Deep vein thrombosis in orthopaedic surgery.ppt

To define the terms associated with VTE and offer evidence-based guidance to care for patients.

To enable healthcare professionals to give patients advice so that patients understand their risks, and know what they can do to help reduce their risk of a VTE event.
VTE is a major cause of morbidity and mortality in the UK
VTE deaths are 5 times more than total deaths from hospital acquired infection, breast cancer, road traffic accidents and AIDS.
Cost to NHS is £640 million (2005)
Cost of treating venous leg ulcers around £400 million a year. 25% of DVT patients develop Post Thrombotic Syndrome .

To define the terms associated with VTE and offer evidence-based guidance to care for patients.

To enable healthcare professionals to give patients advice so that patients understand their risks, and know what they can do to help reduce their risk of a VTE event.
Incidence of DVT in the hospital is 10-40% per month for medical or general surgical patients and 40-60%
•Increased spending for investigation symptomatic .
Fondaparinux vs Enoxaparin for the Prevention of Venous Thromboembolism in Major Orthopedic Surgery: A Meta-analysis of 4

Randomized Double-blind Studies. Arch Intern Med. 2002;162(16):1833-1840

Methods: A meta-analysis of 4 multicenter, randomized, double-blind trials in patients undergoing elective hip replacement, elective major knee surgery, and surgery for hip fracture (N = 7344) was performed to determine whether a subcutaneous 2.5-mg, once-daily regimen of fondaparinux sodium starting 6 hours after surgery was more effective and as safe as approved enoxaparin regimens in preventing VTE. The primary efficacy outcome was VTE up to day 11, defined as deep vein thrombosis detected by mandatory bilateral venography or documented symptomatic deep vein thrombosis or pulmonary embolism. The primary safety outcome was major bleeding.

Results: Fondaparinux significantly reduced the incidence of VTE by day 11 (182 [6.8%) of 2682 patients) compared with Enoxaparin (371 [13.7%) of 2703 patients), with a common odds reduction of 55.2% (95% confidence interval, 45.8% to 63.1%; P<.001); this beneficial effect was consistent across all types of surgery and all subgroups. Although major bleeding occurred more frequently in the fondaparinux-treated group (P=.008), the incidence of clinically relevant bleeding (leading to death or reoperation or occurring in a critical organ) did not differ between groups.

Conclusion: In patients undergoing orthopedic surgery, 2.5 mg of fondaparinux sodium once daily, starting 6 hours postoperatively, showed a major benefit over enoxaparin, achieving an overall risk reduction of VTE greater than 50% without increasing the risk of clinically relevant bleeding.Fondaparinux (Arixtra®)

• Fondaparinux -synthetic pentasaccharide fac- Xa inhibitor.

• O-methyl group + five monomeric sugar units

Binding of heparin/HS to has been shown to increase the anti- coagulant activity of antithrombin III 1000 fold.
Dvt prophy

1. Chapter Five
Venous Disease Coalition
Investigation of Suspected VTE
VTE Toolkit

2. Investigation of Suspected DVT
VTE Toolkit
• Ascending contrast venography
• Impedance plethysmography
• Radioactive fibrinogen scan
No longer used
•Doppler ultrasonography (Duplex scan): sensitive
and specific for symptomatic proximal DVT
•CT venography: contrast timing critical
•MR venography: may be useful for pelvic vein
thrombosis

3. Investigation of Suspected DVT
VTE Toolkit
•Try to never miss acute PROXIMAL DVT
•Some Doppler labs over-call DVT (especially calf
DVT)
•No one knows if / how calf DVT should be
managed
•Be aware of CLINICAL-IMAGING
DISCORDANCE (the clinical features don’t fit
with the imaging results)

4. Clinical Predictive Model for DVT
VTE Toolkit
Wells - Lancet 1997;350:1795
0
10
20
30
40
50
60
70
80
Low Mod High
%DVT
Low = < 0Mod = 1-2High = > 3
Active cancer < 6 mos 1
Paralysis, paresis, recent plaster cast 1
Bedridden > 3 d or major surgery < 1 mo 1
Localized tenderness along deep vein 1
Entire leg swollen 1
Calf swelling 3 cm > asymptomatic side 1
Pitting edema symptomatic leg 1
Collateral superficial veins 1
Alternative diagnosis > likely -2

5. D-dimer in Suspected VTE
VTE Toolkit
•D-dimers are degradation products resulting from the
action of plasmin on fibrin
•The presence of D-dimer indicates initiation of blood
clotting but many conditions other than DVT give a
positive D-Dimer test result
•Therefore, a positive D-dimer does NOT rule in DVT,
but a negative D-dimer can help exclude the diagnosis
•D-dimer may be useful in outpatients with low pre-test
probability for VTE as part of a formal algorithm

6. Compression Doppler Ultrasound
VTE Toolkit

7. Compression Doppler Ultrasound
VTE Toolkit
Without Compression With Compression

8. VTE Toolkit
Suspected DVT
Doppler
Ultrasound (DUS)
DUS demonstrates
DVT
Treat
DUS negative
Low clinical prob
or alternative
Dx reasonable
DVT suspicion
remains
Stop
Repeat DUS
in 5-7 days

9. VTE Toolkit
Suspected DVT in an Outpatient
Clinical probability assessment
Low Moderate-High
PositiveNegative
DVT
excluded
Positive
Negative
Treat
• stop
• repeat DUS 5-7 d
• use D-dimer
D-dimer
Proximal DUS

10. VTE Toolkit
DUS demonstrates
proximal DVT
Proximal DUS
negative
Treat
Proximal Doppler
ultrasound
Continue DVT
prophylaxis
Suspected DVT in an Inpatient

11. CT Can Diagnose Proximal DVT
VTE Toolkit

12. Investigation of Suspected PE
VTE Toolkit
•No diagnostic value of blood gases in suspected PE
• V/Q scans:
–At least 60% are non-diagnostic
–Consider in some patients with renal dysfunction or severe contrast
allergy
–Reasonable option for outpatients with normal CXR, and either very
high probability of PE or low probability
–Role in pregnancy and young women (because of reduced radiation
dose)
• CT Pulmonary Angiogram (“Spiral CT”):
–Accurate for segmental or larger PE
–Accuracy and clinical relevance of sub-segmental abnormalities is
uncertain

13. Wells Clinical Predictive Model for PE
VTE Toolkit
History
Previous proven DVT or PE 1.5
Immobilization > 3 d or surgery prev. month 1.5
Malignancy (current or < 6 mos.) 1
Hemoptysis 1
Physical exam
Signs of possible DVT (leg swelling, tenderness 3
HR > 100 1.5
Alternative diagnosis
PE as likely or more likely than alternative 3
Wells -
Thromb Haemost (2000)
Ann Intern Med (2001)
Pre-test probability score VTE
High >6.0 41-50%
Moderate 2.0-6.0 16-19%
Low <2.0 1-2%

14. Revised Geneva Score for
PE Assessment
VTE Toolkit
based on 8 clinical variables (not on clinical judgment)
Points
Age > 65 1
Surgery/fracture past month2
Active cancer 2
Hemoptysis 2
Previous DVT/PE 3
Unilateral leg pain 3
HR 75-94 3
HR > 95 5
Unilat. edema + tenderness4
PE
Risk Points prevalence
Low 0-3 8 %
Intermediate 4-10 29 %
High > 11 74 %
Le Gal – Ann Intern Med 2006;144:165

15. Highly Abnormal Perfusion Scan
VTE Toolkit

16. CT Pulmonary Angiogram
VTE Toolkit

17. VTE Toolkit

18. VTE Toolkit

19. Subsegmental “Something”
Is it PE? Is it important?
VTE Toolkit

20. VTE Toolkit
Low Moderate High
PositiveNegative
PE
excluded
?
CTPA: nondiagCTPA: no PE CTPA: definite PE*
• DUS of
prox veins
• repeat CTPA
TreatPE
excluded
*At least segmental filling defect and “reasonable” clinical suspicion
D-dimer
CTPA
Clinical probability assessment
Suspected PE in an Outpatient

21. VTE Toolkit
Suspected PE in an Inpatient
CTPA
No definite PEDefinite* PE
Treat
Continue
prophylaxis
*At least segmental filling defect and “reasonable” clinical suspicion

22. Venous Disease Coalition
www.vasculardisease.org/venousdiseasecoalition/
VTE Toolkit