Risk Factors for Venous Thromboembolism Following Prolonged Air Travel: A “Prospective” Study

The aim of this study was to analyze patients with air-travel-related venous leg thromboembolism (VTE) concerning the occurrence of patient-related and cabin-related risk factors. Twenty-five patients, still in hospital, with deep-vein thrombosis (DVT) and/or pulmonary embolism (PE) with onset of symptoms during or after air travel were questioned according to a study protocol. There were 14 women and 11 men with an age range of 36-79 years. Flight times were 5-18 hours. All patients had DVT, and nine (36%) had PE as well. The proximal extensions of the thrombus were in tibial vein, five patients; popliteal vein, two patients; superficial femoral vein, three patients; common femoral vein, four patients; greater saphenous vein, four patients; and iliac vein, seven patients. All but two patients (92%) had one or more patient-related risk factors; the mean was three. Overweight was present in 76% of the patients; chronic heart disease in 44%; hormone medication in 40%; chronic disease, except chronic heart disease and malignancy in 32%; history of previous VTE in 28%; malignancy in 28%; smoking in 20%; recent lower limb injury in 16%; and recent surgery in 12%. Only two patients had no known patient-related risk factor. The flight travel itself does not seem to be an important risk factor in healthy individuals. However, when patient-related risk factors are superimposed, there is increasing evidence that cabin-related risk factors, such as immobilization, cramped “coach” position, insufficient fluid intake, low humidity, and hypoxia contribute to development of VTE. Improved information is required so that passengers can prepare their travel in good time. Active precautions are recommended.

Effect of Long-Distance Flights on Oedema of the Lower Extremities

Objective:

During long-distance flights, passengers complain of leg heaviness and oedema in the feet, ankles and distal parts of the lower extremities. Among the rarer complications are thrombophlebitis, thrombosis and pulmonary embolism. The aim of this study was to compare the efficacy of class II elastic stockings with no stockings and a venoactive compound (dried extract of vine leaves) and with a diuretic combination for preventing venous oedema during a long-distance flight.

Design:

Open, randomized study on outward-bound and return flights, volunteers having been administered the venoactive compound Antistax ( n = 13) or no medication ( n = 13); nine subjects received the fixed diuretic combination only on the outward-bound flight. Each subject ( n = 35) wore a class II compression stocking (Sigvaris 902/A-D) on one leg.

Main outcome measures:

Water displacement volume measurements of the lower limb; secondary end-points: clinical oedema, subjective symptoms, phlebological status, clinical and Doppler findings.

Results:

The most effective measure in preventing lower limb oedema was the individually fitted elastic support stockings. The venoactive drug Antistax was ineffective. The diuretic combination did have an effect in combination with the compression stocking.

Conclusion:

During long-distance flights, compression stockings are more effective in preventing oedema in the lower limbs than the venoactive dried extract of vine leaves. The diuretic combination had a marked effect in combination with compression.

Graduated compression stockings (20-30 mmHg) do not compress leg veins in the standing position

BACKGROUND

Since graduated compression stockings (GCS) reduce the risk of deep venous thrombosis (DVT) in both hospital and ambulant patients, we checked the compressive efficiency of 20-30 mmHg GCS in the standing position.

METHODS

In 30 volunteers (17 normal legs, 13 varicose legs), duplex ultrasound was used to measure the internal diameters of the long saphenous vein, posterior tibial veins, peroneal veins, and soleal veins in the lying and standing position and with and without 20-30 mmHg GCS.

RESULTS

Graduated compression stockings effectively compressed both superficial and deep veins in supine individuals but not the superficial or the deep veins when standing. In the varicose leg, the stockings did not compress the long saphenous vein at the mid-calf level even when supine. In the varicose leg the long saphenous vein was constricted at the upper band of the stocking, which might explain why superficial venous thrombosis is more common when compression stockings are worn.

CONCLUSIONS

In the standing position, GCS did not compress the deep or superficial veins of the calf.

Risk factors for venous thromboembolism following prolonged air travel. Coach class thrombosis

Venous thromboembolism (VTE) in legs and lungs is a potentially life-threatening condition. The incidence of VTE associated with air travel is still unknown, but it may have increased. Most travelers who develop symptoms do so within 24 hours after their flight takes off. Predisposing risk factors may be divided into patient-related and cabin-related factors, both of which are described. It is emphasized that better information and better inflight precautions can minimize these risk factors.