Transcript Lecture 3 : Coronary Artery Disease

Coronary Artery Disease
IMAD THULTHEEN
KING SAUD UNIVERSITY
Arteriosclerosis
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Arteriosclerosis - “hardening of the arteries”.
Atherosclerosis – build up of plaque
(atheroma) on the lining of arteries.
End results for both are the same
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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
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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
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Atherosclerosis
Vasospasm
Thrombus or embolus
Non-modifiable Risk Factors
Contributing To CAD
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Heredity
Increasing age
Gender
Modifiable Risk Factors
Contributing To CAD
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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),
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Hypertension
Smoking
– Carbon monoxide displaces oxygen on
Hgb
– Nicotinic acid triggers release of
catecholamines
– Nicotine increases platelet aggregation
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Diabetes
Physical inactivity - beneficial effects of
exercise
– Increases HDL
– Decreases LDL, triglycerides, glucose
– Increases insulin sensitivity
– Decreases BP and body mass
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Obesity
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Metabolic syndrome
Stress
Elevated C-reactive protein (CRP)
Angina Pectoris
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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
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Physical exertion
Exposure to cold
Eating a heavy meal
Stress or emotional situation
Various Classifications of Angina
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Stable angina – classic angina
Unstable angina – pre-infarction angina
Variant angina – Prinzmetal’s angina
Clinical Manifestations of
Typical Angina
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Heaviness, squeezing, pressure,
tightness in upper chest
Choking or smothering sensation
Indigestion or gas
Radiation to neck, jaw, shoulders and
arms
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Feeling of weakness or numbness in
arms, wrists or hands
Associated symptoms
– Dyspnea
– Diaphoresis
– Dizziness
– N/V
– Anxiety
Diagnostic Findings With Angina
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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
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Decrease oxygen demands of
myocardium or myocardial oxygen
consumption
Increase oxygen supply
Treatment of Angina
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Pharmacologic therapy
Control risk factors
Revascularization
– Invasive interventional procedures
– Coronary artery bypass grafting (CABG)
Pharmacologic Therapies For
Angina
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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
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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
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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)
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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)
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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
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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
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Oxygen therapy
– Administered usually at 2 L/min per nasal
cannula
– Increases amount of O2 delivered to
myocardium
Nursing Interventions For Client
With Angina
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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
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Reduce anxiety
Teach self care
– Risk factor modification
– Medications
– When to call physician
– When to call emergency
Invasive Intracoronary
Interventions
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Percutaneous
Transluminal
Coronary
Angioplasty (PTCA)
Directional Coronary
Atherectomy (DCA)
Laser ablation
Intracoronary stent
Complications Related To Invasive
Intracoronary Interventions
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Dissection, perforation, abrupt closure,
vasospasm
Acute MI
Dysrhythmias
Cardiac arrest
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Restenosis of coronary artery
Bleeding or hematoma formation
Retroperitoneal bleeding
Arteriovenous fistula
Arterial thrombosis
Post Procedure Nursing Care
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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
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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
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Classic coronary artery bypass grafting
(CABG)
Minimally invasive direct CABG –
MIDCABG
Transmyocardial laser revascularization
Graft Selection For CABG
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Greater saphenous vein
Lesser saphenous vein
Cephalic and basilic vein
Internal mammary arteries
Radial artery
Complications After CABG
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Dysrhythmias
Hemorrhage
Fluid and electrolyte imbalances
Respiratory dysfunction
Wound infection and dehiscence
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Thrombus and embolus
Intra-operative stroke or MI
Renal failure
Multiple organ failure
Death
Nursing Interventions Post CABG
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Maintain patent airway
Promote lung re-expansion
Monitor cardiac status
Monitor and maintain fluid and
electrolyte balance
Monitor cerebral circulation
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Provide pain relief
Monitor GI function
Monitor and prevent thrombophlebitis
Monitor for dysrhythmias
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Post operative education
– Walking
– Activity restrictions
– Resumption of sexual activity
– Wound cleaning
– Symptoms to report to MD
Expected Outcomes
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Relief of angina
Decreased anxiety
Absence of complications
Verbalizes understanding of treatment
regimen
Adheres to self-care program
Pathophysiology of
Myocardial Infarction
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Interruption of blood flow
Ischemia develops
Ischemia lasting greater than 20 min
results in infarction
Acidosis in myocardial cells leads to
conduction disorders
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Zones of damage
– Zone of infarction
– Zone of hypoxic injury
– Zone of ischemia
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Remodeling occurs
Depth Of Myocardial Infarction
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Transmural infarction – Q wave MI or
ST segment elevation MI (STEMI)
Subendocardial infarction – Non Qwave MI or non-ST segment elevation
MI (Non-STEMI)
Locations Of Myocardial Infarction
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Anterior myocardial infarction (AMI)
– From occlusion of LAD
– Risk for failure, shock, conduction problems
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Inferior myocardial infarction (IMI)
– From occlusion of RCA
– Risk for dysrhythmias due to effect on SA & AV
node
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Lateral infarction (LMI)
– From occlusion of LCX
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Posterior infarction (PMI)
– From occlusion of LCX or PDA
Clinical Manifestations Of An MI
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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
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12 lead ECG
Cardiac enzymes
ECHO
Cardiac catheterization
Major Goals For Care Of Client
With MI
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Initiate prompt care
Minimize myocardial damage
Manage complications
Rehabilitate and educate client and
family
Provide Immediate Care To Client
With Suspected MI
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Keep client calm and quiet
O2 per NC
Assess VS
Connect client to heart monitor
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Perform 12 lead ECG
Administer NTG
Start IV lines, draw blood for labs
Administer ASA
MONA Greets Everyone At The
Door
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Minimize Myocardial Damage
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Interventions to reduce pain – indicates
ischemia
– O2
– Coronary vasodilators
– Morphine sulfate
– Beta blockers
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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
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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
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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
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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
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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
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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
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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
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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
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Papillary muscle rupture
– Monitor for new systolic murmur, heart failure
– Emergency valve surgery required
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Ventricular septal rupture
– Monitor for new systolic murmur
– Emergency surgical correction required
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Cardiac rupture
– Monitor for CP, hypotension, elevated JVD,
dyspnea
– Death occurs
Educate and Rehabilitate Client and
Family
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Provide education on
– Progressive activity guidelines
– Diet
– Medications
– When to call EMS
– Symptoms to inform physician of
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Expected Outcomes
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Relief of angina
No signs of respiratory difficulties
Adequate tissue perfusion
Absence of complications
Decreased anxiety
Adherence to self-care program
Pacemaker
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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
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Temporary
Permanent
Pacemaker Design
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Electronic pulse
generator
– Circuitry that senses
cardiac activity
– Battery that
generates impulses
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Lead wire
– Flexible conductive
wire with electrode at
end
– Relays cardiac info
back to generator
and delivers impulse
to myocardium
Pacing Methods
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Transcutaneous (External) pacing
– Used in emergencies
– Large amounts of energy needed to
traverse tissues to heart resulting in burns
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Epicardial (Transthoracic) pacing
– Generally used with open heart surgeries
– Four electrodes attached to epicardium
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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
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Fixed rate mode (asynchronous)
– Set to fire continuously at preset rate
– If fires during repolarization, can cause VT
or VF
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Demand mode
– Senses heart’s intrinsic activity
– Fires only when heart rate fall below preset
rate
Complications Associated With
Pacemaker Insertion
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Infection
Thrombophlebitis
Bleeding or hematoma
Ventricular dysrhythmias
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Pneumothorax, hemothorax
Lead displacement
Pacemaker malfunction
Stimulation of phrenic nerve or
diaphragm
Cardiac tamponade
Nursing Care of Client Post
Pacemaker Insertion
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Monitor VS frequently
Obtain chest x-ray
Continuous ECG monitoring
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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
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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
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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
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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
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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)
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Cardioverts/defibrillates lethal
dysrhythmias
Can perform overdrive pacing or
demand pacing
Inserted the same as permanent pacer
Complications same as permanent
pacer