VTE Flashcards
Venous thrombi
Composed of RBC, fibrin, and some platelets
Mostly RBCs
VTE symptoms present when
Flow is obstructed
Vasc tissue is inflammed
DVTs and PEs
All PEs come from DVTs
Not all DVTs lead to PEs
Virchow’s triad
Conditions that increase clotting risk
Hypercoagulable state
Endothelial injury
Circulatory state
Hypercoagulable state
Abnormal clotting components
Ex. pregnancy, cancer
Endothelial injury
Abnormal surfaces in contact with blood flow
Ex. post-op, traumatic injury
Circulatory stasis
Abnormal blood flow
Ex. long period of immobility, hospitalization
Coagulation cascade overview
Cascade initiates -> increases production of thrombin -> results in clot formation
Factor II
Prothrombin
Factor IIa
Thrombin
Postthrombotic syndrome
Long-term complication of DVT
Caused by damaged venous valves
Pigmentation and skin hardening
DVT risk factors
Age > 40 years
HF, MI
Obesity
Pregnancy
Immobilization > 10 days
DVT non-pcol treatment
Bed rest w anticoag prn
Elevate feet
Pain management
Compression stockings
PE non-pcol treatment
Oxygen
Mechanical ventilation
Compression stockings
Ideal anticoagulant
Oral
Once daily dosing
Quick onset
Limited monitoring and drug interactions
Available and effective antidote
Wide therapeutic index
Low cost
UFH
Rapid parenteral anticoag
Variable response -> incr aPTT monitoring
Heparin associated thrombocytopenia (HAT)
Non-immune mediated
Mild platelet decrease
48-72 hours post-admin
Don’t need to d/c heparin
Heparin induced thrombocytopenia (HIT)
Immune mediated
7-14 days post-admin
Platelet decrease > 50% or to < 100,000 mm3
HIT management
Stop all heparin products
Give alt anticoag
Don’t give platelet infusions
Don’t give warfarin until platelet > 150,000
LMWH vs UFH
LMWH usually preferred
Better bioavailablility
Predictable dose response
Longer half life -> less freq dosing
Less risk HIT
Injectable FXa inhibitors and DTIs
Fondaparinux : prophylaxis and tx
- Don’t use if renal dysfunction
- Can be used in HIT
Lepirudin: HIT tx
Bivalirudin: HIT tx, alt to UFH during PCI
Argatroban: HIT tx
Warfarin available forms
Coumadin, Jantoven, warfarin
1, 2, 2.5, 3, 4, 5, 6, 7.5, 10mg tablets
Warfarin MOA
Inhibit vitamin K formation and dependent clotting factors (FII, VII, IX, X, Protein C and S)
Test before warfarin if
Warfarin naïve AND
Results available before sixth dose AND
Pt at high risk of bleeding w high INR
Drugs that incr INR w warfarin
Erythromycin
Anabolic steroids
Metronidazole
Bactrim
Ciprofloxacin
Acute alcohol use
Drugs that decr INR w warfarin
Rifampin
Carbamazepine
Chronic alcohol ingestion
Extreme Vit K ingestion
Antiplatelets in VTE
Limited role
ASA if CHA2DS-VASc score = 1
Dipyridamole w warfarin if prosthetic heart valves
Adjunct w anticoags and incr bleeding risk
Bleeding management
Discontinue meds
Manual compression
Maintain BP
Surgical or radiological intervention
BP products ± PCC ± targeted antidote
Bleeding targeted reversal
UFH, LMWH: protamine sulfate
Dabigatran: idarucizumab
FXa inhibitors: andexanet alfa
Bleeding w warfarin
INR 4.5-10 + no bleeding -> avoid vit K
INR > 10 + no bleeding -> PO vit K
Major bleeding -> PCC pref to FFP
VTE prophylaxis
UFH, LMWH, FXa inhibitors, Vit K antagonists
VTE: low risk
< 10%
No specific pcol tx recommended
VTE: moderate risk
10-40%
Most non-orthopedic surgeries
- UFH, LMWH, fondaparinux
Acute illness
- UFH, LMWH, fondaparinux, rivaroxaban, betrixaban
VTE: high risk
40-80%
Orthopedic surgery
- LMWH, fondaprinux, rivaroxaban, apixaban, dabigatran (hip), UFH, vit K antagonist
Major trauma or spinal cord injury
CHA2DS2-VASc measures
Risk factors for stroke or systemic VTE
ONLY w afib pts
HAS-BLED measures
Risk factors for bleeding
CHA2DS2-VASc factors
CHF: 1
HTN: 1
Age ≥ 75 years: 2
Diabetes: 1
Stroke: 2
Vascular disease: 1
Age 65-74 years: 1
Female: 1
HAS-BLED factors
HTN: 1
Abnormal renal/liver funct: 1 or 2
Stroke: 1
Bleeding risk: 1
Labile INR: 1
Age > 65 years: 1
Drugs or EtOH: 1 or 2
Dabigatran approved indications
Hip prophylaxis
Non-valvular afib
DVT/PE tx
Rivaroxaban approved indications
Post-op prophylaxis
Non-valvular afib
DVT/PE tx - 1st line
Secondary prevention of repeat DVT/PE
VTE prophylaxis - usually in-pt use
Apixaban approved indications
Post-op prophylaxis
Non-valvular afib
DVT/PE tx - 1st line
Secondary prevention of repeat DVT/PE
Edoxaban approved indications
Non-valvular afib (adjust w renal impair)
DVT/PE tx
Warfarin dosing
Initial dose: 5mg po q1d
Healthy outpt dose: 10mg po q1d x2d
Bridge w UFH/LMWH/Xa for ≥ 5 days AND until INR is therapeutic (~2-3)
Recommended INR goals
2.5-3.5
- Mechanical heart valve (mitral, caged ball, high risk)
2-3
- VTE prophylaxis
- VTE/PE tx
- Systemic embolism prophylaxis
- Mechanical heart valve (aortic)
1.5-2
- Mechanical On-X
Five D’s when interviewing pt
Drugs
Diseases
Doses
Diet
Drinking
Bridging procedure w warfarin
Done w invasive procedures
Stop warfarin 5 days before surgery
Give LMWH or UFH until surgery
- Stop LMWH 24 hrs before
- Stop UFH 4-6 hrs before
Resume warfarin 12-24 hrs post-op
