DVT Flashcards
General findings
Una DVT con concomitante PE richiede trombolisi urgente🧨
Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein of the legs, thigh, or pelvis. Thrombosis is most often seen in individuals with a history of immobilization, obesity, malignancy, or hereditary thrombophilia. Vascular endothelial damage, venous stasis, and hypercoagulability, collectively referred to as the Virchow triad, are the main factors contributing to the development of DVT. Symptoms usually occur unilaterally and include swelling, tenderness, and redness or discoloration. Pulmonary embolism (PE), a severe complication of DVT, should be suspected in patients with dizziness, dyspnea, and fever. The diagnostic test of choice for DVT is compression ultrasound. In most cases, a negative D-dimer test allows thrombosis or PE to be ruled out, but a positive test is nonspecific. Initial acute treatment of DVT consists of anticoagulation with heparin and, if the thrombus is large or unresponsive to anticoagulation, may also include thrombolysis or thrombectomy.
!Secondary prophylaxis is achieved with oral warfarin or direct factor Xa inhibitors and supportive measures such as regular exercise and compression stockings.
Risk factors
History of DVT or PE (30x increased risk) [1]
Immobilization: e.g., post-surgery, long-distance flights, trauma (20x increased risk)
Age > 60 years
Malignancy
Hereditary thrombophilia (especially factor V Leiden)
Pregnancy, estrogen use (oral contraceptives)
Obesity
Smoking
IV drug use
Nephrotic syndrome!
Insufficient thrombosis prophylaxis, noncompliance with prophylaxis
Clinica
-May be asymptomatic (A previously asymptomatic DVT may first manifest with features of chronic venous insufficiency.)
- Localized unilateral symptoms
1. Typically affects deep veins of the legs, thighs, or pelvis
2. More common in the left lower extremity
3. May-Thurner syndrome: compression of the left iliac vein between the right iliac artery and a lumbar vertebral spur (occurs in > 20% of adults) (Affected individuals may be asymptomatic or present with left iliofemoral venous thrombosis.) - Swelling, feeling of tightness or heaviness
- Warmth, erythema, and possibly livid discoloration
- Progressive tenderness, dull pain
- Homan sign: calf pain on dorsal flexion of the foot
- Meyer sign: Compression of the calf causes pain.
- Payr sign: pain when pressure is applied over the medial part of the sole of the foot
- Distention of superficial veins
- Distal pulses are normal💥
- General symptoms: fever
!Possible signs of pulmonary embolism: dyspnea, chest pain, dizziness, weakness
Phlegmasia cerulea dolens
A severe form of phlebothrombosis, characterized by obstruction of ALL VEINS of one extremity with subsequent restriction of arterial flow and associated with a high mortality
- Severe swelling, edema, and pain
- Coldness, cyanosis, and pulselessness (attenzione, nella DVT classica i polsi degli arti inferiori sono presenti!🧨)
- Emergency surgery: venous thrombectomy, fasciotomy
- Fibrinolysis if surgery fails
- Amputation as last resort
Complications: shock, gangrene, acute renal failure (due to rhabdomyolysis)
Paget-Schroetter disease (upper extremity DVT)
Acute thrombosis of a brachial, axial, or subclavian vein
- Effort-induced thrombosis: triggered by repetitive strenuous activity of the upper extremities (e.g., weight-lifting, operation of a jackhammer)
- Thoracic outlet syndrome (compressione)
- Presence of a foreign object in veins (e.g., central venous catheter, pacemaker lead)
Treatment: anticoagulation, fibrinolysis
Diagnosi
The diagnostic approach for suspected DVT is determined by the Wells score. Compression ultrasonography and D-dimer levels are the main diagnostic tests.
Wells criteria for deep vein thrombosis (ci indica una probabilità di DVT, ma non fa diagnosi)
A different version of the score may be used to determine the probability of PE (see Wells criteria for PE).
0: low risk
1–2: moderate risk of DVT
≥ 3: high risk of DVT
Active cancer +1
Previously documented DVT +1
Immobilization
Paralysis or recent (cast) immobilization of lower extremity +1 Recently bedridden (≥ 3 days) or Major surgery (< 12 weeks) \+1 Clinical symptoms
Tenderness localized along the deep venous system +1
Swelling of the entire leg +1
Calf swelling ≥ 3 cm compared to asymptomatic calf +1
Unilateral pitting edema in symptomatic leg +1
Presence of collateral (non-varicose) superficial veins +1
Compression ultrasonography with Doppler (test of choice)
Noncompressibility of the obstructed vein, visible hyperechoic mass, absent or abnormal flow in Doppler imaging
Venography (angiography)
- Most accurate assessment of calf veins and valvular competency
- Indications: obesity, severe edema, equivocal results in previous tests
D-dimer
- High sensitivity (∼ 95%), low specificity (∼ 50%)
- Useful for ruling out DVT (normal D-dimer levels rule out DVT)
- Elevated D-dimers alone are not proof of DVT
Anticoagulation
✔Acute therapy
1.Heparin bolus plus constant heparin infusion for 4–5 days
-Unfractionated heparin or low molecular weight
heparin (see also parenteral anticoagulation)
-Alternatively: fondaparinux (factor Xa inhibitor)
Target: achieve and maintain an aPTT of 1.5x–2.5x the mean of the control value or upper normal limit.
Simultaneous initiation of warfarin once aPTT is therapeutic !💥
✔Secondary prophylaxis
Warfarin with target therapeutic INR of 2.0–3.0
Duration of treatment
- First thrombosis: usually 3–6 months
- For confirmed thrombophilia and recurrent thrombosis: indefinite
OR
Direct oral factor Xa inhibitor (i.e., rivaroxaban, apixaban)
Regular monitoring of coagulation parameters not required → improved patient compliance
-Duration of treatment: at least 3 months
Thrombolysis
Goal: faster resolution of thrombi
Indications
-Slow response to anticoagulation
-Pulmonary embolism with hemodynamic instability💥
-Can be considered for acute proximal DVT of the leg
Agents: streptokinase, urokinase, tissue plasminogen activator
Catheter-directed thrombolysis: The thrombolytic agent is administered directly at the site of obstruction via a venous catheter.
Thrombectomy
Intravenous thrombus removal via a catheter
Indications
- Insufficient response to anticoagulation and thrombolysis
- Extensive thrombus
- Phlegmasia cerulea dolens
- Low-dose heparin is required prior to the procedure.
Inferior vena cava filter
Indicated in patients with DVT at high risk of developing pulmonary embolism who have contraindications to anticoagulation, thrombolysis, and thrombectomy (e.g., active bleeding, recent major surgery, recent intracranial hemorrhage)
DDx
Superficial thrombophlebitis
Inflammation and thrombosis of a superficial vein, most commonly in the leg. It may co-exist with DVT, and it rarely causes PE.
Risk factors
Same as for DVT (see risk factors for deep vein thrombosis above), but also
- Varicose veins
- Venous cannulation, IV drug administration
- Behçet disease
- Thromboangiitis obliterans
Variants
- Thrombophlebitis migrans (Trousseau syndrome)
- Superficial thrombophlebitis of the breast (Mondor disease)
Clinica
Pain, tenderness, induration, and erythema overlying a superficial vein, often with a palpable cord (the thrombosed vein)
Diagnostics
Typically a clinical diagnosis
Treatment
- Symptomatic: NSAIDs, compression, elevation of the affected limb
- Anticoagulation (e.g., LMWH, fondaparinux) if larger segments of the vein (≥ 5cm) are affected
- DVT treatment if the thrombus is close to the junction with the deep venous system
Other differential diagnoses of DVT
- Muscle or soft tissue injury (i.e., posttraumatic swelling or hematoma)
- Lymphedema
- Venous insufficiency
- Ruptured popliteal cyst
- Cellulitis
- Compartment syndrome
