Cardio Patho 2

Angina Pectoris • severe pain riginating from the heart • inadequate oxygen supply to the myocardial cells. • pain of angina : radiate down the left arm, to the back, to the jaw, or into the abdominal area

• workload of any tissue increases  oxygen demand increase • Inc. oxygen demand increases  the coronary arteries dilate and bring more blood flow and oxygen to the muscle. • If the coronary arteries are stiffened or narrowed with atherosclerosis and cannot dilate in response to an increased demand for oxygen, myocardial ischemia (inadequate blood supply) occurs

• Anaerobic glycolysis • is very inefficient • production of lactic acid. • Lactic acid • decreases myocardial pH and causes the pain associated with angina pectoris.

• If the energy demands of the cardiac cells are lessened, the oxygen supply becomes adequate and the muscle cells revert to oxidative phosphorylation for energy production.

Types of Angina • There are three types of angina: • Stable • Prinzmetal's (variant) • Unstable.

Stable angina

• also called classic angina • occurs when atherosclerotic coronary arteries cannot dilate to increase flow when oxygen demand is increased.

• Increased work of the heart can accompany physical exercise such as sports participation or climbing stairs. • Exposure to the cold • increases the metabolic demands of the heart • a strong stimulator of classic angina.

Stable angina • Mental stress • anger • mental tasks such as mathematic . The pain of stable angina typically goes away when the individual stops the activity.

Prinzmetal's angina • without any obvious increase in the workload of the heart • during rest or sleep • a coronary artery undergoes a spasm • Sometimes the site of spasm is related to atherosclerosis. •

Prinzmetal's angina • damage to the endothelial layer may be present. • This allows vasoactive peptides access directly to the smooth muscle layer, causing its contraction. • Dysrhythmias are common with variant angina.

Unstable angina • combination of classic and variant angina • individual with worsening coronary artery disease. • accompanies an increased workload of the heart

• result from coronary atherosclerosis, characterized by a growing, spasm-prone thrombus. • Spasm occurs in response to vasoactive peptides released from platelets drawn to the area of damage

• The most potent constrictors released by the platelets are • Thromboxane • Serotonin • platelet-derived growth factors.

Clinical Manifestations • Constricting or squeezing pain in the pericardial or substernal area of the chest • radiating to the arms, jaw, or thorax. • Stable and unstable angina • pain is typically relieved by rest. • Prinzmetal's angina • unrelieved by rest • usually disappears in about 5 minutes.

Diagnostic Tools • Alteration in the ST segment of the ECG may occur. • Areas of reduced blood flow may be observed using radioactive imaging during an induced angina episode as part of an exercise stress test. • Cardiac enzymes and proteins may be measured to rule out MI.

Treatment • Prevention: • Aspirin is sometimes prescribed to prevent anginal symptoms. • Avoid stressors • They are strongly encouraged not to smoke.

Treatment • Invasive techniques • percutaneous transluminal coronary angioplasty (PTCA) • coronary artery bypass surgery • reduce episodes of classic angina.

Treatment • PTCA • the atherosclerotic lesion is dilated by a catheter inserted through the skin into the femoral or brachial artery and fed into the heart. • Once in the affected coronary vessel, a balloon in the catheter is inflated. • This cracks the plaque and stretches the artery

Treatment • Bypass surgery • the diseased piece of a coronary artery is tied off • an artery or vein taken from elsewhere in the body is connected to nondamaged areas. • Flow is reinstated through this new vessel. • saphenous vein and the internal mammary artery.

Treatment • Treatment is geared at reducing energy demands: • Rest • allows the heart to pump out less blood (decreased stroke volume) at a slower rate (decreased heart rate). • therefore its oxygen requirements. • Sitting is the preferable posture for rest, since lying down increases blood return to the heart, leading to increased end-diastolic volume, stroke volume, and cardiac output.

Treatment • Nitroglycerin and other nitrates • act as potent dilators of the venous system • decreasing venous return of blood to the heart • A decreased venous return decreases end diastolic volume, allowing the heart to decrease stroke volume. • Nitrates dilate the arterial system as well, reducing the afterload against which the heart must pump, and increasing coronary blood flow. •

Treatment • Beta-adrenergic blockers • reduce angina by reducing heart rate and contractility of the heart, thereby reducing its oxygen demands.

• Calcium channel blockers • reduce the afterload against which the heart must pump by dilating the arteries and arterioles downstream and are particularly effective in reducing the spasm of variant angina.. • Oxygen therapy eases demands on the heart.

Coronary Artery Anatomy

Myocardial Ischemia • Lack of blood flow in a coronary artery causes injury to the heart • Improvement in blood flow will reverse the injury

Myocardial Infarction • Prolonged lack of blood flow leads to death of myocardial cells • This is called a myocardial infarction (“heart attack in layman’s terms) • MIs are irreversible

Pathophysiology Risk Factors

Non-modifiable

Age, gender, race, heredity

Modifiable Stress, diet, sedentary living, Smoking, Alcohol, HPN, DM, Obesity, Contraceptive pills, Hyperlipidemia/hypercholesterolemia

Endothelial injury

Desquamation of endothelial lining (peeling off)

Increased permeability/ adhesion of molecules LDLs & platelets assimilate into the area Plaques begins to form Decreased coronary tissue perfusion Coronary ischemia Decreased myocardial oxygenation ANGINA PECTORIS

MYOCARDIAL INFARCTION

Risk factors for Coronary Artery Disease • • • • • • • • •

Age Gender Family history Hyperlipidemia Smoking Hypertension Diet Diabetes Obesity

Diagnosis of CAD • Patient History • • • •

Physical exam Lab studies Diagnostic studies Invasive studies

Symptoms Angina - classic description is a heavy, tight sensation under the sternum that is provoked with exertion Arm pain Jaw pain Indigestion Shortness of breath

Symptoms • • • • • •

Lightheadedness Palpitations Fear or dread Diaphoresis (sweating) Atypical (often in women) Cardiac arrest/Sudden death

Diagnosis

• Lab Studies

• Acute - infarcted heart cells release chemicals in blood stream: • Troponin • CPK isoenzyme

• Stable • Lipid studies • Blood glucose

Diagnosis • Acute - looks for specific changes • Stable - looks for signs of prior MIs

• Resting EKG

Diagnosis • Stress testing is used to evaluate patients for ischemia when they are stable • EKG tracings at rest are compared with those during taken during exercise

Diagnosis • Myocardial perfusion study- uses radioactive contrast in conjunction with a “stressor” medication

Diagnosis • Cardiac catheterization

Acute Treatment • • • • • •

Emergent care - cardiovascular resuscitation Oxygen Aspirin Nitrates Thrombolytic therapy (“clot busters”) Surgical management

Treatment • Balloon angioplasty

Treatment

• Coronary artery bypass grafting

Chronic Treatment Decrease Risk Factors Drugs that reduce clots: • Aspirin • Plavix

Drugs that reduce work on heart: • Nitrates (nitroglycerine) • Calcium channel blockers • Beta-blockers

Anti-lipid therapy

Buerger’s Disease • Also known as Thromboangiitis obliterans • Usually a disease of heavy cigarette smoker/tobacco user men • 25-40y/o • Inflammatory arterial disorder that causes thrombus formation often extends to adjacent veins & nerves http://nursinglectures.blogspot.co m

• Affects medium-sized arteries (usually plantar & digital vessels in the foot or lower legs) • unknown pathogenesis but it had been suggested that: • tobacco may trigger an immune response or • unmask a clotting defect; → these 2 can incite an inflammatory reaction of the vessel wall

Manifestations Pain – predominant symptom; R/T distal arterial ischemia  Intermittent claudication in the arch of foot & digits Increased sensitivity to cold (due to impaired circulation Absent/diminished peripheral pulses

Color changes in extremity (cyanotic on dependent position; digits may turn reddish blue) Thick malformed nails (chronic ischemia) Disease progression ulcerate tissues & gangrenous changes may arise; may necessitate amputation

Diagnosis & Treatment • Diagnostic methods – those that assess blood flow (Doppler ultrasound & MRI) • Tx: mandatory to stop smoking or using tobacco • Meds to increase blood flow to extremities • Surgery (surgical sympathectomy) • amputation

Rynaud’s Disease Mechanism: intensive vasospasm of arteries & arterioles in the fingers Cause: unknown Usually affects young women Precipitated by exposure to cold & strong emotions

• Raynaud’s phenomenon – associated with previous injury • Frostbite, occupational trauma associated with use of heavy vibrating tools, collagen diseases, neuro d/o, chronic arterial occlusive d/o)

Manifestations • Period of ischemia (ischemia due to vasospasm) • • • •

•

change in skin color = pallor to cyanotic 1st noticed at the fingertips later moving to distal phalanges Cold sensation Sensory perception changes (numbness & tingling)

Period of hyperemia – intense redness

• Throbbing • Paresthesia • of fingers (rare occasions)

http://nursinglectures.blogspot.co m

• Return to normal color • Note: although all of the fingers are affected symmetrically, only 1-2digits may be involved • Severe cases: arthritis may arise (due to nutritional impairment) • Brittle nails • Thickening of the skin of fingertips • Ulceration & superficial gangrene

Diagnosis & Treatment Dx: initial = based on Hx of vasospastic attacks  Immersion of hand in cold water to initiate attack aids in the Dx  Doppler flow velocimetry – used to quantify blood flow during temperature changes  Serial Computed thermography (finger skin temp) – for diagnosing the extent of disease

Tx: directed towards eliminating factors causing vasospasm & protecting fingers from injury during ischemic attacks  PRIORITIES: Abstinence in smoking & protection from cold

 Avoidance of emotional stress (anxiety & stress may precipitate vascular spasm)  Meds: avoid vasoconstrictors (i.e.. Decongestants) -Calcium channel blockers (Diltiazem, Nifedipine, ine Nicardipine) – decrease episodes of attacks

Care Plan for Clients with Altered Cardiovascular Oxygenation A. Assessment: 1. Hx of symptoms (pain, esp. chest pain; palpitations; dyspnea) 2. v/s B. Nursing Dx: 1. ineffective tissue perfusion (cardiopulmonary) 2. Impaired gas exchange 3. Anxiety due to fear of death (clients with MI or Angina) An

C. Goals: 1. Relief of pain & symptoms 2. Prevention of further cardiac damage D. Nursing Interventions: 1. Pain control 2. Proper medications 3. Decrease client’s anxiety 4. Health teachings (meds, activities, diet, exercise, etc)