Coagulation disorders Flashcards
What are the RFs for VTE?
Age H/o VTE Venous stasis Venous injury Hypercoaguable disorders Drug therapy
What are the pieces of Virchow’s triad?
Venous stasis
Vascular injury
Hypercoagulability
What are the types of venous stasis?
Immobility
Paralysis
A fib
LV dysfunction
What are the types of vascular injury?
Indwelling catheter
Trauma
Surgery
What are the types of hypercoagulability?
Protein C and S deficiencies
Antithrombin deficiency
Malignancy
What are the types of hypercoagulable hereditary disorders?
Activated protein C resistance/Favtor V Leiden mutation Prothrombin gene mutation Protein C deficiency Protein S deficiency Antithrombin deficiency
In patients with Factor V Leiden mutation, what happens to clot formation?
Continues unchecked
What is protein C?
Endogenous anticoagulant responsible for degrading factor V and preventing further activation of the coagulation cascade
What does the prothrombin gene mutation cause?
Increased levels of prothrombin (needed in clot formation)
What is protein S?
One of the cofactors responsible for activation of protein C
What is antithrombin responsible for?
Inactivation of factors X and II
What are acquired hypercoagulable disorders?
Pregnancy
Antiphospholipid antibodies
Drug therapy
Malignancy
How does pregnancy cause hypercoagulable disorders?
D/t increased levels of estrogen during pregnancy and the immediate postpartum period
Where are antiphospholipid antibodies commonly found?
Patients with autoimmune disorders such as lupus or inflammatory bowel disease
What do antibodies do in the coagulation cascade?
Activate the coagulation cascade and platelets while inhibiting the activity or proteins C and S
What are s/sx of SVT?
Unilateral calf, leg or thigh swelling Leg pain/calf tenderness Increased leg warmth Edema Erythema Palpable thrombosed vein Homan's sign
What are the s/sx of PE?
Dyspnea Tachypnea Tachycardia Hemoptysis Chest pain and/or tightness Cough
What is the diagnosis of DVT/PE?
D-dimer
What is the D-dimer normal range?
0-250
Does the D-dimer have a low or high positive predictive value and specificity?
Low
What are non-invasive DVT-specific diagnostic testing?
Duplex ultrasonography
What is duplex ultrasonography?
Can measure the rate and direction of blood flow and visualize clot formation in proximal veins of the legs
What is preferred to venography?
Duplex ultrasonography
What are he invasive diagnostic tests for DVT?
Contrast venography
What are the contraindications for Contrast venography?
Nephrotoxicity
Dye allergy
Metformin use (must d/c during therapy)
What is the gold standard for DVT diagnosis?
Contrast venography
What drug must be d/c before using contrast venography?
Metformin
What are the contraindications for contrast venography?
Nephrotoxicity
Dye allergy
What does contrast venography used to visualize?
Entire venous system in lower extremity and abdomen
What are PE specific non invasive diagnostic tests?
Ventilation-perfusion (V/Q) scanning
Contrast-enhance spiral chest CT
What are the PE specific invasive diagnostic tests?
Pulmonary angiography?
What is the gold standard for PE diagnosis?
Pulmonary angiography
What are the contraindications to pulmonary angiography?
Renal dysfunction
Dye allergy
What are the indications UFH?
Acute DVT +/- PE
What are the doses for UFH treatment?
80 U/kg IV bolus + 18 U/kg/hr IV
What are the indications for enoxaparin?
Acute DVT w/ or without PE
What is the treatment fosing for enoxaparin with a CrCl < 30?
1 mg/kg SC once daily
What is the outpatient enoxaparin treatment dosing for enoxaparin w/o a PE?
1 mg/kg SC q12h
What are the inpatient treatment options for enoxaparin?
1 mg/kg SC q12h
OR
1.5 mg/kg SC once daily
What is dalteparin indicated for?
VTE in cancer
What is the dosing schedule for dalteparin?
200 IU/kg SC once daily for 1 month
Then
150 IU/kg SC once daily for 5 months
What is the dalteparin dosing in CrCl < 30?
Anti-Xa level target 0.5-1.5 IU/ml
What is the indication for tinzaparin?
Acute DVT +/- PE
What is the dosing for tinzaparin?
175 IU/kg SC daily
What are the indications for fondaparinux?
Acute DVT or PE
What are the doses for fondaparinux?
<50 kg: 5mg SC daily
50-100 kg: 7.5mg SC daily
> 100 kg: 10mg SC daily
When is fondaprinux contraindicated?
CrCl <30 ml/min
What labs are we monitoring for UFH?
aPTT or anti-Xa
Range 0.3-0.7
What are the labs we are monitoring for LMWH?
Anti-Xa levels
Range 0.5-1.0
What labs do we monitor for fondaparinux?
none
What labs do we monitor for Warfarin?
INR
What labs do we monitor with DOACs?
None
If a patient has cancer and their first episode with DVT?
For at least 6 months
When is indefinite therapy with LMWH an option?
Second episode or recurrent VTE
What are the disadvantages of warfarin in cancer?
NTI
Frequent monitoring
Potential interactions with a range of other drugs and foods
Frequent interruptions may be necessary d/t invasive procuders
Warfarin resistance
What are the advantages of LMWH over warfarin in cancer?
Body weight adjusted dose
No lab monitoring
Predictable anticoagulant response
Rapid onset of action
What did the CLOT study compare?
LMWH vs Oral anticoagulants
What did CLOT prove?
Less recurrence of VTE with LMWH
Less bleeding with LMWH
What are the oral anti-Xa inhibitors?
Rivaroxiban
Apixiban
Edoxaban
What are the direct thrombin inhibitors?
Dabigatran
According to the NCCN, DOACs can be used for acute management when?
Patients who refuse or have compelling reasons to avoid LMWH
Which DOACs can be used for acute management of VTE?
Apixaban
Rivaroxaban
According to the NCCN, DOACs can be used for chronic management when?
For patients who refuse or have compelling reasons to avoid LMWH
Which DOACs are acceptable alternatives as second line agents for chronic management of VTE?
Apixaban
Dabigatran
Edoxaban
Rivaroxaban
What is the UFH regimens for prophylaxis?
5,000 units SC every 8 hours
What is the obesity dosing for UFH prophylaxis?
7,500 units SC every 8 hours
What is the enoxaparin prophylactic dose?
40 mg SC once daily
What is the enoxaparin obesity prophylactic dose?
40mg SC every 12 hours
What is the dalteparin prophylactic dose?
5,000 units SC once daily
What is the dalteparin prophylactic obesity dose?
Consider 7,500 units SC daily
What is the tinzaparin prophylactic dose?
75IU/kg SC once daily
What is the tinzaparin prophylactic obesity dose?
Limited data
What is the fondaparinux prophylactic dose?
2.5 mg SC daily
What is the fondaparinux obesity prophylactic dose?
5mg SC daily
What are the prophylactic recommendations for hospitalized patients?
UFH
LMWH
fondaparinux
What are prophylaxis recommendations for post surgery?
UFH
LMWH
fondaparinux
Mechanical compression devices combination in high risk patients
What are prophylaxis recommendations for extended post-surgical prophylaxis?
Up to 4 weeks post surgery in high risk patients
What are prophylaxis recommendations for ambulatory patients with cancer?
No prophylaxis recommended
What are prophylaxis recommendations for patients with central venous catheters?
No prophylaxis recommendations
What prophylaxis regimens are recommended in renal insufficiency?
UFH recommended
Caution with LMWH
Fondaparinux CI
What prophylaxis regimens are recommended in obesity or weight less than 50 kg?
UFH recommended
Caution with LMWH and fondaparinux
What prophylaxis regimens are recommended in active chemotherapy?
Recommended in myeloma patients receiving thalidomide or lenalidomide plus chemotherapy or dexamethasone
What special populations are contraindicated for anticoagulants?
Mechanical compression devices
If an ambulatory patient is recieving thalidomide or lenalidomide with chemotherapy or dexamethasone, what anticoagulant should be used?
LMWH
Adjusted dose warfarin (INR ~ 1.5)
If a patient is undergoing surgery, what kind of therapy should be used?
Start prophylaxis preoperatively or early postoperatively
For an average risk patient undergoing surgery, how long should we use prophylaxis treatment?
Continue for 7-10 days
High-risk: continue for 4 weeks
What are mechnical compression devices?
Intermittent pneumatic calf compression devices (IPC’s)
Graduated compression stockings (GCS’s)
What are the underlying complications of DIC?
Severe sepsis
Solid tumors
Severe trauma
Obstetrical complications
What does DIC stand for?
Disseminated Intravascular coagulation
What is the pathophysiology of bleed?
- Systemic activation of coagulation
- Intravascular deposition of fibrin (thrombosis of small and midsize vessels and organ failure)
- Depletion of platelets and coagulation factors (bleeding)
What are the diagnostic tests for DIC?
Elevated D dimer Decreased antithrombin Decreased fibrinogen Thrombocytopenia Decreased Protein C and S Increased fibrinopeptides A and B Elevated prothrombin fragments 1 and 2 Evidence of end-organ failure
What are the s/sx of DIC?
Bleeding and/or thrombosis
Petechiae
Cyanosis
Hemorrhagic bullae
What is the treatment of DIC?
Treat underlying disorder FFP Cryoprecipitate Anticoagulation Vit K
What are packed RBCs (PRBCs) used for?
To restore oxygen-carrying capacity to the blood
How long do PRBCs last?
Up to 42 hours after donation
1 unit of PRBCs should raise hgb by how much to have an appropriate response?
1
How can PRBCs be modified?
Leukoreduction
Irradiated
Washed RBS to remove plasma
When are PRBCs used?
Hgb < 7 Active bleeding Oncologic patients -undergoing myelosuppressive therapy -palliative care
How do we premedicate for PRBCs?
APAP
Antihistamine
When is FFP used?
Bleeding d/t excessive warfarin Vit K deficiency DIC Deficiency of multiple coagulation factors Part of massive transfusion protocols Plasma exchange
What is cryoprecipitate?
The precipitate that remains when FFP is thawed at 4C
What are the components of cryoprecipitate?
Factor VIII Fibrinogen Fibronectin Factor XIII von Willebrand factor
When is cryoprecipitate used?
Replacement of factor XIII or fibrinogen
Bleeding in von Willebrand factor deficiency
Uremic bleeding
What are AEs of all blood products?
Anaphylaxis
Transfusion-relate acute lung injury
Cause volume overload
