TSOAC Case Study 1. Question. TSOAC Case Study 1 Continued

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1 TSOAC Case Study 1 An otherwise healthy 56-year-old man presents to the emergency department with left leg pain and swelling for the last 3 days. Compression ultrasonography confirms left common femoral DVT. There is no recent history of surgery, trauma, cast immobilization, or other provoking factors. His only medication is atorvastatin. His kidney function is normal. 1 Which of the following is not a recommended initial treatment strategy? A. LMWH bridge to warfarin B. Dabigatran C. Rivaroxaban D. UFH bridge to warfarin E. Apixaban 2 TSOAC Case Study 1 Continued The patient is discharged from the ED with a prescription for rivaroxaban 15 mg BID and a followup appointment with his PCP in 3 weeks. He completes 3 weeks of treatment as instructed. His leg symptoms improve during treatment. He misses the follow-up appointment with his PCP Two weeks later, he presents to the ED again with worsening left leg pain and swelling similar to his initial presentation. Ultrasound shows extension of the previously noted DVT. 3 1

2 What is the most likely reason for DVT extension in this patient? A. The patient was not treated with a parenteral anticoagulant prior to starting rivaroxaban B. The patient failed rivaroxaban C. Atorvastatin reduces serum levels of rivaroxaban D. Rivaroxaban was discontinued prematurely 4 TSOAC Case Study 2 A 72-year-old woman with hypertension and osteopenia is diagnosed with paroxysmal non-valvular atrial fibrillation. Her renal function is normal. Her medications include hydrochlorothiazide, alendronate and calcium. Her cardiologist prescribes dabigatran 150 mg BID. She tolerates dabigatran well. Six months later, her internist prescribes ketoconazole for a fungal rash and fluoxetine for depression. A week later she presents to the ED with a large GI bleed. 5 What is the most likely reason for the GI bleed? A. Interaction between dabigatran and fluoxetine B. Interaction between dabigatran and ketoconazole C. Fluoxetine-induced inhibition of platelet function D. Reduced intake of vitamin K due to depression and poor appetite 6 2

3 TSOAC Case Study 2 Continued The patient has bled down to a hemoglobin of 7 g/dl and continues to have bright red blood per rectum. She is hemodynamically stable. Her last dose of dabigatran was 10 hours ago. Her renal function is normal. 7 What is the most appropriate next step in her management? A. Intravenous fluids and RBC transfusion B. Oral activated charcoal C. Hemodialysis D. Activated prothrombin complex concentrate 8 Case 3 (81 y.o female) Test Patient Result Reference Range Thrombin Time >100 H sec Thrombin Time 1:1 Mix = >100 Inhibitor Pattern <19 sec Reptilase Time sec Fibrinogen Activity, Clauss Fibrinogen Antigen 359 H mg/dl mg/dl 3

4 What might explain these results? A. Dysfibrinogenemia B. Heparin Therapy C. Dabigatran D. B & C E. All of the above Test Thrombin Time Thrombin Time 1:1 Mix Reptilase Time Fibrinogen Activity, Clauss Fibrinogen Antigen Patient Result Reference Range >100 H sec = >100 Inhibitor Pattern <19 sec sec mg/dl 359 H mg/dl How might you distinguish heparin from Dabigatran? A. Anti Xa B. Protamine Sulfate C. Hepzyme D. All of the above Final Diagnosis Dabigatran 4

5 Case 4 51 year old Male with massive DVT is admitted to the hospital and started on a heparin drip. Day 2 he is started on warfarin with an anticipated discharge when his INR is > 2. The medical team learns that he has a FH of thrombophilia. Is it okay to order a thrombophilia panel? If you were to order thrombophilia tests, which of the following may be abnormal due to either heparin or warfarin? A. Factor V Leiden B. Anticardiolipin Antibodies C. aptt D. ATIII Antigen Lupus Anticoagulant Evaluation Clot-based Assays with Heparin Neutralizers reflex ** reflex** Screen Confirmatory Test Mixing Study 1. PTT-LA Hexagonal Phase Confirm* Thrombin Time 2. drvvt Screen drvvt Confirm drvvt 1:1 Mix *The Hexagonal Phase Confirm includes a source of normal pooled plasma in the test, which overcomes factor deficiencies and warfarin effects. Therefore, a separate mixing study is not required but is available if desired (TC 8922X). 5

6 : The patient is on warfarin. Which of the following statements is true: A. The PTT-LA & drvvt Screen may both be prolonged B. The Hexagonal Phase Confirm contains a source of normal plasma, therefore, a warfarin effect should be neutralized C.The drvvt Confirm ratio, although it does not contain normal plasma, can still distinguish a warfarin effect from a Lupus Anticoagulant D. All of the above Clot-based Assays with Heparin Neutralizers reflex ** reflex** Screen Confirmatory Test Mixing Study 1. PTT-LA Hexagonal Phase Confirm* Thrombin Time 2. drvvt Screen drvvt Confirm drvvt 1:1 Mix *The Hexagonal Phase Confirm includes a source of normal pooled plasma in the test, which overcomes factor deficiencies and warfarin effects. Therefore, a separate mixing study is not required but is available if desired : The patient is on heparin therapy. Which of the following statements is true? A.The PTT-LA should be abnormal B.The drvvt Screen should be normal C.The Hexagonal Phase Confirm contains a heparin neutralizer therefore all heparin will be neutralized D. All of the above Clot-based Assays with Heparin Neutralizers reflex ** reflex** Screen Confirmatory Test Mixing Study 1. PTT-LA Hexagonal Phase Confirm* Thrombin Time 2. drvvt Screen drvvt Confirm drvvt 1:1 Mix *The Hexagonal Phase Confirm includes a source of normal pooled plasma in the test, which overcomes factor deficiencies and warfarin effects. Therefore, a separate mixing study is not required but is available if desired : Which of the following can cause false positive LA results? A. Dabigatran B. Argatroban C. Rivaroxaban D. All of the above Clot-based Assays with Heparin Neutralizers reflex ** reflex** Screen Confirmatory Test Mixing Study 1. PTT-LA Hexagonal Phase Confirm* Thrombin Time 2. drvvt Screen drvvt Confirm drvvt 1:1 Mix *The Hexagonal Phase Confirm includes a source of normal pooled plasma in the test, which overcomes factor deficiencies and warfarin effects. Therefore, a separate mixing study is not required but is available if desired 6

7 CASE 5 46 Year Old Male No Clinical History Provided Lab Studies PT 47 sec ( ) + Inhibitor on Mix (22.0 sec) PTT-LA 146 sec ( 40) + Inhibitor on Mix (99.3 sec) Hexagonal Phase Confirm Delta 10 sec (<8) Thrombin Clotting Time >100 sec (16-23) Anti Xa <0.1 IU/ml (<0.1) What is the most likely diagnosis? A. Patient has a weak Lupus Anticoagulant B. Patient is on Warfarin C. Patient is on Heparin D. Patient is on a Direct Thrombin Inhibitor HITT patient transitioning from Argatroban to Warfarin If the patient is on both anticoagulants how does one know when the warfarin level is adequate? A. Target an INR of 3-4 (nl is 2-3) B. Chromogenic Factor X C. A & B 7

8 Bonus Case Bonus Case 36 Year Old Female no clinical history provided Sample was submitted for Factor Assays Laboratory Studies Factor VIII Activity <1% (50-150) Factor IX Activity <1% (60-160) What could explain these results? A. Serum B. STRONG Lupus Anticoagulant causing intrinsic pathway pseudodeficiencies C. Drug Inhibitor D. B & C E. All of the above 8

9 Bonus Case Additional History Patient presented with DVT/PE and treated w/ therapeutic dose LMWH. Thrombophilia evaluation revealed an inhibitor pattern with mixing study. Bonus Case Final Diagnosis Pseudofactor Deficiencies Due to LMWH 9