Can aspirin prevent DVT in high-risk flyers?

Nicky, a 48-year-old business executive, asked me for advice about deep vein thrombosis (DVT) prophylaxis prior to travel to the US.

She was a carrier for factor V Leiden. She had used enoxaparin (Clexane) in the past, but recently read about aspirin on the internet. Is this a reasonable choice?

CLINICAL QUESTION

What is the effect of aspirin, as compared to low-molecular weight heparin (LMWH), on the incidence of DVT in long-haul flight travellers who have risk factors for venous thrombosis?

What does the research evidence say?

Step 1: The Cochrane Library

The Cochrane Library did not have a systematic review that answered this question.

Step 2: Trip Database

Next, I conducted a search using the Trip Database PICO search tool (P: ‘long haul flight’, I: ‘aspirin’, C: ‘low