Chapter 24: Venous and Lymphatic Disease

KEY POINTS

1. Thrombolytic therapy, surgical thrombectomy, and placement of inferior vena cava filters are adjunctive treatments that may be indicated in patients with extensive and complicated venous thromboembolism.

2. Deep vein thrombosis (DVT) and pulmonary embolism are frequent complications after major abdominal and orthopedic procedures. The risk is further increased in patients with malignancy and a history of venous thromboembolism. Options for DVT prophylaxis include intermittent pneumatic compression, use of graduated compression stockings, and administration of low-dose unfractionated heparin, low molecular weight heparin, fondaparinux, and vitamin K antagonists. However, prophylaxis should be stratified based on the patient's level of risk.

3. In patients with established DVT, unfractionated heparin, low molecular weight heparin, and fondaparinux are options for initial antithrombotic therapy. The duration and type of long-term anticoagulation should be stratified based on the ­provoked or unprovoked nature of the DVT, the location of the DVT, previous occurrence of DVT, and presence of concomitant malignancy.

4. Saphenous vein stripping, endovenous laser treatment, and radiofrequency ablation are effective therapies for patients with saphenous vein valvular insufficiency. Concomitant varicose veins may be managed with compression therapy, sclerotherapy (for smaller varices), and phlebectomy.

5. The mainstay of treatment for chronic venous insufficiency is compression therapy. Sclerotherapy, perforator vein ligation, and venous reconstruction may be indicated in patients in whom conservative management fails.

6. Lymphedema is categorized as primary (with early or delayed onset) or secondary. The goals of treatment are to minimize edema and prevent infection. Lymphatic massage, sequential pneumatic compression, use of compression garments, and limb elevation are effective forms of therapy.

VENOUS ANATOMY

Veins are part of a dynamic and complex system that returns low-nutrient deoxygenated blood to the heart. Venous blood flow is dependent on multiple factors such as gravity, venous valves, the cardiac and respiratory cycles, blood volume, and the calf muscle pump. Alterations in the intricate balance of these factors can result in venous pathology.

Structure of Veins

Veins are thin-walled, highly distensible, and collapsible. Their structure specifically supports the primary functions of veins to transport blood toward the heart and serve as a reservoir to prevent intravascular volume overload.

The venous intima is composed of a nonthrombogenic endothelium with an underlying basement membrane and an elastic lamina. The endothelium produces endothelium-derived relaxing factors such as nitric oxide and prostacyclin, which help maintain a nonthrombogenic surface through inhibition of platelet aggregation and promotion of platelet disaggregation.¹ Circumferential rings of elastic tissue and smooth muscle located in the media of the vein allow for changes in vein caliber with minimal changes in venous pressure. The adventitia is most prominent in large veins and consists of collagen, elastic fibers, and fibroblasts. When a vein is maximally distended, its diameter may be several times greater than that in the supine position.

In the axial veins, unidirectional blood flow is achieved with multiple venous valves. The inferior ...