Venous thromboembolism - PowerPoint Presentation

Slide1

Venous thromboembolismSlide2

Learning objectives

Gain organised knowledge in the subject area VTE

Be able to correctly interpret diagnostic information in suspected VTE

Know and apply the relevant evidence and/or guidelines to different clinical presentations of VTE

Be aware of common cognitive biases in the diagnosis and management of VTESlide3

ScenariosSlide4

Scenario 1

A 34-year-old

man was

admitted

with acute onset of heaviness

, pain

and functional impairment of

his right

arm. The arm was cyanotic

and swollen. For the past few weeks

, he reported transient

paraesthesia of

his right arm during

weightlifting.

He had

a fracture of the right clavicle after

a ski

accident 5 years

previously which was

managed

conservatively. There

was no personal or family

history of

thrombosis.Slide5
Slide6

Doppler USS right arm showed axillary and subclavian vein thrombosis

In small groups answer the following Qs:

What are the treatment options in this case?

What further investigations should be performed?

What follow-up is required?Slide7

Upper limb DVT: summary

Increasing incidence 5-10% all DVTs

Primary

Effort-related thrombosis

(

Paget-Schroetter Syndrome). Weights, tennis, repeated overhead activities (swimming, decorating). Most have underlying VTOS

Idiopathic

*

Secondary most common

Indwelling central venous catheters/ports

Cancers, mainly lung and lymphoma

Surgery/trauma/immobilisation of arm

Pregnancy and ovarian hyperstimulation syndromeSlide8

Upper limb DVT: summary

Initial management

Anticoagulation: 3 months for idiopathic and catheter related (if catheter removed); indefinite if on-going risk factors

Catheter directed thrombolysis /

pharmaco

-mechanical

thrombectomy

in selected patients

Investigations/follow-up

Doppler USS initial investigation of choice

If primary upper limb DVT: imaging of the thorax +/- thrombophilia screen

If secondary: address underlying cause (e.g. catheter)

OP vascular surgery referral

Complications

Post

-thrombotic syndrome (in one study, 53%

pts

with upper limb VTE due to

VTOS

)Slide9

Common cognitive biases in the diagnosis and management of upper limb DVT

Knowledge gaps

 application of the wrong heuristic

i.e. treating upper limb DVT the same as lower limb DVT and applying inappropriate diagnostic, management and further investigation strategiesSlide10
Slide11

Any questions at this point?Slide12

Scenario 2

A 50-year-old woman was admitted with pain, redness and swelling of her thigh that had developed over the preceding 48 hours ?cellulitis.

Her only past medical history was gastro-oesophageal reflux disease and varicose veins.Slide13
Slide14

She was started on iv flucloxacillin by the FY1 doctor

In small groups answer the following Qs:

What

is the diagnosis?

What further investigations should be performed?

What are the treatment options in this case?Slide15
Slide16

Superficial thrombophlebitis: summary

Inflammation of the superficial veins

Swelling, pain, redness

Scanty evidence base re: management

SIGN guidelines and NICE ‘clinical knowledge summary’ broadly agreeSlide17

Superficial thrombophlebitis: summary

SIGN Guideline 122

10-21% of

pts

have a DVT, more likely if >5cm inflammation or within 10cm of

sapheno

-femoral junction

Topical treatments only alleviate symptoms

Oral NSAIDs prevent extension, recurrence and progression to DVT, so does LMWH

Not clear if LMWH (prophylactic or therapeutic doses) is better than NSAIDs – but in high risk cases LMWH recommended*

NICE CKS

T

he risk of DVT should be considered

Treat with oral NSAIDs and paracetamol, class 1 AES and advice. Topical NSAIDs can be used for symptomatic relief

LMWH not routinely recommended, but experts advise it should be used in high risk cases (no dose recommendation)

Treat super-added infection with antibioticsSlide18

Common cognitive biases in the diagnosis and management of superficial thrombophlebitis

Knowledge gaps

application of the wrong heuristic

(i.e. treating as ‘cellulitis’)

n

ot knowing the risk of occult DVT at presentation

Confirmation bias if the patient has been seen first by someone elseSlide19

Any questions at this point?Slide20

Scenario 3

A 45 year old man presented to Ambulatory Care with right leg swelling and pain, which had occurred spontaneously over the last 3 days

On examination, his right calf was 5cm wider than the left

His only past medical history was hypertensionSlide21
Slide22

Doppler USS right leg showed a femoral vein thrombosis

In small groups answer the following Qs:

What is the management in this case?

(pharmacological and non-pharmacological)

What is the duration of anti-coagulation?

What further investigations should be performed?

What follow-up is required?Slide23

Duration of treatment?

Cancer patients

6 months then review risks/benefits

LMWH only

Provoked DVT/PE

3 months then review risks/benefits

Unprovoked DVT/PE

6 months then review risks/benefits

Question

:

What is the risk of a recurrent DVT in a 30 year old man who presents with a single unprovoked DVT?Slide24

Lower limb DVT: summary

?DVT

 history, exam and Wells Score

If DVT suspected plus Wells =

likely

then do a proximal Doppler USS (whole leg not recommended)

NICE recommends doing a d dimer in likely cases so that if the proximal scan is negative they can be offered a repeat scan in one week if their d dimer is high …

This is because proximal scans may miss calf DVTs that could extend – you don’t need a repeat scan if a whole leg USS was performed first

If DVT suspected plus Wells =

unlikely

then get a d dimer, if positive get a scan, if negative DVT is virtually excluded

For all cases, if you can’t get a Doppler within 4 hours then treat and get a scan within 24 hours

Consider and communicate alternative explanations for symptoms in patients with negative scans

Don’t forget to arrange further investigations/FU for new DVT casesSlide25

What’s this called?Slide26

Common cognitive biases in the diagnosis and management of lower limb DVT

Groupthink (‘that’s the way we do things around here’)

Psych-out error and visceral bias (IVDUs)

Omission bias (the

tendency towards inaction, rooted in

the principle

of ‘first do no

harm’ e.g. radiation, anxiety/harm from further Ix, explanation and treatment) …Slide27

Any questions at this point?Slide28

Scenario 4

A 54 year old female smoker was admitted with gradually worsening breathlessness over the last 10 days. She reported a cough but no obvious fever or discoloured sputum.

Her past medical history included a DVT 5 years previously.

Her chest X-ray showed some patchy consolidation at the left base. She was started on treatment for community acquired pneumonia in ED.Slide29
Slide30

CT or V/Q scan?

CTPA

Preferred – simple positive/negative result, can visualise other lung pathology, RV dysfunction and proximal leg veins

90% sensitivity, 95% specificity - a negative CTPA essentially rules out PE

However, high sensitivity –> increased incidence of PE and probably diagnosing unimportant PEs

V/Q

Recommended in young/pregnant patients with normal CXRs and no history of lung disease (e.g. asthma) to reduce radiation

Role in patients who cannot have contrast

Different sensitivity and specificity figures in literature - non-diagnostic scans with high clinical suspicion still need CTPA –

but see next

Much more sensitive than CTPA in diagnosing chronic PEs (e.g. Ix of pulmonary hypertension)Slide31

Sensitivity and specificity of planar

V/Q scan

(after removing non-diagnostic scans from the analysis)

PE absent

Non-diagnostic

scan

PE present

Normal/very low probability

Low/intermediate probability

High probability

Modified PIOPED ll

Scintigraphic

Criteria

(V/Q result compared with DSA or CTPA + Wells)

Sensitivity 77.4%

Specificity 97.7%

The % of patients with a PE absent or PE present scan was 73.5%Slide32

V/Q SPECT

V/Q SPECT (single photon emission tomography) is the latest gold standard type of V/Q scan

3D images, greater diagnostic accuracy compared with planar V/Q scans … possibly comparable to CTPA

Reported as ‘no PE’ or a description of PE(s) present rather than probability (PIOPED

ll

)Slide33

Diagnosing PE: things to consider

Patients require respiratory OP follow up (not small peripheral PEs)

Over 40’s with idiopathic PEs require cancer screening same as DVTs

Duration of anti-coagulation same as DVTs

Thrombolysis is considered more often in PE – you need to know the criteria

Investigation is different in pregnant patients: bilateral leg Doppler USS first. (Treatment and follow-up for VTE in pregnancy is different too)*Slide34

How do you decide whether a patient can be investigated and treated for PE in Ambulatory Care?Slide35

Simplified PE Severity Index (PESI) Score

Patients with a score of 0

are

determined to be low risk, while those with a score of 1 or more

are

considered high riskSlide36

PE: summary

?PE

 history, exam and Wells Score

If

PE

suspected plus Wells =

likely

then

image the chest

If PE suspected plus Wells =

unlikely

then do d dimer

If the d dimer is raised, remember that it is NOT diagnostic, it just means imaging is required to exclude PE

If

d dimer is negative then PE is virtually

excluded

For all cases, if you can’t get

imaging within

4 hours then treat and get a scan within 24 hours

Consider and communicate alternative explanations for symptoms in patients with negative scans

Don’t forget to arrange further investigations/FU for new

PE casesSlide37

Common cognitive biases in the diagnosis and management of PE

Misinterpretation of diagnostic tests (d dimer, planar V/Q)

Knowledge gaps (e.g. different Ix and management in pregnancy)

Representativeness, premature closure, search satisficing, confirmation bias ..?Slide38

Any questions at this point?Slide39

Scenario 5

A 75-year-old woman was sent to Ambulatory Care for investigation of a raised d dimer (900

μg FEU

/

L). She had been admitted two weeks previously with pleurisy and had a negative CTPA. On discharge the Practice Nurse repeated the d dimer test to see if it was still raised and referred the patient back to Acute Medicine to ‘find the clot’.

The patient’s past medical history consisted of: COPD, heart failure, hypertension.

On examination the patient was well with no new symptoms and had mild bilateral lower leg oedema.Slide40

Correct interpretation of d dimer

Ginsberg

and colleagues found that the combination of a low pre-test probability and a normal d dimer had a negative predictive value of 99%, whereas the negative predictive value was only 78% in patients with a high pre-test probability and a normal d

dimer

A rule of thumb is that a ‘positive’ d dimer is non-diagnostic

However … should

a d dimer of 900 be interpreted the same as a d dimer of 10,000?Slide41

Any questions at this point?Slide42

Summary of Guidelines and MCQsSlide43

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