Deep Vein Embolism: Did You Know?

Today, deep vein thrombosis is increasingly recognized. The right treatment can prevent the clot from growing in size and breaking off, causing dangerous complications such as a pulmonary embolism. The following article will provide all the necessary information about this disease.

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• 1. What is Deep Vein Thrombosis?
• 2. Mechanism of formation and risk factors for deep vein thrombosis
• 3. What symptoms do deep vein thrombosis usually cause?
• 4. Diagnosis of deep vein thrombosis
• 5. Treatment of deep vein thrombosis
• 6. How to prevent venous thrombosis?
• 7. What are the complications of deep vein thrombosis?

1. What is Deep Vein Thrombosis?

Deep vein thrombosis is a blood clot in a vein located deep inside, not close to the skin. From there, the thrombus causes a complete or partial blockage of blood flow in the vein.

Deep vein thrombosis is most common in the veins of the lower extremities. Nevertheless, embolism of the arm, portal, spleen, and mesentery has occasionally been reported.

2. Mechanism of formation and risk factors for deep vein thrombosis

2.1 Mechanism of formation

Venous thrombosis is caused by a combination of 3 factors:

• Stagnation of venous circulation.
• Disturbances in the blood coagulation process cause hypercoagulability.
• Vascular damage.

These three factors form the Virchow triangle, which is the basis for determining risk factors.

2.2 Key risk factors

Acquired risk factors:

• Recent major surgery, especially orthopedic surgery. For example, hip replacement, femur fracture...
• Trauma: spinal vertebrae, spinal cord…
• Immobilization: due to the disease itself or prescribed by a doctor. For example heart failure, stroke...
• Cancer, especially advanced cancer.
• Pregnant.
• Hormone replacement therapy, or estrogen-containing birth control pills.
• Nephrotic syndrome.
• Antiphospholipid syndrome.
• History of venous thromboembolism.

Risk factors for deep vein thrombosis

Hereditary risk factors are those that cause congenital hypercoagulability:

• CO deficiency
• Protein deficiency WILL
• Factor V Leyden mutation
• Prothrombin gene mutation
• Antithrombin III deficiency

3. What symptoms do deep vein thrombosis usually cause?

3.1 Clinical Manifestations

• Usually on one side of the leg.
• Pain to palpation, aggravated by dorsal flexion of the foot and lower leg.
• Local increase in temperature, erythema.
• Increased spasticity, decreased flexibility.
• Dilated superficial veins: floating green zigzag thread.
• Increased circumference of calves, thighs (over 3 cm), ankle edema.

Deep vein thrombosis of the lower extremities is usually unilateral

3.2 Differential diagnosis

Clinical manifestations of deep vein thrombosis are sometimes similar to those of a number of other conditions:

• Cellulitis

Common in people with venous insufficiency of the lower extremities, lymphatic occlusion, diabetic foot ulcers.

• Venous thrombosis of the lower extremities

Common after infusion, or in people with venous insufficiency of the lower extremities.

• Baker's cocoon burst

Swelling, sudden pain on one side of the calf.

• Blood in the muscle

Common after trauma, or coagulation disorders due to cirrhosis, anticoagulants.

• Drug-induced edema

Side effects of antihypertensive drugs of calcium channel blocker group: amlodipine…

Therefore, clinical symptoms have low specificity and are not reliable enough to make diagnostic decisions. Therefore, doctors will use the scale to assess the risk of deep vein thrombosis. On the basis of the assessment of the risk of embolism, the doctor will choose the laboratory investigation to approach the diagnosis.

4. Diagnosis of deep vein thrombosis

4.1 The first clinical examination

• D-dimer test

In low-risk patients, D-dimer to rule out lower extremity deep vein thrombosis. D-dimer can be increased in some diseases such as cancer, infection, pregnancy, advanced age, etc.

• Doppler ultrasound of veins

In patients with intermediate-high risk, ultrasound is definitive. Doppler ultrasound is also the “gold standard” because of its high sensitivity and specificity. This probe is simple, safe, and can be performed many times. However, it depends on the person doing it. The conclusions you may see on the ultrasound paper include thrombus filling the venous lumen, preventing the venous pressure from collapsing or only partially collapsing and/or having a color defect on color Doppler, spectral Doppler does not change with respiratory rate.

4.2 Subclinical finding the cause

Next, the patient will be assigned to do more laboratory tests to screen for the cause of inherited blood clotting disorders in the following cases:

• Patient under 50 years old, with spontaneous deep vein thrombosis of unknown etiology
• Venous thrombosis in uncommon locations: visceral, portal, intracerebral veins
• Recurrent venous thrombosis of unknown etiology
• Family history of venous thromboembolism
• Skin necrosis caused by anticoagulants of the vitamin K . type

In-depth tests to do include

• Quantification of protein C, protein S, antithrombin III.
• Look for Leyden factor V mutations, prothrombin G2010A . mutations
• Test for systemic disease, test for antiphospholipid syndrome.

Time to do Protein C, Protein S, Antithrombine III tests:

• Before anti-Vitamin K or
• After stopping the use of Vitamin K antagonists: stop at least 2 weeks
• Preferably outside of acute thrombosis: after 6 weeks.

4.3 Care should be taken in the diagnosis of cancer

In patients with venous thromboembolism with unknown predisposing factors and no cancer detected, appropriate diagnostic investigations for cancer are indicated, depending on the clinical findings suggestive of the disease.

• Clinical: weight loss, lymphadenopathy, hemoptysis, bloody stools, hematuria...
• Routine paraclinical exploration: X-ray of the heart and lungs, ultrasound of the abdomen, appendages, urine tests, liver and kidney function, blood count, erythrocyte sedimentation rate...
• Extensive paraclinical exploration: Computed tomography of the chest, abdomen, gastroscopy, colonoscopy, testing for cancer markers. Note: tumor markers are not indicated for cancer screening purposes.

5. Treatment of deep vein thrombosis

Consists of:

• Treatment in the acute phase: 0 - 10 days.
• Maintenance period: from 10 days to 3 months.
• Extended maintenance phase: extended treatment, after 3 months.
  Anticoagulation is the cornerstone of venous thromboembolism treatment. The goals are to prevent thrombosis from spreading, progressing in the acute phase and preventing recurrence.

5.1 Treatment of the acute phase

Antifreeze

Indications for treatment:

• Proximal deep vein thrombosis: popliteal vein, femoral vein, iliac veins.
• Symptomatic distal thrombosis: leg veins.
• Asymptomatic but potentially widespread distal embolism:

           Thrombosis of unknown predisposing factor.
           – D-dimer > 500 mg/mL.
           - Thrombosis occurs in many veins with length > 5 cm, diameter > 7 mm.
           – Cancer is active.
           - History of venous thrombosis.
           - Prolonged immobility.

Anticoagulation can be started immediately in cases of high clinical probability of deep vein thrombosis pending a definitive diagnosis.

Other therapeutic measures in the acute phase:

• Early use of compression bandages, grade II medical compression stockings, and maintenance for at least 2 years is recommended.
• Early movement.
• Filter placement of the inferior vena cava with proximal venous thrombosis has contraindications to anticoagulation (recent surgery, intracranial bleeding, progressive bleeding) or recurrent venous thrombosis despite treatment. optimal anticoagulation.
• For acute massive thrombosis of the iliac-femoral region, with a potentially life-threatening risk of limb necrosis due to arterial compression in patients with a prognosis of >1 year: consider systemic thrombolysis or catheterization (if necessary). no contraindications) or thrombectomy.

In the acute phase, how does the patient note activity?

• The patient can walk and do everyday tasks.
• In case of a lot of swelling and pain: rest, raise your legs.
• Sports activities should be limited for the first 10-14 days after embolization.
• The patient can exercise the arms and torso if the embolism is in the leg, and the leg and trunk if the embolism is in the arm.
• Avoid flying for the first few weeks following a venous thromboembolism.

5.2 Maintenance treatment and prolonged maintenance

Duration of anticoagulation: At least 3 months, depending mainly on the underlying medical condition and predisposing factors, weighing the risk of recurrent venous thrombosis against the risk of bleeding with anticoagulation:

Should not be used for more than 3 months in cases of:

• Temporary predisposing factor: post-surgery
• High risk of bleeding

Prolonged treatment is recommended if:

• The motivating factor is unknown
• There is also a driving factor: cancer
• Congenital and hereditary hypercoagulable diseases: deficiency of protein C, protein S, antithrombin III, antiphospholipid syndrome

6. How to prevent venous thrombosis?

6.1 General principles

• Using a number of risk assessment scales: PADUA, CAPRINI…
• Bleeding risk assessment: IMPROVE score and contraindications to anticoagulation.
• Weighing the benefits and risks of anticoagulation
• Select appropriate preventive measures and backup time.

6.2 Preventive measures

• Get the patient to exercise early.
• Mechanical measures such as intermittent pressurized inflators, medical pressure socks/bandages:

Used in patients with high bleeding risk or contraindications to anticoagulation

• Anticoagulants.

7. What are the complications of deep vein thrombosis?

Deep vein thrombosis has an acute complication such as a pulmonary embolism with a high mortality rate, and a chronic complication is a post-thrombotic syndrome.

7.1 Pulmonary embolism

Up to 79% of patients with acute pulmonary embolism present with deep vein thrombosis. In contrast, more than 50% of patients with deep vein thrombosis have pulmonary embolism complications.

Pulmonary embolism is extremely dangerous because it can suddenly cause chest pain, shortness of breath, low blood pressure, shock and death.

Pulmonary embolism is a dangerous complication of deep vein thrombosis

7.2 Postthrombotic syndrome

This is the leading complication with chronic venous disease (pain, edema, dystrophy, ulceration), occurring secondary to venous thromboembolism.

Treatment of this syndrome includes:

• Internal medicine: Medical compression stockings/elastic bandages in combination with rehabilitation exercises and intravenous drugs.
• Intervention: Place stents in the femoral and pelvic veins in case of post-thrombotic femoral - iliac vein stenosis.
• Surgery: Grafting or transferring deep veins, creating new deep vein valves.

Although it takes 3-6 months to completely resolve a blood clot, deep vein thrombosis always needs to be treated thoroughly to avoid serious complications such as pulmonary embolism. If you have risk factors for this disease, you should see a doctor early for appropriate advice and treatment.

Doctor Tran Hoang Nhat Linh