PAD: Arteriosclerosis and Atherosclerosis

Pathophysiology of Arterial Vascular Disease (PAD)

• Arteriosclerosis involves the hardening of arteries
• It is the most common disease of the arteries
• Arteriosclerosis causes muscle fibers and endothelial lining of arteries to thicken and stiffen
• Arteriosclerosis potentially restricts blood flow in arteries
• Atherosclerosis is a form of arteriosclerosis
• Atherosclerosis is the buildup of fat, cholesterol, and other substances forming plaque on artery walls
• Plaque restricts blood flow
• If plaque ruptures, a blood clot will form
• Peripheral arteries refer to any artery that is not a coronary artery
• Arterial insufficiency of the extremities most often affects the legs
• The primary cause of PAD is atherosclerosis
• Other causes of PAD include trauma, embolism, thrombosis, vasospasm, inflammation, or autoimmunity

Collateral Circulation in PAD

• Healthy peripheral arteries are open and functioning
• Partial peripheral artery closure can lead to collateral circulation being established
• Total peripheral artery occlusion can result in collateral circulation bypassing the occlusion to supply blood to the extremity
• Collateral blood flow can develop in response to occlusion of the right common iliac artery and the terminal aortic bifurcation

Risk Factors in PAD

• Modifiable risk factors for PAD include smoking, diet, hypertension, diabetes, hyperlipidemia, stress, sedentary lifestyle, elevated CRP, and elevated homocysteine
• Nonmodifiable risk factors for PAD include increasing age, female gender, and family history/genetics

Clinical Manifestations in PAD

• Claudication is defined as pain that occurs with activity
• Excruciating pain can occur
• Intermittent claudication (pain with activity) occurs early on in the disease
• Rest pain occurs late in the disease
• Elevation or horizontal positioning of an extremity increases pain, and dependent positioning helps relieve or lessen pain
• The extremity may be cool, pale, and cyanotic with elevation
• Bruits may be present
• Pulses may be diminished or absent
• Nails may be thick and opaque
• The skin may be shiny and atrophied
• There may be sparse hair growth
• Wounds may heal slowly because of poor perfusion. Ulcerations may occur
• Wounds have a punched-out look with well-defined borders
• Wounds area usually round, small, circular, and deep
• Wounds are often found between or on the tips of the toes, on the heels, on the outer ankle, or where there is pressure from walking or footwear
• Wounds may be caused by a combination of ischemia and pressure
• The 6 Ps of PAD include pain, pallor, pulselessness, paresis, paralysis, and poikilothermia

Collaborative Care in PAD

• Modification of risk factors is recommended, and smoking cessation is critical
• Recommend a controlled exercise plan to maximize functional status
• Recommended exercise is to the point of pain to stimulate collateral circulation development
• Pharmacologic therapy includes antiplatelets/anticoagulants, lipid-lowering medications, and thrombolytic and heparin therapy for acute peripheral arterial occlusions
• Pain management is an important consideration
• Radiologic endovascular interventions include angioplasty, stents, and intravascular thrombolytics
• Surgical interventions include bypass grafting, endarterectomy, and amputation
• Patient education is essential
• Avoid pressure on vessels in the extremities
• Do not wear constrictive clothing
• Use compression hose/devices
• Avoid elevating extremities and keep in a dependent position
• Avoid trauma to extremities and provide special care for any injuries/lesions
• Practice meticulous foot care
• Do not ever go barefoot
• Examine feet daily
• Take medications as prescribed

Aneurysms

• An aneurysm is a localized sac or arterial dilation formed at a weak point in the wall of an artery due to damage to the media (muscle) layer of the artery
• Aneurysms are most often caused by atherosclerosis
• Rupture of an aneurism can lead to hemorrhage and death
• Collaborative care includes monitoring the size of the aneurysm, treating hypertension, managing other risk factors, and potentially surgical intervention with endoscopic repair or open surgical repair

Arterial Dissection

• A tear develops in the intima or media in an atherosclerotic artery
• Blood enters that space, creating a false lumen and furthering tears the artery
• Reduce blood flow in the lumen of the vessel
• Arterial dissection may cause blockage of blood flow, potentially resulting in the formation of a thrombus
• Dissection spreads to the primary artery and branches of the artery
• Manifestations are usually abrupt
• Severe, persistent tearing pain occurs in the area of dissection
• High mortality is possible
• Collaborative care is similar to that of aneurysm patients

Vasospastic Arterial Disorders: Raynaud's Disease

• Raynaud's Disease involves intermittent arteriolar vasospasm
• It is a primary or secondary disorder
• Raynaud's Disease may be associated with migraines and Prinzmetal angina
• Clinical manifestations include triphasic color change due to sudden vasospasm involving pallor, then cyanosis, and then rubor (hyperemia)
• Numbness, tingling, and burning pain
• Symptoms are usually symmetrical and most often in fingers but can occur in toes
• Serious complications of Raynaud's Disease, such as gangrene and amputation, are rare
• Patients should avoid precipitating factors such as smoking, cold, trauma, and stress
• Calcium channel blockers may be prescribed
• Ligation of the sympathetic nerve (sympathectomy) may help some patients

Peripheral Venous Disease

• Venous thromboembolism is discussed in the Ventilation Module
• Chronic venous insufficiency results from obstruction of venous valves in legs or reflux of blood through the valves, causing veins to distend
• Manifestations include chronic venous stasis/edema and venous stasis ulcers
• Complications can include venous stasis ulcers
• Collaborative care involves elevation of legs/avoiding leg dangling when seated, compression stockings, and protection from injury
• Venous stasis ulcers are characterized by aching pain or a heavy sensation with an edematous foot and ankle
• Ulcers usually occur on ankles and are large and highly exudative with irregular borders

Peripheral Venous Disease: Teaching Points

• Elevate the legs when sitting
• Flex the feet when sitting
• Avoid prolonged standing
• Avoid dangling of feet and/or pressure on the popliteal area of leg
• Avoid constrictive clothing
• Use graduated compression stockings, applying to legs post elevation