Recommendations
14.

If a patient presents with signs or symptoms of both DVT (for example a swollen and/or painful leg) and PE (for example chest pain, shortness of breath or haemoptysis), carry out initial diagnostic investigations for either DVT or PE, basing the choice of diagnostic investigations on clinical judgement.

Relative values of different outcomesThe most important outcome is to follow the appropriate diagnostic pathway, so that the correct treatment can be initiated. It is also important not to miss other alternative diagnosis or causes for the symptoms.
Trade off between clinical benefits and harmsFollowing the correct diagnostic path means diagnosis can be confirmed accurately and appropriate treatment plans initiated and continued. Unnecessary radiation exposure was also considered. Chest CT is approximately equivalent to 3.6 years of natural background radiation (UK average 2.2 mSv per year taken from referral guideline from the Royal College of Radiologists)208.

It is unlikely that there are harms from following this recommendation.
Economic considerationsDiagnostic pathways for PE and for DVT have different costs. Given the importance of long-term management, the GDG thought it was cost-effective to confirm both diagnoses when required.
Quality of evidenceThis is a supporting recommendation and was made based on GDG consensus.
Other considerationsThe GDG discussed the advantages and disadvantages to the patient in following each pathway:
  • The ultrasound scan used in the DVT algorithm avoids radiation exposure and the administration of contrast compared with CTPA which is used in the PE diagnostic algorithm. A CTPA is approximately equivalent to 3.6 years of natural background radiation (UK average 2.2 mSv per year taken from referral guideline from the Royal College of Radiologists).
  • One advantage of CTPA is that it also looks at all of the other structures within the chest including whether there is evidence of right ventricular dilatation which has prognostic implications and can identify other causes for the patient’s symptoms.
  • The DVT diagnosis algorithm may be chosen for a patient with a possible provoked DVT and PE because there will be no change to the pharmacological treatment as a result of diagnosis and they would be exposed to no radiation or intravenous contrast (see recommendations in section 7.5).

From: 6, Diagnosis of pulmonary embolism

Cover of Venous Thromboembolic Diseases
Venous Thromboembolic Diseases: The Management of Venous Thromboembolic Diseases and the Role of Thrombophilia Testing [Internet].
NICE Clinical Guidelines, No. 144.
National Clinical Guideline Centre (UK).
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