Antithrombotic Therapy for VTE:
CHEST Guidelines 2016
Jennifer Mah, MD
March 2016
Case
A 44-year-old man is evaluated in follow-up for an episode of
unprovoked left proximal leg deep venous thrombosis 3
months ago. Following initial anticoagulation with lowmolecular-weight heparin, he began treatment with warfarin.
INR testing done every 3 to 4 weeks has shown a stable
therapeutic INR. He has mild left leg discomfort after a long
day of standing, but it does not limit his activity level. He
tolerates warfarin well. Family history is unremarkable, and
he takes no other medications.
Which of the following is the most appropriate management?
A. Continue anticoagulation indefinitely
B. Discontinue warfarin in another 3 months
C. Discontinue warfarin now
D. Discontinue warfarin and perform thrombophilia testing
Objectives
•
•
•
•
Recognize subgroups of VTE
Review medications for VTE anticoagulation
Learn guidelines for duration of therapy
Understand differences in therapy based on type
of VTE
Subgroups of VTE
•
•
•
•
Cancer-associated vs No cancer
Provoked vs Unprovoked
Proximal vs Distal DVT
Upper extremity vs Lower extremity DVT
VTE and No Cancer
• Use NOAC – preferred! (Grade 2B)
▫ Rivaroxaban, apixaban
 No bridging needed
▫ Dabigatran, edoxaban
 Start with parenteral anticoagulation x5 days
• If contraindications to NOAC, then use VKA
therapy (warfarin) (Grade 2C)
▫ Overlap with parenteral anticoagulation x5 days,
▫ And INR >2 for 24 hours
Contraindications to NOACs
• Extreme BMI (>40)
• CrCl <30
• Significant increased risk of bleeding
Cancer-Associated Thrombosis
• Use LMWH (Grade 2C)
▫ Enoxaparin 1 mg/kg/dose BID
Provoking Transient Risk Factors
for VTE
•
•
•
•
•
Surgery
Estrogen therapy
Pregnancy
Leg injury
Flight >8h
Location of VTE
• Lower extremity DVT
▫ Proximal – Popliteal or more proximal veins
▫ Distal – Calf veins
• Upper extremity DVT
▫ Proximal – Axillary or more proximal veins
▫ Catheter-associated
Duration of Therapy
Isolated
Distal
DVT
Proximal
DVT or PE
Unprovoked
Provoked
3 months
(Grade 1B)
Low
bleeding
risk
Extended
therapy
(first VTE Grade 2B,
second VTE Grade 1B)
Mod
bleeding
risk
Extended
therapy
(first VTE Grade 2B,
second VTE Grade 2B)
High
bleeding
risk
3 months
(first VTE Grade 1B,
second VTE Grade 2B)
Mild
symptoms
or high
bleeding
risk
Serial
imaging
x2 weeks
(Grade 2C)
Extending
thrombus
Anticoagulate
(Grade 1B, 2C)
Severe
symptoms
or risk for
extension
Anticoagulate
(Grade 2C)
Cancerassociated
Upper
extremity
DVT
Extended
therapy
Anticoagulate
(Grade 1B)
(Grade 2C)
Special Considerations for
Upper Extremity DVT
Catheterassociated
Proximal
Catheter
functional?
Anticoagulate
Yes
Catheter still
needed?
Yes
Leave catheter in
and anticoagulate
No
No
Remove and
anticoagulate
x3 months
Risk Factors for Bleeding on
Anticoagulant Therapy
•
•
•
•
•
•
•
•
•
•
Age >65
Age >75
Previous bleeding
Cancer
Metastatic cancer
Renal failure
Liver failure
Thrombocytopenia
Previous stroke
Diabetes
•
•
•
•
•
•
•
•
Anemia
Antiplatelet therapy
Poor anticoagulant control
Comorbidity and reduced functional
capacity
Recent surgery
Frequent falls
Alcohol abuse
NSAID use
Low risk
0 risk factors
Moderate risk
1 risk factor
High risk
≥2 risk factors
Risk Factors for Extension of
Distal DVT
• Positive D-dimer
• Extensive thrombus
▫ >5cm long, involves multiple veins, >7mm
diameter
•
•
•
•
•
Thrombus close to proximal veins
No reversible provoking factor
Active cancer
History of VTE
Inpatient status
What if my patient stops
anticoagulation?
• Aspirin is NOT a reasonable alternative to
anticoagulation for extended therapy
▫ Much less effective at preventing recurrent VTE
• However, aspirin is better than nothing (Grade 2B)
Recurrent DVT on Anticoagulation
• If on therapeutic warfarin or NOAC, then switch
to enoxaparin temporarily (minimum 1 month)
(Grade 2C)
▫ Is this really recurrent VTE?
▫ Is my patient compliant with therapy?
▫ Is there underlying malignancy?
• If on enoxaparin and compliant, then increase
the dose by 25-33% (Grade 2C)
Case Revisited
A 44-year-old man is evaluated in follow-up for an episode of
unprovoked left proximal leg deep venous thrombosis 3
months ago. Following initial anticoagulation with lowmolecular-weight heparin, he began treatment with warfarin.
INR testing done every 3 to 4 weeks has shown a stable
therapeutic INR. He has mild left leg discomfort after a long
day of standing, but it does not limit his activity level. He
tolerates warfarin well. Family history is unremarkable, and
he takes no other medications.
Which of the following is the most appropriate management?
A. Continue anticoagulation indefinitely
B. Discontinue warfarin in another 3 months
C. Discontinue warfarin now
D. Discontinue warfarin and perform thrombophilia testing
Duration of Therapy
Proximal DVT
or PE
Provoked
3 months
Isolated
Distal DVT
Unprovoked
Low to
moderate
bleeding
risk
Extended
therapy
High
bleeding
risk
Mild
symptoms
or high
bleeding
risk
Severe
symptoms
or risk for
extension
Serial
imaging
x2 weeks
Anticoagulate
3 months
Extending
thrombus
Anticoagulate
Cancerassociated
Upper
extremity
DVT
Extended
therapy
Anticoagulate
Case Revisited
A 44-year-old man is evaluated in follow-up for an episode of
unprovoked left proximal leg deep venous thrombosis 3
months ago. Following initial anticoagulation with lowmolecular-weight heparin, he began treatment with warfarin.
INR testing done every 3 to 4 weeks has shown a stable
therapeutic INR. He has mild left leg discomfort after a long
day of standing, but it does not limit his activity level. He
tolerates warfarin well. Family history is unremarkable, and
he takes no other medications.
Which of the following is the most appropriate management?
A. Continue anticoagulation indefinitely
B. Discontinue warfarin in another 3 months
C. Discontinue warfarin now
D. Discontinue warfarin and perform thrombophilia testing
Summary
• NOACs are preferred over warfarin for
anticoagulation
• Except if VTE is cancer-associated, then use
enoxaparin
• Duration of therapy is usually 3 months, with
extended therapy based on risk factors for
recurrent VTE
References
• Kearon C, Akl EA, Ornelas J, et al.
Antithrombotic Therapy For VTE Disease:
CHEST Guideline And Expert Panel Report.
CHEST. 2016;149(2):315-352.
doi:10.1016/j.chest.2015.11.026.
• MKSAP 17