Should a patient with a history of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) take DVT prophylaxis during travel, and if so, what type, given a negative thrombophilia workup and planned travel?

DVT Prophylaxis for Travel in Patients with Prior VTE

Your patient with a history of travel-related DVT and PE should use mechanical prophylaxis with properly fitted below-knee graduated compression stockings (15-30 mmHg at the ankle) during her upcoming long-distance travel, combined with frequent ambulation and calf exercises. 1

Guideline-Based Risk Assessment

Your patient falls into the high-risk category for travel-related VTE based on the American College of Chest Physicians (ACCP) guidelines, which specifically identify "previous VTE" as an increased risk factor for long-distance travelers 1. The fact that her thrombophilia workup is negative does not eliminate this risk—a history of VTE alone is sufficient to warrant prophylaxis 1.

Recommended Prophylaxis Strategy

Mechanical Prophylaxis (Primary Recommendation)

The ACCP guidelines specifically recommend properly fitted, below-knee graduated compression stockings providing 15-30 mmHg of pressure at the ankle for long-distance travelers at increased risk of VTE, including those with previous VTE 1. This recommendation applies to flights or travel exceeding 4 hours 2.

• The stockings should be worn during the entire journey 3
• This provides an absolute risk reduction of approximately 540 fewer proximal DVTs per 1,000 travelers 3
• The British Journal of Haematology guidelines support this approach for highest-risk travelers on journeys over 3 hours 2

Non-Pharmacologic Measures (Essential Adjuncts)

The ACCP guidelines suggest the following additional measures for high-risk travelers 1:

• Frequent ambulation during travel (every 2 hours minimum) 3
• Calf muscle exercises while seated (ankle pumps, knee extensions) 1, 3
• Aisle seating when feasible to facilitate movement 1, 3
• Adequate hydration (though evidence for preventing VTE specifically is limited) 2

Pharmacologic Prophylaxis (NOT Recommended by Guidelines)

The ACCP explicitly recommends AGAINST the use of aspirin or anticoagulants for long-distance travelers to prevent VTE (Grade 2C) 1. This applies even to high-risk travelers like your patient.

• Aspirin is an antiplatelet agent that works on arterial thrombosis, not venous thrombosis 3
• The LONFLIT-3 study showed aspirin had minimal benefit (3.6% DVT rate vs 4.8% in controls) compared to LMWH (0% DVT rate), but guidelines still recommend against routine anticoagulant use for travel 4
• Major bleeding occurs in approximately 5 per 1,000 patients per year with aspirin use 3

Important Clinical Considerations

Duration of Risk

VTE may be attributable to travel if it occurs up to 8 weeks following the journey 2. Your patient should remain vigilant for symptoms during this extended period.

Window vs Aisle Seating

A window seat compared with an aisle seat has been associated with a twofold greater risk of VTE 1. In the LONFLIT-3 study, 85% of DVTs were observed in passengers in non-aisle seats 4. This makes aisle seating particularly important for your patient.

Contraindication to Routine Anticoagulation

The guidelines are clear that even for patients with previous VTE who are asymptomatic and not on chronic anticoagulation, routine pharmacologic prophylaxis for travel is not recommended 1. The exception would be if she were already on anticoagulation for another indication, but this doesn't apply to your patient who is "perfectly fine now" and has completed her treatment course.

Common Pitfalls to Avoid

Do not prescribe aspirin reflexively for flight DVT prevention—both the ACCP and American Society of Hematology agree this should not be done due to lack of evidence and bleeding risk 3.

Do not recommend sedatives or sleeping aids for the flight, as these would prevent the frequent ambulation and calf exercises that are cornerstone prevention strategies 3.

Do not assume that a negative thrombophilia workup eliminates her risk—the history of VTE itself is the risk factor that matters for travel prophylaxis 1, 2.

Summary Algorithm

For your patient with prior travel-related VTE and negative thrombophilia workup:

1. Prescribe properly fitted below-knee graduated compression stockings (15-30 mmHg) 1
2. Instruct to wear stockings during entire journey 3
3. Advise aisle seating, ambulation every 2 hours, and seated calf exercises 1, 3
4. Do NOT prescribe aspirin or anticoagulants for travel prophylaxis 1, 3
5. Counsel about symptom awareness for 8 weeks post-travel 2