Peripheral Vascular Disorders

BLOOD VESSELS  MICROSCOPIC ANATOMY OF BLOOD VESSELS Three layers (tunics) in blood vessels (except the capillaries) Tunica intima forms a friction-reducing lining Endothelium Tunica media Smooth muscle and elastic tissue Controlled by sympath...

BLOOD VESSELS  MICROSCOPIC ANATOMY OF BLOOD VESSELS Three layers (tunics) in blood vessels (except the capillaries) Tunica intima forms a friction-reducing lining Endothelium Tunica media Smooth muscle and elastic tissue Controlled by sympathetic nervous system Tunica externa forms protective outermost covering Mostly fibrous connective tissue Supports and protects the vessel  Tunica intima Artery Vein Endothelium Loose connective tissue Internal elastic lamina Tunica media Smooth muscle Elastic fibers External elastic lamina Tunica externa Collagen fibers Valve Venule Arteriole Capillary Lumen bed Lumen Basement membrane Endothelial cells (b) Capillary  MICROSCOPIC ANATOMY OF BLOOD VESSELS Structural differences in arteries, veins, and capillaries Arteries have a heavier, stronger, stretchier tunica media than veins to withstand changes in pressure Veins have a thinner tunica media than arteries and operate under low pressure Veins also have valves to prevent backflow of blood Lumen of veins is larger than that of arteries Skeletal muscle “milks” blood in veins toward the heart  Valve (open) Contracted skeletal muscle Valve (closed) OPERATION OF Vein THE MUSCULAR PUMP. Direction of blood flow  CAPILLARIES Structural differences in arteries, veins, and capillaries (continued) Capillaries Only one cell layer thick (tunica intima) Allow for exchanges between blood and tissue Form networks called capillary beds that consist of: A vascular shunt True capillaries Blood flow through a capillary bed is known as microcirculation  Vascular shunt Precapillary sphincters True capillaries Terminal arteriole Postcapillary venule (a) Sphincters open; blood flows through true capillaries. THE GREAT VESSELS  AORTIC BRANCHES Ascending Aorta Aortic Arch Thoracic Arch Abdominal Aorta VENA CAVA  A permanent localized dilation of an artery, which enlarges the artery to at least 2 times its normal diameter ANEURYSM Types: Fusiform – diffuse dilation affecting the entire circumference of the artery Saccular – an outpouching affecting only a distinct portion of the artery  ANEURYSM Aneurysm tends to occur at specific anatomic sites but most commonly in the abdominal aorta ANEURYSM  ANEURYSM Aneurysm forms when the middle layer (T. media) of the artery is weakened, producing a stretching effect in the inner layer (T. intima) and outer layers (T. adventitia) of the artery As the aneurysm grows, the risk of arterial rupture increases  Atherosclerosis is the most common cause of all aneurysm with ANEURYSM hypertension & ETIOLOGY cigarette smoking being contributing factors  Most are asymptomatic until discovered by routine examination or during radiographic study performed for another reason Steady with a gnawing quality ANEURYSM abdominal, flank, or back PAIN ASSESSMENT especially if its AAA With a rupturing AAA, signs include hypotension, diaphoresis, mental obtundation, oliguria & dysrhythmias (S/S of hypovolemic shock)  ANEURYSM DIAGNOSTIC TESTS X-ray reveals “eggshell” appearance in cases of AAA  ANEURYSM DIAGNOSTIC TESTS Standard tool: CT scan (determines the size and location)  ANEURYSM DIAGNOSTIC TESTS Ultrasonography; noninvasive technique that provides accurate diagnosis, as well as information about the size & location of AAA  ANEURYSM INTERVENTIONS Nonsurgical management: goal is to monitor the growth of the aneurysm (frequent CT scanning) and maintenance of BP at a normal level to i risk of rupture w/ hypertension; treated with anti-hypertensive agent  ANEURYSM INTERVENTIONS Surgical Management Abdominal Aortic Aneurysm Resection – excision of aneurysm from the abdominal aorta to prevent or repair the rupture Goal: to secure a stable aortic integrity & tissue perfusion throughout the body PERIPHERAL VASCULAR DISEASES Jacquelyn Joyce Galler-Nicolas, MAN RN  PERIPHERAL VASCULAR DISEASE Disorders that alter the natural flow of blood through the arteries & veins of the peripheral circulation most frequently affected are the lower extremities  VESSEL CIRCULATORY PUMP FAILURE ALTERATIONS INSUFFICIENCY Inadequate blood flow Obstruction & trauma Arterial Insufficiency LSHF – Pulmonary Congestion Atherosclerosis Venous Insufficiency RSHF – Systemic Congestion Arteriosclerosis INADEQUATE BLOOD FLOW ISCHEMIA CELLULAR NECROSIS CIRCULATORY INSUFFICIENCY  ARTERIAL VENOUS INSUFFICIENCY INSUFFICIENCY PAIN Intermittent claudication Aching, cramping Present, assessment may PULSE Diminished or absent be difficult due to edema Increased pigmentation SKIN Dependent rubor in the GAITER area  ARTERIAL VENOUS ULCER INSUFFICIENCY INSUFFICIENCY LOC ATI Tip of toes, heels Medial malleolus, lateral ON (pressure areas) malleolus, anterior tibial areas DEPTH Deep, may affect the joint superficial SHAPE circular irregular ULCER B ASE Pale to black, dr y gangrene Granulation tissue LEG EDEMA minimal Moderate to severe PERIPHERAL ARTERIAL DISEASE  Arteriosclerosis – Thickening or hardening of the arterial wall Atherosclerosis – A type of arteriosclerosis that involves the formation of plaque within the arterial wall Pathophysiology: Vascular damage; Inflammation Fatty streak formation Plaque  PERIPHERAL ARTERIAL DISEASE CLASSIFICATIONS INFLOW OBSTRUCTION involves the distal end of the aorta & the common, internal, external iliac arteries (located above the inguinal ligament) OUTFLOW OBSTRUCTION involves femoral, popliteal & tibial arteries (below the superficial femoral artery)  PERIPHERAL ARTERIAL DISEASE ETIOLOGY & RISK FACTORS ATHEROSCLEROSIS Most common cause Risk factor includes hypertension, hyperlipedimia, DM, CIGARETTE SMOKING, obesity & familial predisposition  PERIPHERAL ARTERIAL DISEASE PAIN ASSESSMENT Intermittent claudication Rest Pain Inflow disease – discomfort in the lower back, buttocks or thighs Outflow disease – burning or cramping in the calves, ankles, feet & toes  PERIPHERAL ARTERIAL DISEASE ASSESSMENT Loss of hair on the lower calf, ankle & foot; dry, scaly, dusky, pale or mottled skin; thickened toenails Cold extremity & cyanotic; pallor occurs when the extremity is elevated Diminished or absent distant peripheral pulses  PERIPHERAL ARTERIAL DISEASE DIAGNOSTIC ASSESSMENT Arteriography Segmental Systolic BP measurements Ankle-Brachial Index – an ABI of