1. Venous Thromboembolism: Diagnosis and Managament
R. Cavalcanti and B. Laluck
April, 2007

2. Learning objectives Review factors affecting risk of VTE
Understand an approach to diagnosis of VTE
Review aspects of treatment of VTE

3. Outline Cases Diagnostic algorithm Prophylaxis
Type and duration of anticoagulation
IVC filters

4. Case 1 68F Post op day #2 after R TKR Referred for fever + SOB
PMHx: HTN, osteoporosis, 40pyr smoker
Meds: Alendronate, Atenolol/HCTZ, Dalteparin 5000, Moxifloxacin
Over 2 d has needed increasing O2

5. Case 1 (cont) Inv: OE: CBC: 98 11.7 318 Lytes 138 104 3.5 26
HR110 RR24 BP90/50
SPO2 90% on 50%FM T 38.5
CVS N hs; JVP 4-5 cm ASA
Chest: Fine crackles over bases, long expiratory time
Inv:
CBC:
Lytes
ABG: on FiO2 0.5

8. CT Angio Chest
No PE
Diffuse interstitial changes consistent with pulmonary edema
Left lower lobe opacity

9. Case 2 23 F presents with shortness of breath
OCP, smoker and recently flew in from Berlin
Now requires 2L O2 NP for SpO2 96%

10. Case 3 83 F presenting with BRBPR Doppler US LE: Positive for DVT
C-Scope: large rectal tumour
Unilateral R leg swelling
Doppler US LE: Positive for DVT
Management?

11. Tests for VTE Wells score: D-dimers: Venous Doppler US CT Angio Chest
VQ scan
Conventional pulmonary angiography

12. Estimating risk

14. Risk of DVT

15. Wells Prediction Rule for Diagnosing Deep Venous Thrombosis: Clinical Evaluation Table for Predicting Pretest Probability of Deep Vein Thrombosis
Clinical Characteristic
Score
Active cancer (treatment ongoing, within previous 6 months, or palliative) 1
Paralysis, paresis, or recent plaster immobilization of the lower extremities 1
Recently bedridden >3 days or major surgery within 12 weeks requiring
general or regional anesthesia
Localized tenderness along the distribution of the deep venous system 1
Entire leg swollen
Calf swelling 3 cm larger than asymptomatic side (10 cm below tibial tuberosity) 1
Pitting edema confined to the symptomatic leg 1
Collateral superficial veins (nonvaricose) 1
Alternative diagnosis at least as likely as deep venous thrombosis –2
Note: Clinical probability: low 0; intermediate 1–2; high 3. In patients with symptoms in both legs, the more symptomatic leg is used.
Reprinted from The Lancet, Vol 350, Wells PS, Anderson DR, Bormanis J, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management, pp 1795–1798, Copyright 2002, with permission from Elsevier.

16. Adapted from Wells, Thromb Hemost 2000

17. Diagnostic approach

18. Diagnostic approach Assess risk D-dimer Lung Imaging Leg imaging
CT angiography of Chest
VQ Scan
Leg imaging
CT venography
Venous doppler US

19. First step Assess risk Wells prediction rule
Validated in number of studies (17 DVT / 3 PE)
Induvidual features low predictive value
Works best for younger patients without comorbitidies or a history of VTE
Clinical judgement should be used in older patients with co-morbidities

20. D-dimer Usefulness depends on number factors When used alone
Sensitivity (must be high or 3rd generation)
Other reason for +
Any trauma, surgery enough to get blood to clot will elevate D-dimer
Probability of disease
When used alone
In patient’s with comorbidity, older age, longer duration of symptoms in low to moderate risk
Only 40 – 50% specificities

21. Wells + D-dimer
If you have a patient with low pretest probability of DVT / PE and a HIGH – sensitivity D-dimer is negative
0.5% incidence of in 3 months of DVT
No need for further imaging
If you have a patient with mod to high pretest probability of DVT / PE and a HIGH – sensitivity D-dimer is negative
3.5% and 21.4% DVT risk within 3 months
Further imaging needed

22. Leg Ultrasound performance depends on symptoms
NO SYMPTOMS
Proximal DVT
positive test rules in
negative test DOESN’T rule-out
sensitivity 60%
specificity 90-95%
SYMPTOMS PRESENT
Proximal DVT
positive test rules in
negative test rules out sensitivity 90-95% specificity 95%
Distal DVT
negative test DOESN’T rule out
sensitivity 60%;
specificity 90-95%

23. PIOPED II CT Angio chest CT Angio chest + CT Venography Sn 83% Sp 96%

24. Prevalence of PE by CT Angio Results and Wells Score
High
Interm.
Low
Total
CT +
99%
89%
38%
86%
CT -
39% 7%
0.5% 5%
PIOPED II NEJM 06

25. Controversy Are the next generation multidetector CTs better
To what level does the study see clots (segmental, subsegmental?)
What should come first
Leg doppler vs CTA?
In a patient with a high pretest probability for PE
Is CTA sufficiently sensitive?

26. Treating medical and surgical patients at high risk of developing DVT
VTE Prophylaxis
Treating medical and surgical patients at high risk of developing DVT

27. VTE Prophylaxis - non pharmacological
Mobilization
If possible
Graduated compression stockings (GCS)
TEDS
Intermittent pneumatic compression (IPC)
For surgical patients

28. VTE Prophylaxis - Rx Low dose unfractionated heparin (LDUH)
5000 u sc q12h or q8h
Low molecular weight heparin intermediate dose (LMWH)
Enoxaparin 30 mg bid or 40 mg od
Dalteparin 5000 u od
Fondaparinux 2.5 mg sc od

29. VTE Treatment

30. VTE Treatment - Rx High dose unfractionated heparin (UFH)
IV Titrated drip
Low molecular weight heparin treatment dose (LMWH)
Enoxaparin
Tinzaparin
Dalteparin and others
Fondaparinux
Coumadin (INR 2 – 3)
With at least 4-5 days of heparin
Direct thrombin inhibitors
For patients with HIT (done via hematology)

31. VTE Treatment Heparin vs LMWH Safety and efficacy Multiple studies
LMWH superior for treatment
Less mortality and major bleeding
Magnitude not very large
LMWH at least as effective as UFH

32. VTE Treatment Outpatient vs Inpatient Treatment Number of studies
Likely that LMWH at home is as least as safe as inpatient treatment for DVT
In appropriately chosen patients with required supports in place

33. VTE Treatment duration
If OR is only RF - reversible
Recommeded duration 3 months
If ongoing RF
At least 6 months
For ongoing malignancy
LMWH (CLOT trial)

34. IVC Filters Limited evidence: no RCTs
Retrievable filters are available
Can be removed up to 6 weeks
Recent case series: 91% retrievable
Risk of migration
Can be adjunctives in patients with existing recent DVT in which anticoagulation contraindicated