Deep Vein Thrombosis

Guidance for medical examiners when assessing a patient for either a general topic or condition – Deep Vein Thrombosis.

Aeromedical implications

Effect of aviation on condition

  • Long periods of immobility
  • Dehydration (dependent on operations)

Effect of condition on aviation

  • Overt incapacitation
    • Sudden death
    • Distracting pain.

Effect of treatment on aviation

  • Risk of distraction due to bleeding
  • Risk of incapacitation secondary to bleeding

Approach to medical certification

Based on the condition

  • confirmed diagnosis of deep vein thrombosis
  • exclusion of other diagnoses
    • clinically evident pulmonary embolus
    • predisposing disease pro-thrombotic malignancy, pro-thrombotic haematological disease
  • Acceptable prognosis - risk of recurrence, risk of incapacitation.

Based on treatment

  • Acceptable, stable treatment without significant side effects
  • Demonstration of adherence
    1. If commencing warfarin, a minimum of three INRs are required at least one week apart and must be within the therapeutic range (see guidelines for Anticoagulation – Warfarin)
    2. If commencing NOAC then confirmation of adherence to medication (see guideline for Anticoagulation - NOACs).

Demonstrated stability

  • Absence of symptoms e.g. distracting calf pain, chest pain and shortness of breath
  • Interval ultrasound evidence of thrombus stabilisation

Risk assessment protocol - information required

New cases

  • Confirmed diagnosis
    • Provoked or Unprovoked DVT
    • Exclusion of PE (see guidelines on Pulmonary Embolus)
    • Pre-disposing co-morbidities
  • Clinical status
    • history of condition
    • details of any symptoms
  • Investigations conducted
    • procoagulant screen (conducted before or after anticoagulant treatment)
    • ultrasound or CT scans
  • Management
    • treatment: response to treatment and side effects
    • monitoring regimen including adherence with and stability of
    • anticoagulant medication
    • (ie, serial INR results (or proof of NOAC adherence)
    • any side-effects
  • Underlying cause of thrombosis
  • Estimate of annualised percentage risk of recurrence
  • Estimate of annualised percentage risk of incapacitation
  • Follow-up plan.

Interval assessment at 6 – 12 months

  • Clinical status
    • history of condition
    • details of any symptoms
  • Investigations conducted
    • pro-coagulant screen (if not done prior)
    • ultrasound or CT scans
  • Management
    • treatment: response to treatment and side effects
    • monitoring regimen including adherence with and stability of
    • anticoagulant medication
    • (ie, serial INR results (or proof of NOAC adherence)
    • regimenany side-effects
  • Underlying cause of thrombosis
  • Estimate of annualised percentage risk of recurrence
  • Estimate of annualised percentage risk of incapacitation
  • Follow-up plan. 

Renewal

DAME comments. (Additional reports may be needed for long-term treatment.)

Indicative outcomes

  • Initial notification to CASA and grounding required pending diagnosis
  • Clearance by CASA required before exercising privileges
  • Interval assessment at 6 months
  • Audit will be required with review at 12 months
  • Both due to the risk of recurrent DVT/PE and anticoagulation treatment, certificates may be subject to long term multi-crew/proximity restriction (Class 1 and 3)
  • See guidelines for Anticoagulation – Warfarin and Anticoagulation - NOACs

Favourable

  • Successful treatment of deep vein thrombosis
  • Absence of co-morbid conditions
  • Acceptable recurrence risk

Unfavourable

  • Clexane (other than initial treatment for DVT during grounding period)
  • Poor adherence to anticoagulation treatment
  • Unstable or out of target range INR
  • Side effects of treatment (e.g. epistaxis, gastrointestinal haemorrhage, stroke)
  • Recurrent thrombosis or pulmonary embolus
  • Positive procoagulant screen
  • Presence of co-morbid conditions

Pilot and controller information

  • DVT is an aero-medically significant medical condition because blood clots can move and affect the lungs heart or brain
  • Pilots and controllers who have been diagnosed with DVT are required to ground themselves and notify this condition to their DAME or CASA.
  • Anticoagulant medication is associated with well recognised hazards (e.g. bleeding) which must be considered as a separate risk to aviation safety
  • Effective and stable treatment is critical in reducing these risks
  • If cleared to exercise the privileges of a medical certificate, long term multi-crew/proximity restriction and audit may be required (Class 1 and 3)

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Disclaimer

The clinical practice guidelines is provided by way of guidance only and subject to the clinical practice guidelines disclaimer.

Last updated:
Online version available at: https://www.casa.gov.au//licences-and-certificates/medical-professionals/dames-clinical-practice-guidelines/deep-vein-thrombosis
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