Dr Arvind Kohli
Deep Vein Thrombosis (DVT) is serious condition that occurs when a blood clot forms in a deep vain. A blood clot is a clump of blood that is in a gelatinous, solid state forms inside the lumen of vein.
Deep vein blood clots typically form it thigh or lower leg veins, but they can also develop in other areas of body. Other names for this condition include thromboembolism, post-thrombotic syndrome, and post-phlebitic syndrome.
Risk factors
Who is at risk for deep vein thrombosis ?
DVT occurs most commonly in people who are over 50 years in age. Certain conditions that alter the milieu of circulation i.e how blood moves through veins can raise risk of developing clots. These include : immobilization for a prolonged period, history of injury to venous system, having a family history of DVT or having a catheter placed in a vein, history of taking oral contraceptive pills smoking (especially heavy usage) and major surgeries especially in orthopaedic.
Treatment
The mainstay of medical therapy has been anticoagulation (Blood thinning) since the introduction of heparin in the 1930s. Other anticoagulation drugs have subsequently been added to the treatment armamentarium over the years, such as vitamin K antagonists (Warfarin) and low-molecular-weight heparin (LMWH) and more recently NOACS (New oral anticoagulants like Rivaroxaban, debigatran & Apixaban ). These modalities do lead to dissolution of the thrombus but usually takes months for that and patient has to alter the life style accordingly.
More recently, Mechanical thrombolysis has become increasingly used as endovascular therapies have increased which hastens the clot dissolution. Absolute contraindications to anticoagulation treatment include intracranial bleeding, severe active bleeding, recent brain, eye, or spinal cord surgery, pregnancy and malignant hypertension. Relative contraindications include recent major surgery, recent cerebrovascular accident and severe thrombocytopenia.
The immediate symptoms of DVT often resolve with anticoagulation alone, and the rationale for intervention is often reduction of the 75% long-term risk of Post Thrombosis Syndrome (PTS). Systemic Intravenous thrombolysis once improved the rate of thrombosed vein recanalization; however, it is no longer recommended because of an elevated incidence of bleeding complications, slightly increased risk of death and insignificant improvement in PTS. The lack of a significantly reduced incidence of PTS after systemic thrombolysis (40-60%) likely reflects the inadequacy of the relatively low threshold volume of thrombus removal that was considered successful.
Thrombolytic therapy is recommended (systemic preferred over catheter directed in hypotensive individuals with an Pulmonary Embolism(PE) where a segment of clot progresses to the lung territory and becomes life threatening.
Those with high-risk PE presenting in shock should undergo systemic thrombolysis; when thrombolysis is contraindicated owing to high risk of bleeding, consider surgical thrombectomy or catheter direct thrombolysis as choice of management
The bleeding risk of systemic thrombolysis is similar to that of catheter-directed thrombolysis, and the risk of Post Thrombotic Syndrome may further decrease risk.
However, whether chatheter-directed thrombolysis is preferred to anticoagulation has not been examined. The addition of Percutaneous mechanical thrombectomy to the interventional options may facilitate decision making, because recanalization may be achieved faster than before and with a decreased dose of lytic; therefore, the bleeding risk may be decreased.
Percutaneous transcatheter treatment of patients with deep venous thrombosis (DVT) consists of thrombus removal with catheter-directed thrombolysis, mechanical thrombectomy, angioplasty, and /or stenting of venous obstructions. Consensus has been reached regarding indications for the procedure, although it is based on midlevel evidence from nonrandomized controlled trials. The goals of endovascular therapy include reducing the severity and duration of lower-extremity symptoms, preventing pulmonary embolism, diminishing the risk of recurrent venous thrombosis and preventing post thrombotic syndrome.
Indications for intervention include the relatively rare phlegmasia dolens or symptomatic inferior vena cave thrombosis that responds poorly to anticoagulation alone, or symptomatic iliofemoral or femorpopliteal DVT in patients with a low risk of bleeding.
Contraindications are the same as those for thrombolysis in general. Absolute contraindications include active internal bleeding or disseminated intravascular coagulation, a cerebrovascular event, trauma, or neurosurgery within 3 months.
Percutaneous mechanical thrombectomy devices are a popular adjunct to catheter-directed thrombolysis. Although these devices may not completely remove thrombus, they are effective for debulking and for minimizing the dose and time required for infusing a thrombolytic. Percutanesous mechanical thrombectomy has developed as an attempt to shorten treatment time and avoid costly ICU stays during thrombolytic infusion. The most basic mechanical method for thrombectomy is thromboaspiration, or the aspiration of thrombus through a sheath. Mechancial disruption of venous thrombosis has the potential disadvantage of damaging venous endothelium and valves, in addition to thrombus fragementation and possible pulmonary embolism.
Mechanical thrombectomy devices are the new current treatment for DVT however at present the cost effective ness of these devices put them slightly away from the patients, however making them cost effective shall enable the patients to get treated from DVT effectively in good span of time.
Courtsey: Jammu Vascular Society
(The author is Vascular Surgeon)
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