#290 Stroke and TIA Triple Distilled

August 18, 2021 | By Matthew Watto, MD

Enjoy this rapid clinical overview of afib (atrial fibrillation) based on Curbsiders episode #164 with Neurologist Dr. Chris Favilla! 

This mini episode is not available for CME, but episode #164 on Stroke and TIA is available for CME credit through the ACP!

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Credits

• Written, Produced, and Hosted by: Matthew Watto MD, FACP; Paul Williams MD, FACP; Beth Garbitelli

Editor: Matthew Watto MD (written materials); Clair Morgan of nodderly.co

Sponsor: Ten Thousand tenthousand.cc

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Show Segments

• Intro, disclaimer, guest bio
• Afib prevention
• Workup for afib
• Treatment of afib
• Updates on ablation, Left atrial appendage occlusion
• Outro

Episode #164 Stroke and TIA

Featuring Dr. Chris Favilla, production by Molly Heublein, and Graphic by Matt Watto

Sizing things up

• High risk if multiple recent events referable to the same territory, elevated ABCD2 score, or prior stroke on MRI.
• A TIA manifests as focal neurologic symptoms with quick onset to maximal intensity.  Dr. Favilla notes that vague, diffuse confusion or bilateral symptoms are rarely TIA. (expert tip)
• Correlate imaging with presentation (ie: localize the lesion, think about if the symptoms fit the finding). 

TIA/Stroke Workup 

Dr. Favilla considers the heart, blood, vessels, and brain parenchyma when evaluating the patient with stroke. Below are the tests he recommends for each site (see figure):

• Parenchyma: CT head w/o for bleeding, MRI brain w/o for parenchyma
• Blood: CBC, lipids, A1C. 
• Vessels: Carotid US (anterior circulation only); MRA or CTA w/contrast (anterior and posterior circulation). 
  • Note: CT or MR angiography may be used in the acute ischemic stroke (symptoms <24 hours) to evaluate who may benefit from thrombectomy, but was not discussed with Dr. Favilla (Dynamed 2021).
• Heart: ECG, Echocardiogram, Cardiac monitor. 
  • Note: Shorter duration appropriate for cryptogenic stroke in young patients w/o risk factors for atrial fibrillation, but extended (≥28 days) monitoring recommended otherwise (expert opinion).
• Bubble study: Consider if young with cryptogenic stroke (Collado 2018). PFO is common. Thus, avoid for those with clear risk factors for TIA/stroke and those over 60 years old. Otherwise, we risk overdiagnosis.
• Syphilis testing should be based on risk (expert opinion). 
• Thrombophilia workup can be omitted for most. Might pursue if young with unexplained thrombosis, or family history of clotting (expert opinion). 

Classification of TIA/Stroke

• TOAST trial (Adams 1993): Cardioembolic, small vessel (lacunar), large vessel (carotid or intracranial), cryptogenic (no etiology identified up to 30% of strokes after significant eval —Dynamed 2021), or other drug-induced, carotid dissection). 
• ESUS (embolic stroke of unknown source) is a subgroup of cryptogenic stroke. It’s diagnosed when neuroimaging suggests an embolic source (e.g. bilateral and multiple infarcts), but no clear etiology is found.  
• Do not indiscriminately start anticoagulation for ESUS. Anticoagulation has an increased risk of harm (bleeding, ICH) without proven benefit over aspirin (Dr. Leep Hunderfund, ACP IMM 2021). Further, afib is probably the etiology of ESUS in a minority of cases. Other sources include paradoxical embolism (PFO), and unstable carotid or aortic plaques Tsivgoulis, 2019.

TIA and Stroke Treatment

• Treat lipids: The SPARCL Investigators 2006 treated patients with atorvastatin 80 mg. Achieving an LDL of 70 reduced the risk of stroke. However, Dr. Favilla suggests there might be less benefit from aggressive lipid control if another etiology for the stroke is found (ie afib). In these cases, it’s okay not to push high-dose statins.
• Antiplatelet monotherapy: Dr. Favilla is not convinced that one antiplatelet is best (aspirin vs aspirin/dipyridamole vs clopidogrel). The CAPRIE study (Creager 1998) showed slight benefit of clopidogrel over aspirin. That said, this needs to be balanced with the higher cost and inconvenience of clopidogrel requiring a prescription.
• Dual antiplatelet therapy: POINT trial (Johnston 2018) looked at an international population of patients with minor stroke or TIA. Patients were treated with aspirin plus clopidogrel (with loading dose) started within the first 24 hours of symptoms and continuing for 3 months. There was a reduction in stroke and a slight increase in hemorrhage. The CHANCE trial (Wang 2013) had shown the same results in a Chinese population. Dual antiplatelet therapy provides a front-loaded benefit so Dr. Favilla suggests the adoption of 21-day dual treatment followed by aspirin monotherapy thereafter (expert opinion).
• DOACs: The DOACs (Rivaroxaban, apixaban, dabigatran) are noninferior to warfarin in afib for stroke prevention. Apixaban versus warfarin was the only DOAC to demonstrate superiority and improved mortality (Saraiva 2018).

Minor Stroke + TIA Treatment by Classification

Below are the recommended treatments for minor stroke or TIA based on type (Source: slides by Dr. Leep Hunderfund, ACP IMM 2021)

• Cardioembolic due to afib: anticoagulation
• Extracranial carotid stenosis: 
  • ASA monotherapy before and after CEA
  • DAPT before and for 30 days after stenting
• Intracranial carotid stenosis: DAPT for 90 days than single-agent therapy
• Small vessel disease or cryptogenic: DAPT for 21 days then single-agent therapy
• Do not start anticoagulation for ESUS due to increased harm (bleeding, ICH) without proven benefit of anticoagulation over aspirin –Dr. Leep Hunderfund, ACP IMM 2021; Tsivgoulis, 2019. 

Goal

Listeners will the key concepts and clinical pearls from past Curbsiders episodes on stroke and TIA

Learning objectives

After listening to this episode listeners will…  

1. Classify stroke and recommend appropriate long term therapy
2. Develop a framework to risk stratify and evaluate the patient with stroke or tia

Disclosures

The Curbsiders report no relevant financial disclosures. 

Citation

Watto MF, Williams PN, Garbitelli B. “#290 Stroke and TIA Triple Distilled”. The Curbsiders Internal Medicine Podcast. http://thecurbsiders.com/episode-list Final publishing date August 18, 2021.