in certain patients are emerging, many patients are still disabled. This stresses the importance of continued research in stroke recovery. One area to watch will be in the field of neuromodulation, for which several groups reported benefit when performed in conjunction with traditional rehabilitation. Studies included vagus nerve stimulation for upper limb recovery and noninvasive brain stimulation techniques (tDCS and rTMS) with speech therapy for poststroke aphasia. While sample sizes were small, future research will include larger multicenter studies to examine the efficacy, safety and feasibility of these therapies.
With advances in prehospital triage and intervention, as well as acute intervention, Sg2 expects to see more patients become eligible for functional rehabilitation, highlighting the future potential for this type of technology.
Implications and Forecast
As organizations continue to work to improve the System of CARE for stroke, access to thrombolytics and advanced treatments (eg, endovascular revascularization) will broaden; however, growth for the latter will be limited to organizations with access to neuroendovascular expertise. While not all organizations will have the volume or resources to provide this, participation in telestroke networks may be a viable option to increase patient access.
Sg2 Senior Analyst Katherine Zentner contributed to this post.
Sources: Sg2 Analysis, 2015; Berkhemer OA et al. N Engl J Med. 2015;372:11–20; Goyal M et al. N Engl J Med. 2015;372:1019–1030; Campbell BC et al. N Engl J Med. 2015;372:1009–1018; Saver JL et al. Int J Stroke. 2015;10:439–448; Hughes S. REVASCAT: More Endovascular Success in Stroke. Medscape. Apr 19, 2015; University of Virginia website; Medscape website; All websites accessed March–April 2015.