RT Book, Section A1 Kadian-Dodov, Daniella A1 Olin, Jeffrey W. A2 Fuster, Valentin A2 Harrington, Robert A. A2 Narula, Jagat A2 Eapen, Zubin J. SR Print(0) ID 1161720984 T1 DIAGNOSIS AND MANAGEMENT OF DISEASES OF THE PERIPHERAL VENOUS SYSTEM T2 Hurst's The Heart, 14e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9780071843249 LK accesscardiology.mhmedical.com/content.aspx?aid=1161720984 RD 2024/03/28 AB The lower extremity venous system includes the deep, superficial, and perforating veins, which work in concert to return blood to the heart (Fig. 97–1).1 Unlike the arterial system, the venous system has low resistance and must overcome gravitational and hydrostatic pressure forces to achieve blood return to the heart. The venules and veins have very thin walls and low resting basal tone, which allows for enormous distensibility. As a result, small changes in hydrostatic forces, central pressure, and/or external forces result in changes of the vein diameter. Venous blood flow is reliant upon muscular leg contraction, historically referred to as “the peripheral heart,”2 as well as bicuspid venous valves that open and close to prevent backflow. Together, muscular leg contraction and venous valves help to overcome hydrostatic forces within the vein itself. Venous disease results from degeneration and dysfunction of the veins and/or valves, which may occur following an obstruction such as deep vein thrombosis or in the setting of increased central pressures, as in congestive heart failure. Venous disease is associated with a wide array of clinical manifestations caused by complex hemodynamic and anatomic failures. A basic understanding of these complexities is essential in the evaluation, diagnosis, and appropriate treatment of venous disease.