9/7/2023 Stroke Warafin AC
1.
You are working in TCC when you get the following page:
“STROKE PAGE: 65 yo male R sided weakness, LKN 30 min ago. To CT then 5R”
The patient is wheeled back from triage and a weight is obtained. It is an ODD day and therefore the EM team performs the NIHSS while the neurology team works on obtaining history, chart review, and collateral.
The patient reports that he was feeling normal until approximately 30 minutes ago when he noticed that he was having trouble moving his right arm when he tried to grab the remote while watching television. He tried to get up but then felt like his right leg was weak too. His wife came down and brought him to the ED. The patient does not know his medications, but his wife tells you that he has high blood pressure and an abnormal heart rhythm, and she gives him all of his medications daily which are Metoprolol, Warfarin and Amlodipine.
The patient is moved into the CT scanner where he is hooked up to the monitor and the following vital signs are obtained:
HR: 90
BP: 175/95
RR: 14
O2 sat: 98% on RA
T: 37 C
A point of care glucose is within normal limits
The ED team performs the NIHSS. The patient receives 2 points for partial right facial paralysis ,2 points for right upper extremity weakness (effort against gravity) and 2 points for right lower extremity weakness (effort against gravity). He receives 1 point for moderate right sided sensory loss in the upper/lower extremity. He receives 1 point for gaze deviation towards the left side.
What are your next steps?
Nursing rapidly obtains an IV in the right antecubital fossa. Labs are sent off while a point of care INR is run at bedside as the patient is on Warfarin. It results at 1.4. The patient undergoes a non-contrast CT head. This is rapidly read by the radiology attending who calls back and reports that there is no intracranial hemorrhage. A repeat blood pressure is unchanged.
What are your next steps?
The patient is consented for TNK. Given that his INR is <1.7 he does not have any exclusion criteria. He is able to understand the risks and benefits and both he and his wife agree that he should receive the treatment. TNK is ordered in Epic (0.25 mg/kg) and pharmacy pulls it form the Pixis. A timeout is performed, and all team members agree on the dose, the patient’s last know well time and agree that the patient should receive TNK. TNK is given.
What are your next steps?
Given that the patient’s NIHSS is greater than 6, he undergoes a CTA head and neck, which does not show a large vessel occlusion. The patient is monitored per protocol in the ED and is admitted to the neurology step down unit.
Wrap Up
This was a case of a left middle cerebral artery ischemic stroke in a patient with atrial fibrillation on Warfarin. This case brings up a few key points for us to consider.
i) Thrombolytics in patients on anticoagulation
This is absolutely essential history that we should ask all patients. Be thorough with your rapid chart review. Use the search feature in Epic and call family for collateral history if this cannot be obtained reliably from the patient. Note that we do not need to wait for the INR or anti-Xa level unless we have reason to believe based on our history, exam or chart review that the patient is taking an anticoagulant or is coagulopathic. However, if we suspect that the patient may be at high risk for bleeding or is taking an anticoagulant, we should make every attempt to expedite INR or anti-Xa level results.
1) Warfarin
Warfarin use alone is not an exclusion for thrombolytics. However, the INR must be <1.7 (cannot be 1.7). Patients with an INR of 1.7 or greater are excluded from receiving thrombolytics. We have a point of care INR that is part of the nursing protocol order set. Regarding thrombectomy, patients with an INR of >3.0 are generally excluded.
2) Direct Oral Anticoagulants (DOACs)
Included in this category are medications such as Apixaban (Eliquis), Rivaroxaban (Xarelto), and Edoxaban (Lixiana) all of which are factor Xa inhibitors and Dabigatran (Pradaxa), which is a direct thrombin inhibitor.
a) Factor Xa inhibitors
For these patients, we utilize the anti-factor Xa level. Patients with a level >0.10 are excluded from thrombolytic therapy based on our protocol. Many institutions will not have a rapidly available anti-Xa level. In this case, patients who have taken a factor Xa inhibitor within the last 48 hours are excluded from receiving thrombolytics. Patients with an anti-Xa level >0.4 are generally excluded from thrombectomy if taking Rivaroxaban or Apixaban. For Edoxaban the cutoff is >0.15.
b) Direct thrombin inhibitors
In patients taking direct thrombin inhibitors, a thrombin time should be sent. If the patient’s thrombin time is <30, they are potentially a thrombolytics candidate. Patients are generally excluded from thrombectomy if their thrombin time is >30 AND the PTT is >70.
3) Heparin products (enoxaparin, fondaparinux, dalteparin, tinzaparin)
Although it is less common for patients to be on heparin products, these are sometimes utilized, particularly in patients with cancer. Enxoaparin (Lovenox) is the most common. Prophylactic dosing of injectable anticoagulants is not an exclusion. However, if the patient has received a dose of an injectable anticoagulant in the past 24 hours (36 hours for patients with moderate or severe renal dysfunction) then they are excluded from receiving lytics. For patients who are on unfractionated heparin (probably less common in the ED), the PTT should be <40 to receive thrombolytics. Interestingly, if the patient would still be within the window then the heparin can be stopped and the PTT rechecked after an hour and if <40 the patient would be eligible for lysis.
Thank you to everyone who participated in this simulation. We appreciate your efforts to learn, improve our team dynamics and make our patients safer.
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