Venous Thromboembolism - DVT - Clinical Exam + Ultrasound can Guide Dx and Rx

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VENOUS THROMBOEMBOLISM - DVT: CLINICAL EXAM + ULTRASOUND CAN GUIDE Dx AND Rx

Clinical Bottom Line:
Clinical exam + ultrasound can guide diagnosis and therapy.

Risk

Category

% of

all patents

% with VTE

Clinical Interpretation of Ultrasound

LR+

LR-

High

1%

75%

(63 to 84%)

VTE so likely that a negative US should go to venography. Positive US rules-in DVT.

4.1

0.10

Moderate

33%

17%

(12 to 23%)

Negative US can be repeated, or can go to venography. Positive US rules-in DVT.

>100

0.07

Low

56%

3%

(1.7 to 5.9%)

Negative US rules-out VTE, and VTE so unlikely that despite the LR+, a positive US should go to venography

>100

0.10

Citation: Wells PS, Anderson DR, Bormanis J, Guy F, Mitchell M, Gray L, Clement C, Robinson KS, Lewandowski : Value of assessment of pretest probability of deep-vein thrombosis in clinicla management. Lancet 1997;350:1795-8.

Prepared by Sackett in March 1998.

Study Patients:
593 consecutive patients with painful &/or swollen legs and clinically-suspected DVT in Halifax or Ottawa, Canada; mean age 57, 58% women, mean duration of symptoms: 9 days. Excluded patients with suspicion of pulmonary embolism, imminent death, prior objectively documented DVT, requirement for long-term anticoagulation, <18 or geographically unavailable for follow-up.

Clinical Scoring System:

High Risk 3+ Moderate Risk 1-2 Low Risk 0 or negative

Clinical Feature	Score
Active cancer (if palliated or treatment now or within prior 6 months)	+1
Paralysis, paresis, or plaster immobilisation of a leg	+1
Recently bedridden >3 days or major surgery within past 4 weeks	+1
Localised tenderness along deep venous system	+1
Entire leg swollen	+1
Calf circumference 10 cm below tibial tuberosity >3cm greater than other calf	+1
Pitting oedema greater in symptomatic leg	+1
Collateral dilated (but not varicose) veins	+1
Alternative diagnosis as or more likely than DVT	-2

Kappa agreement between study physicians and nurses: 0.75

Considered and rejected: age, symptom duration, sex, recent trauma, family history, erythema, hospital admission.

Comments:

Ultrasound: from common femoral to trifurcation of popliteal. Could use Doppler/colour Doppler to identify the veins, but the sole criterion was lack of compressibility.
This policy resulted in 1 extra visit for every 3 patients.

Needs review and updating in 6 months: September 1998

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