#385 TIA/Stroke for the Hospitalist featuring Dr. Karima Benameur

March 13, 2023 | By Meredith Trubitt

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We’ve got the hard-hitting questions and must-know answers on all things TIA and stroke from neurology expert, Dr. Karima Benameur (Emory University). Topics: TIA and stroke supportive management, indicated workup, and anticoagulation and antiplatelet management pearls for the hospitalist.

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Show Segments 

• Intro, disclaimer, guest bio
• Case 1 from Kashlak; Definitions
• Initial stroke triage, imaging, and assessing for interventions 
• Supportive care for stroke
• Managing patients already on antiplatelet or anticoagulant therapy
• Inpatient stroke workup
• Dual antiplatelet therapy
• Case 2 from Kashlak; Definitions
• TIA workup and management
• Transitions of care: “the invisible deficits”
• Brain health and nutrition
• Guest questions and Picks of the Week*
• Outro

TIA/Stroke for the Hospitalist Pearls 

1. A non-contrast CT head should be obtained immediately for all patients with clinical suspicion of stroke, to both evaluate for stroke and assess appropriateness for potential interventions.
2. If patients present <24 hours of last seen normal, CT angiogram head and neck and CT perfusion should be obtained as well to assess for tPA or thrombectomy candidacy.  If >24 hours, either a CT OR MRI can be used to obtain vessel imaging.
3. Supportive inpatient management includes permissive hypertension for 24-48 hours, avoiding fevers.
4. All patients can be started on 81 mg, with no indications for a loading dose or a double dose if they had a stroke already while on aspirin 81 mg. All patients can be continued on antiplatelets (e.g. aspirin, clopidogrel) and anticoagulation only needs to be held for ischemic strokes if the infarct is large (>⅓ the MCA territory).
5. DAPT with aspirin and clopidogrel is indicated for high risk TIAs and mild-moderate strokes for 3 weeks, as well as all TIAs and non-disabling strokes for 3 months if the patient has severe ICAD. 
6. Initial ischemic stroke and TIA workup for all patients includes brain imaging, vessel imaging, and a cardiac workup to assess for cardioembolic etiology.

TIA/Stroke for the Hospitalist Show Notes

Initial triage, imaging, and assessing for interventions

When any patient presents with positive BE FAST (Balance, Eyes, Face droop, Arm weakness, Speech  – Time to call 911, or stroke alert if inpatient) symptoms, they should receive a rapid evaluation with vital signs, blood sugar and exam before going straight to imaging with a non-contrast CT head. This is because you must rule out a hemorrhagic stroke before considering thrombolytics (Aroor 2017). 

If a patient arrives within the window of potential intervention (<24 hours), patients will also receive emergent vessel imaging with CT angiogram head and neck to assess for large vessel occlusion (LVO), as well as a CT head perfusion to assess for any potentially salvageable tissue (i.e., the core infarct versus the penumbra). Patients must be within 4.5 hours of last seen normal (not the time when deficits were discovered) to be an IV tPA candidate and within 24 hours to be a thrombectomy candidate, however there are multiple other criteria that go into making those decisions as well, such as the amount of salvageable tissue (i.e., the core-penumbra mismatch) seen on CT perfusion (Powers 2019, Greenberg 2022). Contraindications to tPA include hemorrhagic stroke, being on anticoagulation (including DOAC in previous 24 hours or being on warfarin with INR >1.5), a 3-month history of stroke, head trauma, or surgery, or any current active bleed. 

Vessel imaging modalities

If the patient arrives >24 hours from last seen normal, there is no need for emergent vessel imaging, but it will still be part of the inpatient workup(Powers 2019). When deciding between CT and MRI for vessel imaging, Dr. Benameur discusses that there are pros and cons to both modalities. CTA is a quicker exam, is more widely available, has a slightly superior sensitivity/specificity compared to MRA, and is the only modality that has been studied in large RCTs for LVOs. MRA has advantages though as you can obtain it without contrast (i.e., a time-of-flight MRA) which is helpful for CKD patients or patients with a contrast allergy. It also has an advantage in that you can obtain MRA vessel wall imaging if you’re evaluating for vasculitis as a potential etiology of the stroke. 

When to get a MRI brain

Dr. Benameur thinks about the MRI brain in practical terms. If the patient’s symptoms match what is demonstrated on CT, a MRI will likely not further change management and she does not usually recommend it. However, if the CT does not fully explain the patient’s presentations, an MRI is very helpful, and its multiple phases provide clinicians with lots of information. For example, diffusion imaging is the most sensitive modality for acute ischemia and can detect an acute infarct not demonstrated on CT. 

Inpatient management 

Supportive Care

In addition to routine inpatient care, supportive stroke management includes:

• Permissive hypertension: this allows for maximum cerebral perfusion to the penumbra. The duration should be 24-48 hours after the patient’s onset of symptoms (not the discovery of the stroke on imaging (Powers 2019). Contraindications include hemorrhagic stroke or end organ damage from hypertension. Dr. Benameur adds the caveat that if the patient is having stuttering symptoms, you can allow permissive hypertension for up to 5 days.
• Fevers: animal models show that fevers are deleterious to an injured brain from trauma or stroke. Thus, normothermia is favored. If a post-stroke patient develops a fever, a thorough infectious workup is warranted given high prevalence of UTIs and pneumonias (especially aspiration pneumonia given potential post-stroke dysphagia) in this population. If the infectious workup is unrevealing, consider central fever as a result of the stroke (Powers 2019).
• DVT Prophylaxis:  the original version of this episode mischaracterized the recommendation for chemical DVT prophylaxis in acute stroke. The guidelines give prophylaxis with UFH or LMWH a IIb rating because trials showed chemoprophylaxis lowered risk of VTE, but also increased risk for ICH and extracranial bleeding. The guidelines note while chemical prophylaxis may benefit a subgroup of patients, we lack prediction tools to identify them (Powers 2019).

Managing patients already on antiplatelet or anticoagulant therapy

Aspirin can be started immediately upon patient arrival if a stroke is suspected, with no need to delay for imaging confirmation, and quality metrics measure whether aspirin is started within 24-48 hours of presentation. The dose of aspirin is 81 mg daily, unless the patient has atrial fibrillation and is not an anticoagulation candidate, in which case you can use aspirin 325 mg daily. There is no need for a higher loading dose, or to increase the dose if a patient has a stroke while already on aspirin 81 mg. 

If a patient is already on an antiplatelet agent (e.g. clopidogrel), this can be continued in the setting of an acute ischemic stroke. If a patient is already on an anticoagulant (e.g. a DOAC or warfarin), this potentially should be held based on the size of the ischemic stroke. Per Dr. Benameur, the rule-of-thumb is that if the stroke is a large stroke (>⅓ the size of the MCA territory), the anticoagulation should be held for 10-14 days, regardless of the indication for anticoagulation due to the risk of hemorrhagic conversion, and repeat imaging is sometimes obtained before restarting therapy. Otherwise, the anticoagulation can be continued for smaller strokes. 

Inpatient workup: the 5 stroke etiologies

The TOAST trial (Adams Jr. 1993) organizes strokes into 5 etiologies: cardioembolic, large artery atherosclerosis, small vessel disease, other determined etiology (e.g. vasculitis, dissection, sickle cell disease, etc.), and unknown (i.e. cryptogenic) etiology. Discerning between these etiologies is important as it will dictate therapy – cardioembolic will likely require anticoagulation, whereas large vessel atherosclerosis or small vessel disease will warrant antiplatelet therapy. 

Initial stroke workup for all patients includes brain imaging, vessel imaging, and a cardiac workup to assess for cardioembolic etiology. Cardiac imaging includes TTE with bubble study for all patients, with additional TEE if suspecting embolic etiology or endocarditis based on clinical picture and brain imaging, such as infarcts in multiple vascular territories. Further, if Dr. Beneameur is working up a cryptogenic stroke, she will also recommend a TEE. Cardiac monitoring is also routine, with telemetry while inpatient and an outpatient monitor if a cardioembolic etiology is suspected but no arrhythmia was captured on telemetry (Powers 2019).

Dual antiplatelet therapy

There have been several important trials on dual antiplatelet therapy (DAPT) for ischemic strokes: 

• SAMMPRIS (Chimowitz 2011): demonstrated benefit of aggressive medical management with DAPT with aspirin and clopidogrel  for 90 days and a health coach compared to intracranial stenting for patients with moderate-severe intracranial atherosclerotic disease (ICAD). Dr. Benameur notes that she thinks the health coach also made a big difference here.
• POINT (Johnston 2018) and CHANCE (Wang 2013): demonstrated benefit of DAPT with aspirin and clopidogrel for 3 weeks in patients with high risk TIA (ABCD² ≥ 4) and  mild stroke (NIHSS <5). 

Consider switching a patient from clopidogrel to ticagrelor if there is evidence of clopidogrel resistance, which can be assessed with a lab assay (e.g. PRU). Additionally, Dr. Benameur’s expert opinion is that the reported interaction between clopidogrel and omeprazole is of little clinical significance.

TIA 

TIA was previously defined as transient symptoms lasting <24 hours. However, with the advent of MRI and diffusion imaging, more patients were found to be experiencing transient symptoms with a MRI demonstrating stroke. Subsequently, the definition has shifted from being time-based to tissue-based, and is defined as transient symptoms without infarct seen on MRI. 

The workup for TIA is identical to stroke. Similarly to NIHSS for stroke, the ABCD² score can be used to measure severity of TIA and to guide treatment. High risk TIAs (ABCD² ≥ 4) warrant 3 weeks of DAPT per the POINT (Johnston 2018) and CHANCE (Wang 2013) trials, whereas low risk TIAs should receive aspirin monotherapy. All should have cardiovascular risk factor modification, including hypertension. 

Transitions of care: “The invisible deficits”

Post-stroke cognitive decline and depression are known as “the invisible deficits”. The prevalence of post-stroke cognitive decline is high, with U.S. data showing up to 69%, and cognitive decline post-stroke is the most common overall cause of cognitive decline. Post-stroke depression occurs in about 1/3rd of patients. They impact post-stroke care including medication adherence, lifestyle modification, and returning to their previous lives before stroke and thus, it is recommended that patients receive post-stroke depression screening (Powers 2019).

Brain health and nutrition

Several trials have demonstrated the effect of lifestyle modifications, especially the mediterranean diet, in secondary stroke prevention. The PREDIMED trial (Estruch 2018) demonstrated 30% lower risk of stroke in group randomized to mediterranean diet compared to those randomized to low-fat diet. Dr. Benameur notes that the effect size of aspirin in secondary stroke prevention is 15% and number needed to treat is 154, and that the effect size of the mediterranean diet is 30% and number needed to treat is 60 – lifestyle changes have a bigger impact than our medications, but we don’t do a good enough job counseling patients on lifestyle modifications. 

Dr. Benameur notes that it is important to be culturally cognizant when recommending a “mediterranean diet” and tailoring those nutrition recommendations to their culture. She notes it is also important to counsel on lifestyle modifications in the acute phase while inpatient. Her team performed a feasibility study that demonstrated patients were adherent to lifestyle changes they were counseled on immediately following a stroke for 90 days and were able to achieve lower A1Cs. 

Picks/Recommendations

1. Netflix Series Mo
2. End of January Parties!
3. The beach in LA
4. Instagram account Pattie Gonia – queer and environmental activist

Goal

Listeners will develop a framework to approach the inpatient evaluation and acute management of TIA and stroke.

Learning objectives

After listening to this episode listeners will…

1. Define stroke and TIA, and differentiate between the two.
2. List the 5 etiologies of TIA/stroke.
3. Distinguish appropriate uses of MRI vs CT in evaluation of TIA/stroke.
4. Identify correct dosing of aspirin for TIA/stroke.
5. List duration of DAPT therapy for TIA/stroke.

Disclosures

Dr. Benameur reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation 

Benameur M, Amin M, Trubitt M, Coleman C. “#385 Inpatient Stroke Management”. The Curbsiders Internal Medicine Podcast. https://thecurbsiders.com/episode-list March 13, 2023