**Chapter 1: Gross Anatomy of the Central and Peripheral Arterial Systems**
AORTIC ARCH:
-several branching vessels
-Innominate/brachiocephalic artery
-arises on the right only; first branch off of the aortic arch
-terminates at the carotid bifurcation
-Left Subclavian Artery
-third branch of the aortic arch
-terminates at the thoracic outlet
UPPER EXTREMITY ARTERIES:
-Subclavian Artery
-runs laterally and downward to the outer border of the first rib; there is becomes the axillary artery as it travels along the shoulder to the upper arm
-arches above the clavicle, in front of the apex of the lung and behind the scalenus anterior muscle
-most important branches are vertebral, thyrocervical, internal thoracic, and costocervical arteries
-Axillary artery becomes the brachial after giving off seven branches:
-superior, thoracic, thoracoacromial, lateral thoracic, subscapular, anterior and posterior humeral, thoracodorsal
-Branchial Artery:
-courses down the upper arm, usually ending about 1 cm distal to the bend of the elbow
-there it divides into the radial and ulnar arteries
-Radial Artery
-originates from the branchial artery and travels down the lateral side of the forearm into the hand
-gives off a branch in the hand to form the superficial palmar arch
-terminates in the deep palmar arch of the hand by joining the deep branch of the ulnar artery
-Ulnar Artery:
-originates from the brachial artery and travels down the medial side of the forearm into the hand
-gives off a deep palmar branch and then terminates in the superficial palmar arch
-is the predominant source of blood flow to the hand
-Superficial Palmar (Volar) Arch:
-the distal portion of the ulnar artery, as it continues into the hand
-a branch of the radial artery
-Deep Palmar (Volar) Arch:
-deep palmar branch of the ulnar artery
-distal portion of the radial artery
-Digital Arteries
-arise form the palmar arches
-extend into the fingers
-divide into lateral and medial branches
THORACIC AND ABDOMINAL ARTERIES:
-Ascending Aorta:
-arises from left ventricle
-two branches: right and left coronary arteries
-Aortic Arch:
-formed by the ascending aorta
-gives off the three branches: innominate, left common carotid, left subclavian arteries
-Descending Thoracic Aorta:
-extends downward from the aortic arch to just above the diaphragm
-Major Visceral Branches of the Abdominal Aorta:
-Celiac artery: feeds the stomach, liver, pancreas, duodenum, spleen
-Celiac artery: branches into left gastric, splenic, and common hepatic arteries
-SMA: feeds small intestine, cecum, ascending colon, part of transverse colon
-SMA: 1 cm distal to the celiac artery; SMA and celiac artery can share a common trunk
-Renal Arteries: supply blood to kidneys, suprarenal glands, and ureters
-Inferior Mesenteric Artery: supplies left half of the transverse colon, descending, iliac, and sigmoid colon, and part of the rectum
-Major Parietal Branches of Abdominal Aorta: inferior phrenic artery, lumbar arteries, middle sacral artery
-terminal branches of abdominal aorta are the right and left common iliac arteries; distal-most branches of the aorta carrying blood to the pelvis, abdominal wall, and lower limbs
LOWER EXTREMITY ARTERIES:
-common iliac arteries divide into the internal (hypogastric) and external iliac arteries at the level of the lumbosacral junction, about 5 cm from their origin
-internal iliac arteries: 3-4 cm in length, descend into pelvis and each divide into two vessels anterior and posterior at upper margin of greater sciatic foramen, branches are variable, specific branches provide arterial flow to pelvic wall, gluteal muscle, pelvic viscera, thigh, and perineum
-external iliac arteries: continuous with corresponding common iliac artery; larger than internal iliac artery in adults; travels in a lateral and inferior direction along the medial side of the psoas major; when it passes underneath the inguinal ligament it becomes common femoral artery
-common femoral artery divides into superficial and deep femoral arteries
-superficial femoral artery: runs the length of the thigh and enters the popliteal fossa behind the knee; Hunter's canal is where the superficial femoral artery becomes the popliteal artery
-deep femoral artery: large branch and arises about 5 cm from inguinal ligament on the lateral side
-popliteal artery: distal continuation of the superficial femoral artery; becomes this once it travels through Hunter's canal and gives off gastrocnemius arteries; at the interval between the tibia and fibula at the lower portion of the popliteus muscle it branches into the anterior tibial artery and the tibioperoneal trunk which is called the trifurcation
-anterior tibial artery: first branch of distal popliteal artery; passes superficial to the interosseous membrane and runs deep in the front of the leg along the anterior surface of the interosseous membrane
-tibioperoneal trunk: second branch of the distal popliteal artery, gives rise to posterior tibial and peroneal arteries
-posterior tibial artery: extends obliquely down the posterior and medial side of the leg; one of two branches of tibioperoneal trunk; divides into medial and lateral plantar arteries in the foot below the medial malleolus to supply the sole of the foot
-peroneal artery: arises at distal end of the tibioperoneal trunk along with the posterior tibial artery; passes toward the fibula and travels down medial side of that bone to supply structures in the lateral side of the leg and in the calcaneal region of the foot
-plantar arch and digital arteries: plantar arch consists of the deep plantar artery and the lateral plantar artery; dorsal metatarsal arteries distribute blood into the digits
-Arterioles:
-arteries progressively decrease in size from the aorta (largest) to the arterioles (smallest)
-considered to be resistive vessels; help regulate flow by contracting and relaxing
-Capillaries:
-vessels of microcirculation
-not much more than a mm long
-8-10 microns in diameter (similar to a RBC)
-steady flow quality with low flow velocity
-walls that consist of endothelial cells, forming a layer one cell thick
-supplied by arterioles which transport gases, nutrients, and other essential substances to the capillary beds
Upper Extremity Arterial Variations with Percentages of Occurrence:
-Common origin or right innominate and left common carotid artery: 22%
-Radial artery originates from axillary artery: 1%-3%
-Ulnar artery originates from axillary artery: 2%-3%
-Early division of brachial artery: 19%
Lower Extremity Arterial Variations with Percentages of Occurrence:
-High bifurcation of the popliteal artery: 4%
-High bifurcation of the popliteal artery with the peroneal artery arising from the anterior tibial artery: 2%
-Absent posterior tibial artery: 1-5%
-Hypoplasia or aplasia of the anterior tibial artery 4-12%
-Anomalous location of the dorsalis pedis artery: 8%
MICROSCOPIC ANATOMY OF THE ARTERIAL WALL:
-Function of the artery is to transport blood, gases, and nutrients, and other essential substances it contains, away from the heart and out to the tissues.
-Tunica Intima: innermost layer of the arterial wall, is thin and consists of a surface layer of smooth endothelium over a base membrane and connective tissue
-Tunica Media: intermediate layer of the arterial wall, thicker and composed of smooth muscle and connective tissue, largely of the elastic type; components usually arranged in circular pattern
-Tunica Externa (or adventitia): outer layer of the arterial wall; thinner than media and contains white fibrous connective tissue and at times a few smooth muscle fibers, all arranged longitudinally
-three coats of the arteries can be separated by internal and external elastic membranes
**Chapter 2: Physiology and Fluid Dynamics**
ARTERIAL SYSTEM:
**Chapter 3: Testing Considerations, Patient History, Mechanisms of Disease, and Physical Examination
TESTING CONSIDERATIONS FOR NONINVASIVE ARTERIAL TESTING:
Appropriate Indications for Testing:
-MD is responsible for making determination that a diagnostic study is medically necessary
-specific guidelines on appropriate indications related to reimbursement policies
Integration of Outside Data:
-relevant clinical history and documentation of physical examination findings obtained
-documentation of protocol specific lab findings may be included
-identification of risk factors and knowledge of differential diagnoses are important
Environment:
-warm, promote comfort
-adequate gel
PATIENT HISTORY: SIGNS AND SYMPTOMS:
Chronic Occlusive Disease:
-Claudication: pain in muscles during exercise; true claudication results from inadequate blood supply to the exercising muscle, which may be caused by arterial spasm, atherosclerosis, arteriosclerosis, or an occlusion
*Buttock claudication: strongly suggests aortoiliac disease; if unilateral, suggests iliofemoral disease
*Thigh claudication: suggests distal external iliac/common femoral disease
*Calf claudication: suggests femoral/popliteal disease
-Ischemic Rest Pain: more severe symptom of diminished blood flow to most distal portion of lower extremity; pain at rest usually occurs when the limb is not dependent position and the patient's BP is decreased (like when sleeping); symptoms occur in forefoot, heel, toes, but NOT in calf
-Tissue Death: aka necrosis; usually due to deficient or absent blood supply; most severe symptom of arterial insufficiency
Acute Arterial Occlusion:
-five Ps: pain, pallor, pulselessness, paresthesia, and paralysis; some include polar and purplish
-occlusion may result from thrombus, embolism, or trauma
-emergency situation since the abrupt onset does not provide for the development of collateral channels
Cold Sensitivity:
-changes in skin color such as pallor (paleness), cyanosis (bluish discoloration), or rubor (dark red coloration)
-Raynaud's phenomenon exists when symptoms of intermittent ischemia of the fingers or toes occur in response to cold exposure as well as emotional stress
RISK FACTORS AND CONTRIBUTING DISEASES:
Diabetes:
-mellitus is most common form
-atherosclerosis is more common among diabetics and occurs at a younger age
-diabetics have a higher incidence of occlusive disease of the distal popliteal artery and tibial vessels
-medical calcification develops in the lower extremity arteries
-higher incidence of gangrenous changes and, ultimately, amputations
-poor sensation as a result of neuropathy leads to increased likelihood of trauma
Hypertension:
-high BP may or may not be a causative factor or enhances and complicates the development of the atherosclerotic process
-systemic hypertension is associated with a greater incidence of coronary atherosclerosis and also increases an individual's susceptibility to peripheral and cerebrovascular involvement
Hyperlipidemia:
-elevated plasma lipids are closely associated with the development of atherosclerosis; increased lipids may result from metabolic problems associated with hyperlipidemia
Smoking:
-chemicals in cigarettes irritate the endothelial lining of the arteries in addition to causing vasoconstriction
Other factors: age, family history, male
MECHANISMS OF DISEASE:
Atherosclerosis:
-most common arterial pathology; term is applied to a lot of conditions in which there is thickening, hardening, and loss of elasticity of the walls of the arteries; these changes occur in the intima and media layers of the vessels
-most often occurs at the carotid bifurcation, origins of the brachiocephalic vessel, origins of the visceral vessels, infrarenal aortoiliac system, common femoral bifurcation, superficial femoral artery at the adductor canal, and popliteal trifurcation
Embolism:
-obstruction of a blood vessel by a foreign substance or blood clot; may be solid, liquid, or gaseous and may arise within the body or from without; most frequent case of embolism is plaque or thrombosis breaking loose and traveling distally until it lodges in a small vessel
-emboli move distally and become stuck in smallest caliber vessels resulting in toe ischemia
Aneurysm:
-true aneurysm, dissecting aneurysm, and pseudoaneurysm
-true aneurysm: bulging of all three layers whereas false doesn't involve all three
-most common location is infrarenal; after one aneurysm patient is more likely to have another
-cause is unknown but may include poor arterial nutrition, congenital defects, infection, atherosclerosis, trauma, and iatrogenic injury
-Dissecting aneurysm: occurs when small tear of intima allows blood to form a cavity between two wall layers; a new lumen (false lumen) is formed and blood may flow through it
-Pseudoaneurysm: pulsating hematoma; a hole in the arterial wall permits blood to escape under pressure, into a contained area in the adjacent tissue
Arteritis:
-inflammation of the arterial wall; often results in thrombosis of the vessel and can affect tibial and peroneal arteries as well as the smaller more distal arterioles and nutrient vessels
-most common form is Buerger's disease which has the following characteristics:
-associated with heavy cigarette smoking
-occurs primarily in men younger than 40 years of age
-patients present with occlusions of the distal arteries
-rest pain and ischemic ulceration occur early in the course of the disease
-inflammation of the arterial wall occurs and often results in thrombosis of the vessel
-superficial thrombophlebitis is a secondary trait
-common clinical presentation includes patchy areas of ulceration
Coarctation of the Aorta:
-congenital narrowing or stricture of the thoracic aorta that may affect the abdominal aorta as well
-clinical findings may be: hypertension due to decreased kidney perfusion or manifestations of lower extremity ischemia
Dissection:
-media is weakened; intima develops a tear through which blood leaks into false lumen between intima and media
-flow velocities differ in each lumen (main and false)
-dissection can affect the aorta and peripheral arteries
-distinguishing US feature is the thin membrane that divides the arterial lumen into two compartments
-aortic dissections usually start from the thoracic aorta and can also extend to the iliac arteries; may occur as consequence of hypertension or severe chest trauma
Vasospastic Disorders/Cold Sensitivity:
-change in skin color, paresthesia, and pain; trophic changes in more severe cases
-Raynaud's phenomenon exists when symptoms of intermittent ischemia of the fingers or toes occur in response to cold exposure as well as emotional stress
-primary (idiopathic) Raynaud's is intermittent digital ischemia caused by digital arterial spasm; common in young women, may be hereditary, usually bilateral
-secondary Raynaud's consists of normal vasoconstrictive responses of the arterioles superimposed on a fixed arterial obstruction
Entrapment Syndromes:
-entrapment of popliteal artery is the most written about entrapment syndrome
-caused by compression of the popliteal artery by the medial head of the gastrocnemius muscle of fibrous bands
-commonly found in young men and is bilateral in about a third of the cases
Miscellaneous Pathologies:
-Collagen Vascular Disorder: problems with immune system affect collage which contributes to structure of tendons, bones and connective tissue. Example: temporal arteritis
-Ehlers-Danlos Syndrome: group of inherited disorders affecting connective tissue such as skin, joints, and blood vessel walls
-Livedo Reticularis: vascular condition characterized by purplish discoloration of the skin, more often found on legs than in the upper extremity; discoloration is "net-like" in appearance
-Necrobiosis Lipoidica: collagen degeneration with thickening of blood vessel walls, fat deposition, and granulomatous response; shiny, red-brown patches on the skin that enlarge over time
-Vasculitis: aka angiitis and arteritis, vasculitis is an inflammation of the blood vessels causing changes such as thickening, weakening, scarring, and narrowing in the blood vessel walls
PHYSICAL EXAMINATION:
Skin Changes:
Color:
-pallor: result of deficient blood supply; skin in pale
-rubor: dark reddish discoloration, suggests damaged, dilated vessels or vessels dilated as a result of reactive hyperemia or infection
-cyanosis: bluish discoloration of the skin and mucous membranes, occurs when there is a concentration of deoxygenated hemoglobin
-livedo reticularis: purple patches similar to bruising on the skin of the dorsum of the foot; usually result of dilated capillary and venule filling, not arterial obstruction
Temperature:
-skin should be warm to the touch; essential to feel
Lesions:
-Ulcerations: result of arterial insufficiency are usually deep and regular in shape
-Gangrene: depth of tissue, usually caused by deficient or absent blood supply
Trophic Changes:
-loss of hair on the extremity may reflect poor nutritional state caused by lack of circulation; skin can also have a shiny, scaly appearance
-thickened toenails are commonly seen
Capillary Filling:
-health flesh color blanches in appearance as superficial vessels are constricted by manual pressure
-normal skin color should return immediately upon the release of the pressure
-increase in the capillary refill time (greater than 3 seconds) denotes decreased arterial perfusion
Elevation/Dependency Changes:
-elevating extremity produces cadaveric pallor because of very poor arterial perfusion
-returning to dependent position causes a slow return to normal followed by the red discoloration called dependent rubor
Palpation:
-feel for pulses, vibrations, or thrills
-palpable pulses include the aorta and femoral, popliteal, dorsalis redis, and posterior tibial arteries
Auscultation (Bruits):
-abnormal, low-frequency sounds head on auscultation
-one that extends through diastole suggests more severe arterial disease
