AB is a 76 year-old female with a past medical history of hypertension, type 2 diabetes, and obstructive sleep apnea. At her most recent primary care visit, she was diagnosed with atrial fibrillation and is being considered for anticoagulation therapy.
Vitals:
Ht: 5’10”
Wt: 183 lbs
Temp: 98.6 F
BP: 128/76 mmHg
HR: 137 bpm
RR: 18 bpm
SCr: 1.0 mg/dL
O2sat: 98%
Based on her demographics and past medical history, what would be the most appropriate assessment and intervention for AB?
A. Her CHA2DS2-VASc score is 5; Begin apixaban 5mg PO BID
B. Her CHA2DS2-VASc score is 3; Begin apixaban 2.5mg PO BID
C. Her CHA2DS2-VASc score is 1; Begin aspirin 81mg by mouth daily
D. AB is not indicated for anticoagulation therapy
Answer with rationale:
Atrial fibrillation (AFib) is an abnormal heart rhythm described as being irregularly irregular. Having atrial fibrillation increases stroke risk because the atria and ventricles beat irregularly and out of sync. This causes blood to pool in the atria, specifically in the left atrial appendage, which can lead to clot formation and stroke. Lifelong anticoagulation is needed if indicated by the CHA2DS2-VASc scoring system. The score is based on patient demographics (such as age and sex) and past medical history. One point each is assigned for heart failure, hypertension, diabetes, vascular disease, age 65-74, and female. Two points each are assigned for age > or = 75 as well as previous stroke. Anticoagulation is definitely indicated when the score is ≥3 for females and ≥2 for males. Anticoagulation with warfarin is preferred for valvular Afib and anticoagulation with direct oral anticoagulants (DOACs, e.g., dabigatran, rivaroxaban, apixaban, and edoxaban) is preferred for non-valvular Afib.
Answer A is correct. AB has a CHA2DS2-VASc score of 5 (2 points for age ≥75, 1 point for being female, 1 point for hypertension, and 1 point for diabetes. Since she is female and her score is ≥3, she is at high risk of stroke and is indicated for lifelong anticoagulation. Apixaban at 5mg PO BID is the appropriate dose. Patients with two of the following (SCr > or = 1.5 mg/dL, Age > 80 years, Weight < 60kg) should receive 2.5mg PO BID to limit their risk for bleeding. Of note, these dose adjustments using these criteria are only for atrial fibrillation, not VTE treatment.
Answer B is incorrect. This answer choice is incorrect because the ≥2 point cutoff is for males and the patient is female and her score is 5 not 3. This would also be the incorrect apixaban dosage as she doesn't meet criteria for dose reduction.
Answer C is incorrect. This answer choice is incorrect because AB’s CHA2DS2-VASc score is 5. Aspirin therapy would be inappropriate because it is not an anticoagulant and is no longer recommended as an option even in low scores.
Answer D is incorrect. Atrial fibrillation is not always an indication for anticoagulation, but most patients as outlined above would be candidates like AB. If the patient had known falls and/or other reasons for potential high bleeding risk then a risk:benefit assessment would be made to ascertain feasability of long-term anticoagulation. There are no known reasons like these given for AB so she should receive anticoagulation.
Brands/generics covered:
Coumadin (warfarin), Pradaxa (dabigatran), Xarelto (rivaroxaban), Eliquis (apixaban), Savaysa (edoxaban)
NAPLEX content domains covered:
1.C.1
Domain 1: Foundational Knowledge for Pharmacy Practice- C. Pharmaceutical Calculations 1. Patient parameters or laboratory measures
2.A.2
Domain 2: Medication Use Process- A. Prescriptions and medication order interpretation 2. Indications, usage, and dosing regimens
3.C.2
Domain 3: Person-Centered Assessment and Treatment Planning- C. Patient health conditions 2. Appropriateness of therapy