dvt

2. ETIOPATHOGENESIS

3. • Abnormalities of flow
• Abnormalities of vessel wall
• Hypercoagulability of blood
ETIOPATHOGENESIS

4. Objectives/Outline
 Rationale for thromboprophylaxis
 Summary of the 7th ACCP
thromboprophylaxis guidelines
 Implementation strategies

5. Rationale for Thromboprophylaxis
I. High prevalence of VTE in certain
patient groups
II. Adverse consequences of
unprevented VTE
III. Efficacy, effectiveness and cost-
effectiveness of thromboprophylaxis

6. Risk Factors for VTE
 Previous venous thromboembolism
 Increased age
 Surgery
 Trauma - major, local leg
 Immobilization - bedrest, stroke, paralysis
 Malignancy and its Rx (CTX, RTX, hormonal)
 Heart or respiratory failure
 Estrogen use, pregnancy, postpartum, SERMs
 Central venous lines
 Thrombophilic abnormalities

7. Risk Factors for VTE
 Previous venous thromboembolism
 Increased age
 Surgery
 Trauma - major, local leg
 Immobilization - ? bedrest, stroke, paralysis
 Malignancy & its Rx (CTX, RTX, hormonal)
 Heart or respiratory failure
 Estrogen use, pregnancy, postpartum, SERMs
 Central venous lines
 Thrombophilic abnormalities

8. Some Basic Principles of
Thromboprophylaxis
• Group prophylaxis rather than individual
• Mechanical prophylaxis only if high risk of
bleeding
• No role for aspirin alone as DVT prophylaxis
• Epidural analgesia and anticoagulant
thromboprophylaxis are compatible
7th ACCP Conference on Antithrombotic Therapy

9. DVT Prophylaxis:
3 Patient Groups
Low risk
Moderate risk
High risk

10. Patient group: Age < 40 years
Medical – fully mobile, brief admission
Surgical – procedure < 30 min, mobile,
no additional risk factors
Recommendations:
 no specific prophylaxis
 mobilization
[Grade 1C]
Low risk
7th ACCP Conference on Antithrombotic Therapy

11. Patient group: Age between 40 – 60 years + minor surgery
or age < 40 with risk factors
Medical – bedrest / sick
Surgical – major general, urologic,
gynecologic procedures
Evidence: LDH ~ LMWH
Options:  LDH [Grade 1A] 5000 bid
 LMWH [Grade 1A] <= 3400 u once daily
 TEDS, IPC (high bleeding risk) [1C+]
Start: as soon as possible
Duration: until discharge (not “ambulation”)
Moderate risk
7th ACCP Conference on Antithrombotic Therapy

12. Patient group: Major orthopedics (THR, TKA, HFS)
Age 40 – 60 years with major surgery (G +U)
Minor surgery, Age > 60, +/- risk factors
Evidence:
1. Venography: fondaparinux > LMWH > OVKA
2. Clinical: LMWH ~ OVKA
Options:  LMWH [Grade 1A] > 3400 sc daily
 fondaparinux [Grade 1A]
 oral vitamin K antagonist (INR 2-3) [1A]
 LDH or LMWH + GCS or IPC
Start: Postop (preop if HFS delayed)
Duration: > 10 days (2-4 weeks)
7th ACCP Conference on Antithrombotic Therapy
High risk

13. HIT with LDH or LMWH for Prophylaxis
Martel – Blood 2005;106:2710
• meta-analysis of 7 prospective studies comparing
prophylactic LDH and LMWH
Prophylactic
anticoagulant HIT
Heparin 41/1,730 (2.37 %)
LMWH 1/1,762 (0.06 %)
* NNT=43

14. Routine Prophylaxis NOT
Recommended:
• vascular surgery
• laparoscopic surgery
• knee arthroscopy
• spine surgery
• isolated lower extremity fractures
• long distance travel
7th ACCP Conference on Antithrombotic Therapy
Any additional risk factors
will mandate consideration of thromboprophylaxis

15. Benefit:risk favors
routine prophylaxis
• Major orthopedic surgery
(THR, TKR, HFS)
• Major trauma
• Spinal cord injury
• Major general, gyne,
urologic surgery
• Major neurosurgery
• Medical patients with
additional risk factors
• Most ICU patients

16. Benefit:risk favors
routine prophylaxis
• Major orthopedic surgery
(THR, TKR, HFS)
• Major trauma
• Spinal cord injury
• Major general, gyne,
urologic surgery
• Major neurosurgery
• Medical patients with
additional risk factors
• Most ICU patients
Benefit:risk favors
no prophylaxis
• Surgical patients:
- brief procedure
- fully mobile
- no additional RFs
• Medical patients:
- fully mobile
- no additional RFs
• Long distance travel

17. Benefit:risk favors
routine prophylaxis
• Major orthopedic surgery
(THR, TKR, HFS)
• Major trauma
• Spinal cord injury
• Major general, gyne,
urologic surgery
• Major neurosurgery
• Medical patients with
additional risk factors
• Most ICU patients
Benefit:risk uncertain-
local practice or
individual prophyl.
• Laparoscopic surgery
• Vascular surgery
• Cardiac surgery
• Elective spine surgery
• Arthroscopic surgery
• Burns
• Isolated lower
extremity fracture
Benefit:risk favors
no prophylaxis
• Surgical patients:
- brief duration
- fully mobile
- no additional RFs
• Medical patients:
- fully mobile
- no additional RFs
• Long distance travel

18. Thromboprophylaxis Use in
Practice 1992-2002
Prophylaxis
Patient Group Studies Patients Use (any)
Orthopedic surgery 4 20,216 90 % (57-98)
General surgery 7 2,473 73 % (38-98)
Critical care 14 3,654 69 % (33-100)
Gynecology 1 456 66 %
Medical patients 5 1,010 23 % (14-62)

19. Recommended VTE Prophylaxis Strategies
in Surgical Settings
Indication Prevention Strategy
General Surgery UFH 5,000 units q 8h, 1
st
dose 2h
preoperatively, continued for 7 days or
LMWH once daily
Cancer Surgery Enoxaparin 40 mg daily or equivalent, 1
st
dose 10-14h preoperatively if possible,
for 28 days
UFH = unfractionated heparin
LMWH = low molecular weight heparin

20. Recommended VTE Prophylaxis Strategies
in Surgical Settings (cont.)
Indication Prevention Strategy
Total Hip
Replacement
Enoxaparin 40 mg daily or equivalent,
beginning preoperative evening, continuing
out-of-hospital for 21-28 days
Enoxaparin 30 mg BID or equivalent, 1
st
dose 12-24h postoperatively, until hospital
discharge
Dalteparin 2,500 units ≥ 4h post-op, then
5,000 units daily until hospital discharge or
for 35 days

21. Recommended VTE Prophylaxis Strategies
in Surgical Settings (cont.)
Indication Prevention Strategy
Total Hip
Replacement (cont.)
Fondaparinux 2.5 mg 4-8h post-op, then ≥
12h after 1st dose, then daily for 5-9 days
Warfarin daily, 1
st
dose 7.5 mg 24-48h
preoperatively, adjusted to target INR of 2.0-
3.0
Warfarin daily, 1
st
dose 5 mg preoperative
evening, adjusted to target INR of 2.0-3.0 and
continued 4-6 weeks

22. Recommended VTE Prophylaxis Strategies
in Surgical Settings (cont.)
Indication Prevention Strategy
Total Knee
Replacement
Enoxaparin 30 mg BID or equivalent, beginning 12-
24h postoperatively, continued for an average of 9
days
Fondaparinux 2.5 mg, 1
st
dose 4-8h postoperatively,
2
nd
dose ≥ 12h after 1
st
dose, then daily for 5-9 days
Hip Fracture
Surgery
Fondaparinux 2.5 mg, 1
st
dose 4-8h postoperatively,
2
nd
dose ≥ 12h after 1
st
dose, then daily for 5-9 days. If
surgery is delayed > 24-48h after admission, give 1
st
dose 10-14h preoperatively

23. Recommended VTE Prophylaxis Strategies
in Surgical Settings (cont.)
Indication Prevention Strategy
Neurosurgery Enoxaparin 40 mg daily or equivalent, 1
st
dose ≤ 24h postoperatively, continued until
hospital discharge, plus GCS
Craniotomy for Brain
Tumor
Enoxaparin 40 mg daily or UFH 5,000 units
BID, 1
st
dose on 1
st
postoperative morning,
continued until hospital discharge, plus
GCS/IPC, plus predischarge venous
ultrasonographyGCS = graduated compression stockings
IPC = intermittent pneumatic compression devices

24. Duration of Prophylaxis
Recommendations for extending the duration of
prophylaxis in high-risk scenarios:
Geerts WH, et al. Chest. 2004;126(suppl 3):338S-400S.
Cancer surgery 28 days postoperatively
Total hip
replacement and
hip fracture repair
28-35 days postoperatively
Trauma Throughout inpatient
rehabilitation and after
discharge in patients with
significantly impaired mobility

25. Objectives/Outline
 Rationale for thromboprophylaxis
 Summary of the 7th ACCP
thromboprophylaxis guidelines
 Implementation strategies

26. Strategies to Improve
Thromboprophylaxis Success
• Excellent quality guidelines
• National body endorsement
• Hospital accreditation (JCAHO)
• Pay for performance (CMS)
• Local written policy (care pathway) for
the hospital / program / patient care unit
• Pharmacist responsibility
• Pre-printed orders
• Computerized orders

27. Take-Home Points
• Know the common VTE risk factors
• Assess VTE risk for each hospitalized patient
individually
• Become familiar with the various VTE
prophylaxis regimens for different at-risk patient
groups
• Apply the current ACCP guidelines to prevent
VTE in hospitalized patients

28. Prevention of VTE: Summary
1. Thromboprophylaxis is indicated for most
hospitalized patients
2. But is under-utilized
3. Not ASA; mechanical rarely; warfarin scary
4. Chest 2004;126(suppl):338S-400S
5. Systems approach / hospital policy
6. Keep it simple, routine: Pre-printed orders
Just do it!

29. Thank you
http://webmm.ahrq.gov
Bill Geerts, MD, FRCPC, FCCP
University of Toronto