Deep Venous Thrombosis, Pulmonary Embolism and use of Warfarin

Guidance on certification of applicants with DVT, PE, Warfarin

Deep Venous Thrombosis (DVT), Pulmonary Embolism (PE) and use of Warfarin or Direct Oral Anticoagulants (DOACs)

Certification is possible provided that,

  1.       the pilot has recovered from the underlying condition or the condition has been stabilised and does not in itself preclude flying AND
  2.       the total incapacitation risk of the medication, the condition for which anticoagulation is indicated and any other conditions is 
          acceptable.

Acceptable DOACs are Dabigatran, Rivaroxaban and Apixaban.

Likely indications include:

• DVT/PE: Screening should have been undertaken for underlying causes, including coagulation abnormalities.  DVT is likely to be the least problematic for certification; For pilots taking warfarin target INR is normally within the range 1.8-2.5 (with an ideal 2.0-2.3) - see stability requirement below.  In all cases of pulmonary embolism follow-up reviews should be with a chest physician and reports should include relevant investigations. 
• atrial fibrillation may be associated with other risk factors, which require assessment using the CHA2DS2Vasc score  (See Atrial Fibrillation flow chart and guidance material)
• cardiac valve replacement.  The target INR following valve replacement and other co-morbidities should be taken into account. 
(See Aortic Valve Replacement flow chart).


Prior to certification, for pilots taking warfarin the INR should be demonstrated to be within the target range for 6 months (4 results at 2 monthly intervals) and 2 monthly laboratory testing should be continued on an ongoing basis.  If the INR varies considerably within the target range on the initial readings, a longer period of surveillance may be required.  Pilots taking DOACs should be free of side effects for a period of 3 months prior to fitness reassessment.

Class 1 applicants treated with warfarin are required to measure their INR on a ‘near patient’ testing system (such as CoaguChek S) 12 hours prior to flight and only fly if the INR is within the target range.  The INR should be recorded in the Log Book.  The Log Book should be reviewed at each medical certificate revalidation examination.

For LAPL pilots, a shorter period of stabilisation (6 weeks for DOACs and 4 months for warfarin) may be acceptable provided there are no side effects and there is reliable evidence of INR stability in pilots taking warfarin.