Chapter 11 Flashcards
Which of the following is a recommended risk assessment model for estimating VTE risk
specific to general surgical patients?
A. The modified Caprini risk prediction score
B. The Wells risk prediction score
C. The Padua risk prediction score
D. The PESI risk prediction score
Option A: Correct. The Caprini risk prediction score has been validated to predict risk of VTE and general surgical patients and is recommended for use by the American College of Chest Physicians guidelines for antithrombotic therapy prophylaxis in these patients.
Which VTE prevention strategy is not appropriate for a 61-year-old man undergoing elective hip replacement surgery? The patient weighs 109 kg (240 lb), has an estimated creatinine clearance of 76 mL/min/1.73 m 2 (0.73 mL/s/m 2 ), and has no known contraindications to anticoagulant medications.
A. Warfarin
B. Apixaban
C. Dabigatran
D. Early ambulation combined with graduated compression stockings (GCS)
Option D: Correct. Ambulation with GCS alone (without anticoagulation) is not an effective
option in a patient status post total hip replacement given the high risk of VTE development in
this population.
Which of the following prophylactic strategies is most appropriate for a 65-year-old patient
who is admitted to hospital with left-sided paralysis following an acute hemorrhagic stroke?
A. Early ambulation
B. Intermittent pneumatic compression (IPC)
C. Low-molecular-weight heparin
D. Warfarin
Option B: Correct.
Which of the following anticoagulants would be an appropriate option as single therapy for the
initial acute-phase treatment of a patient diagnosed with an acute lower extremity DVT?
A. Rivaroxaban
B. Dabigatran
C. Edoxaban
D. Warfarin
Option A: Correct. Rivaroxaban and apixaban are the only two oral anticoagulants that have
been approved and shown effective for the initial acute-phase treatment of patients diagnosed
with DVT without the initial use of an injectable anticoagulant.
Which of the following is not an independent risk factor for major bleeding in patients taking
anticoagulants for VTE treatment?
A. Uncontrolled hypertension
B. Concomitant use of aspirin
C. Previous major bleeding
D. Taking a factor Xa inhibitor versus warfarin
Option D: Correct. Taking a factor Xa inhibitor is not associated with an increased bleeding risk
compared to warfarin for treatment of VTE or PE.
Which of the following statements is true regarding drug interactions with the direct oral
anticoagulants in patients with normal renal function:
A. Avoid use of rivaroxaban with combined strong CYP3A4 inhibitors and P-glycoprotein
inhibitors
B. Avoid use of rivaroxaban with combined moderate CYP3A4 inhibitors and P-glycoprotein
inhibitors
C. Avoid use of dabigatran with combined strong CYP3A4 inhibitors and P-glycoprotein
inhibitors
D. Avoid use of dabigatran with combined moderate CYP3A4 inhibitors and P-glycoprotein
inhibitors
Option A: Correct. In patients with normal renal function, avoid concomitant use of rivaroxaban
with strong dual inhibitors of CYP3A4 and P-gp (eg, ketoconazole, ritonavir, erythromycin) and
strong dual inducers of CYP3A4 and P-gp (eg, rifampin, phenytoin, carbamazepine).
Which of the following VKORC1 and CYP2C9 genotype combinations would predict the
lowest warfarin dose requirement to maintain INR between 2 and 3?
A. VKORC1 GG and CYP2C9 1/2
B. VKORC1 AA and CYP2C9 1/1
C. VKORC1 AA and CYP2C9 3/3
D. VKORC1 GG and CYP2C9 2/2
Option C: Correct. VKORC1 genotype GG is likely to have the relatively highest warfarin dose
requirement, with AG middle, and AA requiring relatively lower warfarin doses due to lower
vitamin K epoxide reductase production. The CYP2C9 *1 allele predicts a relatively higher
warfarin dose requirement than the variant *2 and *3 alleles, which result in reduced warfarin
metabolism. Patients who carry two variant alleles of the same gene (ie, CYP2C9 2/2 or 3/3
or VKORC1 AA) are more likely to require less warfarin than a patient who is heterozygous
with a wildtype allele (ie, CYP2C9 1/2, 1/3 and VKORC1 GA).
Which of the following is the most appropriate treatment for a patient with active cancer and a
newly diagnosed acute PE?
A. Enoxaparin SC 1 mg/kg twice daily
B. Fondaparinux SC 2.5 mg daily
C. Dabigatran 150 mg BID
D. Warfarin dose adjusted to achieve an INR goal of 2 to 3
Option A: Correct. Weight-based enoxaparin (1 mg/kg twice daily) is one agent recommended
by American Society of Clinical Oncology guidelines for treatment of DVT or PE in the setting of active cancer.
Which of the following is the most appropriate initial treatment option in a patient with an
acute DVT and a documented history of heparin-induced thrombocytopenia (HIT) 7 months ago
but no history of prior VTE?
A. Clopidogrel
B. Rivaroxaban
C. Dalteparin
D. Warfarin
Option B: Correct. Rivaroxaban, a direct factor Xa inhibitor, is the preferred option in this case
as it would be expected to have low cross-reactivity with antiplatelet antibodies in patients with a previous history of HIT.
Short-term (3-month) duration of anticoagulation should be considered for which of the following patients?
A. A patient with history of two unprovoked proximal DVTs whose prescription drug insurance
prefers warfarin over DOACs
B. A patient with history of one unprovoked bilateral massive PE and antiphospholipid antibody
syndrome who has a low bleeding risk
C. A patient with history of two unprovoked proximal DVTs who has a low bleeding risk
D. A patient with distal DVT provoked by surgery who has a low bleeding risk
Option D: Correct. Extended DVT treatment (> 3 months) is indicated for most patients with
VTE. Three months of therapy is recommended for patients with provoked DVT by transient risk
factors (eg, surgery, trauma), an isolated distal DVT, or patients with high bleeding risk.
A 59-year-old African American man presents to the emergency department (ED) with
shortness of breath and is subsequently diagnosed with pulmonary embolism (PE). He was recently in the hospital (discharged home 1 week ago) for a knee replacement surgery, and he is still walking on crutches. He weighs 162 kg (358 lb; body mass index [BMI] 44 kg/m 2 ).
Medications on admission include aspirin, metoprolol, enalapril, ibuprofen (PRN), and ginseng tablets. He smokes one pack of cigarettes per day and drinks alcoholic beverages three to four times per week. His sister died (age 45) of PE 4 years ago. Which of the following factors most likely predisposed this patient for venous thromboembolism (VTE)?
A. Age, ibuprofen use, smoking, alcohol use
B. Immobility, male sex, obesity, family history
C. Age, African American ancestry, ginseng use, regular alcohol consumption
D. Recent surgery, immobility, age, obesity
Option D: Correct. Recent surgery (orthopedic surgery—knee replacement), immobility related
to his surgery, age over 50 years, and obesity are all risk factors for VTE (DVT/PE; Table 11–1).
A patient had knee replacement surgery 12 days ago. He now presents with a right lower
extremity DVT. He is admitted to the hospital for anticoagulation treatment. Following surgery,
he received enoxaparin 30 mg SC twice daily for 10 days. It was noted that his platelet count
dropped from 390 × 10 3 /mm 3 (390 × 10 9 /L) following the surgery to 160 × 10 3 /mm 3 (160 × 10 9 /L) on the day of discharge. He has no previous history of thromboembolic events. Which of the following treatment options would be the best recommendation in this patient’s case?
A. Unfractionated heparin (UFH) and warfarin should be started now, and the patient should be evaluated for thrombotic thrombocytopenic purpura.
B. Apixaban should be started now, and the patient should be evaluated for thrombotic
thrombocytopenic purpura.
C. Enoxaparin should be continued, and the patient should be evaluated for heparin-induced
thrombocytopenia.
D. Fondaparinux should be started now, and the patient should be evaluated for heparin-induced
thrombocytopenia.
Option D: Correct. Fondaparinux (a synthetic pentasaccharide) has been reported to have a low cross-reactivity rate and can be used in this patient.
A 47-year-old man is being treated with warfarin 5 mg daily for PE diagnosed 6 weeks ago.
Today, he presents to clinic for an INR check and is found to have an INR of 11.7. His CBC is
normal, and he has no complaints or signs/symptoms of bleeding. Which plan is best to manage his INR?
A. Hold his warfarin until INR less than 2 and then resume warfarin at 5 mg daily
B. Give vitamin K 2.5 mg PO and hold his warfarin until INR less than 2, then resume warfarin at 5 mg daily
C. Give vitamin K 2.5 mg IV and hold his warfarin until INR less than 2, then resume warfarin at
5 mg daily
D. Give vitamin K 10 mg IV and admit patient to the hospital until INR less than 2, then resume
warfarin at 5 mg daily
Option B: Correct. Since INR is greater than 10, small dose PO vitamin K is recommended.
A 65-year-old man presents to the emergency department via ambulance for computed
tomography (CT)-verified intracerebral hemorrhage deemed to be life threatening in severity.
The patient has taken rivaroxaban 20 mg daily to prevent stroke in the setting of atrial fibrillation
for the past 3 years. His most recent dose of rivaroxaban was 3 hours prior to emergency room presentation. Which of the following is the best treatment course for this patient?
A. Protamine sulfate
B. Idarucizumab
C. IV vitamin K
D. Andexanet alfa
Option D: Correct. Andexanet alfa is FDA-approved to treat life-threatening bleeding in patients taking rivaroxaban.
A 74-year-old woman presents to the emergency department with first unprovoked lower extremity DVT. She is 64 in (163 cm) tall, weighs 59 kg (130 lb), and has serum creatinine of 1.7 mg/dL (150 µmol/L) (this is her baseline). She will be treated with warfarin indefinitely.
What is the most appropriate dose of enoxaparin for this patient as an outpatient?
A. Enoxaparin 40 mg subcutaneous daily
B. Enoxaparin 60 mg subcutaneous daily
C. Enoxaparin 60 mg subcutaneous Q12 hours
D. Enoxaparin 90 mg subcutaneous daily
Option B: Correct. This patient requires DVT treatment dose enoxaparin with a dose reduction given her CrCl of 27.5 mL/min (0.46 mL/s). VTE treatment dosing for patients with CrCl under 30 mL/min (0.29 mL/s/m 2 ) is 1 mg/kg once daily. Given her weight is 59 kg (130 lb), dosing would be enoxaparin 60 mg subcutaneously every 24 hours.
