Chapter 17: Peripheral Vascular System

Peripheral Vascular System exploration of the peripheral vascular system details the intricate network of arteries, veins, and lymphatics essential for systemic perfusion and fluid balance. The arterial section examines the three distinct tissue layers—intima, media, and adventitia—and describes the progression of atherosclerosis, a chronic inflammatory process where lipid ingestion by macrophages leads to plaque formation and potential vessel occlusion. It distinguishes between large elastic arteries, medium muscular arteries, and the small arterioles known as resistance vessels, which are primary determinants of blood pressure. Clinical assessment focuses heavily on identifying peripheral arterial disease (PAD), emphasizing warning signs like intermittent claudication, where muscle pain during exertion is relieved by rest, and atypical symptoms such as non-healing wounds or erectile dysfunction. The chapter also highlights the life-threatening nature of abdominal aortic aneurysms (AAA) and mesenteric ischemia, the latter often manifesting as a "food fear" due to postprandial pain. The venous system is characterized by its high distensibility and the presence of unidirectional valves and the calf muscle pump, both critical for returning blood to the heart against gravity. Assessment of the deep and superficial venous systems is vital for detecting deep vein thrombosis (DVT) and chronic venous insufficiency. Furthermore, the lymphatic system is presented as a secondary circulatory route that filters fluid through nodes and maintains immune surveillance. Practical examination techniques are detailed, including the grading of arterial pulses from 0 to 3+, the use of the Allen test to evaluate hand perfusion, and the four-point scale for measuring pitting edema. A significant diagnostic focus is placed on the Ankle-Brachial Index (ABI), a noninvasive ratio of blood pressure in the foot versus the arm used to confirm PAD. Finally, health promotion strategies are discussed, specifically advocating for ultrasound screening for AAA in older male smokers and utilizing the ABI to identify asymptomatic patients at high risk for cardiovascular events.