PE, DVT, and Thee By Paul Rega, MD, FACEP OMNI Health

1
PE, DVT, and Thee

• By
• Paul Rega, MD, FACEP
• OMNI Health Services
• (You knowthe docs
• who work the ER)

2
VTE

• Definition Spectrum of diseases that includes
  DVT and PE

3
Introduction

• 2 million diagnosed with DVT annually
• Maybe 80-117/100,000 persons occur annually.
• 900/100,000 by age 85
• 1 person in 20 will develop a DVT in his/her
  lifetime.
• 600,000 hospitalizations per year occur for DVT
  in the United States.
• In hospitalized patients, the incidence of venous
  thrombosis is considerably higher and varies from
  20-70.

4
More Introduction

• 600,000 diagnosed with PE annually
• Death from DVT is attributed to massive PE
• Causes 200,000 deaths annually in the United
  States.
• Prospective studies in patients with proven DVT
  but without any signs or symptoms to suggest PE
  find that roughly half of these "asymptomatic"
  patients have experienced undiagnosed PE.

5
Peripheral
6
Interesting

• Prospective studies show that in the absence of
  prophylaxis acute DVT may be demonstrated in any
  of the following
• General medical patients placed at bed rest for a
  week (10-13)
• Patients in medical intensive care units (29-33)
  
• Patients with pulmonary disease kept in bed for 3
  or more days (20-26)
• Patients admitted to a coronary care unit after
  myocardial infarction (27-33)
• Patients who are asymptomatic after coronary
  artery bypass graft (48)

7
What is the Virchow Triad?

• Not a type of Kishka
• Blood sausage from Poland
• For you WASPS out there.

8
Virchow Triad

• All recognized risk factors for VTE arise from
  the 3 underlying components of the Virchow triad
  
• Venous stasis,
• Hypercoagulability, and
• Vessel intimal injury.

9
Risk Factors

• General
• Age
• Immobilization longer than 3 days
• Pregnancy and the postpartum period
• Impaired fibrinolysis
• Major surgery in previous 4 weeks
• General anesthesia (500x)
• Impaired fibrinolysis
• Long plane or car trips (gt4 h) in previous 4
  weeks
• Obesity?
• Trauma
• Multiple trauma
• CNS/spinal cord injury
• 40 in post-op
• Burns
• Lower extremity fractures

• Medical
• Cancer
• Previous DVT
• 5x
• Stroke
• 50 in 5d post-stroke
• Acute myocardial infarction (AMI)
• Congestive heart failure (CHF)
• Sepsis
• Nephrotic syndrome
• Ulcerative colitis
• Fibrinogen/VIII up
• Antithrombin III down
• Hyperlipidemia

10
Risk Factors (continued)

• Hematologic
• Polycythemia rubra vera
• Thrombocytosis
• Inherited disorders of coagulation/fibrinolysis
• Antithrombin III (anticoag) deficiency
• Liver disease
• Protein C (anticoag) deficiency
• Natural/acquired
• Protein S (anticoag) deficiency
• Prothrombin 20210A mutation
• Factor V Leyden
• 7 of general population
• 50 of idiopathic DVT
• Dysfibrinogenemias and disorders of plasminogen
  activation
• Type A in reproductive women

• Vasculitis
• Systemic lupus erythematosus (SLE) and the lupus
  anticoagulant
• 9
• Behçet syndrome
• Homocystinuria
• Drugs/medications
• Intravenous drug abuse
• Oral contraceptives
• Impaired fibrinolysis
• 3-12 x higher
• Estrogens
• Heparin-induced thrombocytopenia
• ChemoRx
• Reduce anticoag/increase procoag

11
What about

• The upper extremity (UE)?

12
Upper Extremity DVT

• Growing incidence
• Due to indwelling catheters and dialysis .
• PE from UE DVT as frequent as PE from LE DVT.
• Sounds like a cryptic message from al-Qaeda,
  doesnt it?
• 512 patients with arm DVT (Chest.
  2008133143-8.)
• 196 patients (38) had cancer and 228 patients
  (45) had catheter-related DVT.
• Patients with arm DVT have less often clinically
  overt PE than those with lower-limb DVT, but
  their 3-month outcome is similar.
• Among patients with arm DVT, those with cancer
  have the worse outcome.

13
What are the signs and symptoms of DVT?

• Lower extremity (LE)
• Proximal
• Distal
• Most clinical PEs come from
• Popliteal v.
• Femoral v.
• Iliac v.

14
A Dilemma

• Even when a patient has a swollen, painful,
  congested leg that appears to be clinically
  obvious DVT, the chance that DVT is the correct
  diagnosis is only 50.
• Most cases of DVT lack classic signs or symptoms
• Thus, diagnostic tests must be performed whenever
  the diagnosis of DVT is being considered.

15
Propagation

• 10-30 of distal clots propagate to proximal
  legs.
• The single largest autopsy series ever performed
  to specifically to look for the source of fatal
  PE was performed by Havig in 1977, who found that
  one third of the fatal emboli arose directly from
  the calf veins.

16
Wells Clinical model for predicting pretest
probability of deep-vein thrombosis

• Active CA (Rx ongoing, given within previous 6
  mos. or palliative) 1
• Paralysis, paresis, or recent plaster
  immobilization of lower limbs 1
• Recently bedridden gt3d or major surgery within
  previous 12 wk requiring general or regional
  anesthesia
  1
• Localized tenderness along deep venous system
  1
• Swelling of entire leg
  1
• Calf swelling gt3cm more than uninvolved leg (10
  cm below tibial tuberosity) 1
• Pitting edema confined to symptomatic leg 1
• Collateral superficial veins (nonvaricose) 1
• Previously documented DVT 1
• Alternative diagnosis at least as likely as DVT
  -2

Score 2 or more DVT probability likely Score
lt 2 DVT probability unlikely.
High probability 3 (gt65) Moderate
probability 1-2 Low probability 0 or less (lt10)
17
Case 1

• 35 YO Female
• Left leg pain
• What do you want to know?

18
Case 1

• Present Hx
• Past Hx
• Family Hx
• Medications

19
Case 1 The Exam

• Examining the leg

20
Case 1

• Probability?

21
Case 2

• 85 YO Male
• Deep ache in right leg just above ankle.
• What do you want to know?

22
Case 2

• Probability?

23
Case 3

• 50 YO Female
• Pain and swelling left leg.
• What do you want to know?

24
Case 3

• Probability?

25
Now the test
26
In the days of King ArthurIPG

• Records changes in blood volume of an extremity,
  which are directly related to venous outflow.
• Sensitive and specific for proximal vein
  thrombosis
• Insensitive for calf vein thrombosis.
• Insensitive for UE DVT

27
IPG

• Noninvasive
• Inexpensive
• Safe
• No radiation
• Portable
• Accurate
• Proximal DVT
• Recurrent DVT

• Operator dependent
• Insensitive (false neg.)
• Calf DVT
• Non-obstructing thrombi
• Nonspecific (false pos.)
• Increased intra-abdominal pressure
• Increased CVP
• Decreased blood flow to legs
• Nonthrombotic venous outflow obstruction

28
Venogram

• Sensitive
• 100 (Proximal)
• Specific
• 100 (Proximal)
• Acute vs Chronic
• Less operator dependent
• Most accurate for calf DVT

• Invasive
• Expensive
• Not portable
• Contraindications
• Renal insufficiency
• Contrast allergy
• Painful
• Cause DVT

29
Venogram

• Gold standard?
• Radiologists
• Uncomfortable/unwilling
• With non-expert radiologists
• Up to 30 are technically inadequate
• Phlebitis
• Allergic reaction
• Largely replaced by Doppler US.

30
US

• Compressibility of veins
• Doppler
• Flow characteristics
• Sensitivity of duplex ultrasonography
• Proximal vein DVT 97
• Calf vein DVT 73
• Specific
• 95

31
US

• Noninvasive
• Safe
• Portable
• Relatively inexpensive
• Available
• No radiation
• UE DVT

• Operator dependent
• Less accurate
• Chronic DVT
• Calf DVT
• Pelvic DVT
• Difficult
• Obesity
• Edema

32
US

• In U.S., 500,000 patients evaluated for DVT
• 80 normal at 1st US
• Only 2 abnormal 5-7 days later
• Spending a lot of when most of the tests
  come back negative.

33
US

• Negative at Day 0
• 50 Positive at Day 1
• 50 Positive by day 7

34
MRI

• In limited studies, accuracy approaches that of
  venography.
• The diagnostic test of choice for suspected iliac
  vein or inferior vena caval thrombosis when CT
  venography is contraindicated or technically
  inadequate.
• In the second and third trimester of pregnancy,
  MRI is more accurate than duplex ultrasonography
  because the gravid uterus alters Doppler venous
  flow characteristics.
• Said to be as sensitive as US in detecting calf
  and pelvic DVTs.

35
MRI

• Sensitive
• Specific
• Safe
• Pelvic/IVC DVT
• No radiation
• Acute vs chronic

• Claustrophobic
• Expensive
• Not portable
• Metallic devices
• Insensitive
• Calf DVT

36
D-Dimer

• Fibrin degradation product
• Value increases with clots, surgery, trauma, CA,
  infection, Gabby Hays.
• Many types
• Most accurate Quantitative
• ELISA (Enzyme-linked immunosorbent assay)
• STA Liatest immunoturbidimetric D-dimer assay
• Cut-off 0.21 µg/mL
• Low risk patients normal D-dimer lt1
  probability of DVT.
• D-dimer Not to be used alone to r/o DVT in
  patients with moderate or high probability of DVT
• Sensitivity is always lower for calf DVT

37
Bottom Line

• A positive D-dimer needs further testing.

38
Determination of pretest probability of DVT
DVT unlikely (score 1)
DVT likely (score gt1)
Good D-Dimer test
Good D-Dimer test
_
_


Ultrasound
No DVT
Ultrasound
Ultrasound
_
_

_


Treat with anticoagulants
Repeat US in 1 week
Treat with anticoagulants
No DVT
No DVT
_

No DVT
One Guideline
39
Treatment
40
Importance of Proper/Prompt DVT Therapy

• Decreases risk of recurrent DVT to 5
• Decreases risk of fatal PE to lt1

41
Leg DVT

• Heparin/Lovenox OK
• Fibrinolysis
• Unclear
• If Limb-threatening
• Remember Thrombolytic therapy increases the
  risk of major bleeding 1.5-fold to threefold in
  patients with acute venous thromboembolism

42
Heparin

• Binds to Antithrombin
• Accelerates ability of Antithrombin to inactivate
  Thrombin, factor Xa, Factor IXa.
• 1/2 life 60
• Bioavailability
• Variable due to protein binding.
• Bleeding complication
• The risk of bleeding associated with IV
  unfractionated heparin (UFH) in patients with
  acute venous thromboembolism is lt 3 in recent
  trials.
• Bleeding risk may increase with increasing
  heparin dosages and age (gt 70 years).

43
Low-Molecular-Weight Heparin

• Derived from heparin
• Result of depolymerization
• 1/3rd the size of heparin
• Research on thousands
• Safe
• Effective
• Convenient

44
LMWH

• Enoxaparin (Lovenox), dalteparin (Fragmin), and
  tinzaparin (Innohep) have received US Food and
  Drug Administration (FDA) approval for the
  treatment of DVT in the United States.
• Enoxaparin Approved for inpatient and outpatient
  treatment of DVT.
• No monitoring
• gt90 bioavailable
• Minimal protein binding
• Levels are predictable
• No heparin-induced thrombocytopenia (1)
• No anti-heparin antibodies
• In plasma for 12-16h
• Allows for BID dosing
• Associated with less major bleeding compared with
  UFH in acute venous thromboembolism.

45
Fondaparinux (Arixtra)

• New
• A synthetic pentasaccharide
• Catalyzes the inhibition of factor Xa, but not
  thrombin, in an antithrombin-dependent fashion
• Binds only to antithrombin
• therefore, HIT and osteoporosis are unlikely to
  occur.
• Excellent bioavailability when administered
  subcutaneously
• Has a longer half-life than LMWHs.
• Given once daily by subcutaneous injection in
  fixed doses, without anticoagulant monitoring.

46
Direct Thrombin Inhibitors

• Hirudin
• Bivalirudin
• Argatroban
• Melagatran
• Parenteral

47
Greenfield Filter

• When anticoagulation has failed or
• Risk of serious hemorrhage
• May double risk of recurrent DVT

48
Proven Clinically Significant DVT
Any reason for hospitalization ? Comorbidity? Comp
liance concerns? Logistical issues?
Yes
No

• LMWH
• Coumadin 5mg q day
• VNA for BID
• injections
• Evaluate
• discontinuation of LMWH
• 5) Evaluate q 5-7d

Hospitalize
49
Central
50
PE

• 300,000/annually
• 2 die within 1st day
• 10 get recurrent PE
• Death rate 45

51
PE A Difficult Diagnosis

• 2 Studies
• Univ. of Toronto
• 44 die from PE
• 30 (68) diagnosed at autopsy
• Henry Ford
• 20 die from PE
• 14 (70) diagnosed at autopsy
• 2/3rd of patients with proven PE have no DVT
  symptoms, and
• 1/3rd of patients Impossible to find the
  original site of DVT without an autopsy.

52
What are the SS of PE?

• Come on. What are the signs and symptoms of PE?

53
A Conundrum

• Hemoptysis, dyspnea, chest pain occur in fewer
  than 20 of patients in whom the diagnosis of PE
  is made
• Most patients with those symptoms are found to
  have some etiology other than PE to account for
  them.
• Of patients who go on to die from massive PE
• 60 have dyspnea
• 17 have chest pain
• 3 have hemoptysis
• PE has been diagnosed in 21 of young, active
  patients who come to the ED complaining only of
  pleuritic chest pain.

54
Signs Seen in Massive PE

• 96 Tachypnea (respiratory rate gt16/min)
• 58 Rales
• 44 Tachycardia (heart rate gt100/min)
• 43 Fever (temperature gt37.8 C)
• 36 Diaphoresis

• 32 Clinical signs and symptoms suggesting
  thrombophlebitis
• 24 Lower extremity edema
• 23 Cardiac murmur
• 19 Cyanosis

55
Atypical Presentations

• Patients with PE may present with atypical
  symptoms, where strong suspicion in a high-risk
  patient often leads to consideration of PE in the
  differential diagnosis
• Seizures
• Syncope
• Abdominal pain
• Fever
• Productive cough
• Wheezing
• Decreasing level of consciousness
• New onset of atrial fibrillation

56
Wells Clinical Prediction Rule for PE

• Clinical symptoms of DVT
  3
• Other dx less likely than PE
  3
• Heart rate gt100 bpm
  1.5
• Immobilization/surgery within past 4 wks 1.5
• Previous DVT/PE
  1.5
• Hemoptysis
  1
• Malignancy
  1

Risk Score gt 6 High risk (78.4) 2-6
Moderate risk (27.8) lt2 Low risk (3.4).
57
What non-imaging tests can help you?

• Come on What non-imaging tests can help you?

58
What tests?

• EKG?
• Nonspecific changes or tachycardia usually
• S1-Q3-T3 pattern In only 20 of patients with
  proven PE.
• ABGs?
• Nonspecific
• Moderately sensitive
• pO2 may be normal with minor PE
• ? pO2 and ?pCO2
• Seen in conditions other than PE
• D-dimers?
• Depends
• Others?

59
CXR?

• What would you expect to find?

60
CXR

• Virtually always normal.
• Rarely the Westermark sign
• A dilatation of the pulmonary vessels proximal to
  an embolism along with collapse of distal
  vessels, sometimes with a sharp cutoff.
• Over time, an initially normal CXR often begins
  to show atelectasis, which may progress to cause
  a small pleural effusion and an elevated
  hemidiaphragm.
• After 24-72 hours, one third of patients with
  proven PE develop focal infiltrates that are
  indistinguishable from an infectious pneumonia.
• A rare late finding of pulmonary infarction
• The Hampton hump, a triangular or rounded
  pleural-based infiltrate with the apex pointed
  toward the hilum, frequently located adjacent to
  the diaphragm.

61
V-Q Scan
Scan
Clinical Probability
80 100 20 - 79
0 - 19
High 82-99
78-94 21-86
Intermediate 49-80 22-34
8-27
Low 16-68
11-22 1-11
Normal 0-52
2-16 0-9
Bottom line Only use scans with high
probability or normal for clinical
decision-making. N.B. Only 40 of scans in PE
patients are high probability.
62
MDCTA

• High-resolution multidetector computed
  tomographic angiography
• Has sensitivity and specificity comparable to
  that of contrast pulmonary angiography
• Accepted both as the preferred primary diagnostic
  modality and as the criterion standard for making
  or excluding the diagnosis of pulmonary embolism.
  
• Caution Multiple small emboli that have lodged
  in distal vessels
• Overall negative predictive value of MDCTA for
  pulmonary embolism is greater than 99.
• Future Simultaneous MDCTA Below-the-pelvis CT
  venography without added contrast

63
Pulmonary Angiography

• Complications 3-4
• Arrhythmias, cardiac perforation, cardiac arrest,
  hypersensitivity
• Gold standard
• A positive pulmonary angiogram provides virtually
  100 certainty that an obstruction to pulmonary
  arterial blood flow does exist.
• A negative pulmonary angiogram provides greater
  than 90 certainty in the exclusion of PE.
• Being replaced by MDCTA

64
Transthoracic Echocardiography (TTE)

• TTE alone is not sensitive or specific enough for
  detecting PE
• New study The ratio of right ventricular to
  left ventricular (RV/LV) end diastolic dimension
  was the most accurate predictor for PE, with a
  sensitivity and specificity of 66 and 77,
  respectively.
• Might lead cardiologist in the right direction
• Echocardiography 2008 25 584-590

65
SS of PE
SS of PE
Pre-test PE probability score
CT pulmonary angiography
Negative
Positive
Treat PE
Doppler US of legs
Negative
Positive
Treat VTE
Pre-test PE probability score
Intermediate
Low
High
D-dimer or serial US
Angiography
Negative
Positive
Treat PE
Follow-up for alternative dx
Diagnosing PE with CT (adapted from Am Fam Phys
2004 69 12)
66
SS of PE
SS of PE
Pre-test PE probability score
V-Q Scan
Normal
High Probability
Low/Intermediate Probability
Follow-up for alternative dx
Pre-test PE probability score
Follow US protocol from prior slide
Intermediate
Low
High
Angiography
Negative
Positive
Treat PE
Follow-up for alternative dx
Diagnosing PE with V/Q Scanning (adapted from Am
Fam Phys 2004 69 12)
67
Case 1

• 35 YO Female
• Mom 2 days ago
• I feel a little shaky, a little short of
  breath.

68
Case 1

• What do you want to know?

69
Case 1

• What do you want to do?

70
Case 2

• 85 YO Male
• Admitted for cellulitis of the left leg
• My damn heart is doing flippity-flops, Cutie.

71
Case 2

• What do you want to know?

72
Case 2

• What do you want to do?

73
Case 3

• 50 YO Female
• Being worked up for spread of breast CA.
• I cant breathe all of a sudden.

74
Case 3

• What do you want to know?

75
Case 3

• What do you want to do?

76
Treatment
77
The Drugs

• UFH
• LMWH
• Arixtra

78
Heparin (UFH)

• 5000U or 80 U/kg IV to start
• Heparin-Induced Thrombocytopenia (HIT)
• 9/332 (2.7)
• Consider
• Thrombotic syndrome
• Platelets fall gt50
• Especially if treated within 2 weeks
• Usually between 5-14 days of heparin initiation
• May not be on heparin at the time
• Bleeding
• The risk of major bleeding associated with IV
  unfractionated heparin (UFH) in patients with
  acute venous thromboembolism is lt 3 in recent
  trials. This bleeding risk may increase with
  increasing heparin dosages and age (gt 70 years).
• 35/1853 (1.9)

79
Suspected or Confirmed HIT? What to do?

• An alternative, nonheparin anticoagulant
• Danaparoid
• Lepirudin (Refludan)
• Argatroban
• Fondaparinux (Arixtra) or
• Bivalirudin (Angiomax) over the further use of
  unfractionated heparin (UFH) or
  low-molecular-weight heparin (LMWH) therapy or
  initiation/continuation of vitamin K antagonists
  (VKAs)
• For patients receiving Coumadin at the time of
  diagnosis of HIT, vitamin K (10 mg po or 5 to 10
  mg IV) is recommended
• When to re-start? Controversial.

80
LMWH Dosages

• Lovenox 1 mg/kg q 12h or 1.5 mg/kg/d SC
• Max. 180 mg/d
• Fragmin 100U/kg q 12h or 200 U/kg/d SC
• Max. 18,000U/d
• Innohep 175U/kg/d SC
• Max. 18,000U/d

81
Fondaparinux (Arixtra)

• A synthetic pentasaccharide
• Catalyzes the inhibition of factor Xa, but not
  thrombin, in an antithrombin-dependent fashion
• Binds only to antithrombin
• therefore, HIT and osteoporosis are unlikely to
  occur.
• Excellent bioavailability when administered
  subcutaneously,
• Has a longer half-life than LMWHs.
• Given once daily by subcutaneous injection in
  fixed doses, without anticoagulant monitoring.

82
Recent Recommendations for VTE Therapy (Confirmed)

• Patients with objectively confirmed deep vein
  thrombosis (DVT) or pulmonary embolism (PE)
• subcutaneous (SC) low-molecular-weight heparin
  (LMWH),
• monitored IV, or SC unfractionated heparin (UFH),
  
• unmonitored weight-based SC UFH, or
• SC Fondaparinux
• At least 5 days
• With Coumadin

83
Recent Recommendations for VTE Therapy (Suspected)

• Patients with a high clinical suspicion of DVT or
  PE
• Treatment with anticoagulants while awaiting the
  outcome of diagnostic tests.

84
Recent Recommendations for PE Thrombolytic Therapy

• Confirmed PE
• Early evaluation of the risks to benefits of
  thrombolytic therapy.
• Thrombolytic therapy increases the risk of major
  bleeding 1.5-fold to threefold in patients with
  acute venous thromboembolism
• Hemodynamic compromise
• Short-course thrombolytic therapy
• Nonmassive PE
• Use of thrombolytic therapy not recommended

85
Thrombolytics

• Reteplase (Retavase) Preferred (fast)
• Alteplase/t-PA (Activase) Preferred (fast)
• Urokinase (Abbokinase)
• Streptokinase (Kabikinase, Streptase)
• Least desirable of the 4 Antigenic problems and
  other adverse reactions force the cessation of
  therapy in a large number of cases.
• Total pulmonary resistance (along with pulmonary
  artery pressure and cardiac index) improved
  significantly after just 0.5 hours in the
  reteplase group as compared to 2 hours in the
  alteplase group.

86
Surgical Thromboembolectomy

• Reserved for patients in whom fibrinolysis has
  failed or cannot be tolerated.

87
Disposition

• PE
• Admit
• DVT
• Another story

88
A Word about Special Cases
89
Pregnancy

• Pulmonary embolism (PE) Leading cause of
  maternal mortality during pregnancy and up to 6
  weeks postpartum.
• Most common nontraumatic cause of maternal death
  in pregnancy
• Compared with nonpregnant women, pregnant women
  have a 5-fold increased risk for VTE.
• Prevalence is even higher in the postpartum
  period.
• LMWH over UFH for the prevention and treatment of
  VTE
• Throughout pregnancy 6 weeks post-partum
• Thrombolytics (same dosage) if condition warrants.

90
Imaging in Pregnancy

• Helical computed axial tomographic pulmonary
  angiography (HCTPA ) vs. V/Q vs. MRI?
• HCTPA is associated with lower radiation doses
  when compared with V/Q scanning during all
  trimesters of pregnancy.
• MRI
• Fetus is not exposed to ionizing radiation or
  intravenous contrast material.
• Sensitivity and specificity of MRI have been
  reported in ranges comparable to HCTPA for the
  diagnosis of PE.
• Disadvantages Long acquisition times, with the
  need for respiratory and cardiac gating.
• What does X-Ray do here?????

91
Kids

• Anticoagulant therapy with either unfractionated
  heparin (UFH) or low-molecular-weight heparin
  (LMWH)

92
In Conclusion

• Ahhhhhhh..hhh, finally!

93
VTE Prophylaxis in Hospital

• No to aspirin alone as thromboprophylaxis for any
  patient group
• Mechanical methods of thromboprophylaxis OK for
  patients at high bleeding risk or possibly as an
  adjunct to anticoagulant thromboprophylaxis
• Major general surgery, thromboprophylaxis with a
  low-molecular-weight heparin (LMWH), low-dose
  unfractionated heparin (LDUH), or Fondaparinux
• Routine thromboprophylaxis for all patients
  undergoing major gynecologic surgery or major,
  open urologic procedures with LMWH, LDUH,
  Fondaparinux, or intermittent pneumatic
  compression (IPC).
• Elective hip or knee arthroplasty, one of the
  following three anticoagulant agents is
  recommended LMWH, Fondaparinux, or a vitamin K
  antagonist (VKA)
• Hip fracture surgery (HFS), the routine use of
  Fondaparinux, LMWH, a VKA or LDUH is recommended
• All major trauma and all spinal cord injury (SCI)
  patients should receive thromboprophylaxis
• Acute medical illness, thromboprophylaxis with
  LMWH, LDUH, or Fondaparinux is recommended
• All ICU patients be assessed for their risk of
  VTE, and that most receive thromboprophylaxis on
  admission

94
References

• Clinical Policy Critical Issues in the
  Evaluation and Management of Adult Patients
  Presenting with Suspected Lower-Extremity Deep
  Venous Thrombosis. Ann Emerg Med 2003 42
  124-135.
• Bates SM, Ginsberg JS. Treatment of Deep-Vein
  Thrombosis. NEJM 2004 351 268-277.
• Linken LA, Choi PT, et al. Clinical Impact of
  Bleeding in Patients Taking Oral Anticoagulant
  Therapy for Venous Thromboembolism. Ann Intern
  Med 2003 139 893-900.

95
References

• Kearon C, Hirsh J. Venous Thromboembolism.
  www.acpmedicine.com/sam/chapters/ch0118.htm.
  Accessed 1/5/05.
• Ramzl DW, Leeper KV. DVT and Pulmonary Embolism
  Diagnosis. Am Fam Physician 2004692829-2836.
• Kyrte PA, Eichinger S. Deep Vein Thrombosis.
  Lancet 2005 365 1163-1174.
• Ho WK, Hankey GJ, et al. Venous Thromboembolism
  Diagnosis and Management of Deep Venous
  Thrombosis. MJA 2005 182 476-481.

96
References

• Kearon C, Ginsberg JS, et al. A randomized Trial
  for Diagnostic Strategies after Normal Proximal
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