DVT Flashcards
Where do most DVTs occur?
DVTs are formations of a blood clot in a deep vein, most commonly in the lower extremities.
90% are proximal (femoral and iliac veins), 10% are distal (posterior tibial vein).
What is Virchow’s Triad?
The three major risk factors for thrombosis: endothelial injury, venous stasis, and hypercoagulability.
What are common risk factors for DVT?
Cancer, surgery, obesity, smoking, oral contraceptives, pregnancy, immobility, and hereditary thrombophilia.
What genetic disorders increase the risk of DVT?
Factor V Leiden mutation, prothrombin gene mutation, protein C or S deficiency, and antithrombin III deficiency.
What is the most common inherited thrombophilia leading to DVT?
Factor V Leiden mutation.
What autoimmune disorder increases the risk of DVT?
Antiphospholipid syndrome (associated with recurrent miscarriages and arterial/venous thrombosis).
What is the most common cause of upper extremity DVT?
Effort-induced thrombosis (Paget-Schroetter syndrome), often in young athletes who perform repetitive arm movements (e.g., baseball pitchers).
What are the common symptoms of DVT?
Calf pain (Homan sign, pain with dorsiflexion), tenderness, erythema, swelling, and superficial vein dilation. Symptoms are often unilateral.
The right or left lower extremity is often implicated with DVTs?
Right > Left
Acute asymmetric lower extremity edema (right > left) is concerning for deep vein thrombosis (DVT). DVT should be suspected in patients with acute unilateral edema, which may be accompanied by pain, warmth, erythema, or tenderness to palpation. Although these symptoms may be present, they are not specific. The presentation may be subtle. The most reliable and possibly the only finding of DVT is increased circumference of the affected leg due to localized edema, resulting from increased venous hydrostatic pressure distal to the thrombus and inflammatory disruption of vascular membrane integrity.
What is Homan’s sign?
Calf pain upon dorsiflexion of the foot, which is a nonspecific finding for DVT.
What is the first-line diagnostic test for DVT?
Lower extremity ultrasound with Doppler.
What is the gold standard test for DVT diagnosis?
Contrast venography, but it is rarely used clinically due to invasiveness.
What is the Well’s score used for?
Risk stratification of suspected DVT based on clinical probability.
<1 = low
1-2 = moderate
>3 = high
What are the criteria in the Well’s score?
Previous DVT, active cancer, immobilization, localized tenderness, leg swelling, asymmetric calf swelling, pitting edema, collateral superficial veins, hemoptysis, malignancy.
How is DVT risk stratified using the Well’s score?
Low (<1), moderate (1-2), high (≥3).
How do you manage low-risk patients (Well’s score <1)?
Order a D-dimer; if elevated, perform an ultrasound.
How do you manage high-risk patients (Well’s score ≥3)?
Proceed directly to ultrasound imaging.
What is the treatment for proximal DVT?
Anticoagulation with heparin, warfarin, low molecular weight heparin (LMWH), or direct oral anticoagulants (DOACs). Factor Xa inhibitors are considered the first-line therapy because they are administered orally (unlike low-molecular-weight heparin) and do not require a heparin bridge or laboratory monitoring (unlike warfarin).
What is the duration of anticoagulation therapy for DVT?
Recent clinical guidelines by the American College of Chest Physicians recommend ≥3 months of an oral factor Xa inhibitor (eg, rivaroxaban) for patients with DVT or pulmonary embolism (PE).
When should an IVC filter be considered for DVT?
When anticoagulation is contraindicated (e.g., active bleeding).
When should a CTA of the lungs be performed in the setting of DVT?
A CT scan of the chest is typically recommended for patients with DVT who have pulmonary symptoms (eg, chest pain, shortness of breath, hemoptysis). Treatment of PE is often the same as for DVT.
What is the treatment for distal DVT?
Anticoagulation or close observation with serial ultrasound if asymptomatic.
What is the management of massive proximal DVT?
Massive proximal DVT (involving the iliac or femoral veins) is a serious condition, particularly if it is associated with phlegmasia cerulea dolens (PCD), which can lead to limb ischemia and gangrene. The management approach depends on the hemodynamic status, presence of limb-threatening symptoms, and risk of embolization. Anticoagulation (First-Line Therapy) is given, such as Direct Oral Anticoagulants (DOACs) (e.g., rivaroxaban, apixaban): Suitable for stable cases without phlegmasia cerulea dolens or limb ischemia. Low-Molecular-Weight Heparin (LMWH) (e.g., enoxaparin 1 mg/kg SC BID): Preferred in stable patients without immediate intervention needs. Unfractionated Heparin (UFH) IV: Preferred if high risk of bleeding or procedural intervention (thrombolysis, thrombectomy) is planned. Thrombolytics (tPA) or surgical thrombectomy if severe swelling or ischemia is present.
What is the recommended anticoagulation for pregnancy-associated DVT?
Low molecular weight heparin (LMWH), as warfarin is teratogenic.
Are antiplatelets ever used in DVT?
Antiplatelet therapy is not commonly used in the treatment of DVT. Antiplatelet therapy such as aspirin is often used for primary or secondary prevention of cardiovascular disease (eg, coronary artery disease, heart attack, stroke).
What are complications of untreated DVT?
Pulmonary embolism (PE), post-thrombotic syndrome (chronic venous insufficiency), and phlegmasia cerulea dolens (severe pain and edema with blue discoloration due to ischemia from excessive proximal DVT; indication for thrombolytic surgical thrombectomy).
What is phlegmasia cerulea dolens?
A severe DVT complication causing ischemia, massive swelling, and blue discoloration.
What is post-thrombotic syndrome?
Chronic venous insufficiency due to prior DVT, presenting with pain, edema, and skin changes.
Who should receive DVT prophylaxis in the hospital?
Patients with ICU admission, cancer, stroke, CHF, MI, age >75, prior DVT, renal failure, obesity, or prolonged immobility.
What are pharmacologic options for inpatient DVT prophylaxis?
LMWH, unfractionated heparin, or fondaparinux (unless contraindicated due to bleeding risk).
What are non-pharmacologic options for DVT prophylaxis?
Mechanical compression devices (e.g., graduated compression stockings, intermittent pneumatic compression).
Which cancers are commonly associated with DVTs?
Pancreatic cancer, lung cancer, and gastrointestinal malignancies (Trousseau syndrome).
What is Trousseau syndrome?
Migratory superficial thrombophlebitis associated with malignancy.
