Download Venous Thromboembolism in the Surgical Patient

Venous Thromboembolism in
the Surgical Patient:
Prophylaxis and Treatment
Pamela Hebbard
August 11, 2005
Prophylaxis
Scenario 1
You are going through consent with a 60 y.o.
F going for laparotomy for non-resolving
SBO.
What is the risk of VTE in the average
general surgery patient without prophylaxis?
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A. 10% DVT, 0.001% fatal PE
B. 5% DVT, 0.01% fatal PE
C. 25% DVT, 0.05% fatal PE
D. 50% DVT, 1% fatal PE
Incidence
In general surgery patients without
prophylaxis:
– 15 - 30% DVT
– 0.2% - 0.9% fatal PE
Risk is higher with pelvic surgery, cancer
surgery
Of all surgery orthopedic surgery carries the
highest risk, at 50-60% DVT
Scenario 2
52 y.o. F going for R hemicolectomy for cecal
cancer. What will you choose for VTE
prophylaxis?
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A. aspirin to start post-op
B. a low-dose heparin
C. mechanical compression device/stockings
D. warfarin to start post-op
E. some combination of the above
Methods of Prophylaxis
1. Aspirin
• 20% risk reduction compared to placebo (5
trials)
2. Graded compression stockings
• 44% risk reduction
• Knee-length equally effective and easier to use
than thigh-length
• Need to be fitted for them
Methods of Prophylaxis
3. Heparins
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Low-molecular weight and unfractionated
~70% risk reduction
Equally effective
Risk of bleeding related to dose (LMWH)
Methods of Prophylaxis
4. Intermittent pneumatic compression
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88% risk reduction
equally effective as heparin
Probably better than stockings
From small, older studies
Also need to be fitted and requires equipment
Methods of Prophylaxis
5. Warfarin
• does have a risk reduction
• Older studies, mostly orthopedics
• Impractical
6. Heparin + mechanical method
• Stockings + LDUH have been shown to
enhance protection from VTE by a further 75%
(from 15% to 4%).
Scenario 3
You have chosen to use a heparin as VTE
prophylaxis for your post-op patient with cecal
ca. Exactly what order will you write?
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A. heparin 5000 u sc bid
B. heparin 5000 u sc tid
C. heparin 15000 u sc bid
D. heparin ACS/DVT protocol
E. enoxaparin 30mg sc bid
F. enoxaparin 40 mg sc od
G. enoxaparin 80 mg sc bid (1 mg/kg)
H. enoxaparin 120 mg sc od (1.5 mg/kg)
Heparin Dosing-Prophylaxis
Unfractionated heparin:
– 5000 u bid/tid
Lovenox:
– 30 mg sc bid
– 40 mg sc od**
Scenario 4
Patient 1: 20 y.o. M - inguinal hernia repair
Patient 2: 60 y.o. M - APR
What post-op orders will you write?
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A. no heparin for either
B. heparin for both
C.1 - none, 2 - heparin
D.1 - heparin bid, 2 - heparin tid
Risk Stratification
Low - Risk
• “Minor” surgery
• <40 y.o
• No additional risk factors
Recommendation
• Early ambulation only
Risk Stratification
Moderate Risk
– Minor surgery in patients with additional risk
factors
– Any surgery in pts aged 40-60 w/o additional risk
factors
– Major surgery in patients <40 y.o w/o additional
risk factors
Recommendation
• Heparin 5000 bid
• LMWH <= 3400 IU/day (Lovenox 30mg od)
• May consider stockings if contraindication to heparin
Risk Stratification
High Risk
• Multiple risk factors
• age > 60 y.o.
• Age 40-60 y.o. with an additional risk
Recommendation
• Heparin 5000 tid
• LMWH >3400 IU/day (Lovenox 40mg od or
more)
Risk Stratification
Very High Risk
• Major surgery in >40 y.o. with: cancer, previous
VTE, or known hypercoagulable state
• Major ortho surgery, elective neurosurgery,
multiple trauma, acute SCI
Recommendation
• High risk heparin dosing + stockings/ IPC
Scenario 5
You are going to give your pt heparin
prophylaxis for major abdominal
surgery. When do you give the first
does?
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A. 2 hrs pre-op
B. in recovery room
C. once up to the floor
D. after the epidural comes out
Timing
Optimal timing is 2 hrs pre-op
DVT’s begin intra-operatively
Timing may need to be adjusted if
neuraxial anesthesia is being used (no
strict guidelines?)
Scenario 6
Consider again your patient with colon
cancer. How long should you continue
her VTE prophylaxis?
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A. until ambulating
B. 7 days
C. until discharge
D. 4 weeks
E. 6 months
Timing
For most patients, heparin until
ambulating well is satisfactory.
For high risk patients, heparin should
continue for 7-10 days minimum
Abdominal or pelvic surgery for cancer:
4 weeks of LMWH reduces the
incidence of DVT compared to 1 week.
Treating DVT/PE
Scenario 7
Your post-op patient is noted to have a
swollen firm left calf. U/S documents proximal
DVT. What is your initial treatment?
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A. heparin 5000 u sc tid
B. heparin ACS/DVT protocol
C. enoxaparin 30mg sc bid
D. enoxaparin 80 mg sc bid (1 mg/kg)
E. enoxaparin 120 mg sc od (1.5 mg/kg)
Initial Treatment
Choice of heparin infusion or LMWH sc
Both shown to be equally effective and
safe
Same treatment for DVT and PE
LMWH easier to administer, cheaper-assuming no contraindications
Initial Treatment
Start warfarin at same time as heparin
Continue heparin for at least 5 days and
INR 2-3
Out-patient therapy is equally as safe as
in-hospital treatment
Scenario 8
70 y.o. M post-op from Hartmann’s for
diverticulitis. DVT post-op. PHx DM, HTN,
CAD, and stroke. How long does he continue
on warfarin?
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A. 3 mo at INR 2-3
B. 6 mo at INR 2-3
C. 12 mo at INR 2-3
D. 6 mo at INR 2-3, then indefinitely at INR 1.5-2
E. Indefinitely at INR 2-3
Warfarin Therapy
First episode of DVT -- usually 6 months
DVT due to transient risk factor (Surgery): 3
months of tx may be considered
PREVENT and ELATE have shown that
indefinite treatment does decrease the risk of
recurrence. They disagree on the necessary
target INR.
Long-term therapy needs to be balanced
against the risk of bleeding.
Scenario 9
62 yo w/ recently diagnosed mucinous
adenocarcinoma in the liver with no known
primary. Presents with syncope, now
normotensive, and found to have PE on CT.
Treatment?
• A. Start LMWH and warfarin, continue warfarin
indefinitely or until cure
• B. Start heparin drip and warfarin, continue warfarin
indefinitely.
• C. LMWH indefinitely
• D. LMWH for 6 months
VTE in Cancer Patients
LMWH is better than unfractionated
heparin for cancer patients.
Antithrombotic and antineoplastic
effects
LMWH is better than warfarin for longterm tx in cancer patients (less fatal
bleeding)
Scenario 10
You are called to see a post-op pt with a
swollen leg. It is indeed swollen, tense and a
deep red-purple colour. You note some skin
necrosis. An U/S documents DVT. Treatment?
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A. IV heparin
B. full-dose Lovenox
C. debride skin
D. thrombectomy
Surgery for DVT
Phlegmasia ceruluea dolens/ venous
gangrene is an absolute indication for
surgery.
Femoral venotomy
Interventional radiology
High incidence of post-phlebitic
syndrome
Other Treatments
Thrombolytics
• Controversial
• Best evidence in unstable patient with PE
• Indicated in massive ileofemoral thrombolysis
and low-risk to bleed
New medications
• Fondaparinux
• ximelagatran
IVC Filters
Protect against fatal PE
In general, for use in patients with
contraindication to anticoagulation
May consider filter + anticoag is patient with
severe cardiopulmonary dz where recurrent
PE may be fatal.
Information based on poor, older studies
Retrievable filters (new)
Further Info
ACCP Guidelines
Chest, Sept 2004, Vol126, supp 3.
AJS 2005, 189:14-25.