# Presentation: 366062

## DIAGNOSIS OF VTE

**Structured clinical assessment**
**	****- establish pretest probability**
**Objective testing**
**	****- non-invasive**
**	****- invasive**

## STRUCTURED CLINICAL ASSESSMENT

**	****Risk factors**
**	****Symptoms and signs**
**	****Alternative diagnosis**

## ASSESSING PRETEST PROBABILITY OF

**FIRST DVT**

**	****Feature****	****	****	****	****	****Score**
**Active cancer****	****	****	****	****	****     1**
**Paralysis/paresis****	****	****	****	****     1**
**Bedridden > 3 d or recent major surgery****	****	****     1**
**Localized tenderness****	****	****	****	****     1**
**Entire leg swollen****	****	****	****	****     1**
**Calf swelling > 3 cm****	****	****	****	****     1**
**Pitting edema in symptomatic leg****	****	****	****     1**
**Non-varicose collaterals****	****	****	****	****     1**
**Alternative diagnosis****	****	****	****	****    -2**
**Low ****≤ 0; moderate 1-2; high ≥ 3**
**Wells, *****Lancet***** 1995**

## Traditional Objective Tests

- Reference standard tests are expensive, invasive and require contrast

- DVT: Venography

- PE: Pulmonary Angiography

## OBJECTIVE TESTING FOR DVT

**	****D-dimer**
**	****Compression ultrasonography**
**	****Venography**

## D-dimer

**Degradation product of cross-linked fibrin**
**Assayed in plasma or whole blood**
**Sensitivity over 95%, but specificity only 65%**
**Test has high negative predictive value****	**

## SimpliRED D-dimer

**Notes:**
The SimpliRED assay is a whole blood assay that can be performed at the bedside using 10μl of blood obtained from either a venipuncture sample or on finger stick sample.
The advantages of this assay over other methods of D-dimer detection include
absence of a requirement for plasma preparation and, therefore,
provision of a bedside result within 5 minutes
a better specificity than the other classes of D-dimer assay (66-77%).
However, the assay is a qualitative one that is manually read.  Therefore, experience in obtaining results with this method is important. Because of difficulty in discriminating between weak positive and normal results, agreement among interpreters may vary.

## Compression ultrasonography (CUS) 

**    ****Sensitivity and specificity over 95% **
**       ****for symptomatic proximal DVT**
**    ****Sensitivity and specificity of 60 to 70% **
**       ****for isolated symptomatic calf DVT**

## Compression Ultrasonography (CUS)

**Compression Ultrasonography (CUS)**

## SUSPECTED DVT

**SUSPECTED DVT**

**PRETEST PROBABILITY**

**Low**

**D-dimer**

**Moderate or high**

**Negative**

**Positive**

**Positive**

**Negative**

**No DVT**

**CUS**

**CUS**

**DVT**

**D-dimer**

**Negative             Positive**

**No DVT                DVT**

**Positive              Negative**

**Repeat CUS **
**in 5-7 days**

**No DVT**

## AREAS OF CONTROVERSY

**	****Calf DVT**
**	****Recurrent DVT**

## DIAGNOSIS OF PE

**	****Structured clinical assessment**
**	****Objective testing**
**	****	****- non-invasive**
**	****	****- invasive****	**

## OBJECTIVE TESTING FOR PE

**	****D-dimer**
**	****CT angiography (or V/Q)**
**	****MR angiography**

## CT Pulmonary Angiography (CTPA)

**CT Pulmonary Angiography (CTPA)**

## SUSPECTED PE

**SUSPECTED PE**

**PRETEST PROBABILITY**

**Low**

**D-dimer**

**Moderate or high**

**Negative**

**Positive**

**Positive**

**Negative**

**  ****No PE**

**+ CUS**

**+ CUS**

**PE**

**D-dimer**

**Negative             Positive**

**No PE                   PE**

**Positive              Negative**

**Repeat CUS **
**in 5-7 days**

**No PE**

**CT (or V/Q)**

**CT (or VQ)**