Venous thrombo-embolism (VTE) disease includes deep vein thrombosis (DVT) and pulmonary embolism. The incidence is 0.1 to 0.2% per annum in the general population. The risk increases with age. A pulmonary embolism may result in subtle or sudden incapacitation, including death and is likely to affect flight safety.
Thrombo-embolic disease has a high risk of recurrence of 5 -7% per year following a first episode, or about 50 times the risk of someone who has not suffered an episode of DVT. The risk is much higher following a recurrent episode. The risk decreases over time.
Since anticoagulation has its own risks, an episode of VTE currently treated with anticoagulants implies an increased risk to flight safety.
A provoked VTE episode means an occurrence in the presence of a temporary risk factor, for instance pregnancy, surgery, trauma or prolonged immobilisation.
An unprovoked or idiopathic VTE episode means an occurrence where no temporary clinical risk factor can be identified. DVTs due to malignancy and congenital coagulopathy are not idiopathic but should generally be considered as unprovoked when making treatment decisions.
Treatment is by anticoagulants. The American College of Chest Physicians (ACCP) Guidelines recommends the following anticoagulation treatment duration, taking into account the risk versus benefit of treatment.
|Provoked distal DVT||
|Unprovoked isolated distal DVT||
|Provoked proximal DVT||
|Unprovoked proximal DVT||
|Second provoked DVT||
|DVT and active cancer||
The following parameters need considering since they do increase the risk of recurrence (J Fahrni and al; Assessing the risk of recurrent venous thromboembolism – a practical approach; Vascular Health and Risk Management 2015:11 451-459). The relative risk (RR) is between 1.5 and 2.8 depending on the parameter considered. These are:
Male sex and positive D-dimer test following anticoagulation have the highest relative risk (RR) of 2.8 and 2.6 respectively while Asian and Pacific Islander ethnicity decreases the risk, with a RR = 0.7.
Following an episode of VTE:
An applicant who has suffered from a recent thromboembolic episode, currently treated with anticoagulants:
An applicant who has suffered a first thromboembolic episode more than 6 months ago and who is no longer requiring anticoagulants or is only requiring an anti-coagulant for prophylactic reasons may be considered as having a condition that is not of aeromedical significance if: