Venous Thromboembolism:

Diagnosis and Managament

R. Cavalcanti and B. LaluckApril, 2007

Learning objectives

• Review factors affecting risk of VTE• Understand an approach to diagnosis

of VTE • Review aspects of treatment of VTE

Outline

• 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: 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

• 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

Active cancer (treatment ongoing, within previous 6 months, or palliative) 1

Paralysis, paresis, or recent plaster immobilization of the lower extremities1

Recently bedridden >3 days or major surgery within 12 weeks requiring general or regional anesthesia

1Localized tenderness along the distribution of the deep venous system

1Entire leg swollen

1Calf swelling 3 cm larger than asymptomatic side (10 cm below tibial tuberosity) 1Pitting edema confined to the symptomatic leg 1Collateral superficial veins (nonvaricose)

1Alternative 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.

Clinical Characteristic Score

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

• 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%

• NO SYMPTOMS• Proximal 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