VTE/Ischemia Flashcards
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
Answer: A
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.
Option B: Incorrect. The WELLS Criteria is a scoring system to evaluate the Pretest Probability of VTE (DVT or PE).
Option C: Incorrect. The PADUA score is used for VTE risk prediction in hospitalized medical patients.
Option D: Incorrect. PESI is a PE severity index used for risk stratification of pulmonary embolism after the diagnosis has been made.
Which VTE prevention strategy is most appropriate for a 74-year-old female who is undergoing a hip fracture surgery, weighs 84 kg (184 lb), has an estimated creatinine clearance of 58 mL/min (0.97 mL/s), and has no known contraindications to anticoagulant drugs?
A. Warfarin
B. Apixaban
C. Dabigatran
D. Early ambulation combined with graduated compression stockings (GCS)
Answer: A
Option A: Correct. Approved and guideline recommended options for VTE prophylaxis in hip fracture surgery include LMWH, fondaparinux, LDUH, adjusted dose warfarin, and ASA.
Options B and C: Incorrect. Apixaban and Dabigatran have not been evaluated and are not approved for this indication.
Option D: Incorrect. Ambulation with GCS alone (without anticoagulation) is not an effective option.
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
Answer: B
Option A: Incorrect. Early ambulation is not effective in this patient at high risk of VTE.
Option B: Correct.
Options C and D: Incorrect. Anticoagulants are contraindicated given that patient had a hemorrhagic stroke.
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
Answer: A
Option A: Correct. Rivaroxaban and apixaban are the only 2 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.
Options B, C, and D: Incorrect. Dabigatran, edoxaban, and warfarin all require treatment with an injectable anticoagulant first (5–10 days) before transition to the oral anticoagulant.
A patient is diagnosed with Pulmonary Embolism (PE) and is initiated on enoxaparin and warfarin therapy concurrently. How long should enoxaparin and warfarin be overlapped?
A. For at least 3 days and until the INR is greater than 2
B. For at least 5 days and until the INR is greater than 2
C. For 7 days and until the INR is greater than 2
D. Until the INR is greater than 2
**Answer: B
Option A: Incorrect.
Option B: Correct. In patients with acute VTE (DVT and/or PE) who are initiated on injectable anticoagulation and then transitioned to warfarin, therapy has to be overlapped for a minimum of 5 days and until the INR is greater than 2. Given the different t1/2 of the 4 vitamin K dependent clotting factors (II, VII, IX, X), the minimum 5-day overlap will allow for sufficient time for warfarin to reach steady-state and clotting factors to be depleted. In addition, we want the patient to reach therapeutic anticoagulation on warfarin (INR > 2) by the time the injectable anticoagulant is stopped.
Option C: Incorrect.
Option D: Incorrect.
**
The following statement 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
Answer: A
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).
Option B: Incorrect. Use of moderate CYP3A4 inhibitors and P-glycoprotein inhibitors with rivaroxaban is not contraindicated.
Options C and D: Incorrect. Use of dabigatran in patients with normal renal function is contraindicated in patients receiving concomitant use with P-gp inducers (eg, rifampin).
In patients presenting with acute PE, thrombolytic therapy is recommended if:
A. The patient has palpitations and hemoptysis
B. Started within 4 hours of when patient first experiences symptoms
C. The patient appears to be in shock (eg, systolic blood pressure < 90 mm Hg)
D. The patient has elevated D-dimer concentration greater than 1000 ng/mL (mcg/L)
Answer: C
Options A, B, and D: Incorrect. Options A, B, and D are incorrect alone if the patient does not present with shock or hypotension.
Option C: Correct. Thrombolytic therapy should be reserved for patients who present with shock or hypotension. Diagnosis must be objectively confirmed before initiating thrombolytic therapy.
Which of the following is the most appropriate treatment for a pregnant patient (first trimester) with a newly diagnosed acute PE?
A. Enoxaparin SC 1 mg/kg twice daily
B. Fondaparinux SC 2.5 mg daily
C. UFH SC 333 units/kg followed by 250 units/kg twice daily
D. Warfarin dose adjusted to achieve an INR goal of 2 to 3
Answer: A
Option A: Correct. Weight based enoxaparin (1 mg/kg twice daily) does not require monitoring, is more convenient to use throughout pregnancy and is the preferred option for this patient.
Option B: Incorrect. Data with fondaparinux is lacking.
Option C: Incorrect. While UFH could be an option, SC weight based UFH requires close monitoring and dose adjustments, so this is not an ideal treatment option.
Option D: Incorrect. Warfarin is contraindicated in pregnancy (teratogenic).
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
Answer: B
Option A: Incorrect.
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.
Option C: Incorrect.
Option D: Incorrect.
Which of the following statements accurately describes a potential advantage of the direct oral anticoagulants (apixaban, edoxaban, dabigatran, rivaroxaban) over warfarin in the treatment of VTE?
A. More patients can tolerate the direct oral anticoagulants than warfarin.
B. Adherence with direct oral anticoagulants is 20%–30% better than adherence to warfarin.
C. When bleeding occurs, direct oral anticoagulants are more easily reversed than warfarin.
D. The onset of anticoagulant activity is more rapid with direct oral anticoagulants when compared to warfarin.
Answer: D
Options A, B, and C: These are incorrect or lack evidence.
Option D: Correct. The onset of anticoagulant activity is more rapid with direct oral anticoagulants when compared to warfarin.
A 59-year-old African American male 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 163 kg (358 lb; body mass index [BMI] 44 kg/m2). 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. The factors that most likely predisposed this patient for venous thromboembolism (VTE) include:
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
Answer: D
Options A, B, and C: Incorrect. Ibuprofen use, smoking, alcohol, male sex, family history, race, ginseng use, regular alcohol consumption are not risk factors reported to have a strong causal relationship with risk of VTE (DVT/PE).
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 10–1).
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 × 103/mm3 (390 × 109/L) following the surgery to 160 × 103/mm3 (160 × 109/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.
Answer: D
Options A and C: Incorrect. Given the magnitude of the drop in platelet count, the patient should be evaluated for heparin-induced thrombocytopenia and agents such as UFH and enoxaparin that can cause or have a high likelihood to cross-react should be discontinued and/or not used.
Option B: Incorrect. Apixaban has no data to support its safety in patients with HIT or suspected HIT.
Option D: Correct. Fondaparinux (a synthetic pentasacharide) has been reported to have a low cross-reactivity rate and can be used in this patient.
47-year-old Caucasian 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. You take the following approach to manage his INR:
A. Hold his warfarin until INR < 2 and then resume warfarin at 5 mg daily
B. Give vitamin K 2.5 mg PO and hold his warfarin until INR < 2, then resume warfarin at 5 mg daily
C. Give Vitamin K 2.5 mg IV and hold his warfarin until INR < 2, then resume warfarin at 5 mg daily
D. Give Vitamin K 10 mg IV and admit patient to the hospital until INR < 2, then resume warfarin at 5 mg daily
Answer: B
Option A: Incorrect.
Option B: Correct. Since INR is greater than 10, small dose PO Vitamin K is recommended.
Options C and D: Incorrect. Since the patient has no signs/symptoms of bleeding, IV Vitamin K is not recommended.
An 82-year-old man was admitted to hospital and recently diagnosed with acute DVT. Treatment has been initiated with intravenous UFH. Twelve hours later, his aPTT is greater than 150 seconds and he is noted to have bright red blood per rectum. Which of the following is the best course of action in the management of this patient?
A. Hold heparin therapy for 60 minutes and then reduce infusion rate by 20%
B. Hold heparin therapy and give vitamin K via slow IV infusion
C. Hold heparin therapy and give recombinant factor VII
D. Hold heparin therapy and give protamine sulfate via slow IV infusion
Answer: D
Option A: Incorrect. Holding the drip with reducing the dose will not be sufficient.
Option B: Incorrect. Vitamin K is not an antidote for UFH.
Option C: Incorrect. Factor VII is not an antidote for UFH.
Option D: Correct. In patients with aPTT greater than 150 sec, protamine sulfate should be given as an antidote to heparin and the heparin drip held until aPTT is therapeutic.
A 29-year-old woman is admitted for acute DVT. She reports that she had a PE last year, 2 weeks following the birth of her daughter. She was treated with enoxaparin and warfarin for 3 months. Her symptoms completely resolved. What is the recommended duration of anticoagulation therapy in this case now?
A. Minimum of 3 months and then reevaluate risks and benefits
B. Minimum of 6 months and then discontinue
C. Minimum of 12 months and then reduce the warfarin dose by 50% for an additional 2 years
D. Lifelong
Answer: A
Option A: Correct. Although the patient has a history of a previous PE post pregnancy 1 year ago, that was considered a “triggered” event—pregnancy related and completely treated and resolved. As this is a new event, recommended duration of treatment is a minimum 3 months and extended duration of therapy beyond this will have to be balanced with risk of bleeding and patient preferences.
Option B: Incorrect.
Option C: Incorrect.
Option D: Incorrect.
