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Stent retrieval devices and time prove beneficial in large vessel occlusions: a synopsis of four recent studies for mechanical retrieval and revascularization.

On the basis of National Institutes of Health estimates, the cost of stroke exceeds $45 billion per year. It is the fifth leading cause of death and one of the leading causes of disability in North America, Europe, and Asia (Higashida et al., 2003; Kochanek, Murphy, Xu, & Arias, 2014). Numerous trials and research have evaluated the efficacy of thrombolytic therapy in acute ischemic stroke (AIS). These trials evaluated intravenous (IV) and intra-arterial (LA) therapy, combinations of both, and mechanical thrombectomy. Mechanical thrombectomy, or the removal of thrombus in patients experiencing AIS, is done through aspiration devices or stent retriever technology (Figure 1, available as Supplemental Digital Content 1 at http://links. In 2013, there were three consecutive trials published in New England Journal of Medicine: Interventional Management of Stroke III, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy, and Local Versus Systemic Thrombolysis for Acute Ischemic Stroke (SYNTHESIS Expansion). These trials failed to show any benefit in the intervention arm compared with the medical arm. However, these trials were limited because they failed to confirm large vessel occlusion (LVO), failed to exclude patients with a large core infarct, had long times to interventional treatments, and used older endovascular (EV) devices. Furthermore, 35%-40% of ischemic strokes are considered LVOs, which are composed of internal carotid artery, middle cerebral artery (MCA), and basilar artery occlusion. The prognoses for these blockages are poor with mortality rates of 53% for internal carotid artery, 27% for MCA, and 80%-90% for basilar artery (Higashida et al., 2003).

With the Food and Drug Administration approval of stent retriever technology in 2012, there is a significant improvement in recanalization rates compared with older devices with regard to LVOs (Fargen et al., 2015). The Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) showed a significant benefit in intervention arm (Berkhemer et al., 2015). This trial corrected many of the mistakes seen in the prior studies: (a) the trial confirmed LVO before randomization, (b) modern thrombectomy devices were used for the entirety of the trial, and (c) most importantly, there was rapid initiation of interventional treatment after confirmation of LVO. Three other trials--(a) Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke (ESCAPE), (b) Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection (EXTEND-IA) trials, and (c) Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke--were halted because of the overwhelming efficacy of arterial thrombectomy over medical therapy in the preliminary analysis performed in response to the results of MR CLEAN.

Summarized below are the clinical outcomes of MR CLEAN, ESCAPE, EXTEND-IA, and Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke (Table 1). As practice guidelines and clinical pathways are developed within an organization, nurses have distinct roles, considerations, and impact on optimal patient outcomes. A brief summary of nursing contributions for the successful implantation is included.

Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands

MR CLEAN was a multicenter prospective randomized trial with blinded assessment at 90 days (Berkhemer et al., 2015). The inclusion criteria were AIS, age greater than 18 years, National Institute of Health Stroke Scale (NIHSS) score of greater than 2, intracranial anterior circulation occlusion confirmed by computed tomography (CT) angiography, and initiation of IA treatment within 6 hours of symptom onset. Five hundred two patients randomized to IA therapy versus usual care. Baseline patient characteristics and time to start altepase from onset of symptoms were similar in both groups. Ninety-seven percent of patients in the interventional arm had stent retrievers used for mechanical thrombectomy.


The interventional group had a substantially higher rate (75%) of vessel recanalization at 24 hours from symptom onset compared with the control group (33%). With regard to patient outcome, 33% of patients in the interventional group had a modified Rankin score (inRS) of <2 (defined as independent) versus 19% for the medical therapy arm. There was no difference in the serious adverse effects between the two groups.


Receiving IA treatment within 6 hours of symptom onset for patients with AIS secondary to proximal arterial occlusion in the anterior circulation is safe and effective. In addition, intervention resulted in a significant increase in functional independence in daily life measured at 3 months without increasing mortality.

Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke

ESCAPE was a randomized, open-label blinded outcome evaluation with use of modern thrombectomy devices (Goyal et al., 2015). Inclusion criteria were similar to MR CLEAN except that EY treatment can be initiated within 60 minutes of non-contrast CT (CCT) and recanalization should be in 90 minutes from CT. Groups were adequately matched at baseline characteristics.


The start time of altepase and randomization was similar between the two groups. Time lapse from onset to first reperfusion was 241 minutes, which is a dramatically lesser time compared with MR CLEAN where onset to groin puncture was 260 minutes. Also remarkable was the time from CT to groin puncture averaging 51 minutes. Regarding patient outcomes, 53% of patients in the interventional group had an mRS < 2 versus 29.3% for the control group. There was a higher risk of death and malignant MCA stroke in the control group.


EV thrombectomy is a safe, highly effective procedure that saves lives and substantially reduces disability when patients are selected carefully and treatment is extremely fast.

Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke


This was another randomized open-label, with-blinded-outcome trial that had similar inclusion criteria as MR CLEAN and ESCAPE trials with 90-minute metric from CT angiography/magnetic resonance angiogram to groin puncture. The control and interventional groups were similarly matched (Saver et al, 2015).


Reperfusion at 24 hours from symptom onset was 82.8% in the intervention group and 40.4% in the control group. The symptom onset time to groin puncture was 184 minutes with a CT-to-groin puncture time of 53 minutes. Patient outcomes again reflected the benefits of rapid treatment with an mRS [less than or equal to] 2 at 90 days--60.2% in the interventional group versus 35.5% for the control group.


In patients with AIS with confirmed LVO, rapid treatment with stent retrievers results in a safe and highly effective method for revascularization and significantly reduces disability in patients at 3 months.

Endovascular Therapy for Ischemic Stroke With Perfusion-Imaging Selection

The purpose of the EXTEND-IA, a randomized trial, is to select patients with the best chance to benefit from reperfusion (Campbell et al., 2015). It compared stent retrievers and IV tissue plasminogen activator (tPA) with IV tPA alone. It had similar inclusion criteria to MR CLEAN with the addition of CT or magnetic resonance imaging perfusion mismatch. A magnetic resonance imaging perfusion mismatch is defined as a core infarct of less than 70 ml with at-risk ischemic tissue greater than 20% in size compared with core infarct. Patients were immediately brought to the interventional laboratory without waiting to assess for tPA failure. The baseline characteristics of the patients in both arms of the trial were similar.


Successful revascularization at 24 hours was 100% in the interventional arm versus 37% in the control arm. The symptom onset to groin puncture time was 210 minutes, and the symptom onset to revascularization time was 248 minutes. Ninety-day mRS for EV intervention was 72% in the intervention group and 39% for the control group. There was also a trend of increased death in the control group, although not statistically significant.


In this population, EV therapy resulted in improved early neurological recovery, improved functional outcome at 3 months, and an excellent safety profile. tPA and stent-retriever thrombectomy should be the standard of care for treatment of LVO, especially if delivered rapidly.

Nursing Roles, Considerations, and Impact

A common element within all of the studies is time. For optimal patient outcomes, the ultimate interdisciplinary team goal is restoration of blood flow after AIS, which is achievable through organizational and regulatory metrics (Lazzaro et al., 2012). Lazzaro et al. (2012) recommend a "door-to-groin puncture" of 60-90 minutes that includes activation of the interventional radiology physicians, technologists, and nursing. As members of the team strive to meet the goal, nurses serve in a timekeeper role and provide constant updates on the throughput process. For an organization to successfully implement the practices outlined in the studies, interdisciplinary leadership must scrutinize each step. Aside from nursing (through leadership and clinical representation), members of the interdisciplinary team should include stroke and interventional physicians, imaging services, laboratory, pharmacy, and emergency medicine. Process methodologies, such as lean, that scrutinize each step of an organization's process, looking for waste and adding value, are proven beneficial to optimize outcomes (Kimsey, 2010; Womack & Jones, 1996).

Clinical nurses must understand inclusion and exclusion criteria for mechanical thrombectomy as well as the physician and organization's adaptations of the criteria. Lazzaro et al. (2012) list medium vessel occlusion to LVO with an NIHSS score of greater than 8 and time since onset of symptoms as key criteria. Exclusion criteria that should be reported to the physician before mechanical thrombectomy include uncontrolled hypertension, platelet counts of less than 30,000, international normalized ratio of greater than 3, glucose of less than 50, or seizure onset. Other exclusion criteria listed are arterial stenosis that hinders safe access to the vessel territory, aortic dissection, and imaging findings (Lazzaro et al., 2012). Rapid and astute nursing assessment and preprocedural screening is paramount in achieving optimal patient outcomes and organizational metrics. Preprocedural screening includes review of contrast, latex, medication, and food allergies; home and hospital medications received; and laboratory and diagnostic imaging results, such as non-CCT and CCT. Assessment parameters comprise an NIHSS (or equivalent) and comprehensive neurological and peripheral vascular systems review. Other roles for nursing during this time frame are patient and family advocacy and education. Reassurance and knowledge of the disease process are obtainable through education and include procedural expectations, medications, activities of daily living, lifestyle changes, and skin changes related to radiation exposure. Discussions with the patient and family about procedural expectations cover preprocedural, intraprocedural, and postprocedural processes and patient goals. Information about medications includes indication, regimen, contraindications, and adverse reactions. Activities of daily living include dysphagia screening before resuming a regular diet and activity limitations immediately after procedure, such as limb restrictions and bathing. The need for rehabilitation is likely before the patient can return to work, exercise, and other routine daily activities. Nurses provide education about lifestyle changes such as quitting smoking, healthy weight and dietary choices, and physical activities such as exercise (National Institutes of Health National Heart Lung and Blood Institute, 2014).


The conclusions of these landmark studies indicate the safety and efficacy of mechanical thrombectomy with stent retrievers for LVO in AIS, if utilized rapidly. The proportion of patients who have a chance for independent life after AIS is substantially increased when patients are provided with a chance of EV intervention in a timely fashion of <6 hours. As key stakeholders, professional nurses have a pivotal role for optimal patient outcomes and obtaining organizational metrics through understanding processes, providing feedback, completing rapid and astute assessments, and initiating patient advocacy with knowledge and education.

Nikhil Mehta, MD, is a Neuro-interventionaI Fellow, University of Texas Southwestern Medical Center, Dallas, TX.

Questions or comments about this article may be directed to Damon Watkins, RN BSN MSN, at damon.watkins@utsouthwestern. edu. He is an RN Clinical Coordinator, Neurosurgical Angiography, University of Texas Southwestern Medical Center, Dallas, TX.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

DOI: 10.1097/JNN.0000000000000164


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TABLE 1. Summarizing Four Recent Trials

                                                  Onset Time to
              Number of      Device Used in       Groin Puncture
Study         Patients        Intervention          (Minutes)

MR CLEAN         500      97% stent retrievers      260
ESCAPE           314      86% stent retrievers      241
SWIFT PRIME      196      100% stent retrievers     184 (213)
EXTEND-IA         70      100% stent retrievers     210 (248)

              Revascularization Rate   Revascularization Rate
                at 24 Hours in the       at 24 Hours in the
Study           Intervention Group         Control Group

MR CLEAN         75% (141/187)             33% (68/207)
ESCAPE           72.4% (113/156)           33% (54/1 64)
SWIFT PRIME      82.8%                     40.4%
EXTEND-IA        86.0%                     37%

                 mRS 0-2,       mRS 0-2,
              Interventional   Control Arm
Study         Arm at 90 Days   at 90 Days

MR CLEAN          33%             19%
ESCAPE            53%             29%
SWIFT PRIME       60.2%           35.5%
EXTEND-IA         71.0%           40.0%

Note. mRS = modified Rankin score; MR CLEAN = Multicenter Randomized
Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in
the Netherlands; ESCAPE = Endovascular Treatment for Small Core and
Proximal Occlusion Ischemic Stroke; SWIFT PRIME = Solitaire FR With
the Intention for Thrombectomy as Primary Endovascular Treatment for
Acute Ischemic Stroke; EXTEND-IA = Endovascular Therapy for Ischemic
Stroke with Perfusion-Imaging Selection.
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Title Annotation:Executive Summary
Author:Mehta, Nikhil; Watkins, Damon
Publication:Journal of Neuroscience Nursing
Date:Oct 1, 2015
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