Stroke Awareness Month: Caring for Ischemic Stroke Patients
- May 2, 2018
- ByMike Lipscomb
Caring for Ischemic Stroke Patients
Medical treatment for stroke patients is ever-changing with new literature and research constantly underway. The American Heart Association and American Stroke Association (AHA/ASA) recently released the 2018 guideline updates, which provide a comprehensive set of recommendations for early management of patients with acute ischemic stroke (AIS).
The new guidelines cover prehospital care, urgent and emergency evaluation and treatment with intravenous and intra-arterial therapies, and in-hospital management.
In honor of Stroke Awareness Month, we’ve highlighted some of the most significant updates relating to emergency medicine providers. This article does not address all topics in the updated guidelines, click here to read the full update.
Pre-Hospital Stroke Management
First aid providers are recommended to use a stroke assessment tool before going to the hospital. EMS personnel should notify the receiving hospital that a suspected stroke patient is in transit so resources are activated prior to arrival.
Patients who present a positive stroke screen or strong suspicion of a stroke should be transferred to the nearest facility capable of providing Tissue Plasminogin Activator (tPA). If there are multiple facilities in the area who are capable of providing tPA, it has not been determined whether it is better for a patient to be taken to a facility that offers a higher level of stroke care and bypass the nearest facility.
For pre-hospital patients with suspected large vessel occlusion (LVO), it is recommended by the Mission: Lifeline Severity-based Stroke Triage Algorithm for EMS to transport the patient to a comprehensive stroke center if travel time is less than 15 minutes compared to the nearest primary stroke center or acute-stroke ready hospital. However, if the travel time is more than 15 minutes, there is not sufficient evidence to recommend a specific threshold of additional travel time to bypass a lesser equipped facility in favor of a primary stroke center.
Hospital Stroke Team
Hospital stroke teams are recommended to establish and utilize a systematized emergency evaluation protocol for suspected stroke patients. Door to needle (DTN) time goals should be established in every facility. The AHA/ASA recommends setting a primary goal of DTN times within 60 minutes in 50 percent or more AIS patients treated with tPA. A new recommendation for 2018 suggests establishing a secondary DTN time goal of 45 minutes in 50 percent or more AIS patients treated with tPA.
To safely increase IV thrombolytic treatment, several multicomponent quality improvement initiatives, such as multidisciplinary teams with access to neurological expertise and ED education, should be in place.
For facilities without in-house imaging expertise, FDA-approved teleradiology systems are recommended for timely review of brain imaging in patients with suspected acute stroke. These FDA approved systems support timely decision making for administration of tPA. With limited availability and distribution of neurological, radiological and neurosurgical consultations, telemedicine resources can ensure appropriate 24/7 coverage and care in a number of different settings.
Evaluation and Management
To promote continuous quality improvement along the spectrum of care, facilities are recommended to use a stroke severity scale, preferably NIHSS during patient evaluation. Stroke scales like NIHSS can be administered rapidly with accuracy and reliability, and have demonstrated value by a broad range of healthcare providers.
Latest recommendations suggest imaging should occur within 20 minutes of arrival for at least 50 percent of all patients who are candidates for mechanical thrombectomy, tPA or both. All admitted patients with suspected AIS should receive brain imaging. In most cases, a noncontract head CT (NCCT) provides enough necessary information for clinical decisions. Because of its cost, a diffusion-weighted MRI is not recommended for routine use, even though it is more sensitive. However, if the CT is negative and the presentation is unclear, an area of restricted diffusion on an MRI may be recommended. Routine MRI is not recommended to exclude cerebral microbleeds before tPA.
A revised recommendation states that there’s insufficient evidence to determine any specific amount of acute CT hypoattenuation extent or severity that affects a patient’s response to tPA. As such, the severity and extent of acute hypoattenuation or early ischemic changes should not be a cause to withhold therapy.
Other new recommendations include:
- CT hyperdense MCA sign should not be used as a criterion to withhold tPA.
- Routine MRI is not recommended to exclude cerebral microbleeds before tPA.
- Multimodal CT and MRI (including perfusion imaging) should not delay the administration tPA.
- For patients who meet the criteria for EVT, it is reasonable to proceed with CTA if indicated in patients with suspected intracranial LVO before obtaining a serum creatinine concentration in patients without a history of renal impairment
- In patients who are potential candidates for mechanical thrombectomy, imaging of the extracranial carotid and vertebral arteries, in addition to the intracranial circulation, is reasonable to provide useful information on patient eligibility and endovascular procedural planning.
- Additional imaging beyond CT and CTA or MRI and magnetic resonance angiography (MRA) such as perfusion studies for selecting patients for mechanical thrombectomy in less than 6 hours is not recommended.
- In selected patients with AIS within 6 to 24 hours of last known normal who have LVO in the anterior circulation, obtaining CTP, DW-MRI, or MRI perfusion is recommended to aid in patient selection for mechanical thrombectomy, but only when imaging and other eligibility criteria from RCTs showing benefit are being strictly applied in selecting patients for mechanical thrombectomy.
According to the updated guidelines, the only serum test that must precede tPA administration is a blood glucose assessment. Additionally, a baseline ECG is recommended for patients presenting with AIS. However, this assessment should not delay the initiation of tPA. It is unclear whether chest x-rays for patients with a suspected stroke and no history of cardiac or pulmonary disease are beneficial. If x-rays are taken, it should not delay administering tPA.
While only a few new recommendations are included in this category, those left unchanged or revised are important for emergency medicine providers to follow.
- Supplemental oxygen should be provided to maintain oxygen saturation greater than 94 percent, otherwise, it is not recommended in nonhypoxic patients with AIS. Only when caused by air embolization is hyperbaric oxygen (HBO) recommended for patients with AIS.
- A new recommendation relating to blood pressure suggests hypotension and hypovolemia should be treated to maintain systemic perfusion levels necessary to support organ function. For patients eligible for tPA, a blood pressure of less than or equal to 185/110 mm Hg is reasonable. The same blood pressure goal applies for patients where intra-arterial therapy is planned.
- Although it is a promising neuroprotective strategy, the benefit for treating patients with AIS with hypothermia has not been proven. Inducing hypothermia in patients with AIS should only be performed during clinical trials. However, patients that present with hyperthermia should be identified and carefully treated with antipyretic medications to lower temperature.
- Hypoglycemia (less than 60 mg/dL) should be treated in AIS patients. Hyperglycemia present in the first 24-hours after AIS is associated with negative outcomes and should be treated to achieve blood glucose levels from 140 to 80 mg/dL. Providers should closely monitor these levels to prevent hypoglycemia in patients with AIS.
IV Alteplase (tPA) & Other Agents
There are several new recommendations for 2018 regarding tPA. These include:
- For eligible patients with mild stroke presenting in the 3-hour to 4.5-hour window, treatment with tPA may be reasonable. Treatment risks should be weighed against possible benefits.
- Ineligible patients who have previously demonstrated a small number (1–10) of CMBs on MRI, administration of tPA is reasonable. If greater than 10, benefits of treatment are uncertain.
- For adult patients with AIS and sickle cell, administering tPA can be beneficial.
- Abciximab should not be administered concurrently with tPA.
- The risk of antithrombotic therapy within the first 24 hours after tPA (with or without EVT) is uncertain. Use might be considered in the presence of concomitant conditions for which such treatment given in the absence of tPA is known to provide substantial benefit or withholding such treatment is known to cause substantial risk.
- Tenecteplase 0.4-mg/kg single IV bolus can be considered an alternative to tPA for patients with minor neurological impairment and no major intracranial occlusion. It has not presented to be superior or noninferior to tPA.
Mechanical Thrombectomy is a common procedure for AIS patients. Patients should receive mechanical thrombectomy with a stent retriever if all of the following criteria are met:
- Prestroke mRS (modified Rankin Scale) of zero to one
- Causative occlusion of the internal carotid artery or MCA segment 1 (M1)
- Greater than or equal to 18-years old
- NIHSS score is greater than or equal to six
- ASPECTS greater than or equal to six (0-10 with higher number indicating more viable brain tissue)
- Treatment can be initiated within six hours of symptom onset
The use of stent retrievers in mechanical thrombectomy may also be reasonable for patients with AIS whose treatment can be initiated within six hours of symptoms beginning, who have MCA segment two (M2) or three (M3) occlusion, anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries. However, in these cases the benefits are uncertain.
Two new mechanical thrombectomy guidelines address DAWN and DEFUSE 3 eligibility criteria. Select patients, who meet DAWN or DEFUSE 3 eligibility criteria, with AIS within six to 16-hours of last known normal and LVO are recommended for mechanical thrombectomy. Mechanical thrombectomy is also reasonable in select patients with AIS within six to 24-hours of last known normal and LVO who meet other DAWN criteria.
Stent retrievers are preferred over the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) device for mechanical thrombectomy. Some other devices may be reasonable depending on the circumstances including salvage therapy with intra-arterial thrombolysis.
In all patients who undergo a mechanical thrombectomy, the blood pressure goal is to maintain less than or equal to 180/105 mm Hg during, and 24-hours after, the procedure.
Antiplatelet Medications & Anticoagulants
Aspirin is the most common antiplatelet medication and is typically recommended for patients with AIS within 24 to 48-hours after onset. Aspirin is generally delayed 24-hours if the patient is treated with tPA, but can be administered in the presence of concomitant conditions. It is not a substitute for tPA or mechanical thrombectomy.
In patients with minor stroke, dual platelet therapy (began within 24-hours) with aspirin and clopidogrel for 21 days can be beneficial for early secondary stroke prevention up to 90-days from symptom onset. For patients with contraindications to aspirin, ticagrelor may be reasonable for acute treatment, however, it is not recommended over aspirin.
The safety and usefulness of several anticoagulants are not well established and further clinical trials are needed. Examples of these include: Factor Xa inhibitors, argatroban, dabigatran, and other thrombin inhibitors and anticoagulation for patients with severe internal carotid artery stenosis or nonocclusive, extracranial intraluminal thrombus.
Up-to-Date Treatments Increase Clinical Quality
Clinical quality is a major focus for hospitals, health systems and provider groups nationwide. With patient outcomes and so many other things dependent on the quality of care received, it is important that providers stay up-to-date with clinical guidelines. Education is one of the easiest ways to ensure all providers are performing at the expected standard of care. At ApolloMD, we provide our team members and hospital partners with educational resources and other tools that encourage top clinical quality performance.