This document discusses the optimal duration of anticoagulation treatment for patients who have experienced venous thromboembolism (VTE) events like deep vein thrombosis (DVT) or pulmonary embolism (PE). It reviews evidence that at least 3 months of anticoagulation is generally recommended as the minimum duration to reduce recurrence risk. Longer durations up to 6-12 months may provide additional small benefits for certain high-risk patients, but data is limited. The role of hypercoagulability testing in determining duration is unclear as many patients who experience clots do not have identifiable hypercoagulable states. The risks of both recurrence and bleeding must be weighed when making decisions around duration of therapy.

1. Hypercoagulability and
Duration of Anticoagulation:
How Long is Long Enough?
Kathryn Hassell, MD
Professor of Medicine
Division of Hematology
University of Colorado Denver

2. Disclosures
• No financial or other conflicts of interest
• Off label use: discussion not planned

3. Objectives
• Assist patients with decision-making about
duration of anticoagulation by providing
information about:
– risk of recurrent venous thrombosis
– risk of complications of therapy (bleeding)
• Decide if hypercoagulabile testing will be useful
for a patient

4. 24 year old man with unprovoked PE.
No bleeding problems, negative hypercoag testing.
How long should he take anticoagulation?
• 3 months
• 6 months
• One year
• Lifelong

5. 19 year old woman with DVT while on OCPs for 3 years.
No bleeding problems, Factor V Leiden positive.
How long should she take anticoagulation?
• 3 months
• 6 months
• One year
• Lifelong

6. 45 year old man with history of 2 clots, (calf, popliteal),
each after arthroscopy. No bleeding, negative testing
How long should he take anticoagulation?
• 3 months
• 6 months
• One year
• Lifelong

7. 60 year old woman with history of PE on tamoxifen for
metastatic breast cancer. No bleeding, no testing.
How long should she take anticoagulation?
• 3 months
• 6 months
• One year
• Lifelong

8. 64 year old man with history of PE after bladder cancer
surgery 5 months ago. “Too much bleeding” to take
anticoagulation after surgery, but in your office now.
How long should he start anticoagulation for his PE?
If yes, for how long?
• 3 months
• 6 months
• One year
• Lifelong

9. Outline of Presentation
• Management of current VTE episode
– Duration of initial/acute therapy (e.g. LMWH)
– Duration of subsequent/chronic therapy
• Based on time (e.g. 3 vs. 6 months)
• Role of other factors (e.g. residual clot or symptoms)
• Impact of hypercoagulable tests
• Prevention of subsequent new episodes
– Balancing risk for recurrent clot vs. bleeding
– Role of factors which may impact estimate of risk
• Review major basic principles along the way

10. Principle of Acute Treatment
• Anticoagulation given to reduce the risk of
new thrombosis
– Anticoagulation doesn’t actively change an acute
thrombus – endogenous thrombolysis occurs
whether or not someone is on anticoagulation
– Anticoagulation simply prevents new thrombosis
from forming
• In areas of recannalization
• Extension beyond original

11. Treatment for Acute VTE
• Risk of no treatment for acute DVT or PE:
– Untreated PE → fatal PE: 26% at 1 year
– Untreated proximal DVT → fatal PE: 5% at 10 days,
10% at 30 days
– No reduction in mortality with IVC filters
Young, Cochrane Database Sys Rev 17:CD006212, 2010
• Judged to be sufficiently high enough to create a
standard to treat of all PE/proximal DVT (VTE)
unless bleeding is likely to be life-threatening
– Guidelines favor treatment of even calf DVT

12. Eighth ACCP 2012 – DVT or PE
• Acute Management
– Subcutaneous LMWH
– Intravenous or subcutaneous UFH
– Fondaparinux
– Rivaroxaban, Apixaban (FDA approved after the
guidelines were developed)

13. Eighth ACCP 2012 – DVT or PE
• Other Management Considerations
– Initiation of VKA (warfarin) on first day (if using
LMWH/heparin/fondaparinux)
– Continue LMWH/UFH until INR stable and ≥
2.0 for at least 24 hours
– Treatment with LMWH/UFH for at least 5 days
– Switch to dabigatran after 5-10 days of LMWH

14. Initial Management of Thrombosis
• Acute intervention: 5 days of active therapy
– Active antithrombotic therapy (e.g. heparin/LMWH/new
oral agents)
– Initiation of long-term maintenance (e.g. warfarin/new
oral agents)
• Underlying thrombophilia does not impact
selection or intensity of anticoagulation
– Heparin OK for AT def
– Warfarin OK for PC/PS deficiencies
Kearon, Current Opin Hematol 19:1, 2012

15. Warfarin-Induced Skin Necrosis
• VERY RARE
– As likely related to acquired/transient protein C/S
deficiency as inherited state
– Not a contraindication to initiate warfarin
• “Active” anticoagulation
(e.g. heparin) protects
against the initial further
drop in levels with warfarin
Crowther, Arch Intern Med 159:46, 1999;
Kearon, Current Opin Hematol 19:1, 2012

16. Management of Thrombosis
• Different INR intensity for APS? No
104 patients with APS (Finazzi, J Thromb Haemost 3:848, 2005)
2-3 >3
Recurrent thrombosis 5.5% 11.1%
All bleeding 14.6% 27.8%
Major bleeding 3.6% 5.3%
INR 2-3 is
current standard
106 patients with APS (Crowther, NEJM 349:1133, 2003)
2-3 3-4
Recurrent thrombosis 3% 10.7%
Per pt-yr 1.3% 4.1%
Major bleeding 4 (19%) 3 (27%)
Anticoagulation stopped 13 21

17. Duration of Treatment For
A Given VTE Episode
• For DVT/PE, 3 months appears to be the
minimum time needed
– HR 1.52 (1.14-2.02) if treated only 1-1.5 months
vs. 3 months or longer
Boutitie, BMJ 342; d3036, 2011
• Up to 40% recurrence if anticoagulation
interrupted during the first 3 months
– 100-fold increase in peri-operative VTE risk if
interruption in the first month
Kearon, NEJM 336:1506, 1997

18. Balancing Risks and Benefits
• Analysis of rate of fatal events and case
fatality rates in the first 3 months on therapy
Event Rate of Fatal Event Case Fatality Rate
Fatal PE 0.4% (0.3-0.6) 11.3% (8.0-15.2)
Fatal bleed 0.2% (0.1-0.3) 11.3% (7.5-15.9)
Carrier, Ann Intern Med 152:578. 2010
Schulman, Sem Thromb Hemost 39:141, 2013

19. Principle: 3 Months of Time
Not 3 Months of Anticoagulation
• Adequacy of anticoagulation doesn’t matter
–Leiden Thrombophilia Study (2003)
– 234 patients followed for recurrence after
stopping their anticoagulation
» Treated for 3, 6, or >6 months
–No increase in long-term recurrence risk for
those who spent more time out of range
» No difference in recurrence risk based on
duration of therapy, either
Gadisseur, J Thromb Hemostas 5:931, 2007

20. Are longer finite periods better?
• No evidence to indicate periods longer than 3
months is helpful to reduce risk of recurrence
– Meta-analysis of 7 studies comparing 3, 6, 12, and
27 months showed no difference is subsequent
recurrence after therapy stopped
– Included provoked, unprovoked, DVT and PE
– Some authors cite “trend” to increased recurrence
after 3 vs. 6 months for unprovoked events:
• HR 1.39 (0.96-2.01)
Boutitie, BMJ 342; d3036, 2011; de Jong, BJH 158:433, 2012

21. What if the clot isn’t gone?
• Anticoagulation does not make the clot go away
– Complete residual occlusion can be asymptomatic
• DVT doesn’t usually go away: e.g. DACUS Study
• After 3 months of therapy:
66.8% had residual vein
thrombosis (RVT) >40% of vein
diameter
• The rest could still have clot,
just less
Siragusa, Amer J Hematol 86:914, 2011

22. Residual Vein Thrombosis
• Conflicting evidence about the role of RVT
predicting recurrence (more later)
• No evidence staying on anticoagulation will
improve resolution of RVT
– Sustaining anticoagulation because of RVT doesn’t
make it go away, doesn’t change outcomes
Prandoni, Ann Intern Med 150:577, 2009

23. What if there’s still symptoms?
• May not be related to residual thrombus
• Anticoagulation does not change the way the blood
flows; the blood is not “thinner”
– Factors are still present, they simply lack carboxyl
groups (due to warfarin) or are bound by drug when
activated (heparin/LMWH/new oral anticoagulants)
– Remember, anticoagulation doesn’t promote
resolution of thrombosis
• The symptoms will not worsen off anticoagulation
unless new clot forms

24. Post-Thrombotic Symptoms
• Rate of chronic PTS symptoms ~25% de Jong, BJH, 2012
• Use of compression stockings: S.O.X. Trial
– Randomized controlled comparison of graded compression
stocking to placebo stockings (no significant pressure
applied)
– Started within a mean of 4 days, used up to 2 years
– 80% of subjects used more than 3 days/week
– No SAEs related to either stocking
• 2% had leg rash/itching
Kahn, Lancet 383(9920):880, 2014

25. Post-Thrombotic Symptoms
• No difference between stockings in moderate/severe
PTS (14-16%), ulceration (3-4%), recurrent VTE
Kahn, Lancet 383(9920):880, 2014

26. Principles (But No Data)
• Some people choose to sustain anticoagulation
hoping for:
– Continued recannulization/resorption of clot
– Symptom improvement with recannulization and/or
collateral formation
• Role of anticoagulation: prevent new thrombosis
from “undoing” the gains made; NOT active therapy
• Duration individualized: continued until desired
improvement attained or the “best it’ll be”

27. What if they have
a hypercoagulable state?
• They HAVE a hypercoagulable state, as
demonstrated by their episode of thrombosis
– Most people don’t ever clot (1:1000)
– Most people don’t clot even when faced with
prothrombotic risk factors
– Some people who clot with prothrombotic risk
factors may not even know they had a clot
• Does it matter if we give it a name?

28. An Example: Orthopedic Surgery
• Even without anticoagulation, only a subset clot, and
fewer have symptoms – those who do are different
0 20 40 60 80 100
Arthroscopy
THA
TKA
Hip Fracture
Distal DVT Proximal DVT PE
6th ACCP Conf on Antithrombotic and ThrombolyticTherapy; Chest, 2001

29. Testing for Thrombophilia
TEST ABNORMAL RESULT
Factor V Leiden (FVL) Present
Prothrombin G20210A mutation (PGM) Present
Protein C*/Antithrombin activity* Low (<30-40%/<50%)
Protein S free antigen* Low (<30-40%)
Anticardiolipin antibodies Mod-High Positive
2glyoprotein-1 antibodies Mod-High Positive
Lupus anticoagulant (e.g. dRVVT) Present
Homocysteine >ULN (12-15)
ACQUIRED INHERITED
*should not be measured during acute event and/or on anticoagulation

30. Testing for Thrombophilia: Pitfalls
• Sensitive activity assays (Protein C/Protein S)
– Affected by oral contraceptive use, inflammation,
antiphospholipid antibodies
– Values of 50-60% of unclear clinical significance
• Protein S testing: low values (<40%) expected during
pregnancy, may take weeks to months to recover post-partum
• Antiphospholipid antibodies may be reactive
• Always repeat abnormal values to confirm
Favaloro, Sem Thromb Haemost 35:695, 2009

31. Optimal Timing of Testing
• No active thrombosis – consumes factors
• No anticoagulants
– AT low with heparin/LMWH/fondaparinux therapy
– PC/PS low with warfarin therapy, dabigatran
• If patient unsure about stopping anticoagulation,
can do testing on warfarin (except Protein C/S)

32. Negative Thrombophilia Testing
• We can detect 7 conditions, but most people with
clots don’t have these conditions
– Example: RVT study of unprovoked VTE
• 1.7% had PC/PS/AT def or LA
• 21% had FVL and/or PGM, which have minimal
impact on risk of recurrence
• “Normal panel” doesn’t change the history of
clotting or risk estimate of recurrence
Prandoni, Ann Intern Med, 2009

33. Role of Positive Thrombophilia
Testing to Predict Recurrence
• Modest or no effect from known inherited
thrombophilias
– FVL: OR=1.39 (1.15-1.67) PGM: OR=1.20 (0.89-1.61)
Marchiori, Haematologica 92:1250, 2008
– PC/PS/AT deficiencies: HR=1.8 (0.9-3.7)
Christiansen, JAMA 293:2352, 2008
– Exceptions may be antithrombin deficiency,
homozygotes for FVL or PGM but limited data
• Stronger effect likely with antiphospholipid antibody
syndrome (OR=4.0 [1.2-13]) for unprovoked VTE
Kearon, Clin Chest Med 31:719, 2010

34. Effect of Inherited Thrombophilias on
VTE Recurrence
• 304 patients with single VTE + family hx
Patients
On anticoagulation
%/year (n=124)
Off anticoagulation %/year (n=180)
Males Females
All 1.1% 9.6% 2.8%
PC def 0.6% 10.8% 2.9%
PS def 0.6% 10.5% 3.1%
AT def 2.7% 11.6% 9.5%
FVL 0% 7.2% 2.2%
Multiple 0.9% 10.7% 2.1%
Vossen, Arterioscler Thromb Vasc Biol 25:1992; 2005

35. High Risk APS Patients
• “High risk” laboratory findings (inconsistent data):
– Lupus anticoagulant > other tests
– Anticardiolipin IgG/IgM >40 or >99th %ile
– β2glycoprotein-1 IgG/IgM >99th %ile
• Clinical features which may predict thrombosis
– Other thrombotic risk factors (e.g. OCP use)
– Co-existent autoimmune disease
– Suspected but unproven (retrospective, conflicting data)
• ITP, valvular lesions, history of obstetrical complications,
livedo rectiularis
Barbhaiya and Erkan, Curr Opin Rheum 13:59, 2011

36. Recurrence Risk in APS
• Risk factors for thrombosis:
– History
• previous thrombosis: 5.4% per pt-yr
• asymptomatic: 0.95% per pt-yr
– ACA level
• >40 GPL: 6.12% per pt-yr
• <40 GPL: 1.25% per pt-yr
– Having SLE/SLE-like disease
Finazzi, Am J Med, 100:530, 1996

37. Principles Based on Available
Hypercoagulable Testing
• Most testing doesn’t matter – negative not useful
• What might indicate higher risk or recurrence off
anticoagulation?
– Male with family history and named condition
• Annual risk 5-10%/year
– Antithrombin deficiency and family history
• Annual risk 9-10%/year
– Antiphospholipid antibody syndrome
• Annual risk 5-6%/year

38. Principle for Continuing After 3
Months
• Role of anticoagulation shifts to prevention of
new episodes
• Individual’s assessment of relative risks
– Risk (fear) of new thrombosis outweighs risk (fear)
and inconveniences of therapy

39. Best Predictor of Recurrence:
Circumstances Around First Event
• Unprovoked events, independent of testing:
– 10-15% recurrence in first 2 years after stopping
warfarin, then 2-3%/year thereafter
Ridker, NEJM 348:1425, 2003
– Cumulative risk at 2-5 years 25%, 10 years 30-40%
Donadini, J Thromb Thrombolysis, 31:301, 2011
• Risk of PE (vs. DVT) as the next event
– 60-70% if first event was PE
– 20% if first event was DVT
Agnelli, J Thromb Haemost 25:37, 2008

40. Recurrence Risk on Placebo
• 9% at one year after stopping anticoagulation
Apixaban (AMPLY-Ext) study of unprovoked VTE
Agnelli, NEJM 2013

41. Recurrence Risk on Placebo
• 10% recurrence in first year after discontinuation
(EINSTEIN-EXT)
NEJM 363:2499, 2010

42. Prediction of VTE Recurrence Risk:
Unprovoked vs. Provoked
• Prandoni, Haematologica 92:199, 2007
Unprovoked:
~20% at 2 years
~50% at 10 years
Provoked:
~10% at 2 years
~20% at 10 years

43. Prediction of VTE Recurrence Risk
• Risk varies with triggering event:
Idiopathic 3.0-10%/year
Venous insufficiency 5.5%/year
Travel-related
Immobilization
Infection
3.0-4.2%/year
Estrogens
Trauma
1.5-4.2%/year
Postoperative 0.7%/year
Schulman, J Thromb Haemost 4:734, 2006; Iorio, Arch Intern Med 170:1710, 2010

44. Travel-Related Thrombosis
• Only with flights (no other modalities)
• Background risk
– 1.1 events/million person-days overall
– 27 clinical VTE/1 million travelers within 14 days
– Symptomatic PE “unheard of” in flights <6 hrs
– Biggest relative risk in flights >8 hrs (>12 hrs)
• OR 3.6 if clinical VTE risk factors
– Mostly asymptomatic calf clot by imaging (1-2%)
– Risk of PE up to 4/million if >12 hour flight
Philbrick, JGIM 22:107. 2007; Kahn, Chest 141 (2)(Suppl):e195, 2012

45. Principle:
Lower Risk After Provoked Events
• Assumes risk factor was transient
– Persistent malignancy associated with 20+% risk of
recurrence in first year if anticoagulation stopped
de Jong, BJH 158:433, 2012
– Re-use of estrogen-based OCPs after stopping
anticoagulation associated with 8-fold risk of
recurrence
• Transdermal estrogen and progesterone-only NOT
associated with increase risk compared to nonusers
• Risk of recurrence in non-users: 5% in first year
Vaillant-Roussel, Contracception 84:e23, 2011

46. Risk of Venous Thrombosis
Increases with Age
Overall risk = 1-2 in 1000/year
AGE
RISK OF THROMBOSIS
<1:50,000
50 y.o. 80 y.o.
1:700
1:200
1:25,000
1:2500
Naess, J Thromb Haemost 5:692, 2007; White, Circ 107:1, 2003

47. Am I in the Recurrence Group?
• Markers of propensity for recurrence
– Elevated factor VIII activity (especially if >200%)
• May double the risk of recurrence
– Elevation of other factors (IX, XI) may be weak
predictors of recurrence
• Current areas of interest:
– D-dimer
– Residual vein thrombosis

48. Role of D-Dimer in Predicting VTE
Recurrence
• Elevation in D-dimer does not indicate the presence
of an acute thrombosis
– The only diagnostic value is a negative result which
rules out an acute thrombosis
Wells, J Thromb Haemost 5 Suppl 1:41, 2007
• However, measurement of D-dimer at least one
month off anticoagulation may risk-stratify
– Negative D-dimer: 3.5%/year
– Positive D-dimer: 8.9%/year
Verhovsek, Ann Intern Med 149:481, 2008
• Which kit? What is “positive”? Age adjusted?

49. Role of Residual Vein Thrombosis
(RVT) in Predicting VTE Recurrence
• Inconsistent association of RVT with increased risk of
recurrent VTE
– 4 studies suggest increase risk of ~2-fold
– 5 studies failed to find an association
Kearon, Clin Chest Med 31:719, 2010
• If there is an association, it likely represents a
systemic biological - not mechanical - phenomenon
– 40-50% of recurrent events are on the opposite leg
• Difficult to standardize (definition, technique)

50. Combination of Stratifying Factors
• PROLONG: utilization of RVT and/or D-dimer to
guide anticoagulation
– 619 subjects with first proximal DVT or PE treated
with anticoagulation for at least 3 months
– D-dimer measured 30 days after discontinuation
• Normal D-dimer (n=310): no further anticoagulation
• Abnormal D-dimer: randomized
– No further anticoagulation (n=99)
– Resume anticoagulation for 18 months (n=81)
– Residual vein thrombosis assessed (as per previous
study e.g. 2 mm in common femoral/popliteal vein)
Cosmi, Eur J Endovasc Surg 39:356, 2010

51. Use of Stratifying Factors
• Impact on recurrence:
– D-dimer if anticoagulation discontinued:
• Normal: 10% (5.5/100 pt-yrs)
• Abnormal: 19% (12/100 pt-yrs) HR=2.1
– RVT: no difference: 11% with vs. 13% without
Cosmi, Eur J Endovasc Surg 39:356, 2010

52. Bottom Line Principle
• If there were no clear precipitating factors, the
likelihood of recurrence VTE is ~20-25% at 2 years,
~50% at 10 years
– Comparable to having APS, AT deficiency, or a male with a
family history and some other defined states
– Likely similar for people with persistent recognized risk
factors (e.g. cancer)
• The weaker the “precipitating factor”, the higher the
risk of recurrence
• D-dimer might discern lower (higher?) risk group

53. Recurrence Risk on Anticoagulation
• Risk of recurrence on warfarin therapy
– Goal INR 2-3: <1%/year
– Goal INR 1.5-2.0: 2-2.5%/year
• Risk of recurrence 1-2% over 2 years in studies of
extended prophylaxis of new oral anticoagulants
• Risk of recurrence on ASA: 5-7%/year
– Same as placebo in one study, better in another and in
meta-analysis (HR ~0.6)
Ridker, NEJM 348:1425, 2003; Kearon, NEJM 349:631, 2003
Agnelli, NEJM 368:699, 2013; Brighton, NEJM 367:1979, 2012
Becattini, NEJM 366:1959, 2012

54. Bleeding Risk of Long-Term
Anticoagulation
• Major bleeding: 0.9-1.4%/year
– Risk increases with age (e.g. lower in young people)
– May be slightly lower with new oral agents 0.6-1.0%
• Annual long-term fatality estimates
Event Rate of Fatal Event Case Fatality Rate
Fatal PE
0.49% (0.36-0.64) 9.0% (6.8-11.8)
(without tx)
Schulman, Semin Thromb Hemost 39:141, 2013
Fatal bleed
(with tx)
0.63% (0.61-0.65) 9.1% (2.5-21.7)

55. Principles Regarding Bleeding
• Anticoagulation doesn’t cause bleeding
– Bleeding occurs when a vessel ruptures
– Anticoagulation doesn’t weaken vessels
–
• Risk of major bleeding, including intracranial,
does not correlate with history of falls
Donze, Am J Med 125:773, 2012
Outcome Placebo
Apixaban
2.5 mg po bid
Apixaban
5.0 mg po bid
Bleeding 22 (2.7%) 27 (3.5%) 35 (4.3%)
Major 4 (0.5%) 2 (0.2%) 1 (0.1%)
Agnelli, ASH, 2012

56. Bleeding Prediction Rules
• Systematic review and performance analysis
– RIETE, HAS-BLED, mOBRI use similar factors
• Age (>65-75), renal/liver disease, history of bleeding,
anemia, hypertension, use of anti-plt agents, alcohol
– Studies often in atrial fibrillation (RIETE in VTE)
– None with sufficient predictive power to
distinguish risk groups
• Low RIETE score may predict a very-low bleeding risk
Loewen and Dahri, Amer J Hematol 90:1191, 2011

57. “Clot-ability Scale”: A Conceptual Model
0 100
50
ME PT #1
PREGNANCY
PT #2
PREGNANCY
LONG-HAUL FLIGHT (?)
AGE
Everyone has number
(inherited/acquired)
We just can’t measure it!
WARFARIN
WARFARIN
WARFARIN
ANTICOAGULATION
Clinical
Clotting
Clinical
Bleeding

58. Duration of Anticoagulation:
ACCP 2012
• Minimum: 3 months for DVT or PE
– Provoked by transient risk factor = sufficient
– Unprovoked: favor “extended” over 3 months
• If bleeding risk is moderate or high, favor 3
months over longer, even if 2nd unprovoked event
• If “extended”, annual risk assessment of
risk/benefit
Kearon, Chest 141:e419S, 2012

59. What if they have
more than one clot?
• No evidence recurrent provoked events are worse
than a single provoked event
– Risk estimate of recurrence is the likely same
• Some data for multiple unprovoked events
30% recurrence
2.5 years of follow-up
Adapted from Schulman, Am J Med 104:332, 1998
First
unprovoked
event,
treated for
6 months
(n=412)
Second
unprovoked
event
14%
6 months
Indefinite 3% recurrence

60. Duration: A Review of Principles
• Anticoagulation does not make clot go away or the
blood to flow better
• The body appears to need 3 months to “stabilize” the
situation (time, not days on drug)
• No evidence that more than 3 months is better, but
could reason that some might need more time to
“heal” before potentially have new clots occur
• A decision to continue otherwise based on more
concern about new clotting than bleeding

61. Deciding on Extended Anticoagulation
• Current literature endorses “acceptable risk” of
recurrence of up to 5%/1 year or 15%/5 years
Kearon, J Thromb Heamost 8:2313, 2012
• Individual should decide what level of risk is OK:
– Risk of recurrence clotting based on analysis of the
initial clotting event
• If unprovoked, risk is 25% at 2 years, 50% at 10 years
• Testing usually doesn’t help, D-dimer might
– Anticoagulation doesn’t cause bleeding, but unlucky if
you have major bleeding while you’re on it, because it
might be worse (0.5-2%/year)

62. Pushes off the edge:
e.g. surgery
Risk One
The closer to the edge you are,
the less it takes to push you off
Normal Risk
1-2 : 1000
Conceptual
Model
Anticoagulation

63. 24 year old man with unprovoked PE.
No bleeding problems, negative hypercoag testing.
How long should he take anticoagulation?
• 3 months
• 6 months
• One year
• Indefinite

64. 19 year old woman with DVT while on OCPs for 3 years.
No bleeding problems, Factor V Leiden positive.
How long should she take anticoagulation?
• 3 months
• 6 months
• One year
• Indefinite

65. 45 year old man with history of 2 clots, (calf, popliteal),
each after arthroscopy. No bleeding, negative testing
How long should he take anticoagulation?
• 3 months
• 6 months
• One year
• Indefinite

66. 60 year old woman with history of PE on tamoxifen for
metastatic breast cancer. No bleeding, no testing.
How long should she take anticoagulation?
• 3 months
• 6 months
• One year
• Indefinite

67. 64 year old man with history of PE after bladder cancer
surgery 5 months ago. “Too much bleeding” to take
anticoagulation after surgery, but in your office now.
How long should he start anticoagulation for his PE?
If yes, for how long?
• 3 months
• 6 months
• One year
• Lifelong

68. The “True” Right Answers?
Anticoagulation should be given for as long as
the person feels the risks of having a new
blood clot are higher or more worrisome than
the risks/inconveniences of the therapy.