Question 1

What are the main preventive measures for patients on bed rest to reduce venous thrombosis risk?

Accepted Answer

Patients on bed rest should change positions every one to two hours and perform foot, knee, and hip exercises every two to four hours while awake, if not contraindicated. Graduated compression stockings and intermittent pneumatic compression devices improve blood flow and prevent clot formation. Those able to mobilize should sit up for meals and walk four to six times daily to maintain circulation.

Question 2

How do the three main classes of anticoagulants differ in treating venous thromboembolism?

Accepted Answer

Vitamin K antagonists like warfarin inhibit vitamin K-dependent coagulation factors for long-term anticoagulation. Thrombin inhibitors include unfractionated heparin and low molecular weight heparins, which require varying monitoring levels. Factor Xa inhibitors such as fondaparinux prevent prothrombin conversion to thrombin, producing rapid anticoagulation with predictable responses.

Question 3

What is the role of catheter-directed thrombolysis in managing deep vein thrombosis?

Accepted Answer

Catheter-directed thrombolysis delivers thrombolytic agents like tissue plasminogen activator directly to clots under imaging guidance to dissolve them. This procedure reduces acute symptoms, improves deep venous flow, and decreases valvular reflux. It is indicated for massive pulmonary embolism with hemodynamic instability or severe DVT with limb gangrene risk.

Question 4

When is endovascular management necessary for deep vein thrombosis?

Accepted Answer

Endovascular management is essential when anticoagulants are contraindicated, venous drainage is compromised, or pulmonary embolism risk is extreme. Key procedures include thrombectomy for mechanical clot removal and vena cava filter placement in the inferior vena cava to trap large emboli and prevent pulmonary embolism complications.

Question 5

How do graduated compression stockings and intermittent pneumatic compression devices work differently?

Accepted Answer

Graduated compression stockings enhance blood flow in the legs and reduce venous stasis through consistent pressure. Intermittent pneumatic compression devices use inflatable sleeves on calves, thighs, and sometimes feet to improve venous return by intermittently inflating and deflating. IPCs are typically used in high-risk patients when compression stockings are contraindicated or insufficient.

Question 6

What monitoring is required for unfractionated heparin versus low molecular weight heparin therapy?

Accepted Answer

Unfractionated heparin requires regular monitoring of clotting status using activated partial thromboplastin time (aPTT) and dose adjustment. Low molecular weight heparins like enoxaparin have more predictable dose responses, longer half-lives, and fewer bleeding complications, typically not requiring ongoing anticoagulant monitoring or dose adjustment.

Question 7

What are the indications for thrombolytic therapy in venous thromboembolism treatment?

Accepted Answer

Thrombolytic therapy is indicated for massive pulmonary embolism with hemodynamic instability, severe deep vein thrombosis with risk of limb gangrene, and failure of conventional anticoagulation therapy. It involves catheter-directed administration of drugs like urokinase or tissue plasminogen activator to dissolve clots and reduce acute symptoms.

التخثر الوريدي III: الرعاية متعددة التخصصات

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