Chapter 23 Med Surge Summer Exam 3
Coronary Artery Disease: CAD
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Is the most prevalent type of cardiovascular disease in adult
Coronary Atherosclerosis:
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Most common cause of cardiovascular disease
Is an abnormal accumulation of lip or fatty substances, and fibrous tissue in the lining of arterial blood vessels
walls
Block/narrow the coronary vessels and reduces blood flow to the myocardium
Involves a repetitious inflammatory response to injury of the artery wall and alteration in the
structural/biochemical properties of the arterial walls
Pathophysiology:
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Inflammatory response involved w/the development of atherosclerosis begins w/injury to the vascular
endothelium and progresses over may years
May be initiated by smoking/tobacco use, HTN, hyperlipidemia
Endothelium stops producing the normal antithrombotic and vasodilating agents
Heart disease is most often caused by atherosclerosis
Clinical Manifestations:
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CAD produces symptoms/complications according to the location/degree of narrowing of the arterial lumen,
thrombus formation, and obstruction of blood flow to the myocardium
Impediment to blood flow is usually progressive, causing inadequate blood supply that deprives cardiac muscle
cells of oxygen
Ischemia Angina Pectoris = chest pain that is brought by myocardial ischemia
o Usually is caused by significant coronary atherosclerosis
A decrease in blood supply from the CAD may cause the heart to abruptly stop beating = sudden cardiac death
Most common manifestation of myocardial ischemia:
o Onset of chest pain
o Unstable angina, MI, sudden cardiac death events
o HX of diabetes or heat failure, SOB, indigestion, nausea, palpitations, numbness
o A major cardiac even may be the first indication of coronary atherosclerosis
o Angina may present a few hours/days before an acute episode
Risk Factors:
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Elevated LDL
Diabetes
Peripheral arterial disease
Abdominal aortic aneurysm
Carotid artery disease
Age, gender, systolic blood pressure, smoking history, level of total cholesterol, and level of HDL
Metabolic syndrome
o Enlarged waist circumference (greater than 35.4 (M) 31.4 (F)
o Elevated triglycerides (> or = to 175mg/dL)
o Reduced HDL (<40mg/dL (M), <50mg/dL (F))
o Hypertension (systolic > 130 and/or diastolic > or = to 80 on average of 2-3 measurements on 2-3
separate occasions)
o Elevated fasting glucose (> or = to 100 on 2 separate occasions)
o Type 2 diabetes
Nonmodifiable Risk Factors
o Family HX of CAD (1st degree relative)
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o Increasing age
o Gender
o HX of premature menopause (before 40) history of pregnancy-associated disorders (preeclampsia)
o Primary hypercholesterolemia (elevated LDL)
Modifiable Risk Factors
o Hyperlipidemia
o Tobacco use
o Hypertension
o Diabetes
o Metabolic syndrome
o Obesity
o Physical inactivity
o Chronic inflammatory conditions (RA, lupus, HIV/AIDS)
o Chronic kidney disease
Prevention:
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4 modifiable risk factors
o Cholesterol, tobacco, hypertension, diabetes
Cholesterol lowering dietary changes
o Mediterranean diet
o Increased consumption of fruits, vegetables, whole-grains, beans, nuts, and seeds
o Limit sweets/sugar sweetened beverages
o Vegetarian diet
Physical Activity
o Regular moderate physical activity
o Moderate aerobic activity of at least 150min per week or vigorous aerobic activity at least 75min per
week or combination of the two
Medications
o Statins, fibric acids (fibrates), bile acid sequestrants (resins), cholesterol absorption inhibitors, and
proprotein convertase subtilisin-kexin type 9 (PCSK9)
Tobacco use
o Nicotinic acid raise HR/BP, coronary artery constriction
o Increase oxidation of LDL (higher probability of thrombus formation)
o Inhalation of smoke increased the blood carbon monoxide levels decreasing the supply of oxygen
HTN
o Systolic greater than 130 and diastolic greater than 80
o Cardiovascular disease increases as BP increases
Diabetes
o Known to accelerate the development of heart disease
o Hyperglycemia fosters dyslipidemia (increased platelet aggregation) and altered red blood cell function
which can lead to thrombus formation
o Insulin, metformin can lead to improved endothelial function/outcomes
Angina Pectoris:
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Clinical syndrome usually characterized by episodes/paroxysm of pain or pressure in the anterior chest
Cause is insufficient coronary blood flow, decreased oxygen supply when there is increased myocardial demand
for oxygen in response to physical exertion or emotional stress
o Need for oxygen exceeds supply
Usually caused by atherosclerotic disease and obstruction of at least one major artery
Angina pain factors
o Physical exertion
o Exposure to cold
o Eating a heavy meal
o Stress or any emotion-provoking situation
Clinical manifestations:
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Mild indigestion to choking or heavy sensation on the upper chest
Severity ranges from discomfort to agonizing pain
Pain may be accompanied by severe apprehension and a feeling of impending death
Felt deep in the chest behind the sternum (retrosternal area)
Pain/discomfort is poorly localized, may radiate to the neck, jaw, shoulders, and inner upper arms, usually the
left arm
Patient w/diabetes may not have severe pain w/angina due to autonomic neuropathy
Feeling of weakness/numbness in the arms/wrists/hands w/SOB , pallor, diaphoresis, dizziness or
lightheadedness, nausea/vomiting (may occur)
Pain subsides w/rest or admin of nitroglycerin
Unstable angina increase in frequency/severity and are not relieved by rest and nitroglycerin admin. (require
medical intervention)
Gerontologic:
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Older adults may not exhibit typical pain profile due to diminished pain transmission
Presenting symptom in older adults is dyspnea
Sometimes no symptoms present (“silent” CAD)
Should recognize chest pain-like symptom (weakness) as a sign to rest or take prescribed meds
Pharmacologic stress testing and cardiac catheterization may be used to diagnose CAD in older patients
Assessment/Diagnostic Findings:
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Begins w/patient’s history related to the clinical manifestations of ischemia
12-lead ECG shows changes indicative of ischemia (T wave inversion, ST segment elevation or abnormal Q wave)
Labs: cardiac biomarker testing to rule out ACS
Exercise or pharmacologic stress test
Nuclear scan or invasive cardiac catheterization, coronary angiography
Medical management: objective is to decrease the oxygen demand of the myocardium and to increase the oxygen
supply
Pharmacologic Therapy:
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Nitroglycerin
o Nitrates are standard treatment for angina pectoris
o Is a potent vasodilator (improves blood flow to heart muscles/relieves pain)
o Dilates the veins and lesser extent the arteries
o Dilation of the veins causes pooling of blood throughout the body
 Less blood returns to the heart preload is reduced
o Relax systemic arteriolar bed, lowering BP and decreasing afterload
 Decrease myocardial oxygen requirements
 Equalizes supply/demand
o Routes: oral, topical, sublingual, IV
Beta-Adrenergic Blocking Agents
o Metoprolol reduce myocardial oxygen consumption by blocking beta-adrenergic sympathetic
stimulation to the heart
o Reduction of HR, slowed conduction of impulses, decreased BP, reduced myocardial contractility (force
of contraction) and amount of oxygen available (supply)
o Helps control chest pain/delays onset of ischemia during work or exercise
o Reduce the incidence of recurrent angina, infarction, and cardiac mortality
o Side effects/contraindications
 Hypotension, bradycardia, advanced atrioventricular block, acute heart failure
 Depressed mood, fatigue, decreased libido, dizziness
 If Given IV MX ECD/BP/HR
Calcium Channel Blocking Agents:
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Decrease sinoatrial node automaticity/atrioventricular node conduction
o Slower HR/decrease in strength of myocardial contraction (negative inotropic effect)
Increase myocardial oxygen supply by dilating smooth muscle wall of the coronary arterioles
Decrease myocardial oxygen demand by reducing systemic arterial pressure and workload of the left ventricle
Most common
o Amlodipine and diltiazem
o Used for angina and hypertension
ACS (acute coronary syndrome): is an emergent situation characterized by an acute onset of myocardial ischemia that
results in myocardial death (MI) if interventions do not occur promptly
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Pathophysiology
o Unstable angina
 Reduced blood flow in a coronary artery – rupture of an atherosclerotic plaque
 Clot begins to form on top of the coronary lesion (artery not completely occluded)
 Can result in chest pain/other symptoms (preinfarction angina)
 Patient will have an MI if prompt interventions do not occur
o MI
 Plaque rupture/subsequent thrombus formation result in complete occlusion of the artery
 Leading to ischemia and necrosis of the myocardium supplied by the artery
 Vasospasm (sudden constriction/narrowing) of a coronary artery, decreased oxygen supply
(acute blood loss, anemia or low BP), increased demand for oxygen (rapid HR, thyrotoxicosis,
ingestion of cocaine), are other causes of MI
 A profound imbalance exist between myocardial oxygen supply and demand
o Area of infarction develops over minutes to hours
o “Time is muscle” reflects the urgency of appropriate treatment to improve patient outcomes
o Descriptions used for MI ID
 NSTEMI, STEMI, location (anterior, inferior, posterior, or lateral wall), point in time w/in the
process of infarction (acute, evolving, or old)
 Differentiation between NSTEMI AND STEMI is determined by diagnostic tests
 12-lead ECG IDs the type/location of the MI
 Q wave, patient history, identify timing
o Goals are to relieve symptoms, prevent or minimize myocardial tissue death, and prevent complications
Manifestations
o Chest pain that occurs suddenly/continues despite rest/meds
o SOB, indigestion, nausea, anxiety, cool, pale and moist skin
o HR/RR may be increased
Assessment/Diagnostic Findings
o Is generally based on the presenting symptoms
 12-lead ECD/labs (serial cardiac biomarkers) used to clarify if patient has unstable angina,
NSTEMI, or STEMI
 Prognosis depends on the severity of coronary artery obstruction and the presence/extent of
myocardial damage
 Physical exam is always conducted
o Cardiac enzymes/biomarkers
 Troponin, creatine kinase (CK), myoglobin
 Used to diagnose an acute MI
 Troponin regulates the myocardial contractile process (C, I, T)
 Increased troponin levels can be detected w/in a few hours during acute MI, remains
elevated for as long as 2 weeks
o Levels may rise w/inflammation/other mechanical stress on the myocardium
(sepsis, HF, resp. failure)
o Patient history
 Description of the presenting symptoms, history of previous cardiac/other illnesses, family
history of heart disease, and risk factors for heart disease
Treatment Guidelines for Acute MI:
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Use rapid transit to the hospital
obtain 12 lead electrocardiogram to be read within 10 minutes
obtain laboratory blood specimens of cardiac biomarkers including troponin
obtain other diagnostics to clarify the diagnosis
began routine medical interventions
o supplemental oxygen
o nitroglycerin
o morphine
o aspirin
o beta blocker
o angiotensin converting enzyme inhibitor within 24 hours
o Statin
evaluate for indications for reperfusion therapy:
o percutaneous coronary intervention
o thrombolytic therapy
continue therapy as indicated
o Ivy heparin, low-molecular-wait heparin, bivalirudin, or fondapariunux
o Clopidogrel
o Bed Rest for a minimum of 12 to 24 hours
o statin prescribed at discharge
S/S: MI
Angina Pectoris or MI:
Areas of Damage: MI
Percutaneous Coronary Interventions: PTCA – percutaneous transluminal coronary angioplasty
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A balloon tip catheter is used to open blocked coronary vessels and resolve ischemia
it is used in patients with angina and as an intervention for ACS
catheter based interventions can also be used to open blocked CABGs
let's see purpose is to improve blood flow within the coronary artery by compressing the atheroma
PTCA Is carried out in the cardiac catheterization laboratory
hollow catheters called sheaths are inserted usually in the femoral or radial artery Providing the conduit for
other catheters
angiography is performed using injected radiopaque contrast agents commonly called dye to identify the
location extent of the blockage
a balloon tip dilation catheter is passed through the sheath and positioned over the lesion
the balloon is then inflated with high pressure for several seconds and then deflated
o this pressure compresses and often cracks the atheroma
o Several inflations of balloons of different sizes may be needed to achieve the goal of improved blood
flow
Intracoronary stents are usually positioned in the intima of the vessel to maintain patency of the artery after the
balloon is withdrawn
Coronary Artery Stents:
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After PTCA the area that has been treated may close off partially or completely - a process called restenosis
The intima of the coronary artery has been injured and responds by initiating an acute inflammatory process
process may include release of mediators that leads to vasoconstriction, clotting, and scar tissue formation
o a coronary artery stent may be placed to overcome these risks
a stent is a metal mesh that provides structural support to a vessel at risk of acute closure
o the stent is initially positioned over the angioplasty balloon
o when the balloon is inflated the mesh expands and presses against the vessel wall holding the artery
open
o the balloon is withdrawn but the stent is left permanently in place within the artery
o endothelium covers the stent and is incorporated into the vessel wall
Complications:
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Complications during a PCI procedure include coronary artery dissection, perforation, abrupt closure, or
vasospasm
o acute MI, serious arrhythmias (ventricular tachycardia), and cardiac arrest
o some complications may require emergency surgical treatment
complications after the procedure may include abrupt closure of the coronary artery and a variety of vascular
complications such as bleeding at the insertion site, retroperitoneal bleeding, hematoma and arterial occlusion
o Additionally there is a risk of acute kidney injury from the contrast agent used during the procedure
Post Procedure Care:
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Patients who are not already hospitalized are admitted the day of the PCI
o if no complications arise patient can go home the same day
when the PCI is performed emergently to treat ACS patients typically go to a critical care unit and stay in the
hospital for a few days
during the PCO patients receive Ivy heparin or a thrombin inhibitor and are monitored closely for signs of
bleeding
help me your stasis is achieved and femoral sheaths may be removed at the end of the procedure by using a
vascular closure device or a device that sutures the vessels
o homeostasis after sheath removal may also be achieved by direct manual pressure, and mechanical
compression device, or a pneumatic compression device
patients may return to the nursing unit with a large peripheral vascular access sheath in place
the sheets are then removed after blood studies (activated clotting time) indicate that the heparin is no longer
active and the clotting time is within an acceptable range
o this usually takes a few hours depending on the amount of heparin given during the procedure
o the patient must remain flat in bed and keep the affected leg straight until the sheets are removed and
then for a few hours afterward to maintain homeostasis
o she's removal and the application of pressure on the vessel insertion site may cause the heart rate to
slow and the blood pressure to decrease (vasovagal response)
 a dose of IV atropine is usually given to treat this response
o after homeostasis is achieved, a pressure dressing is applied to the site
 patients resumed self-care and ambulate unassisted within a few hours of the procedure
coronary artery revascularization:
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coronary artery bypass graft (CABG) is a surgical procedure in which a blood vessel is grafted to an occluded
coronary artery so that blood can flow beyond the occlusion; it is also called a bypass graft
o major indications for CABG
 alleviation of angina that cannot be controlled with medication or PCI
 treatment for left main coronary artery stenosis or multivessel CAD
 prevention of and treatment for MI, arrhythmias, or heart failure
 treatment for complications from an unsuccessful PCI
o the recommendation for CABG it's determined by the number of disease coronary vessels, the degree of
left ventricular dysfunction, the presence of other health problems, the patient symptoms and any
previous treatment
o CABG is performed less frequently in women compared to men
for a patient to be considered for CABG the coronary arteries to be bypassed must have at least a 70% occlusion
or at least 50% occlusion in the left main coronary artery
o if the blockage is not significant flow through the artery will compete with flow through the bypass and
circulation to the ischemic area of myocardium may not improve
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CABG procedures are performed with the patient under general anesthesia
o the surgeon performs a median sternotomy and connects the patient to the cardiopulmonary bypass
machine
o a blood vessel from another part of the patients body is grafted distal to the coronary artery lesion,
bypassing the obstruction
o CPB is then disconnected, chest tubes and epicardial pacing wires are placed, and the incision is closed
o patient is then admitted to the critical care unit
Cardiopulmonary Bypass:
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CPB maintains perfusion to body organs and tissues and allows the surgeon to complete the anastomoses in a
motionless, bloodless surgical field
CPB is accomplished by placing the cannula in the right atrium, vena cava, or femoral vein to withdraw blood
from the body
o the cannula is connected to tubing filled with an isotonic crystalloid solution
o venous blood removed from the body by the cannula is filtered, oxygenated, cooled or warmed by the
machine, and then return to the body
o the cannula used to return the oxygenated blood is usually inserted in the ascending aorta, or it may be
inserted in the femoral artery
o the hardest stop by the injection of a potassium rich cardioplegia solution into the coronary arteries
o the patient receives heparin to clotting and thrombus formation in the bypass circuit when blood comes
in contact with the surfaces of the tubing
o at the end of the procedure when the patient is disconnected from the bypass machine, protamine
sulfates is given to reverse the effects of heparin
o during the procedure, hypothermia is maintained at a temperature about 82.4◦F
patients are frequently admitted to the hospital the day of the procedure
nursing and medical personnel perform a history and physical examination
o preoperative testing consists of a chest X ray; ECG; laboratory tests, including coagulation studies; And
blood typing and crossmatching health assessment focuses on obtaining baseline physiologic,
psychological, and social information
o cognitive status is carefully assessed, as patients with impaired cognitive status will need more
assistance after surgery and may require sub acute care prior to returning home
o the patient usual functional level, coping mechanisms, and available support systems, affect the patient
post operative course, discharge plans, and rehabilitation
o status of the cardiovascular system is determined by reviewing the patient symptoms, including past
and present experiences with chest pain, palpitations, dyspnea, intermittent claudication and peripheral
edema
initial postoperative care focuses on achieving or maintaining hemodynamic stability and recovery from general
anesthesia
o care may be provided in the post anesthesia care unit (PACU) or ICU
when the patient is admitted to the critical care unit or PACU, a complete assessment of all systems are done at
least every four hours
o Nora logical status: level of responsiveness, pupil size and reaction to light, facial symmetry comment
movement of the extremities, and hand grip strength
o cardiac status: heart rate and rhythm, heart sounds, pacemaker status, arterial blood pressure, central
venous pressure; in some patients hemodynamic parameters: pulmonary artery pressure, pulmonary
artery wedge pressure, cardiac output and index, systemic and pulmonary vascular resistance, mixed
venous oxygen saturation
 a pulmonary catheter is often used to monitor these parameters
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respiratory status: chest movement, breast sounds, ventilator settings, respiratory rate, peak inspiratory
, percutaneous oxygen saturation, intitle carbon dioxide, pleural chest tube drainage, arterial blood
gases
o peripheral vascular status, peripheral pulses (color of skin, nailbeds, mucus, lips, and earlobes) skin
temperature, edema, condition of dressings and invasive lines
o renal function: urinary output, serum creatinine and electrolytes
o fluid and electrolytes status: strict intake and output, including all IV fluids and blood products, output
from all drainage tubes, clinical and laboratory indicators of imbalance
o pain: nature, type, location, and duration, apprehension, response to analgesics
assessment also includes checking all equipment and tubes to ensure that they are functioning properly
as the patient regains consciousness and progresses through the post operative period The nurse also assesses
indicators of psychosocial and emotional status
family needs must be assessed, the nurse ascertains how family members are coping with the situation,
determines their psychosocial, emotional, and spiritual needs, and finds out whether they are receiving
adequate information about the patient's condition
decrease cardiac output is always a threat two patients who have received cardiac surgery
o excessive post operative bleeding can lead to decreased intravascular volume, hypo tension, and low
cardiac outputs
o bleeding problems are common after cardiac surgery because of the facts of CPB, trauma from the
surgery, and anticoagulation
preload can also decrease if there is a collection of fluid and blood in the pericardium, which impedes cardiac
filling
cardiac output is also altered if too much volume returns to the heart, causing fluid overload
o afterload alterations occur when the arteries are constricted as a result of postoperative hypertension
or hypothermia, increasing the workload of the heart
possible complications after cardiac surgery
o fluid volume and electrolyte imbalances
o impaired gas exchange
o decrease cardiac output
o impaired cerebral circulation