Venous thrombosis or venous thromboembolism, which includes deep vein thrombosis and pulmonary embolism, is the third most frequent cause of cardiovascular disorders, with an annual incidence of 0.1%, and affects 2-5% of the population at some time in their lives. Approximately 20% of patients with pulmonary thromboembolism will die before the diagnosis is made. For those who survive more than one day after suffering a pulmonary thromboembolism, they will die within the first three months, even with adequate treatment.
Despite this, many of these patients succumb to medical conditions associated with venous thromboembolism, such as cancer. Long-term complications of venous thrombosis include postphlebitic syndrome (usually following deep vein thrombosis) and pulmonary hypertension (following venous thromboembolism), which occurs in more than 40% and 1% to 4% of cases, respectively.
Causes that may contribute to the development of venous thrombosis include: slowing of blood flow through the veins, usually due to prolonged immobilization, for example, in those who have suffered a fracture or undergone a surgical procedure; prolonged hospitalization or long journeys.
Other causes of venous thrombosis are coagulation disorders (disorders that cause the blood to clot too quickly or too slowly) that occur in some congenital or acquired diseases called thrombophilias. Acute injuries to the veins due to surgical procedures (placement of a central line), trauma or diseases accompanied by inflammation are also causes of venous thrombosis.
Additional factors that can cause venous thrombosis include smoking and obesity. One of the most common causes of deep vein thrombosis is immobilization following surgery. The risk of developing thrombosis after surgery can be classified as:
Low risk. Persons under 40 years of age, without risk factors, who require anesthesia for less than 30 minutes and who are scheduled for minor abdominal or thoracic surgery. The risk of developing deep vein thrombosis without prophylaxis is less than 1% and the risk of fatal thromboembolism is less than 1 in 10,000 patients.
Moderate risk. People older than 40 years, with one or more risk factors and requiring anesthesia for more than 30 minutes. The risk of developing deep vein thrombosis without prophylaxis is between 2 and 10% and the risk of fatal thromboembolism is between 1 and 7 in every 1,000 patients.
High risk. People over 40 years of age, scheduled for lower extremity orthopedic surgery or cancer surgery lasting more than 30 minutes, who have a clotting problem or multiple risk factors for venous thrombosis. The risk of developing deep vein thrombosis and/or pulmonary thromboembolism without prophylaxis is 10 to 20% and 1 to 5%, respectively.
Venous thromboembolism may be caused by transient and reversible clinical conditions, such as surgery or exposure to hormones (estrogens) or permanent or long-term disorders such as hemiparesis (paralysis of one side of the body) caused by a stroke. In 25% of cases, a specific cause of venous thrombosis cannot be determined; many of these patients may have a coagulation disorder, such as thrombophilia, which may predispose a person to thromboembolism.
Symptoms of venous thrombosis are caused by a decrease or blockage of the normal blood flow in the veins. When blood accumulates in the affected limb (usually a leg) some signs and symptoms appear such as:
Pain and swelling in the limb that has suffered decreased or blocked blood flow. The affected arm or leg swells, causing pain especially when standing up and trying to walk. Other discomforts include redness and increased skin temperature. Some patients may even have a fever higher than 38°C.
There are other conditions that have signs and symptoms similar to those of deep vein thrombosis and pulmonary thromboembolism. Thus, cellulitis (bacterial infection affecting the skin) and inflammation of the superficial veins of the skin present symptoms similar to deep vein thrombosis. Similarly, myocardial infarction and pneumonia have signs and symptoms similar to pulmonary embolism.
Physical examination by the physician is important for diagnosis, especially to detect anatomical regions where there is swelling, pain, increased temperature and changes in the color of the affected area.
The specialist physician (Angiologist) may perform some laboratory and imaging tests to aid in the diagnosis of this disease. Tests performed to diagnose or rule out the presence of blood clots include:
D-dimer test. D-dimer is a type of protein made by blood clots during their formation. Virtually all patients with some form of severe thromboembolism have increased levels of D-dimer in the bloodstream. When the D-dimer value is within normal values, the presence of pulmonary thromboembolism is ruled out. Currently, this test has gained great importance in the diagnosis of Covid-19, since its elevated values are a risk factor and a poor prognostic factor for Sars-CoV-2 infection.
Among the most commonly used imaging techniques are:
Duplex ultrasound. This is a technique that uses sound waves to produce images that allow visualization of blood flow through the venous system. It is the most valuable imaging technique for the diagnosis of deep vein thrombosis.
Phlebography. A type of radiologic study that uses a contrast dye injected into a large vein in the foot or ankle so that the medical professional can see the deep veins of the leg and hip. It is a more accurate technique for the diagnosis of blood clots, and as mentioned above, it is an invasive procedure, that is, it uses instruments and devices that doctors use to enter the body, so it has been replaced by duplex ultrasound and is used only in certain patients.
Magnetic Resonance Imaging and Tomography. They provide images in venous regions where blood clots have formed. However, they are not the most commonly used imaging tests in the diagnosis of venous thrombosis.
The main complications include:
1. Chronic venous insufficiency
2. Postphlebitic syndrome
3. Pulmonary embolism.
4. Pulmonary hypertension.
Treatment is aimed at: stopping the growth of the thrombotic process, eliminating the formation of new clots, preventing the appearance of a pulmonary embolism, and one of the most important aspects is to prevent the formation of post-thrombotic syndrome, which is characterized by permanent damage to the venous valves. Among the actions to be taken within the treatment of venous thrombosis are:
-A procedure called thrombolysis, which is used to break up or dissolve the clot.
Medications such as heparin that prevent clots from forming (anticoagulant medications).
-Special compression stockings (the correct compression size will be determined by the angiologist) that help reduce the likelihood of blood pooling and clot formation.
-Venous filter which is a small device that is placed in the inferior vena cava (the largest vein in the body). The function of this device is to trap any significant clots, to prevent them from traveling to the heart or lungs, thus preventing the occurrence of pulmonary embolism, which is one of the most serious and often fatal complications of venous thrombosis.
Among the preventive measures, the most important is to avoid complications. Some of these measures include:
-Surveillance at home by the patient or his relatives of the clinical picture and consultation with the family physician for any new developments.
-Rest during the first 48 hours only with partial mobility (bed-chair-bath). While the patient is lying down or sitting, keep the affected leg elevated.
-Subsequently, mobilization should begin with short walks and compressive bandage or elastic stocking below the knee for most of the day and for a longer time one to two years.
-Do not stand without moving or with bent legs and try not to cross your legs.
-The use of anti-inflammatory drugs should be avoided without first consulting the treating physician.
-Oral anticoagulant medications should be taken for 3 to 6 months.
-Coagulation should be monitored by the treating physician by means of a test called prothrombin time expressed as international normalized ratio (INR) whose value should be maintained between 2 and 3 when the patient is taking anticoagulant drugs such as Acenocoumarol or Warfarin sodium.
Notify the treating physician if any alarming signs or symptoms are present, such as:
1. Shortness of breath.
2. Pain in one side of the chest.
3. Deterioration of the patient’s general condition.
4. Loss of consciousness.
5. Appearance of any type of bleeding in the gums, urine, or presence of black stools.
What to avoid
1. A sedentary lifestyle, standing or sitting for long periods of time.
2. Do not wear very tight clothing on the lower half of the body.
3. Overweight, alcohol and smoking.
4. If possible, avoid taking oral contraceptives or use an alternative method of contraception.
5. Prolonged exposure to sunlight and hot water baths.
6. Trauma or scratching in the path of the veins and very tight footwear.
It is advisable to
1. Sleep with legs slightly elevated.
2. Daily baths with cold water for 10 to 20 seconds on each leg.
3. Practice moderate physical activity.
4. Change position at least every half hour, which may vary depending on the age of the affected patient.