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All You Wanted to Know About ... Phlebitis and Blood Clots

Patient information is designed to help you understand what is going on when inflammation in the veins and blood clots have occurred, usually in the leg. In order to help you understand this better we have tried to compartmentalize this overview so that we consider the anatomy and functioning of the veins in the normal state and also in the diseased state. This should help you to understand the chronic changes that take place and what needs to be done to help prevent some of the more severe chronic problems.

Anatomy
In this section we are talking about diseases of the veins. Veins are blood vessels which return blood to the heart after they pass through the nutrient blood vessels and tissues of the body. Since man stands in an upright posture, the blood flow through the veins is usually against the forces of gravity so that a mechanism is required to prevent the blood from rolling back down the veins instead of proceeding upwards to the heart.

A mechanism that has been provided takes the form of valves within the veins and peripheral muscle pumping functions. The valves are present in just about all veins and are shaped like curved doors so that blood is allowed to pass through them in the direction going towards the heart. But if gravity pulls the blood back again, the doors go closed and the blood is maintained above the level of the valve. Each time a step is taken or a muscle is contracted, blood is emptied from the veins within that muscle. The blood is propelled forward toward the heart through the open valves. When the valves are healthy and close tightly there is no leakage, and these are called competent valves. However, when the valves have been damaged by disease or blood clots or by enlargement of the veins so that the valves can no longer come together accurately, then leakage does occur and the valves are said to be incompetent.

There are two main types of veins in the legs. The first are the ones lying deep within the muscles called the deep veins. These are involved in the muscle pump action and are responsible for returning the majority of the blood to the heart. The second type called superficial veins are merely collecting veins located on the surface just under the skin and have very little muscular support.

Acute Venous Disease
Most of the time when we speak of acute venous disease we are talking about deep vein thrombosis or DVT. This results in blood clots forming in the veins which either partially or completely block the flow of the blood through the vein leading to pain from pressure within the leg and significant swelling. It is felt that there are three components which contribute to the formation of DVT. One component is very slow movement of blood through the veins (called stasis). Another component is an inflammation of the vein wall itself. Finally there may be an increased tendency for the blood to clot (hypercoagulability).

Anything that changes any of these three parameters can be responsible for causing DVT. Factors that would contribute to venous stasis (or slowing the flow of blood) would include pregnancy, inactivity, surgery, obesity, injury, or varicose veins. A very common cause of stasis is sitting for a long time with one's legs hanging down. This is many times done in a long trip in the car or bus or train. Conditions which usually affect the vein wall are usually direct injury with trauma to the vein. Many mechanisms can increase the "clotability" of the blood including hormonal drug therapy, cancer, blood disorders, or unusual medical problems. DVT can occur not only in the leg but also in the arm. This is an unusual problem but does account for up to 5 to 10% of the incidence of phlebitis. Symptoms usually consist of pressure and swelling of the arm or leg. There may be enlargement of the superficial veins seen under the skin. And a dusky, bluish discoloration may occur.

Diagnosis
The diagnosis of DVT is not as easy as one might think and even with a thorough history and physical the accuracy of the diagnosis is only about 50%. Therefore, the presence of DVT has to be documented usually by use of one of two methods, either duplex examination or venogram.

A duplex examination is a study whereby ultrasound waves are passed into the extremity both visualizing the vein and any clot that might be in it and listening to the flow of blood through the vein with different testing maneuvers. This is usually our front line test. If a definitive study can be obtained in our office, usually no further studies are required. If, however, duplex study can not be obtained or if the results from a duplex study are questionable, then venography will have to be done. A venogram is done by placing a needle into the vein in the foot or wrist with injection of x-ray dye. X-ray pictures are taken as the dye proceeds toward the heart.


Treatment
The treatment of DVT is basically medical. When blood clots are fresh, they are actively forming more clots and are not well attached to the veins. Our main interest at this point is to stop all clotting by using medications and to prevent the clots from moving by maintaining bedrest. The mainstay of treatment is the use of Heparin. Heparin is a drug which neutralizes all of the active clotting components in the blood and prevents further clots from forming. This drug does not actually dissolve blood clots but prevents new ones from being formed so that the body may resorb clots that have been formed. A second drug called Coumadin is started concurrently for the long term treatment of DVT. Coumadin fools the liver into making some inactive clotting factors instead of active clotting factors that are usually made from Vitamin K.

In this way with a reduced level of active clotting factors present in the blood there is a lower chance that new blood clots will be formed while the body is absorbing the blood clots that are already present in the veins. Heparin must be continued in the hospital until the Coumadin has had a chance to exert its maximum effect. This usually takes about a week, give or take a few days. For the first five days of treatment you are to remain in bed and move around as little as possible until the blood clots that are present within the veins have a chance to attach themselves to the vein walls by formation of scar tissue. Once the clots are fixed to the vein walls, then it is safe to get up and move around. Surgical intervention in deep venous thrombosis is almost never indicated. It is used in only extreme cases. There are some newer drugs on the market which are designed to actually dissolve the blood clots that are present and restore blood flow within the veins. These drugs are used for immediate short term treatment in the hospital and may have some advantages over Heparin and Coumadin. However, the advantages have not been confirmed at this point in time, and they continue to be used in an investigational manner.

More Information About Coumadin
Most experts feel that patients with deep venous thrombosis should be treated with Coumadin for a minimum of three months if clots are present in the smaller veins and up to six months if they are present in the larger veins. If pulmonary embolism occurs, then treatment is extended for about one year. Because this is a long term treatment and because Coumadin can be a dangerous drug information about this particular drug would be given so that you can understand the importance of following all instructions.

Coumadin is basically rat poison! It is the same chemical that the exterminator uses in the garage to kill rats and mice. However, it is prescribed in a very limited and controlled manner. Your clotting parameters are monitored very closely by blood work. It is imperative that you take the Coumadin as directed and also obtain all follow-up studies that are recommended. Chemically Coumadin looks very much like Vitamin K. Vitamin K is made in the bowel by the bacteria, that are resident within the bowel, digesting the portion of the food that you eat but do not digest. The Vitamin K made by the bacteria is then absorbed through the wall of the bowel and carried to the liver. Since Coumadin looks very similar to Vitamin K, the liver is fooled by this and makes some of the clotting factors with Coumadin and some clotting factors with Vitamin K. Coumadin based clotting factors are inactive. Therefore, the total amount of active clotting factors present in the blood becomes lower and the blood takes longer to clot. In examining this mechanism it becomes obvious that a number of factors can affect the effect of Coumadin. This is a dynamic equilibrium with balance between active and inactive clotting factors. Therefore, anything that increases or decreases the amount of Vitamin K presented to the liver with respect to the dose of Coumadin will change the balance of these two chemically similar substances and will change the balance of clotting factors and affect the clotting times. It is therefore recommend that you do not take any vitamin tablets that are not recommended by your physician since some vitamin tablets contain Vitamin K.

Another recommendation is that you maintain the same type of diet and not participate in any "fad diets" or other significant changes in your dietary habits while taking Coumadin unless you discuss these first with your physician. If you become sick and are unable to eat properly or if you develop diarrhea or some other bowel problem, this may also upset the amount of Vitamin K received by the liver. You should notify your physician as soon as possible if something like this occurs. Another way that the body's response to Coumadin changes is by changing the metabolism of the liver. There are any number of drugs on the market that will either increase or decrease the metabolism of the liver causing a significant change in the anticoagulation effect of Coumadin. Before taking any of these drugs you should discuss their effects with your physician so that he will follow your prothrombin time more closely and make needed adjustments in the Coumadin dosage.


Since Aspirin is a direct irritant of the stomach, it should never be taken in conjunction with Coumadin since any ulceration caused by the Aspirin may very well bleed and continue to bleed because of the effects of Coumadin. Early in treatment we obtain prothrombin times frequently to establish the proper dose of Coumadin. Once we are at a steady level we reduce the frequency of these blood tests and in the long term obtain them about once a month unless some change in medication or health would otherwise dictate a more close follow-up. The use of Coumadin is associated with a number of complications not the least of which are bleeding complications if the prothrombin time gets out of range. Nonhemorrhagic side effects are uncommon but include necrosis of the skin (in which dead skin would become black and then ulceration would occur), dermatitis, ( a rash, weeping of the skin, etc.) and a syndrome of painful redness and swelling in areas of large amounts of subcutaneous fat. Most of these changes are reversible if the drug is stopped.

It is very important to remember also that Coumadin is teratogenic, (causes malformed babies) and should never be used during pregnancy or in a lactating mother. In this particular situation subcutaneous Heparin is used for long term management of DVT.

Complications of DVT
The acute complications of DVT are basically two; congestion in the involved extremity, and movement of the blood clot to the lung, a so called pulmonary embolus. This early fresh blood clot is dislodged from the vein. It can be carried through the larger veins and lodge itself in an artery to the lung thereby preventing blood from going into this area of the lung and being oxygenated. This condition is life threatening and is usually accompanied by severe apprehension and shortness of breath with severe chest pain, sweating, and fainting. The pulses are very rapid and occasionally bloody sputum is produced.

If proper anticoagulation is maintained, this usually does not recur and the body will be able to clear the clots in the lungs and return circulation there, however, in the acute phases this is a life threatening condition and intensive medical care is required. Our entire treatment protocol for the treatment of DVT is designed to avoid this complication. The treatment of pulmonary embolus is again mostly medical using anticoagulants, oxygen, and pain medicines, The thrombolytic drugs which actually dissolve blood clots are used more in this acute situation and anticoagulants in the form of Heparin and Coumadin are continued through the later stages of treatment. Occasionally surgery is required for removal of the blood clot in emergency situations, but this is not a standard part of therapy. If anticoagulants can not be used properly or if recurrence of pulmonary embolus occurs, there are a number of ways to interrupt the veins so that further emboli can not proceed to the lungs.

Discussion of Greenfield Filter
The most common way of interrupting the venous return to the heart is by insertion of a "Greenfield filter". This is a basket of bent wires made of Titanium which is inserted usually percutaneously (with a direct stick through the skin) into the vein and then a very small incision to insert the mechanism for delivery of the filter. Guidewires are placed in the vena cava , (the big vein in the abdomen returning blood to the heart) and the filter is delivered over a guidewire to its proper place just below the veins from the kidneys and then fired to stay in the vena cava.

There are pointed feet in this wire basket which dig into the wall of the vein and prevents it from moving. The Greenfield filter can be inserted either through the right groin or through the jugular vein in the right neck. Occasionally we can not obtain a good "stick" of the vein percutaneously, and an incision has to be made to identify the vein for insertion of the filter. However, this is an unusual circumstance. Once the filter is in place, the insertion apparatus is withdrawn. There are no symptoms of having the filter in place and minimal complications occur. One complication that can occur is swelling of the legs. This would be due to passage of clot up to the filter and occlusion of the filter with increased venous pressure in the legs. This is a very unusual complication. It occurs only when a large thrombus is dislodged from the lower veins. It simply signifies the fact that a large pulmonary embolus would have occurred had the filter not been in place. While the swelling of the legs may be an inconvenience, the result of the embolus without the filter would have been death. On the average these filters stay open about 95% of the time so that it is only a very small group of patients who will ever have symptoms from it.

Chronic Changes
The chronic changes of deep venous thrombosis results in venous stasis disease also known as chronic venous insufficiency. While varicose vein formation can develop following deep venous thrombosis, it is not usually the most significant consideration here. While chronic venous insufficiency develops over a period of years, efforts to prevent the complications of chronic venous insufficiency must start immediately. The blood clots that have formed in the veins will take six months to a year to be completely absorbed by the body. While there is obstruction to blood flow there will be swelling of the limb.

This swelling is best controlled using elastic compression in the form of elastic stockings. These will usually make the leg feel much less heavy and prevent it from swelling significantly as the clots are being absorbed. However, even after the clots are absorbed elastic compression is still the mainstay of treatment of venous stasis disease. As the clots are being absorbed, the valves within the veins are also absorbed so that the valvular function is destroyed. As a result, once the calf muscle pump relaxes, blood also flows down the leg, and there is a chronic increased pressure within the veins because of the destroyed valves. As the venous pressure increases, there is a tendency for fluid to leak out of the blood vessels and into the tissues causing chronic leg swelling.

This tissue is rich in protein, and while the water portion of it is reabsorbed, in many cases the protein remains in the tissue and forms a barrier to diffusion of oxygen to the skin. This causes the long term sequela of skin breakdown and ulceration if not corrected. The use of elastic stockings will prevent this swelling and protein accumulation from developing and will prevent the end stage findings of chronic venous stasis disease. The standard symptoms of chronic venous stasis disease include pain when standing, (which is usually relieved with elevation of the leg), swelling, tenderness, skin discoloration, dry, scaly, and itchy skin, and ulcers can also form. Since the symptoms occur primarily in the lower leg below the knee, it is felt that elastic compression up to the knee joint will have the optimal effect in preventing these changes.

Once the end stage changes occur, they are often not reversible so that the key to treatment is prevention. Following an episode of deep venous thrombosis the patient should continue using firm elastic support in a below the knee position for the remainder of his or her life. In the chronic treatment of venous stasis disease it must be remembered that the affected tissues will have a tendency to develop infections much more easily, so that the close observation for the development of early infection needs to be carried out with institution of antibiotic therapy early rather than later in this setting. Also periods of elevation of the legs to significantly reduce the venous pressures from within will contribute to lowering the incidence of long term complications.

Conclusion
We hope that this information has helped you to understand the problem of phlebitis and its sequela and some of the factors that must be considered in proposing a treatment program. Once phlebitis has occurred, there is nothing we can do to prevent that particular problem and the approach is then designed to prevent the long term sequela of chronic venous insufficiency. If you have further questions, please bring them to our attention, and we will be happy to discuss them with you individually.