Atherosclerosis and Peripheral Artery Disease

Atherosclerosis

• Arteriosclerosis involves the thickening, loss of elasticity, and calcification of arterial walls, occurring with aging.
• Atherosclerosis involves plaque formation in the arteries.
• Both arteriosclerosis and atherosclerosis may begin in early childhood, progressing without symptoms until adulthood.
• Atherosclerosis is a primary cause of coronary heart disease (CHD), also known as coronary artery disease (CAD).

Pathophysiology

• Atherosclerosis affects the inner lining of the artery, beginning with injury to endothelial cells, causing inflammation and immune response.
• Endothelial damage stimulates smooth muscle cell growth, which secrete collagen and fibrous proteins.
• Lipids, platelets, and clotting factors accumulate, forming plaque—fatty deposits adhering to the artery wall.
• Plaque consists of smooth muscle cells, fibrous proteins, and cholesterol-laden foam cells.
• A fibrous cap develops on the plaque and calcifies, which can tear or rupture, leading to blood clot formation.
• Clots can completely block the coronary artery or break loose and lodge in smaller arteries.
• Arteries may become stenosed (narrowed) by plaque, causing partial or total occlusion.
• The area distal to the occlusion can become ischemic.

Etiology

• Risk factors for atherosclerosis include modifiable factors like diet and smoking
• Unmodifiable risk factors cannot be changed

Diagnostic Tests

• Total cholesterol levels above 200 mg/dL increase the risk of CAD and myocardial infarction (MI).
• Elevated low-density lipoproteins (LDLs) and low levels of high-density lipoproteins (HDLs) increase CAD risk.
• High levels of Lp(a) cholesterol (a genetic variation of LDL) are a risk factor for premature CAD.
• LDL particle number, measured as apolipoprotein B, is an excellent predictor of MI risk.
• High LDL particle number with a low LDL level is also a high risk for MI because apolipoprotein B particles infiltrate the arterial wall, rapidly causing damage.
• C-reactive protein (CRP) can indicate low-grade inflammation in blood vessels and an increased CAD risk.
• Elevated blood glucose levels increase the risk for atherosclerosis.
• Radiological studies show narrowed or occluded vessels.

Therapeutic Measures

• Managing atherosclerosis includes a healthy lifestyle, preventing risk factors, medications, and regular physical examinations.

Diet

• Adhering to a heart-healthy diet like the DASH eating plan is beneficial as plaque is primarily caused by fatty deposits.

Smoking

• The risk of developing CAD is greater in smokers.
• The risk of developing CAD is proportionate to the number of cigarettes smoked.
• Smoking contributes to a loss of HDL and causes vasoconstriction, leading to angina pectoris and cardiac arrhythmias.
• Thirdhand smoke is residual nicotine and toxic chemicals left on surfaces by tobacco smoke.

Exercise

• Increased activity raises HDL levels.
• Exercise lowers insulin resistance and facilitates weight loss.
• Exercise leads to the development of collateral circulation.

Medications

• Lowering lipid levels is the primary therapy for atherosclerosis.
• Familial hypercholesterolemia, due to a chromosome 19 defect, is treated with injectable monoclonal antibodies like alirocumab (Praluent) and evolocumab (Repatha).

Coronary Artery Disease

• CAD is the obstruction of blood flow through the coronary arteries to the heart muscle cells, typically from atherosclerosis.

Prevention

• Modifiable risk factors should be changed such as those above for atherosclerosis.
• Low-dose aspirin may be recommended to prevent thrombus formation.
• Million Hearts® 2022 is a national initiative to prevent 1 million heart attacks and strokes within 5 years.
• Evidence-based priorities to improve cardiovascular health include cholesterol management, self-measured blood pressure monitoring, hypertension control, tobacco cessation, and cardiac rehabilitation.

Angina Pectoris

• Angina pectoris is chest pain due to ischemia from a reduction in coronary artery blood flow and oxygen delivery to the myocardium. Angina is a symptom, not a disease.

Types of Angina

• Stable angina occurs with moderate exertion in a familiar pattern, is predictable, lasts a few minutes, and is relieved by resting and nitroglycerin.
• Vasospastic angina is is caused by coronary artery spasms, is serious, follows a cyclical pattern, and is longer-lasting than stable angina, occurring with exercise or at rest, often at night.
• Microvascular angina is from spasms in the walls of the tiniest arteries of the heart that reduce coronary blood flow. The pain is often more severe and lasts longer than other types.

Signs and Symptoms

• Anginal chest pain is often described as discomfort, burning, fullness, heaviness, pressure, or squeezing.
• The pain can radiate to one or both arms, shoulders, neck, jaw, or back.
• If pain is present in the shoulders, neck, jaw, arms, or back due to a cardiac problem but there is no chest pain, then it is referred pain.
• Patients may also describe heaviness in their arms or a feeling of impending doom.
• During an episode, the patient may be pale, diaphoretic, or dyspneic.
• Women may also experience chest pain, jaw pain, or heartburn with angina but often have atypical symptoms, including shortness of breath, fatigue, and nausea.

Diagnostic Tests

• Common tests used to diagnose CAD or anginal causes include electrocardiogram (ECG), exercise stress test, echocardiography, chemical stress testing, cardiac computed tomography (CT) scan, cardiac magnetic resonance imaging (MRI)/magnetic resonance angiogram (MRA), radioisotope imaging, and coronary angiography.

Therapeutic Measures

• Treatment, based on identified risk factors, aims to prevent anginal attacks with activity and MI.
• Weight reduction, a heart-healthy diet, smoking cessation, and reduction of emotional stress may help slow disease progression.
• Three major classes of medications—nitrates, beta blockers, and calcium channel blockers—and the antianginal ranolazine (Ranexa) are prescribed alone or in combination.
• Nitroglycerine (NTG), a vasodilator, is the medication of choice for acute anginal attacks.
• For acute use, NTG is sublingual (buccal, powder, spray, tablet) or IV in the hospital.
• Sublingual NTG may relieve chest pain within 1 to 2 minutes.
• Long-acting nitrates (oral or topical: ointment, transdermal patch) are used to prevent acute chest pain.
• To prevent nitrate tolerance, a 10- to 12-hour nitrate-free period is needed for ointment or patch use.
• Beta blockers are initial therapy for exertional angina prevention
• Beta blockers decrease heart rate and contractility and lower blood pressure.
• Beta blockers are not effective for coronary artery spasms.
• Calcium channel blockers dilate the coronary arteries and peripheral vessels, which increases the myocardial oxygen supply and reduces cardiac workload.
• Calcium channel blockers are ineffective in relieving acute anginal attacks.
• Antiplatelets are used to prevent cardiovascular events from blood clots and cause angina.
• Statins prevent and treat atherosclerosis.

Nursing Process for CAD and Angina: Data Collection

• Record height, weight, allergies, medications, herb use, and typical diet.
• Identify the patient’s nonmodifiable and modifiable risks for atherosclerosis and CAD.
• Obtain vital signs and oxygen saturation.
• Note dyspnea, labored respirations, diaphoresis, nausea, skin color, and temperature.
• Note a history of chest pain, fatigue, or activity intolerance.
• Document the patient’s description of anginal pain, factors making it worse or better, how long the patient has had angina, triggering activities, and how the pain has been relieved in the past.

Nursing Process for CAD and Angina: Nursing Diagnoses, Planning, and Implementation

• Acute Pain related to reduced perfusion of coronary arteries
• Administer oxygen as prescribed.
• Administer fast-acting NTG (sublingual) as prescribed.
• Notify HCP if pain is unrelieved after three doses of NTG, or if vital signs change.
• Chest pain unrelieved by nitrates (sublingual) may represent MI.
• Remain with patient and provide emotional support.
• Deficient Knowledge related to ineffective management of regimen for coronary artery disease
• Identify patient’s readiness to learn, desired learning needs, baseline knowledge and feelings about incorporating lifestyle changes into daily routine.
• Include significant other as appropriate to support patient during learning.
• Explain pathophysiology of atherosclerosis and CAD, control of risk factors, management of CAD symptoms, and medications.
• Provide information about community resources that can assist in making lifestyle changes.
• Encourage questions and allow patient the opportunity to verbalize new information and skills.

Nursing Process for CAD and Angina: Evaluation

• Interventions are successful if the patient is pain-free, demonstrates increased understanding of atherosclerosis and CAD, and states plans to modify CAD risk factors

Acute Coronary Syndrome

• Acute coronary syndrome (ACS) refers to conditions involving myocardial ischemia: unstable angina, non–ST-elevation MI (NSTEMI), and ST-elevation MI (STEMI).
• With unstable angina, the ischemia does not cause enough cardiac damage to release cardiac biomarkers.
• NSTEMI is caused by a partial coronary artery blockage.
• STEMI is usually caused by a complete blockage of a coronary artery.
• Silent ischemia occurs without pain, carrying great risk as it goes undetected.
• Older adults, women, and those with hypertension or diabetes most often have silent ischemia.
• Sudden cardiac death is cardiac arrest triggered by lethal ventricular arrhythmias or asystole from an abrupt occlusion of a coronary artery.

Myocardial Infarction: Pathophysiology

• An acute MI results in the death of heart muscle cells from a sudden partial or complete coronary artery blockage.
• Ischemic injury evolves over several hours before complete necrosis and myocardial infarction take place.
• The body’s attempt to compensate for decreased cardiac function triggers the sympathetic nervous system to increase the heart rate.
• Once necrosis takes place, the contractile function of the muscle is permanently lost.
• The heart has a zone of ischemia and injury around the necrotic area.
• If the heart responds to treatment, this area can rebuild and develop collateral circulation.

Myocardial Infarction: Signs and Symptoms

• Chest pain is the classic symptom of an MI.
• The pain begins suddenly and is not relieved by rest or NTG.
• The chest pain can radiate to shoulders, one or both arms, hands, neck, throat, lower jaw, teeth, upper abdomen, or back.
• The pain can imitate indigestion or a gallbladder attack with abdominal pain and vomiting.
• Other classic MI symptoms include shortness of breath, dizziness, nausea, and sweating.
• The heart rate may be rapid and the heart’s rhythm irregular.
• An extra heart sound (S3 or S4) may be present, which is a sign the myocardium is failing.
• Women are likely to have atypical symptoms, including extreme fatigue, epigastric pain, lower jaw pain, indigestion, nausea and vomiting, dyspnea, shortness of breath, or cramping in the chest.
• Prodromal symptoms may occur a month before an acute MI.

Myocardial Infarction: Diagnostic Tests

• Combined indicators of an MI are patient history, ECG changes, and elevated levels of highly sensitive cardiac troponin T (cTnT) or I (cTnI), and myoglobin and creatine kinase (CK)-MB if used.
• The ECG may show the area that is infarcted as well as ischemic areas of the heart.
• Myocardial damage can be seen as ST-elevation, the presence of a Q wave, or T-wave abnormalities.
• Magnesium and potassium levels are checked.

Myocardial Infarction: Therapeutic Measures

• Medical treatment should be sought within 5 minutes for unrelieved chest pain or other symptoms.
• The goal is to restore blood flow to the heart muscle within 90 minutes of the patient’s arrival at the emergency department.
• A stent is an expandable metal mesh tube implanted to support the coronary artery wall at the area of stenosis.
• Drug-eluting stents are coated with immunosuppressant medication to prevent the need for revascularization of the artery.
• Antiplatelet medications are recommended after stent placement to prevent clot formation.
• When used, thrombolytic medication must be started within 1 to 6 hours of symptom onset. The goal is to give a thrombolytic within 30 minutes of ED arrival.
• Chewing one nonenteric aspirin (165–325 mg) is prescribed after diagnosis of acute coronary syndrome.
• For acute cardiac-related pain, NTG is given sublingually or by IV drip.
• Morphine sulfate is given carefully for ischemic pain that is unrelieved by other therapy.
• Dual antiplatelet therapy may be given long term after an MI.
• Antiarrhythmics are given if atrial or ventricular arrhythmias occur.
• Activity: Initially, patients are kept on bedrest.
• Diet: Initially, a low-sodium, clear liquid diet is ordered, then small, easily digested, heart-healthy meals.
• Fluid can be restricted if the patient is in heart failure.

Coronary Artery Bypass Graft

• During CABG surgery, the saphenous vein from the leg and/or an internal mammary artery from the chest wall is used to reroute blood around a narrowed coronary artery.
• The surgery can be done on cardiopulmonary bypass (arrested heart surgery) or off cardiopulmonary bypass (beating heart surgery).
• Minimally invasive surgery approaches include the minimally invasive direct CABG (MIDCAB) and totally endoscopic CABG (TECAB).

Nursing Process for Myocardial Infarction

• Obtain a thorough history to identify risk factors.
• Patients with chest pain are treated for a possible MI until it has been ruled out.
• Continuous cardiac monitoring and serial ECGs and laboratory values determine the degree of damage and detect life-threatening arrhythmias.
• Screen for depression.
• Patients undergoing cardiac surgery will have a chest tube placed: Report drainage more than 200 mL/hr.
• Sternal precautions include no pushing or pulling with arms; hug pillow with all movements; do not use arms to rise out of a chair; do not lift more than 5 to 10 pounds; do not raise elbows above shoulders; and bend elbows and lower head for grooming.

Patient Education

• Education includes information about the disease, medications, diet, activity, and rehabilitation needs
• Sexuality counseling should be offered.
• Sexual activity can be resumed in 1 to 2 months, or when the patient can climb two flights of stairs without symptoms.

Cardiac Rehabilitation and Exercise

• Cardiac rehabilitation improves cardiac function and quality of life beginning when the patient’s acute symptoms are relieved.
• Phase 1 of rehabilitation occurs in the hospital.
• Phase 2 occurs 4 to 6 weeks after discharge in an outpatient program that focuses on returning the patient to previous levels of activity and function.
• Phase 3 follows, and patients are encouraged to maintain optimal physical fitness and continue healthy lifestyles that include exercising and losing weight.

Peripheral Vascular System

• PVD may be either arterial or venous in origin.

Arterial Thrombosis and Embolism

• Acute arterial occlusions are often sudden and dramatic and are most common in the lower extremity.
• Acute arterial thrombi occur with injury, sluggish flow, or plaque formation.
• Other causes of arterial thrombosis are polycythemia, dehydration, and repeated arterial needlesticks.
• Causes of an arterial embolism are arrhythmias, prosthetic heart valves, MI, and rheumatic heart disease.
• Symptoms depend on the artery occluded, the tissue supplied by that artery, and whether collateral circulation is present.
• The clinical signs of acute arterial occlusion are known as the six Ps: pain, pallor, pulselessness, paresthesia (numbness), paralysis, and poikilothermia (assumes the environmental temperature).

Arterial Thrombosis and Embolism: Therapeutic Measures

• Immediate treatment is necessary to save the affected limb.
• IV fluids and anticoagulants are started immediately.
• The patient remains on UFH therapy for several days.
• After 3 to 7 days, a low molecular weight heparin (LMWH) or an oral anticoagulant such as warfarin (Coumadin) is started.
• Warfarin takes 3 to 5 days to reach therapeutic levels.
• Warfarin levels are monitored by international normalized ratios (INRs).
• During an emergency embolectomy or thrombectomy, the artery is cut open, the emboli or thrombus is removed, and the vessel is sutured closed.

Peripheral Arterial Disease

• PAD is a disorder of the arterial circulation usually caused by chronic, progressive narrowing of arterial vessels that leads to obstruction or occlusion.
• PAD usually affects the lower extremities.
• Atherosclerosis is the leading cause of occlusive disease.
• Organic disease is caused by structural changes from plaque or inflammation.
• Functional disease is a short-term localized spasm in the blood vessel, as occurs in Raynaud disease.
• Decreased nutrition, cellular waste accumulation, and development of ischemia occur distal to the obstruction
• Many people with PAD, especially women, may have no early symptoms.
• Pain in the calves associated with activity or exercise is called intermittent claudication.
• As PAD worsens, the pain is present even at rest, indicating severe arterial occlusion.
• Skin color changes are associated with decreased blood supply. The extremity is pale when the leg is elevated. In a dependent position, it becomes reddish-purple or cyanotic.
• Extremities are cool to touch even in warm environments. Hair loss may occur on the lower calf, ankle, and foot.

Peripheral Arterial Disease: Diagnostic Tests

• The ABI is used to compare blood pressures in the upper and lower extremities.
• A duplex ultrasound measures the velocity of the blood flow.
• MRI and CT scan can give definitive images of blood vessels.

Peripheral Arterial Disease: Therapeutic Measures

• Conservative treatment with mild to moderate occlusive disease includes smoking cessation, exercise therapy, and statins.
• Cilostazol (Pletal), an antiplatelet medication, treats claudication to improve walking ability.
• Procedures include balloon angioplasty, stents, atherectomy or grafting.

Raynaud Disease

• Raynaud disease is a local overreaction by the blood vessels that results in vasospasm when exposed to cold or emotional stress.
• Primary Raynaud disease does not result from another disorder.
• Secondary Raynaud disease is seen with collagen diseases such as RA, scleroderma, SLE, or endocrine disorders.
• With exposure to cold or emotional stress, the area of skin may turn white and then blue, with reports of coldness and numbness.
• With warming, pain, tingling, and redness (hyperemia) occur.
• Initial therapy goals improve quality of life and prevent tissue injury from ischemia.
• Treatment includes calcium channel blockers and nitrates

Thromboangiitis Obliterans (Buerger Disease)

• Buerger disease is a rare recurring inflammation and thrombosis of small and medium arteries and veins in the limbs.
• It is only known to be associated with tobacco or cannabis use.
• Symptoms include intermittent pain or claudication in the legs and feet or arms and hands, tingling, numbness, reddish or blue tinged feet or hands, pale fingers or toes with cold exposure, and vein inflammation.

Nursing Process for Peripheral Arterial Disorder

• Assessment includes leg pain, extremity pulses, capillary refill, temperature, color, presence of edema, and activity intolerance.
• Absent pulses are reported immediately.
• Reinforce teaching healthy lifestyle and risk factor control.
• Explain daily foot care to promptly identify and report problems.

Aneurysms

• An aneurysm is a bulging, ballooning, or dilation at a weakened point of an arterial wall.
• Atherosclerosis, hypertension, smoking, trauma, and congenital abnormalities are risk factors.
• AAA is often silent if it is less than 4 cm.
• Men older than age 50 are at the highest risk of death from rupture and bleeding of an AAA.
• A fusiform aneurysm is the dilation of the entire circumference of the artery.
• A saccular aneurysm bulges on only one side of the artery wall.
• A dissecting aneurysm occurs when a cavity is formed from a tear in the artery wall.

Aneurysms: Signs and Symptoms

• AAA usually exhibits few if any symptoms until it enlarges.
• Back or flank pain is the classic symptom.
• Severe, sudden back, flank, or abdominal pain and a pulsating abdominal mass can indicate that the aneurysm may be about to rupture.

Aneurysms: Therapeutic Measures

• Small aneurysms, less than 4 cm, are monitored for enlargement with ultrasound every 6 to 12 months.
• Medical treatment includes smoking cessation, gentle exercise, avoiding lifting of heavy objects, blood pressure control, and beta blockers.
• An open surgical repair or an endovascular stent graft may be done to repair.

Nursing Process for an Abdominal Aortic Aneurysm

• Monitor circulation, movement, and sensation in extremities every 1 to 4 hours.
• Measure abdominal girth every shift.
• Monitor complete blood count (CBC) as ordered.

Varicose Veins

• Varicose veins are elongated, tortuous, dilated veins.
• Wall defects have been identified as a familial tendency.
• Any factor that contributes to increasing hydrostatic pressure within the leg can promote venous dilation.

Varicose Veins: Signs and Symptoms

• The appearance of telangiectasias (spider veins) indicates minor chronic venous disease.
• More advanced disease can cause dull pain, cramping, edema, and feelings of heaviness.
• Edema or ulceration can develop if venous return is severely compromised.

Varicose Veins: Therapeutic Measures

• Primary goals are to improve circulation, relieve pain, and avoid complications.
• Conservative treatment is exercise, leg elevation, and compression therapy.
• Treatment includes injection sclerotherapy, laser/light therapy and minimally invasive ablation.

Venous Insufficiency

• Venous insufficiency is a chronic condition where damaged or aging valves interfere with blood return to the heart.
• Chronic venous insufficiency can lead to venous stasis ulcers.
• Venous stasis ulcers are the end result of CVI.
• Signs include edema and a brownish discoloration of the leg and foot, with the surrounding skin hardened and leathery in appearance.
• Treatment is focused on decreasing edema and healing skin ulcerations: Compression therapy and leg elevations.

Nursing Process for a Venous Disorder

• Identify risk factors and knowledge of contributing factors for teaching plans.
• Note leg appearance, presence of edema, and ulcerations.
• Elevate legs above heart level and avoid long periods of sitting or standing.

Vascular Surgery Data Collection

• Circulatory status and pain control needs are monitored.
• Review laboratory test results, including CBC, INR, partial thromboplastin time (PTT), and bleeding time.
• Acute or Chronic Pain related to ischemia.
• Anxiety related to outcome, pain, powerlessness, or threat of death.

Embolectomy and Thrombectomy

• Surgical removal to restore blood flow to the tissue distal to the occlusion is imperative.

Vascular Bypasses and Grafts

• Vascular bypass surgery involves the use of either autografts or a synthetic graft material.
• The graft is anastomosed to the artery proximal to the occlusion and tunneled past the occlusion.

Endarterectomy

• Arteriosclerotic plaques are dissected from the lining of the arterial wall in a procedure called an endarterectomy.

Complications of Vascular Surgery

• Bleeding and hemorrhage can occur with any vascular surgery.
• Reocclusion is possible with any vascular surgery.
• Loss of a pedal pulse may signify reocclusion.

Nursing Process After Vascular Surgery

• Neurovascular checks are ordered every 15 minutes for the first 2 hours, then every 30 minutes for 1 to 3 hours, and then hourly for aortic or extremity vascular surgery.
• Neurovascular checks include extremity movement and sensation, presence of numbness or tingling, pulses, temperature, color, and capillary refill.

Lymphatic System

• The lymphatic system returns fluid from other tissues in the body to the bloodstream.
• Any interruption results in edema.
• Lymphangitis is inflammation of the lymphatic channels from and infection, causing painful red streaks.
• Fever and chills may be present.
• Treatment is with antimicrobials, moist heat, and elevation.