Deep Vein Thrombosis (DVT)

Most deep vein thromboses (DVTs) are small, harmless and resolve by themselves. However some can go on to damage the deep veins themselves, leading to major problems in the future (leg ulcers and "post phlebitic limb"), or can fly off causing the potentially lethal Pulmonary Embolism (PE).

We have also found patients who have had a "standard" course of Warfarin, usually 3 or 6 months, who are then taken off of the Warfarin without checking the DVT has gone, only to find there is still DVT present or damage to the deep veins causing narrowing - both meaning that Warfarin should probably be continued.

'Standard' prevention, diagnosis and treatment of DVT

Most people who are doing things at high risk of DVT are given advice or help to reduce the risks:

• When flying you are advised to wear properly fitted flight socks and to keep well hydrated
• When having a general anaesthetic most patients have either TED stockings or heparin injections - or both
• When in the heat, you are advised to drink water to keep well hydrated

When DVT is suspected, a variety of tests are used to screen for it

• Venography - An X-ray with contrast injected into the foot - now out of date and not needed
• Thermography - an infra-red device is used to see if the leg is warmer than the other - quite inaccurate and useless if both legs have DVTs!!
• Blood test - tests checking for signs of clots in the blood are simple to perform, and although often right do sometimes give the wrong results. This means either patients get treatment they don't need until a specialist scan is done, or get sent home with a DVT
• Duplex Ultrasound scan - this is the gold standard - but only if done by a specialist who checks from pelvis to ankle (taking 30 mins +). Many non-specialists or doctors or nurses who have "been on a course" will be able to see a massive DVT in the thigh, but will often miss small DVTs in the lower leg, where the veins are tiny.
• Treatment is usually with Heparin injections then oral Warfarin tablets. The level of anti-coagulation (clotting level) is regularly checked with the INR blood test. Warfarin is usually stopped 3 or 6 months after the diagnosis of the DVT.

Whiteley Clinic protocols for DVT

We only use the gold standard test to diagnose DVT - a Duplex Ultrasound scan performed by Vascular technologists who are recognised experts in scanning veins. All veins are checked from groin to ankle.

We do not specify how long treatment should last. Instead, we scan regularly to let the patient's body tell us when the clot has reabsorbed and the deep veins are back to normal. By doing this, we have often avoided stopping Warfarin too soon when clot is still present, or avoided stopping it in patients who have narrowed veins who should stay on the Warfarin to prevent further DVTs.