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Prevention of Venous
Thromboembolic Events inTrauma Patients
Michael L Gimbel, MD
Trauma Conference12/18/01
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Venous Thromboembolic Events
(VTE)
Claim 50,000 lives/yr in US
Cause 300,000 to 600,000 hospitalizations/yr
in US
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Deep Venous Thrombosis (DVT)
Pulmonary Embolism (PE)
Venous Thromboembolic Events
(VTE)
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DVT in Trauma
Increased incidence of DVT/PE in trauma pts
DVT Incidence: 4% to 58% (11.8% AHRQ)
DVT w/ clinical sxs: 1.5% to 25%
Geerts, NEJM, 1994
58% DVT w/o prophylaxis
18% prox vein DVT
3% B/L prox vein DVT
1.5% DVTs clinically suspected
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PE Incidence: 0.2% to 5.8% (1.5% AHRQ)
1/3 PEs are Fatal events (AHRQ)
60% PEs occur in 1st week post-trauma
6% w/ in 1st 24 hrs
25% w/ in 1st 4 days
(Arch Surg, Owings, 1997) Geerts, NEJM, 1994
2% PE w/o prophylaxis (7/349 pts)
PE in Trauma
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Increased incidence of DVT/PE in trauma pts
Mechanisms
Stasis
qAntithrombin III (AT-III)
q Protein C + S
Release of tissue thromboplastin at sites of injury
Vessel wall dysfunction
Vessel wall damage
VTE in Trauma
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Assessment of Risk
oAge
PRBC
Surgery
LE Fxs
Spinal Cord/Column Inj
Head Inj
Coagulapathy
Femoral Catheters
Obesity
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Assessment of Risk(NEJM, Geerts, 1994)
Injury % DVT
SC Injury (SCI) 81
Head Injury (HI) 39
HI + SCI 50
HI + Face + chest/abd 70
HI + LE fx 77
Pelvic fx 61
Femoral fx 80
Tibia fx 77
Ankle fx 74
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Assessment of Risk
x = (0.05xAge) - 3.16 + 0.55(if PRBC)
+ 0.83(if Surgery)
+ 1.57(if Femur/Tibia fx)
+ 2.15(if SC inj)
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Assessment of RiskAHRQ
Spinal cord/column injuries
Age
Injury Severity
No other proven risk factors
but hard to extract risk factors because the entire patient
populationis high risk
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Methods of VTE Prophylaxis
Low Dose Heparin (LDH)
Low Molecular Weight Heparin (LMWH)
Sequential Compression Device (SCD)
Arteriovenous Foot Pump (AVFP)
IVC Filter (IVCF)
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Low
Dose Heparin
Historical method for VTE prevention
Mechanism
inhibits Factor X and thrombin oAT-III activity by 1000-fold
Supported by literature in general surgery pts
Not well supported in trauma pts
Advantages: inexpensive
Disadvantages: unproven, bleeding, HITT
AHRQ: LDH efficacy = SCD = no prophylaxis
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Low Molecular Weight Heparin
Mechanism Same components as LDH, different proportions
q affinity for plasma proteins + endoth cells
o bioavailability
Better than SCD/AVFP not stat signif (J Traum, Knudson,
1996)
Better than LDH for DVT, no diff forPE (AHRQ, caveatwide 95%
conf intervals forPE data)
Better than LDH for DVT, no diff for bleeding (NEJM, Geerts,
1996)
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Low Molecular Weight Heparin(NEJM, Geerts, 1996)
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Sequential Compression
Devices
Mechanism q stasis
o fibrinolytic path activity, effect lost w/in minutes of
removal q extrinsic path by o Tissue FactorPathway Inhibitor
(TFPI)
Advantages
inexpensive, no bleeding cxs
Disadvantages
poor compliance, difficult in LE trauma pts, reports of
pressure necrosis, compart syndrome, nerve palsies
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Sequential Compression
Devices
Literature is sparse
J Trauma, Dennis, 1993
Head injury pts: 17% DVT 1.4% DVT w/ SCDs Spinal cord injury
pts: 27% DVT 10% DVT w/ SCDs
J Trauma, Knudson, 1992
Head injury pts: q DVT rate w/ SCDs
General trauma pts: No change w/ SCDs
AHRQ: SCD efficacy = LDH = no prophylaxis
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A
rteriovenous Foot Pump
Mechanism q stasis
Literature is sparse suggestions of near equivalence to SCDs
but, of course
AHRQ: SCD efficacy = LDH = no prophylaxis
Advantages inexpensive, better compliance than SCDs, no bleeding
cxs,
more easily used with casts/splints/ex-fixes
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VC Filters
Mechanism mechanically prevents clot from ascending
Advantages no bleeding cxs (unless in addition to anticoag),
theoretically
fool-proof
Disadvantages
invasive, expensive, in practice not fool-proof, causes
DVTs,
may occlude, may erode, may migrate,
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VC Filters
Literature is sparse Arch Surg, Rogers, 1998: 3yr f/u IVCFs
5.5% filter tilt (FT), 38% strut malposition (SM) 6.3% w/ FT or
SM had PE, 0% w/o FT/SM had PE
97% 3yr patency, 4.5% DVTs after insertion
J Traum, Wojcik, 2000 44% DVT after placement, No PEs
1% migrated, 1% occluded (mean f/u 29 mos)
AHRQ: No good data to make anyrecommendation
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Screening forDVTs
Venography
Duplex U/S
Impedence Plethysmography
D-dimer Levels
I-125 Fibrinogen Scan
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A Modest Proposal
1. LMWH as 1st line prophylaxis
2. SCD 2nd + AVFP 3rd line if LMWH
contraindicated
3. In HIGH risk pts (per Geerts) with
contraindication to LMWH IVCF
4.In VERY H
IGH risk pts (per Geerts)
IVCF
5. Duplex screening prior to tx to extended
care facility
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t may seem innocuous
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But there is no chicken soup.
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