Endovascular Thrombectomy and Its Role in Ischemic Stroke Treatment

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Introduction

As healthcare professionals, it is our responsibility to be up to date on of all the new medical advancements and treatment options available to our patients; this is no different for stroke care and in this case specifically, ischemic stroke treatment.  

Patients who suffer a stroke due to clotting or blockages typically will have general medical options. For example, medication treatments with IV alteplase (TPA), as well as interventional procedures that include clot removal/retrieval known as Endovascular Thrombectomy (EVT). Are we as caregivers familiar with these newer ischemic stroke treatment procedures beyond the IV infusions of “clot-busters?” These interventional treatments can be done up to 24 hours post-ischemic stroke.  

Nurses are vital in the education of patients and families regarding signs and symptoms of stroke and the options that are offered, as well as knowing contraindications, essential monitoring, and complications.

Stroke Guidelines and Incidence: 

The American Stroke Association (ASA) released updates in 2019 to the “2018 Guidelines for Early Management of Patients with Acute Ischemic Stroke” to reflect new clinical studies. 

The guideline, which is available on the ASA website, enables clinicians to be aware of the best ischemic stroke treatment for improved patient outcomes (1). There are many acute care centers nationwide that are certified by the Joint Commission in Stroke Care that must follow these guidelines. 

Ischemic Stroke Treatment: IV TPA and/or EVT 

IV TPA: 

An IV TPA is given once a hemorrhagic stroke has been ruled out by a CT scan of the head. This infusion is given within 4.5 hours of stroke onset and is standard for most ischemic stroke patients, even if EVT is being considered as an option.  

• The nursing staff should have access to the complete list of contraindications to this medication which include (1):  
• Acute intracranial hemorrhage 
• Recent head trauma 
• Intracranial or spine surgery in the past three months 
•  Recent GI bleed or malignancy 
• The time frame should be as short as possible and is driven by the last time the patient was experienced as normal.  
• IV TPA is given at a rate of 0.9 mg/kg IV, not to exceed a 90 mg total dose. It is preceded by giving a bolus dose of 10% of the total dose over 1 minute and the remainder of the infusion is given over 60 minutes (2). 
• Post– infusion, the patient is admitted to the intensive care unit (ICU) for 24-hour monitoring. The ASA guideline recommends that vital signs, including a neurological assessment. The neuro assessment must be done every 15 minutes during and after TPA for 24 hours. This is followed by vital signs and neurological assessment every 30 minutes for 6 hours, and every 1 hour for 24 hours (2). 
•  Invasive lines (like central and arterial) and urethral catheter insertion should be delayed during immediate and post– TPA administration due to the increased risk of site bleeding (2).

EVT

An EVT is the removal of a thrombus or blood clot under image guidance (4). It is one of the newer ischemic stroke treatment options available to patients.  

EVT evaluation and treatment should be performed as soon as feasibly possible to patients who meet the criteria and are eligible. However, remember that not all acute care facilities have this capability, so urgent transport options may need to be considered as well. 

• The time frame for EVT is recommended to be within 16 and up to 24 hours, in some patients with acute ischemic stroke (4).  
• There are specific imaging criteria that must be met: 
• The occlusion must be located within a larger, more proximal cerebral vessel, usually in the anterior circulation of the brain. (Remember that most of the anterior circulation is fed from the internal carotid artery, which ends in the anterior and middle cerebral artery. Blockage in these vessels can have devastating outcomes) (4).  
• IV TPA and EVT interventions are time sensitive. Processes should be in place to avoid delay from “symptoms to definitive treatment” per ASA guidelines (1).  
• As mentioned, the non-contrast CT scan is done as soon as possible to rule out hemorrhage prior to any treatment with IV clot-dissolving medications or neuro-vascular intervention. 
• A finger-stick blood glucose is recommended prior to TPA IV administration, since glucose abnormalities can mimic stroke, as can other disorders such as drug overdoses, etc. A thorough history and physical examination is crucial, and the patient’s family and/or significant others can provide additional specific vital information.  
• Vital signs (including oxygen saturation) are done along with neurological assessments. 
• Lab work on stroke patients includes cardiac markers for ischemia (ex. troponin) and platelet count. IV TPA is contraindicated in those with platelet count less than 100,000 mm3. PT/INR and aPTT coagulation studies are part of the initial standard of treatment. Alteplase (TPA) is contraindicated with PT greater than 15 sec, INR greater than 1.7 and/or aPTT greater than 40 (1). 

Key Processes: 

• EVT can be done within 6-24 hours, and up to 24 hours after “last known well” time, not from the start of symptoms. Patients who present with symptoms after sleeping can have difficulty in establishing this timeframe.  
• The patient’s Modified Rankin Score (MRS) pre-stroke should be 0-1 (out of 6), meaning a low level of existing disability prior to acute stroke.  
• The CT scan with perfusion or MRI/MRA which shows brain circulation must reveal occlusion of the internal carotid artery or proximal (larger vessel width) middle cerebral artery.  
• EVT is not an acceptable procedure for those under 18 OR for patients with an NIHSS score ≤of 6. (1) 

Potential Complications: 

EVTs are now the most recommended ischemic stroke treatment option for patients. The entire team must be aware of potential intra-procedural and post-procedure complications. Complications should be minimized and effectively treated quickly.  

Unfortunately, there is still approximately a “15% rate of complications with sequelae,“ and these include (3):  

• Groin access site complications or infection 
• Arterial vessel or nerve injury 
• Hematoma   
• Vasospasm 
• Arterial perforation or dissection  
• Device misplacement 
• Rarely symptomatic intracerebral hemorrhage or subarachnoid hemorrhage occurs 
• Embolic formation in the target vessel, or other areas that are listed as a potential complication  

The nursing and neuro team members are key players in monitoring subtle neurological changes, although anesthesia during the procedure can delay post-procedure accuracy. The clinical staff should have unit-based training and education on assessing groin vascular puncture sites, care, and quickly controlling bleeding, assessing labs, and reporting findings in a timely manner. My organization added toe pulse oximetry as an additional tool to assess lower limb perfusion.

Nursing Role Post- Ischemic Stroke Treatment: IV TPA and/or EVT 

For patients who have undergone an ischemic stroke treatment such as IV TPA and/or EVT, it is essential for nurses to frequently check vital signs and perform neurological evaluations, as this can work to ensure positive patient outcomes. Although this task predominately falls under the nursing role, all team members should be trained to recognize any change in signs/symptoms, including our interdisciplinary colleagues (supportive personnel, physical therapist, occupational therapist, and speech therapist, etc.). Here are a few details all nurses should be aware of post- IV TPA and/or EVT.  

• If the patient’s blood pressure is greater than 180 systolic or 105 diastolic, they should be treated with an antihypertensive agent (1). 
•  Labetalol (Trandate) IV or nicardipine (Cardene) IV may be used for blood pressure management. 
• Dysphagia evaluation early in the care of a stroke patient can determine the patient’s choking risk. This is a critical safety step to help prevent any aspiration event.  
• Aspirin is part of the ASA’s ischemic stroke guidelines and is to be given at a dose of 325mg orally or rectally if the patient is NPO and within 48 hours of stroke/transient ischemic attack (TIA) onset.  
• No aspirin is given within 90 minutes up to 24 hours post– IV TPA.

Experience of Regional Stroke Service: Ischemic Stroke Treatment

In 2015, a recognized Stoke Center evaluated 93 cases of EVT procedures. At the time of the study, this organization had an 86% success rate in obtaining cerebral reperfusion of ischemic stroke. The retrospective examination of these cases revealed a 14% failed vessel recanalization, meaning lack of restoration of blood flow in the cerebral artery to the brain. A positive functional outcome was measured by the MRS of equal to or less than 2 (low level of disability) in 55% of studied cases. 

It is hopeful in 2021 that the functional outcome percentage is higher with more experienced stroke centers and a higher volume of procedures. Sadly, this review did reveal 90-day mortality of 22%. It is noted that most cases were received as transfers from outside centers. Again, this proves that timeliness of recognition of ischemic stroke and definitive treatment either within or outside the organization is crucial for improved outcomes, morbidity, and mortality. 

Conclusion

Ischemic stroke treatment options have advanced beyond just medical therapies including IV TPA. The clinical team must recognize EVT as an advanced ischemic stroke treatment that is available in some stroke centers across the country. More importantly, the nurse plays a vital role in assisting the neurological team with obtaining detailed symptom presentation and time frames, as well as frequently monitoring vital and neurological statuses and being cognizant of complications and urgent interventions if needed. 

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