Deep Vein Thrombosis
Questions Received:
Responses:
How long should anti embolism stockings be worn post operatively? We are currently advising patients to wear them until they return to their normal mobility, but a spokesperson from the company which provides our hospital with them said they should be worn for at least 6 weeks post op. How empirical is this evidence?
12th July 1999
We have not yet found any published studies that compare the effectiveness of different periods of application of the stockings, although we are continuing to search. There is an extensive literature about the use of graduated compression stockings in the prevention of deep vein thrombosis after surgery, and in general the stockings are considered to be effective, particularly when used in combination with other preventive measures. However, even within a single study there is rarely consistency in the length of time the stockings are applied. This variation in use probably reflects differences between patients - some are fitter or regain mobility more quickly than others. Thus it may be unrealistic to propose a set time period in all cases. Your advice to continue using the stockings until normal mobility is regained appears appropriate in the circumstances. It would be worthwhile asking the company representative for the independent evidence on which their 6-week minimum recommendation is based.
Reading
Colditz, G.A., Tuden, R.L., and Oster, G. (1986) Rates of venous thrombosis after general surgery: combined results of randomised clinical trials. Lancet, 2(8499), 143-146 (Jul 19).
Perkins, J., Beech, A., and Hands, L. (1999) Vascular Surgical Society of Great Britain and Ireland: randomized controlled trial of heparin plus graduated compression stocking for the prophylaxis of deep venous thrombosis in general surgical patients. British Journal of Surgery, 86(5), 701 (May).
I am currently under a Doctor's care for a deep vein thrombosis below my calf - left leg. After the initial diagnosis, I self administered 70cc once a day of Warfarin injections for 4 days. I then took 4mg Coumadin for one week, then had my blood tested to see if it was thinning. No luck there, I was then advised to take 8mg a day for two days, then 6mg a day for two weeks. Blood was tested with negative results. Once again I was advised to boost my Coumadin to 10mg for two days, then take 7.5mg per day. This brings us to current date.
I tested today, haven't
received the results yet. I'm becoming very pessimistic and depressed of all
this. My three questions which I have/will also ask my Doc:
1. How many times will my dosage have to be adjusted to get the proper effect,
if this doesn't work what other options are there?
2. Does thinning the blood cause joint pain, headaches?
I was very active when this happened, (Hiked at work, coached my son's soccer team, walked daily) initially I felt this vertical pop in my leg below my knee followed by pain and swelling. I did this three times over a course of one month due to ignorance of the healing timeline of whatever I injured. I wore a boot cast for 4 weeks. I am 42 years old, 220lbs, 69 inches tall.
26th January 2005
Here are some observations relating to the questions you have raised:
When warfarin (Coumadin) treatment is being given, frequent blood tests are carried out to measure blood clotting time, also called prothrombin time or protime. The protime results help your doctor adjust the warfarin dose level to avoid the risk of excessive bleeding. A measurement known as the International Normalized ratio (INR) standardizes protime measurements between labs, and for most patients the warfarin dose is adjusted to keep the INR between 2 and 3.
It is worth knowing that many drugs, both prescription and over the counter, can affect the anticoagulant action of warfarin. Some medications enhance its activity, other diminish it. If you are taking other medications at this time, this potential for interaction will have to be taken into account when determining the optimum dose level for the warfarin. Warfarin is metabolized by the liver and excreted by the kidneys, so if you have any liver or kidney dysfunction this will also affect the required dose.
With regard to other options - although there are several other anticoagulants in development, they are not yet licenced for use in the US. The one that is furthest along is ExantaŽ. There have been studies that suggest it has several advantages over warfarin and it is available in Germany, but the FDA has not yet approved its use in the US.
2. Does thinning the blood cause joint pain, headaches?
Joint pain and headaches are recognised side effects of treatment with anticoagulants, and are an indication of bleeding in the vicinity of joints and the brain. If you are experiencing these symptoms, discuss them with your doctor as soon as possible.
Three main factors make a deep vein thrombosis more likely to occur:
Injury to the lining of the vein
An increased tendency for blood to clot
Slowing of blood flow through the vein.
Deep vein thrombosis is more
common in people aged over 40 and in people who have a weight problem. Several
inherited conditions make the blood more likely to clot than usual, for example
deficiencies of certain blood components that normally help to dissolve blood
clots, and defects in enzymes caused by certain vitamin deficiencies. Other
factors include prolonged immobility through illness or during travel, injuries,
surgery, circulatory problems, and diseases and drug treatments that enhance the
tendency of the blood to clot.
The most common cause of injury to a deep leg vein is trauma. You mentioned
wearing a boot cast for four weeks following a repeated injury, which may have a
link with the formation of the deep vein thrombosis. The injury itself may have
initiated damage to a deep vein, or the immobilisation during the wearing of the
cast may have resulted in slowing of blood flow through it due to reduced
muscular activity. It is worth remembering that prolonged sitting, especially
with crossed legs, in a car, train, or plane can increase the risk of deep vein
thrombosis due to the slowing of blood flow.
General Points
A deep vein thrombosis (DVT) is a blood clot (thrombus) that develops in a deep vein, in this case in your left lower leg. Deep vein thrombosis can cause pain in the leg, and can lead to complications if the clot or parts of it travel in the bloodstream to other vital parts of the body such as the lungs and brain. Fortunately, a deep vein thrombosis below the knee is unlikely to cause these serious complications. The presence of a blood clot in the vein causes pooling of the blood in the lower leg and oedema (accumulation of fluid). This is called post-thrombotic syndrome, and can result in pain, swelling, discolouration and sores on the leg. Some thrombi disperse over time, while some heal by being converted to scar tissue.
The aims of the treatment for deep vein thrombosis are to prevent:
The clot becoming larger
The blood clot breaking loose and travelling to the lungs
New clots from forming
Post-thrombotic syndrome
Drugs to dissolve the thrombus - thrombolytic drugs - may be given during the first 48 hours after formation of the blood clot. Anticoagulants are also given to reduce the blood's tendency to clot. These are usually taken for three to six months, depending on the exact circumstances. Anticoagulants can stop new blood clots from forming and old ones growing, but they are unable to dissolve existing clots. Initially, heparin may be given for its immediate anticoagulation action, combined with warfarin (Coumadin). Warfarin is an oral anticoagulant that inhibits the synthesis of clotting factors, and usually takes several days to reach a suitably therapeutic level, after which the heparin may be discontinued.
While taking anticoagulants, patients are advised to avoid activities that could increase the risk of injury and blood loss since their blood will take longer to clot.
To relieve pain and swelling, and to prevent post-thrombotic syndrome, some doctors recommend wearing graduated compression stockings, which are tighter at the foot than higher up the leg. These may need to be worn for several months or more.
Most people with a deep vein thrombosis are advised to place a cushion under their feet while resting or sleeping, so that the feet are raised higher than the hips. This helps to reduce the blood pressure in the veins of the calves and improve lymphatic drainage.
There are several simple measures that can help prevent the occurrence of deep vein thrombosis:
Exercise the legs regularly
Maintain a weight that is appropriate for your height
Avoid sitting in a chair or vehicle seat or lying in bed for long periods of time without moving the legs. Although the added risk of developing a DVT caused by travelling appears to be low, it can be reduced even further by exercising the legs at least once every hour during long-distance travel. This means taking regular breaks if driving, or walking up and down the aisle of a coach, train or plane. The muscles of the lower legs (which act as a pump for the blood in the veins) can be exercised while sitting by lifting the toes towards the knees then relaxing, or by pressing the balls of the feet down while raising the heel
Avoid taking sleeping pills because these cause immobility and increase the risk of deep vein thrombosis.
Wear loose-fitting clothing
Keep the legs uncrossed
Keep hydrated by drinking normally (but not alcohol).