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Deep vein thrombosis (DVT)

  1. Gastroepato
  2. Hematology
  3. Deep vein thrombosis
  4. Oral anticoagulant therapy
  5. Main veins of the human body
  6. Chronic venous insufficiency
  7. The varices of the legs
  8. Trombosis, embolism, thrombophilia and fibrinolysis
  9. Semeiotic of essential varices

notes by dr. Claudio Italiano

Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more deep veins of the body, usually in the legs. Deep vein thrombosis can cause leg pain or swelling, but it can also occur without symptoms.
- Deep vein thrombosis can develop if you have certain medical conditions that affect blood clotting. It can also happen if you don't move for a long time, such as after surgery or an accident, or when you're bedridden.
- Deep vein thrombosis can be very serious because blood clots in the veins can break free, travel through the bloodstream and lodge in the lungs, blocking blood flow (pulmonary embolism).
Thromboembolic disease is divided in to:
Pulmonary embolism
Venous thromboembolism
It is a cause of mortality and high morbidity; it is fatal in its course. It affects more than 100,000 hospitalized US patients each year; it requires prophylaxis which is the only key to reducing the fatal evolution of TE. It is essential to know the risk factors.

Pathogenesis of thromboembolism

In 1856 the Virchow outlines the factors that predispose to the development of TE:
- reduction of flow or venous stasis
- condition of hypercoagulability
- damage to the vessel wall

- Stasis: means a reduction in the linear blood flow rate expressed in cm / min and a reduction in venous return in vol / min, sometimes due to the dilation of varicose veins (venous ectasia) and to the reduction of arterial perfusion (for example a limb, for stenosis). Such situations are determined, for example, in surgical practices, or as a result of factors that increase blood viscosity (eg polycythemia, malignant neoplasms).
- Hypercoagulability: these are conditions that play a key role in the formation of thrombophilia or thrombophilic states; evidence is the high mortality of patients in demolition surgery, hip surgery, surgery on the abdomen and pelvis for neoplasms, gram-negative infections with risk of CID: it follows that in these conditions is found the presence in the circulation of thromboplastinic and procoagulant factors, especially in neoplasms.
- Vessel wall alterations: it means that endothelial cells, that are metabolically active on the hemostatic system and release cell-repellent substances; otherwise the epithelium loses its tromboresistance, as the epithelium plays a key role with its inhibitory factors or activators of the coagulation system. Hypoxia also plays its role or the use of a noose during knee surgery.

Risk factors associated with TE

- old age
- female sex
- blood groups
- obesity
- immobilization
- pregnancy and puerperium
- contraceptives
- neoplasms
- trauma
- burns
- genetic defects: antithrombin III deficiency, protein C defect, S protein defect, dysfibrinogenemia;
- acquired defects: anti-fisfolipid antibodies
- Age: TE is rare under 40, while the incidence is high in the elderly over 75 years with 1 in 10,000 / year;
- Gender: female, perhaps connected also to the use of contraceptives, pregnancies, perperio, alterations of the venous system and varicose veins, for hormonal constellation
- Blood group: subjects with group 0 have lower risk for TE because the subjects 0 have not high level factor of Von Willebrand factor and factor VIII.
- Obesity: because the adipose cells secrete tissue plasminogen inhibitor.
- immobilization: because the flow is reduced, especially in hemiplegics, after prolonged standing, in the bedridden.
- Pregnancy: because during pregnancy the factors II, VII, X and fibrinogen are increased, with reduction of S protein and fibrinolysis.
- Use of oral contraceptics: due to increased coagulation factors II, VII, X and reduction of antithrombin III and S and C proteins
- Malignant neoplasms: because they release coagulants and tissue factor, due to increased coagulation factors;
- Surgical patient: divides in patient A) at high risk B) at medium risk C) at low risk.

Topics of Gastroepato

Cardiology

Dermatology

Diabetology

Hematology

Gastroenterology

Neurology

Nephrology
and Urology


Pneumology

Psychiatry

Oncology
Clinical Sexology

High risk conditions

General surgery over 60 years;
Major general surgery between 40 and 60 years, with history of thromboembolic events
Major orthopedic surgeries of the pelvis, hip and lower limbs
Major surgical interventions in patients with thrombophilia
Fractures of pelvis and hip.

Moderate risk

General surgery with a higher age of 40-60 years without additional risk factors
General surgery of major age <40, in treatment with estrogens or history of TE events
Minor surgeries, aged> 60 years
Minor surgery at age 40-60 on estrogen or estrogen treatment

Low risk

Surgery interventions of greater age <40 years, without additional aphors
minor surgery, age 40-60 without additional risk factors.

Conditions associated with TE risk

In general surgery interventions with age greater than 40, the risk TE and pulmonary embolism (PE), the risk is around 20%, while a good prophylaxis completely avoids this risk. In the interventions of orthopedic surgery the TE risk is particularly high in the reconstruction interventions of the hip and knee, where the frequency of DVT oscillates between 45 and 70%. The results for prophylaxis in these types of intervention are based exclusively on the use of low molecular weight heparins.
Urological surgery. Prostate surgery is associated with a high TE risk that approximates 40% for tranvescical interevenes and 10% for transurethral ones, especially if malignant neoplasms coexist. Gynecological surgery. Generally the risk is around 7% -12% for hysterectomies depending on the case if they are implemented via transvaginal or pearlparotomic. The problem is striking if there are malignant neoplasms, because in this case the risk rises to 20%. Thoracic surgery. In the case of lung carcinoma and of the esophagus, the risk is 45%; In coronary artery bypass the risk is 30%. Neoplastic surgery. The neoplastic cells are able to release coagulants and the risk following interevents salt 2-3 times compared to the non-neoplastic surgery interventions, despite prophylaxis. Surgery in traumas. In major trauma of the pelvis, hip or lower limbs, they have a risk ranging from 30 to 50% for DVT, especially pertrochanteric fractures.

Internal disorders and thromboembolic risk

The internist pathologies subject to TE risk are:
IMA
congestive heart failure
Stroke
Inflammatory bowel disease
Kidney transplantation
institutionalized seniors
Nephrotic syndrome
hyperviscosity syndrome
lymphoproliferative diseases
polycythemia vera
paroxysmal nocturnal hemoglobinuria
The incidence and severity of TE has been documented in these patients both by autopsy studies, in which the TE was around 33% (23% of DVT and 24% of EP), and epidemiological studies, in which the Fatal EP was 8% of cases.

Congenital anomalies related to TE risk

They are the deficiency of AT III, of protein C, of protein S, of heparinic cofactor II. Patients with congenital thrombophilia should be considered at high risk for venous TE and should receive appropriate prophylaxis according to the clinical picture.
Treatment
In all these clinical cases, treatment with low molecular weight heparin (thromboembolism prophylaxis) is imperative.

Hematology