Deep vein Throbosis: 'Do I need blood-thinning drugs to combat deep vein thrombosis?'

"Seventeen years ago I had a deep vein thrombosis (DVT). After blood tests and scans, I was diagnosed with Factor V Leiden. This makes my blood liable to form clots. Should I be taking blood-thinning drugs such as aspirin? I have also recently been discharged from hospital after a suspected heart attack. Has the advice changed in the 17 years since my DVT was diagnosed?"

Dr Fred Kavalier answers your health question:

Factor V Leiden is the term that is used to describe a genetic variation in one of the blood-clotting genes (the F5 gene). People who carry one copy of the Factor V Leiden have a slightly increased risk of developing blood clots. People who carry two copies of the Leiden variant are much more likely to develop clots. In the UK, about 1 in 20 people have one copy of Factor V Leiden. Almost all of these people are unaware of the gene they are carrying, and most will never have problems and do not need regular treatment. The gene can cause problems in pregnancy, but fortunately there are treatments available to prevent this. Your doctors may want you to take aspirin because of your heart attack, but this is true for many heart attack patients, whether or not they have Factor V Leiden.

Please send your questions and suggestions to A Question of Health, The Independent, Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or email Dr Kavalier regrets that he is unable to respond personally to questions.