Anticoagulation

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Anticoagulation






  1. A 55-year-old male presents with acute onset of shortness of breath. He has a computed tomography angiogram in the emergency room and is noted to have bilateral segmental and subsegmental pulmonary emboli (PEs). His past medical history is significant for non-small cell carcinoma of the lung, for which he is undergoing treatment. He reports nausea and vomiting. Which of the following would be the choice of anticoagulation?



    1. Warfarin
    2. Low molecular weight heparin (LMWH)
    3. Dabigatran
    4. Edoxaban



  2. In a patient with deep venous thrombosis (DVT) of the leg, not cancer associated, what would not be the choice of anticoagulation for the first 3 months?



    1. Dabigatran
    2. Rivaroxaban
    3. Apixaban
    4. Edoxaban
    5. Warfarin



  3. Initial parentral anticoagulation is a must with what agents, when used to treat non-cancer-associated DVT or PEs?



    1. Rivaroxaban and apixaban
    2. Dabigatran and edoxaban
    3. Rivaroxaban and edoxaban
    4. Dabigatran and apixaban



  4. A patient is on dabigatran 150 mg BID for paroxysmal atrial fibrillation. He is then prescribed dronedarone for rhythm control. What is the recommendation for dabigatran dosing?



    1. Continue at 150 mg BID
    2. Reduce dosage to 75 mg BID
    3. Stop using dabigatran
    4. Reduce dosage to 75 mg once daily



  5. A 65-year-old male is on ketoconazole therapy. He has paroxysmal atrial fibrillation and his CHA2DS2–VASc score is 4. His physician decides on starting a novel anticoagulant, dabigatran. What is the recommendation regarding dabigatran dosing in this patient?



    1. Start on 150 mg BID
    2. Do not use dabigatran
    3. Start on 75 mg BID
    4. Start on 75 mg once daily



  6. Which of the novel anticoagulants is mostly excreted through the kidneys?



    1. Dabigatran
    2. Rivaroxaban
    3. Apixaban
    4. Edoxaban



  7. Which of the following novel anticoagulants is a direct thrombin inhibitor?



    1. Rivaroxaban
    2. Apixaban
    3. Dabigatran
    4. Edoxaban



  8. Which of the following drugs has been approved by the US Food and Drug Administration for use to reverse the effect of dabigatran?



    1. Idarucizumab
    2. Andexanet alfa
    3. Aripazine
    4. Protamine



  9. Which of the following drugs is being studied to reverse the effect of apixaban and rivaroxaban?



    1. Idarucizumab
    2. Andexanet alfa
    3. Aripazine
    4. Protamine



  10. Which of the following drugs is being evaluated as a universal anticoagulant reversal agent (anti-direct thrombin inhibitors, anti-Xa inhibitors, unfractionated heparin, LMWH, and fondaparinux)?



    1. Idarucizumab
    2. Andexanet alfa
    3. Aripazine
    4. Protamine



  11. For patients undergoing major orthopedic surgery, including total hip arthroplasty, total knee arthroplasty, and hip fracture surgery, what is the current recommendation for thromboprophylaxis from the day of surgery?



    1. Thromboprophylaxis in the outpatient period for up to 35 days
    2. Thromboprophylaxis for 10 days
    3. No need for thromboprophylaxis
    4. Thromboprophylaxis for 14 days



  12. In patients undergoing total hip arthroplasty or total knee arthroplasty, irrespective of the concomitant use of an intermittent pneumatic compression device or length of treatment, what is the recommended choice for thrombopro- phylaxis?



    1. Aspirin alone
    2. Unfractionated heparin
    3. LMWH
    4. Vitamin K antagonist



  13. For patients undergoing total hip arthroplasty, total knee arthroplasty, and hip fracture surgery, what is the recommended time period to start thromboprophylaxis with LMWH?



    1. 4 h preoperatively
    2. 4 h postoperatively
    3. 12 h or more preoperatively or postoperatively
    4. 24 h postoperatively



  14. For acutely sick hospitalized medical patients who are at increased risk for thrombosis, what is the current recommendation for thromboprophylaxis?



    1. LMWH
    2. LDUH BID
    3. LDUH TID
    4. Fondaparinux
    5. All of the above
    6. None of the above



  15. Based on the RE-LY trial, which of the following statements is false?



    1. Dabigatran 110 mg was noninferior to warfarin in preventing stroke or embolism
    2. Dabigatran 150 mg was superior to warfarin in preventing stroke/embolism
    3. Dabigatran was associated with more gastrointestinal bleeds
    4. Dabigatran was associated with more intracranial bleeds



  16. Which of the following is not true regarding novel anticoagulants in nonvalvular atrial fibrillation?



    1. Rivaroxaban was noninferior to warfarin in preventing stroke
    2. Edoxaban was noninferior to warfarin in preventing stroke
    3. Apixaban was superior to warfarin in preventing stroke
    4. Apixaban was noninferior to warfarin in preventing stroke



  17. In a patient with acute isolated distal DVT, what is the current recommendation regarding management?



    1. Serial imaging of the deep veins in 2 weeks when there are no severe symptoms or risk for extension
    2. Serial imaging in 4 weeks
    3. No need to image further
    4. Start anticoagulation



  18. In a patient diagnosed with a distal DVT managed with serial imaging, which of the following statements is not true?



    1. Anticoagulation if the thrombus has not extended
    2. Anticoagulation is recommended if the thrombus has extended but remains confined to distal veins
    3. Anticoagulation is recommended if the thrombus extends into the proximal veins



  19. Which of the following is not true?



    1. In patients with acute DVT of the leg, use of compression stockings is not recommended
    2. In patients with subsegmental PE (not involving proximal pulmonary arteries) without proximal DVT of legs and a low risk for venous thromboembolism (VTE), clinical surveillance is recommended
    3. In patients with subsegmental PE (not involving proximal pulmonary arteries) without proximal DVT of legs and a high risk for VTE, clinical surveillance is recommended
    4. In patients with low-risk pulmonary embolism, treatment at home or early discharge is recommended (before 5 days of treatment)



  20. Which of the following statements are true?



    1. In patients with acute PE being managed by thrombolysis, systemic thrombolytic therapy is recommended over catheter-delivered thrombolysis
    2. In patients with acute PE associated with hypotension, catheter-assisted thrombus removal is recommended when they are at high risk for bleeding, failed systemic thrombolysis, or in shock
    3. In patients with upper extremity DVT involving axillary or more proximal veins, anticoagulation therapy is recommended over thrombolysis
    4. In patients with recurrent DVT on therapeutic doses of warfarin or other NOACS, switching to LMWH for at least 1 month is recommended
    5. Increasing the dose of LMWH by one-quarter to one-third is recommended if recurrent DVT occurs while on therapeutic dose of long-term LMWH therapy
    6. All of the above
    7. None of the above

Answers





  1. B. Low molecular weight heparin (LMWH).


    This patient has just been diagnosed with PEs and is related to his underlying cancer. He also reports vomiting. This patient should be treated with LMWH initially (Kearon et al., 2016).




  2. E. Warfarin.


    According to the recent CHEST guidelines (Kearon et al., 2016), in patients with DVT of the leg or PEs, warfarin is not the choice of therapy (for first 3 months) (evidence grade 2B). See Box 30.1.




  3. B. Dabigatran and edoxaban.


    If novel anticoagulants are chosen to treat a DVT or a PE when not associated with cancer, initial parenteral anticoagulation is recommended with dabigatran and edoxaban and is not needed with rivaroxaban and apixaban and is overlapped with warfarin.




  4. B. Reduce dosage to 75 mg BID.


    Dronedarone inhibits P-glycoprotein and cytochrome P450 3A4 and hence increases the plasma concentration of dabigatran, which may lead to increased bleeding. Hence, the current recommendation is to reduce the dose of dabigatran to 75 mg BID in the USA. See Box 30.3.




  5. C. Start on 75 mg BID.


    Ketoconazole, itraconazole, voriconazole, and posaconazole will increase the serum concentration of dabigatran through P-glycoprotein and breast cancer resistance protein competition and cytochrome P450 3A4 inhibition. Hence, it is recommended to start dabigatran dose at 75 mg BID while on any of the aforementioned antifungals in the USA.




  6. A. Dabigatran.


    Among the drugs listed in the question, dabigatran is cleared through the kidneys (80%), while rivaroxaban (66%), apixaban (25%) and edoxaban (50%) have lower rates of renal clearance.




  7. C. Dabigatran.


    Dabigatran is a direct thrombin inhibitor, while all the other agents are factor Xa (FXa) inhibitors.




  8. A. Idarucizumab.


    Idarucizumab is a humanized, monoclonal, antibody fragment that specifically binds with high affinity to dabigatran, an oral direct thrombin inhibitor. It acts by competitively displacing dabigatran from thrombin to reverse anticoagulation and restore fibrin formation. Dabigatran has an affinity for idarucizumab that is 350 times greater than its affinity for thrombin. The dose currently studied in the phase 3 trial is 5 g. A global phase 3 case series study known as RE-VERSE AD is currently enrolling patients treated with dabigatran who have uncontrolled bleeding or require emergency surgery or procedures. A dose of 5 g idarucizumab will be administered intravenously to reverse the effect of dabigatran. The trial will measure plasma-diluted thrombin time and ecarin clotting time as primary outcome measures. Time to cessation of bleeding will be a secondary outcome. Results from the trial are expected in 2017.




  9. B. Andexanet alfa.


    It is a modified recombinant FXa molecule intended for intravenous (IV) administration. It has been developed as an antidote to reverse anticoagulant activity of oral direct (e.g., apixaban, edoxaban, and rivaroxaban) and injectable indirect (e.g., enoxaparin and fondaparinux) FXa inhibitors. Andexanet alfa acts to target and sequester with high specificity both oral and injectable FXa inhibitors in the blood. Part 1 of the phase 3 ANNEXA-R trial – which was designed to compare the administration of an 800 mg IV bolus of andexanet alfa with placebo in 39 patients pretreated with rivaroxaban 20 mg for 4 days – were presented at the 2015 American College of Cardiology Scientific Sessions on March 16, 2015. Andexanet alfa produced a statistically significant and rapid reduction in anti-FXa activity from baseline (primary outcome); mean percentage change anti-FXa from baseline to nadir was 92% (P < 0.0001 versus placebo). Normalization of coagulation parameters was achieved within 2 min of completing the IV bolus infusion; the effect lasted 1–2 h with the IV bolus dose. Part 2 is ongoing and will investigate IV bolus followed by a 2-h continuous infusion to demonstrate sustained reversal.

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Apr 23, 2020 | Posted by in CARDIOLOGY | Comments Off on Anticoagulation

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