Venous Thromboembolic Disease

Question 1

How is PE classified?

Answer 1

• Massive - clot plus shock or hypertension.
• Submassive - clot in pulmonary trunk or main PA but no shock.
• Small - lobar or segmental arteries only.

Question 2

What symptoms would make you suspect PE?

Answer 2

• Symptoms are NOT specific.

Question 3

You suspect your patient may have had a PE. What should you do next?

Answer 3

• Assess likelihood of PE by:
  
  • Wells Score
  • Revised Geneva Score
  • PERC

Question 4

What questions are included in the Wells Score?

Answer 4

• Low risk = score ≤4
• High risk = score >4

Question 5

What questions are included in a PERC?

Answer 5

• Low risk score = 0
• High risk score >0

Question 6

When should you request a D-dimer?

Answer 6

When clinical risk is low

Question 7

Describe the properties of the D-dimer.

Answer 7

• It is a fibrin degradation product.
• Represents hypercoagulable state.
• Cut off 500µg/L but rises with age.
• High sensitivity → very low false negatives.
• Low specificity for VTE or any other disease → high false positives → unnecessary testing.
• Age-adjusted D-dimer excludes PE and reduces unnecessary radiation exposure in older adlts.
• Specificity improves in patients with a higher D-dimer.

Question 8

What is the definitive test for PE?

Answer 8

CTPA

Question 9

Describe the pathway for investigating ?PE.

Answer 9

Question 10

What does right ventricular strain pattern on ECG indicate?

Answer 10

• RV strain is associated with higher clot load in PE and with higher mortality and greater risk of clinical deterioration.
• ACS can also cause T wave inversion (TWI) but in ACS with TWI in leads V1-V4 it would be unusual to find TWI in leads III and aVF as well.
• RV strain pattern is not pathognomonic for PE as can also occur in patients with chronic respiratory disease including COPD, interstitial lung disease and OSA.
• However, its presence in an acutely breathless patient with no previous respiratory disease and a normal CXR must make APE extremely likely.

Question 11

What ECG changes are caused by PE?

Answer 11

• Sinus tachycardia
  
  • HR>100bpm
• RBBB
  
  • QRS duration >120ms wth rSR pattern V1-V3
• Right ventricular strain pattern
  
  • Simultaneous T wave inversion in the inferior (II, III, aVF) and right precordial leads (V1-V4).
• Right axis deviation
  
  • Dominant S wave lead I with dominant R wave leads II and III.
• P pulmpnale
  
  • Peaked P waves >2.5mm in limb leads or >1.5mm in lead V1.
• S1Q3T3 pattern
  
  • The presence of S waves in lead I and Q waves in lead III, each with amplitudes >1.5mm in association with negative T waves in lead III.
• Clockwise rotation
  
  • Shift the R/S transition point (the point at which the R wave becomes dominant) to V5 or beyond implying rotation of the heart due to ventricular dilation.
• Atrial tachyarrhythmias
  
  • Atrial fibrillation and atrial flutter.

Question 12

Which patients should be treated as PE until proven otherwise?

Answer 12

Patients with acute SOB, no previous cardiorespiratory disease, hypoxaemia, normal CXR and RV strain pattern on their ECG should be treated as PE until proven otherwise.

Question 13

What is the treatment for massive PE?

Answer 13

• Systemic thrombolytic therapy is recommended for massive PE with sustained hypotension (SBP <90mmHg for at least 15 minutes, provided no CI to thrombolysis).
• Rx - alteplase (tPA) 100mg IV given over 2 hours.
• Stop anticoagulant during tPA infusion. Check APTT when infusion complete. Restart unfractionated heparin when APTT <2x ULN.
• Associated with a significantly increased risk of major bleeding.

Question 14

What are the differentials for pleuritic chest pain?

Answer 14

• PE
• Pneumonia
• Pneumothorax
• Pericarditis
• Costochondritis
• Intercostal myalgia

Question 15

Describe the treatment algorithm for pneumonia.

Answer 15

• IMPORTANT - remember that CURB65 can underestimate illness severity in young patients. If in doubt, speak to the consultant prior to discharge.

Question 16

Describe the treatment algorithm for pneumothorax.

Answer 16

Question 17

Describe the treatment of costochondritis.

Answer 17

• Reassure self-limiting and not cardiac.
• Ibuprofen 400mg tds with paracetamol 1g qds till pain settles.
• A good response to local anaesthetic injection supports diagnosis.
• Consider methylprednisolone 20mg injection with LA if fails to settle.

Question 18

Describe the treatment of acute pericarditis.

Answer 18

• Ibuprofen 600mg tds for 1-2 weeks then taper.
• Colchicine 500µg bd for 3 months to prevent recurrence.
• Exercise restriction until resolution of symptoms.
• Pericardiocentesis for tamponade.

Question 19

What are the other potential causes if the D-dimer is high but CTPA is negative for PE?

Answer 19

Question 20

What is the likelihood that a patient whose D-dimer is high but CTPA was negative for PE has an underlying cancer?

Answer 20

• 22 cases of suspected PE whose D-dimer was at least 7.5x upper limit of normal.
• 113 (57%) had PE confirmed by CTPA.
• 85 did not.
• 6/85 (7%) had previously undiagnosed cancers.
  
  • 4 lung
  • 1 colon
  • 1 prostate

Question 21

When a patient has a PE, should you use warfarin or a DOAC?

Defend.

Answer 21

• DOACs are at least as effective an no more likely to cause bleeding when compared to warfarin for treatment of PE.
• Apixaban and rivaroxaban can be used as single-drug regimen without the need for LMWH lead-in period.
• Treatment of PE with DOACs may allow outpatient management of PE and be associated with a shorter LOS in hospital.

Question 22

Describe the first-line treatment of ?PE.

Answer 22

• Treat with LMWH until diagnosis is confirmed.
• Switch to Apixaban can be done at next scheduled dose.
  
  • DO NOT administer LMWH and Apixaban simultaneously.
• Prescribe Apixaban 10mg twice daily for the first 7 days followed by 5mg twice daily.
• After 6 months Apixaban consider prescribing 2.5mg twice daily for prevention of recurrent VTE if patient is to receive long-term anticoagulation.
• Use with caution if creatinine clearance 15-29mL/min.
• Apixaban is not recommended if CrCl is <15mL/min.

Question 23

Describe the treatment of PE with Warfarin.

Question 24

How do you decide whether to treat PE as outpatient?

Answer 24

• Determine degre of risk by the simplified Pulmonary Embolism Severity Index (sPESI) for patients without cancer and by the Hestia criteria for patients with cancer.
• Only those with sPESI=0 or with no risk factors using the Hestia criteria are eligible for OP management.