Coronary Artery Disease

IMAD THULTHEEN

KING SAUD UNIVERSITY

Arteriosclerosis

Arteriosclerosis - “hardening of the arteries”. Atherosclerosis – build up of plaque

(atheroma) on the lining of arteries. End results for both are the same

– Stenosis of the lumen of artery– Ulceration of plaque– Rupture of plaque with thrombus formation– Obstruction of blood flow– Ischemia of tissue distal to thrombus

Inflammatory response secondary to injury is mostly widely accepted theory for development of atherosclerosis.– Endothelial injury from shearing stresses,

radiation, chemicals, hyperlipidemia– Inflammatory response– Beginning of atheroma

Causes of Coronary Artery Disease

Atherosclerosis Vasospasm Thrombus or embolus

Non-modifiable Risk Factors Contributing To CAD

Heredity Increasing age Gender

Modifiable Risk Factors Contributing To CAD

Hypercholesterolemia - dyslipidemia– Measures to reduce cholesterol

• Diet – Therapeutic Lifestyle Changes Diet - total fat < 35%, 50-60% CHO, 15% protein, cholesterol < 200 mg, 20-30 gms fiber

• Exercise• Smoking cessation

• Medications» Drugs – pravastatin (Pravachol),

simvastatin (Zocor), atorvastatin (Lipitor), rosuvastatin (Crestor)

» Most commonly used to decrease LDL and triglycerides, and increase HDL

» Side effects – myopathy (weakness), hepatotoxicit

– Nicotinic acid (Vit B3)» Most effective in increasing HDL and

decreasing triglycerides» Side effects – flushing, hyperglycemia,

upper GI distress, hepatotoxicity, hyperuricemia

» Precautions – take with food, take at bedtime, or take ASA 325 mg 30 min before med

» Drugs – Niaspan, Niacin

– Fibric acid» Used to decrease triglycerides and

increase HDL» Side effects – GI distress, rash,

myopathy, increased risk of cholilithiasis, renal failure

» Precautions – can potentiate action of Coumadin

» Drugs – (Lopid) gemfibrozil

– Cholesterol Absorption Inhibitor» Inhibits absorption of cholesterol in

intestines» Decreases LDL & triglycerides,

increases HDL» Precautions – liver disease» Side effects – abdominal pain, arthralgia,

diarrhea, HA» Drugs - Zetia (ezetimibe), Vytorin (Zetia

& Zocor)

– Bile acid sequestrants (resins)» Decrease absorption of bile acids in

intestines» Effective in decreasing LDL and slightly

increasing HDL» Side effects – constipation, decreased

absorption of other meds, increased flatulence

» Drugs - -(Questran),

Hypertension Smoking

– Carbon monoxide displaces oxygen on Hgb

– Nicotinic acid triggers release of catecholamines

– Nicotine increases platelet aggregation

Diabetes Physical inactivity - beneficial effects of

exercise– Increases HDL– Decreases LDL, triglycerides, glucose– Increases insulin sensitivity– Decreases BP and body mass

Obesity

Metabolic syndrome Stress Elevated C-reactive protein (CRP)

Angina Pectoris

From Latin word meaning “to choke” Clinical syndrome characterized by

episodes of discomfort or pressure in the upper chest

Result of ischemia Atherosclerosis is most common cause

Factors Known To Precipitate Typical Angina

Physical exertion Exposure to cold Eating a heavy meal Stress or emotional situation

Various Classifications of Angina

Stable angina – classic angina Unstable angina – pre-infarction angina Variant angina – Prinzmetal’s angina

Clinical Manifestations of Typical Angina

Heaviness, squeezing, pressure, tightness in upper chest

Choking or smothering sensation Indigestion or gas Radiation to neck, jaw, shoulders and

arms

Feeling of weakness or numbness in arms, wrists or hands

Associated symptoms– Dyspnea– Diaphoresis– Dizziness– N/V– Anxiety

Diagnostic Findings With Angina

Diagnosis often made by evaluating clinical manifestations and history

12 lead ECG Stress test with or without nuclear scan

or ECHO Cardiac catheterization EBCT

Objectives of Medical Management of Angina

Decrease oxygen demands of myocardium or myocardial oxygen consumption

Increase oxygen supply

Treatment of Angina

Pharmacologic therapy Control risk factors Revascularization

– Invasive interventional procedures– Coronary artery bypass grafting (CABG)

Pharmacologic Therapies For Angina

Nitrates – mainstay of treatment– Dilate veins – decreases preload– Dilate arteries – decreases afterload as well as

dilates coronary arteries– Administer- spray, sublingually, PO, IV, topically– Side effects – hypotension, HA, flushing,

tachycardia– Ex: Nitrostat SL or Tridil (nitroglycerin), – Need a nitrate free interval– DO NOT administer with Viagra

Client teaching related to sublingual (SL) nitroglycerine (NTG)– Carry NTG on person at all times– Heat, light, and moisture cause NTG to

lose its potency. Store in original container.

– Renew every 6 months– Sit or lie down when taking– Take one tablet under tongue every 5 min

until angina relieved. If no relief after 3 tabs, call emergency

– May take immediately before activity causing angina

Beta blockers

– Reduce myocardial oxygen consumption by decreasing heart rate, contractility and blood pressure

– Caution client not to stop med abruptly; may cause rebound angina

– Monitor heart failure clients for worsening failure– Side effects – hypotension, bradycardia,

bronchial spasm, masks hypoglycemia– Ex: Lopressor or Toprol (metoprolol), Inderal

(propranolol), Tenormin (Atenolol)

Calcium channel blockers– Dilate arteries – decreases SVR which

decreases workload and O2 consumption– Decrease heart rate and myocardial

contractility – decreases O2 consumption– Avoid in clients with severe heart failure– Side effects - hypotension, bradycardia,

constipation, edema, AV blocks– Ex: Adalat or Procardia (nifedipine),

Cardene (nicardipine), Cardizem (diltiazem)

Antiplatelet medications– Prevent platelet aggregation on atheroma or

thrombus • ASA – side effects: GI irritation, bleeding,

increased bruising• Ticlid (ticlopidine) – side effects: neutropenia,

GI upset, N/V/D, rash. Must monitor CBC• Plavix (clopidogrel) – side effects: increased

bleeding tendencies, N/V/D, rash

Anticoagulants– Heparin

• Given IV in acute situations or subcutaneous in non-acute situations

• Monitor partial thromboplastin time (PTT) • Antidote – Protamine Sulfate• Observe bleeding precautions• Monitor for signs and symptoms of bleeding• Half-life of 1-2 hrs• Monitor for Heparin induced thrombocytopenia

(HIT)

– Coumadin (warfarin)• Used long term; given PO• Effects do not occur for 3-5 days• Monitor Prothrombin time (PT) or International

Normalized Ratio (INR)• Antidote – Vitamin K • Affected by certain foods• Contraindicated in pregnancy, clients with liver

dysfunction or those at risk for bleeding

Oxygen therapy– Administered usually at 2 L/min per nasal

cannula– Increases amount of O2 delivered to

myocardium

Nursing Interventions For Client With Angina

Treat pain – indicates ischemia– Instruct client to stop activities and sit or lie in

semi-Fowler’s position– Assess pain, monitor VS, observe for dyspnea– Administer O2 at 2L per NC if hospitalized– Obtain 12 lead ECG– Administer NTG - reassess client and vital signs

every 5 min.– Inform physician if pain severe or unrelieved

Reduce anxiety Teach self care

– Risk factor modification– Medications– When to call physician– When to call emergency

Invasive Intracoronary Interventions

Percutaneous Transluminal Coronary Angioplasty (PTCA)

Directional Coronary Atherectomy (DCA)

Laser ablation Intracoronary stent

Complications Related To Invasive Intracoronary Interventions

Dissection, perforation, abrupt closure, vasospasm

Acute MI Dysrhythmias Cardiac arrest

Restenosis of coronary artery Bleeding or hematoma formation Retroperitoneal bleeding Arteriovenous fistula Arterial thrombosis

Post Procedure Nursing Care

Achieve homeostasis after sheath removed

Frequent monitoring of VS and cath site for bleeding

Frequent monitoring of access limb for vascular problems

Administration of Heparin or platelet inhibitor ( Aggrastat) as ordered

Administration of IV NTG as ordered Bed rest with HOB elevated 30 degrees Keep access extremity straight Monitor for complications Force fluids

Coronary Artery Revascularization

Classic coronary artery bypass grafting (CABG)

Minimally invasive direct CABG – MIDCABG

Transmyocardial laser revascularization

Graft Selection For CABG

Greater saphenous vein Lesser saphenous vein Cephalic and basilic vein Internal mammary arteries Radial artery

Complications After CABG

Dysrhythmias Hemorrhage Fluid and electrolyte imbalances Respiratory dysfunction Wound infection and dehiscence

Thrombus and embolus Intra-operative stroke or MI Renal failure Multiple organ failure Death

Nursing Interventions Post CABG

Maintain patent airway Promote lung re-expansion Monitor cardiac status Monitor and maintain fluid and

electrolyte balance Monitor cerebral circulation

Provide pain relief Monitor GI function Monitor and prevent thrombophlebitis Monitor for dysrhythmias

Post operative education– Walking– Activity restrictions– Resumption of sexual activity– Wound cleaning– Symptoms to report to MD

Expected Outcomes

Relief of angina Decreased anxiety Absence of complications Verbalizes understanding of treatment

regimen Adheres to self-care program

Pathophysiology of Myocardial Infarction

Interruption of blood flow Ischemia develops Ischemia lasting greater than 20 min

results in infarction Acidosis in myocardial cells leads to

conduction disorders

Zones of damage– Zone of infarction– Zone of hypoxic injury– Zone of ischemia

Remodeling occurs

Depth Of Myocardial Infarction

Transmural infarction – Q wave MI or ST segment elevation MI (STEMI)

Subendocardial infarction – Non Q-wave MI or non-ST segment elevation MI (Non-STEMI)

Locations Of Myocardial Infarction

Anterior myocardial infarction (AMI)– From occlusion of LAD– Risk for failure, shock, conduction problems

Inferior myocardial infarction (IMI)– From occlusion of RCA– Risk for dysrhythmias due to effect on SA & AV

node Lateral infarction (LMI)

– From occlusion of LCX Posterior infarction (PMI)

– From occlusion of LCX or PDA

Clinical Manifestations Of An MI

Similar to unstable angina Discomfort not relieved with rest or 3

NTG Lasts longer then 20 min Sense of impending doom

Diagnostic Tests For MI

12 lead ECG Cardiac enzymes ECHO Cardiac catheterization

Major Goals For Care Of Client With MI

Initiate prompt care Minimize myocardial damage Manage complications Rehabilitate and educate client and

family

Provide Immediate Care To Client With Suspected MI

Keep client calm and quiet O2 per NC Assess VS Connect client to heart monitor

Perform 12 lead ECG Administer NTG Start IV lines, draw blood for labs Administer ASA

MONA Greets Everyone At The Door

MONA

Minimize Myocardial Damage

Interventions to reduce pain – indicates ischemia – O2

– Coronary vasodilators– Morphine sulfate– Beta blockers

Reperfuse coronary artery– Thrombolytics - lyse clots by converting

plasminogen to plasmin• Ex: Streptokinase, Urokinase, recombinant

tissue plasminogen activator (tPA) ie. Activase or Retavase

– Nursing interventions with thrombolytics• Minimize number of skin punctures• Avoid IM injections• Start at least 2 IV lines • Monitor for signs and symptoms of bleeding• Monitor for reperfusion dysrhythmias• Monitor for allergic reactions with Streptokinase• Treat bleeding with direct pressure and notify

physician

– ASA– Heparin– PCI

Reduce myocardial oxygen consumption or demand– Bed rest– Gradually increase activity. Rest 1hr after

meals. No isometric exercises or straining– ACE inhibitors– Beta blockers

Monitor For And Manage Complications

Dysrhythmias– Provide continuous cardiac monitoring– Assess client’s tolerance– Inform physician– Administer anti-dysrhythmics as ordered or

per protocol (Lidocaine, Atropine, Adenosine, Verapamil)

– Defibrillation– Temporary pacing

Cardiogenic shock – occurs due to loss of contractile forces in heart– Monitor for signs of shock– Improve cardiac output – positive inotropic

drugs (Inocor, Dobutamine, Dopamine) or IABP

Heart failure and pulmonary edema – may occur at onset of MI or later– Monitor for signs and symptoms– Monitor daily weights and I&O– May limit fluid intake 2000cc/24 hrs– Restrict diet to 2gm NA– Meds to tx: Lasix, ACE inhibitors, Lanoxin– For PE: high Fowler’s, O2, MS, Lasix

Pericarditis – inflamed area of MI rubs against pericardium causing loss of lubricating fluid– Monitor for chest pain that increases with

movement or deep inspiration– Monitor for pericardial friction rub– Administer anti-inflammatory agents –

Indocin (indomethacin), ASA, ibuprofen, steroids

– Administer analgesics

Dressler’s Syndrome – Form of pericarditis that occurs as late as 6

wks to months after MI– Treatment same as pericarditis

Complications Less Likely To Occur

Papillary muscle rupture– Monitor for new systolic murmur, heart failure– Emergency valve surgery required

Ventricular septal rupture– Monitor for new systolic murmur– Emergency surgical correction required

Cardiac rupture– Monitor for CP, hypotension, elevated JVD,

dyspnea– Death occurs

Educate and Rehabilitate Client and Family

Provide education on– Progressive activity guidelines– Diet– Medications– When to call EMS– Symptoms to inform physician of

Expected Outcomes

Relief of angina No signs of respiratory difficulties Adequate tissue perfusion Absence of complications Decreased anxiety Adherence to self-care program

Pacemaker

Provides an electrical stimulation to the atria or ventricles, or both, which causes contraction

Indications– SA node fails to fire or generates impulses too

slowly– Conduction system fails to conduct impulses

properly– Tachydysrhythmias that are unresponsive to meds

Time Frames For Pacemaker Use

Temporary Permanent

Pacemaker Design

Electronic pulse generator– Circuitry that senses

cardiac activity– Battery that

generates impulses

Lead wire– Flexible conductive

wire with electrode at end

– Relays cardiac info back to generator and delivers impulse to myocardium

Pacing Methods

Transcutaneous (External) pacing– Used in emergencies– Large amounts of energy needed to

traverse tissues to heart resulting in burns Epicardial (Transthoracic) pacing

– Generally used with open heart surgeries– Four electrodes attached to epicardium

Transvenous (Endocardial) pacing– Used in temporary and permanent

situations– Lead wires inserted into subclavian,

brachial, jugular, femoral vein– Temporary use – external generator– Permanent use – generator implanted

under skin

Pacemaker Modes

Fixed rate mode (asynchronous)– Set to fire continuously at preset rate– If fires during repolarization, can cause VT

or VF Demand mode

– Senses heart’s intrinsic activity– Fires only when heart rate fall below preset

rate

Complications Associated With Pacemaker Insertion

Infection Thrombophlebitis Bleeding or hematoma Ventricular dysrhythmias

Pneumothorax, hemothorax Lead displacement Pacemaker malfunction Stimulation of phrenic nerve or

diaphragm Cardiac tamponade

Nursing Care of Client Post Pacemaker Insertion

Monitor VS frequently Obtain chest x-ray Continuous ECG monitoring

Obtain 12 lead ECG with and without magnet if demand pacer

Monitor for infection at insertion site of pulse generator or leads

Exposed epicardial wires must be covered with nonconductive material

Avoid excessive extension or abduction of arm on operative site

Assess client for anxiety Assess and medicate for pain Elevate HOB Educate client and family on home care

Teaching For Client With Pacemaker

Assess wound daily and report any swelling, redness, warmth, drainage

Wear loose fitting clothes over generator Do not lift more than 5-10 lbs with affected

arm for 6 wks Do not raise elbow above shoulder or toward

back for 6 wks Check pulse daily for 1 minute. Report

decreases or increases

Report sensations of heart “racing’, beating irregularly, dizziness, fainting

Avoid strong electromagnetic fields Can safely use most appliances and

tools that are grounded Metal detectors may be triggered. Avoid

use of hand scanners over generator

Do not carry cell phone, turned on, directly over generator

Avoid contact sports Carry medical ID with pacer and

physician info Explain importance of pacer follow-up.

Generator will need to be changed out periodically

Implantable Cardiovertor Defibrillator (ICD)

Cardioverts/defibrillates lethal dysrhythmias

Can perform overdrive pacing or demand pacing

Inserted the same as permanent pacer Complications same as permanent

pacer