Transcript Venous Thromboembolism: Medical Consults

Venous Thromboembolism:
Diagnosis and Managament
R. Cavalcanti and B. Laluck
April, 2007
Learning objectives
• Review factors affecting risk of VTE
• Understand an approach to diagnosis of
VTE
• Review aspects of treatment of VTE
Outline
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Cases
Diagnostic algorithm
Prophylaxis
Type and duration of anticoagulation
IVC filters
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
Case 1 (cont)
• OE:
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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: 98
11.7 318
 Lytes 138 104 3.5 26
 ABG: 7.43 34 65 23 on FiO2 0.5
CT Angio Chest
• No PE
• Diffuse interstitial changes consistent with
pulmonary edema
• Left lower lobe opacity
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%
Case 3
• 83 F presenting with BRBPR
 C-Scope: large rectal tumour
 Unilateral R leg swelling
• Doppler US LE: Positive for DVT
• Management?
Tests for VTE
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Wells score:
D-dimers:
Venous Doppler US
CT Angio Chest
VQ scan
Conventional pulmonary angiography
Estimating risk
Risk of DVT
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)
Paralysis, paresis, or recent plaster immobilization of the lower extremities
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
Entire leg swollen
Calf swelling 3 cm larger than asymptomatic side (10 cm below tibial tuberosity)
Pitting edema confined to the symptomatic leg
Collateral superficial veins (nonvaricose)
Alternative diagnosis at least as likely as deep venous thrombosis
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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.
Adapted from Wells, Thromb Hemost 2000
Diagnostic approach
Diagnostic approach
• Assess risk
• D-dimer
• Lung Imaging
 CT angiography of Chest
 VQ Scan
• Leg imaging
 CT venography
 Venous doppler US
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
D-dimer
• Usefulness depends on number factors
 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
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
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
 positive test rules in
 negative test DOESN’T
rule out
 sensitivity 60%;
 specificity 90-95%
PIOPED II
• CT Angio chest
 Sn 83%
 Sp 96%
• CT Angio chest + CT Venography
 Sn 90%
 Sp 95%
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
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?
VTE Prophylaxis
Treating medical and surgical
patients at high risk of developing
DVT
VTE Prophylaxis - non
pharmacological
• Mobilization
 If possible
• Graduated compression stockings (GCS)
 TEDS
• Intermittent pneumatic compression (IPC)
 For surgical patients
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
VTE Treatment
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)
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
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
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)
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