Week 8: Chp 30: Coronary Artery Disease Flashcards
When does Coronary Artery Disease Occur?
occurs when the blood vessels that deliver oxygen-rich blood to the heart muscle become obstructed or dysfunctional
Coronary Artery Disease is also known as?`
-coronary heart disease
-or ischemic heart disease
>most common cause of heart disease
Modifiable Risk Factors
amenable to intervention
- cigarette smoking
- high total cholesterol, high LDL level, low HDL levels and high triglycerides
- hypertension
- diabetes (hyperglycemia)
- obesity, partially central obesity
- sedentary lifestyle/ physical inactivity
- stress
- excessive alcohol consumption
- hyperlipidemia (high level of fats)
Non-modifiable Risk Factors
not-amenable to intervention
- gender
- race
- age older than 45 for men (increases with age)
- genetics/ family history
- being postmenopausal
What is Coronary Artery Disease? (pathophysiology)
CAD is characterized by the obstruction of blood flow within the coronary arteries
- atherosclerosis, or plaque within the lumen of the vessel, is the principle cause of obstruction to blood flow
- the arterial wall is made up of 3 layers and this is how CAD starts (from atherosclerosis starting in the tunica intima layer)
- can be obstructive or non-obstructive
3 Layers of the arterial wall
- tunica intima
- tunica media
- tunica adventitia
Layer of the arterial wall: Tunica intima
- composed of endothelium and basement membrane
- atherosclerosis begins with an injury to the endothelium that causes an inflammatory response
- that inflammatory response initiates a series of specific cellular and molecular reactions that lead to the accumulation of atherosclerotic plaque
Formation of atherosclerosis starting in the tunica intima layer of the arterial wall; can result in CAD
atherosclerosis begins with an injury to the endothelium that causes an inflammatory response
-low-density lipoprotein (LDL) enters the tunica intima layer of the arterial wall and becomes trapped
-inside the tunica intima layer, the trapped LDL is modified through the process of oxidation
-once modified, the LDL attracts macrophages, which absorb the LDL to become foam cells; fatty streaks within the tunica intima are an accumulation of foam cells
-as the process continues, various components in the blood such as macrophages, calcium, and cholesterol, adhere to the injured part of the vessel forming plaque
-the plaque deposits increase in size over time, causing narrowing of the coronary arteries, which impedes oxygen rich blood flow to the heart
>when the heart muscle does not get enough oxygen and nutrients to meet its demands, myocardial ischemia results (pathology known as obstructive coronary artery disease)
When the heart muscle does not get enough oxygen and nutrients to meet its demands, what results?
myocardial ischemia (pathology known as obstructive coronary artery disease)
What is the principle cause to the obstruction of blood flow?
atherosclerosis (plaque; within the lumen of the vessel)
Most dangerous complication in the development of atherosclerosis?
potential plaque rupture
- when this occurs, platelets aggregate on the ruptured plaque surface; the coagulation cascade is initiated, and thrombus formation is stimulated
- this clotting further decreases or obstructs blood flow altogether, leading to unstable angina, myocardial infarction (MI), or sudden cardiac death
Nonobstructive coronary artery disease
do not have significant plaque that occludes the coronary arteries
- ischemic symptoms are caused by reduced blood flow through the coronary microvascular system
- the microvascular system is not able to dilate in response to the myocardial demand for oxygen or may have stenosis
- have similar symptoms to obstructive coronary artery disease
When do Clinical Manifestations happen?
virtually silent until the artery is approximately 40% blocked by plaque in obstructive disease
- ischemia develops when there is an imbalance between supply and demand of oxygen-rich blood to the heart tissue, resulting in insufficient oxygen to meet the demands of the myocardial tissue
- infarction, or cell death, occurs when that imbalance is severe or prolonged which causes irreversible damage
What develops as a result of a imbalance between supply and demand of oxygen-rich blood to the heart tissue, resulting in insufficient oxygen to meet the demands of the myocardial tissue?
ischemia
What develops as a result of severe or prolonged imbalance between supply and demand of oxygen rich blood to the heart?
infarction, or cell death
-can cause irreversible damage
Clinical Manifestations
Chest Pain (Angina); classified as stable or unstable
- ischemia
- infarction
Stable Angina
chest pain or discomfort that is associated with physical activity
- linked to fixed plaque formations and is predictable
- symptoms often alleviated with rest and/or medications
- nitrates such as nitroglycerin that dilate the coronary arteries, improving oxygen rich blood flow to the heart, are usually prescribed for angina
How to usually treat Stable Angina?
- symptoms alleviated with rest and/or medications
- nitrates such as nitroglycerin that dilate the coronary arteries, improving oxygen rich blood flow to the heart, are usually prescribed
Unstable Angina
chest pain that can occur at rest
- most concerning
- identified as initial phase of acute coronary syndrome (ACS)
- precursor to MI and should be treated as an emergency
- usually prolonged and may not be relieved with medication or rest
Acute Coronary Syndrome (ACS)
a disorder caused by an acute decrease in blood flow through the coronaries to the myocardial tissue
- unstable angina is the initial phase of ACS
- primary complication of CAD
- includes unstable angina and MI
What is a variation of Unstable Angina?
Prinzmetal’s (or variant) Angina
Prinzmetal’s (or variant) Angina
a variation of unstable angina
- the blockage of blood flow in this disorder is caused by coronary artery spasm rather than plaque formation
- occurs at rest and in clusters
- normally occurs at night between midnight and 8 a.m.
Symptoms that may accompany Angina (chest pain)
- angina may radiate to the left arm, back, neck, and jaw
- chest pressure
- shortness of breath or dyspnea
- fatigue
- nausea
- vomiting
- diaphoresis
- weakness
- syncope
- and epigastric discomfort
Non-ischemic causes of chest pain (not associated by cardiac ischemia)
aortic dissection, pericarditis, gallbladder disease, pleuritic pain, pulmonary embolism, pneumonia, and gastroesophageal reflux disease
Diagnosis
diagnosis is made on the basis of clinical presentation and diagnostic findings
- CAD is suspected only when the person presents with clinical symptoms (formation of plaque is a silent process)
- timely recognition is essential
Diagnostic Tests
- gold standard is coronary angiography
- blood tests
- electrocardiogram (ECG)
- Exercise stress test
- CT angiography, MRI, and stress imaging techniques
Gold standard for diagnosing CAD
Coronary Angiography
Coronary Angiography
gold standard for diagnosing CAD
- a left-sided cardiac catheterization with the purpose of evaluating the coronary arteries for blockage
- performed to determine the location of the plaque within the coronary circulation, the degree of occlusion and whether the area can be treated with percutaneous transluminal coronary angioplasty (PTCA)
Blood Tests Performed
assess for presence of risk factors for CAD
- lipid profiles, inflammation, and coagulation studies
- lipid profiles evaluate total cholesterol and triglyceride levels as well as LDL and HDL
- Specific cardiac biomarkers are used to rule out MI; Creatinine Kinase (CK) or creatinine kinase-muscle/brain (CK-MB) and troponin levels rise when myocardial injury occurs and are used to identify when ischemia has led to tissue damage
What do lipid profiles evaluate?
total cholesterol, triglyceride levels, LDL, and HDL
What Specific biomarkers are used to rule out MI?
Creatine Kinase (CK), creatinine kinase- muscle/brain (CK-MB) and troponin levels
- these levels rise when myocardial injury occurs and are used to identify when ischemia has led to tissue damage
- because these markers do not immediately rise with chest pain, they are measured every 6 hours after admission to the hospital to evaluate chest pain (known as serial cardiac enzyme or biomarker testing)
Serial Cardiac Enzyme or Biomarker Testing
because MI markers such as Creatinine-kinase (CK), Creatinine kinase- muscle/brain (CK-MB), and troponin do not immediately rise with chest pain, they are measured every 6 hours after admission to the hospital to evaluate chest pain
Diagnostic Test: Electrocardiogram (ECG)
initial test when CAD is expected
- during anginal episodes or symptoms of ACS, the ECG may show ST segment depression of greater than 0.5 mm or flat or inverted T waves that are indicative of ischemia
- these changes turn to normal when chest pain is relieved
- some patients with ischemia they may be electrically silent with an ECG appearing to be normal; serial ECGs may be done with cardiac biomarkers to rule out infarction
Diagnosis: Exercise Stress Test
done when ECG and cardiac biomarkers appear normal
- done to assess the function of the heart during exercise
- alternatively for those who are unable to use a treadmill or stationary bike, pharmacological agents such as dobutamine can be used to increase HR, mimicking effects of exercise on the heart
- stress echocardiogram can also be done
- goal is to determine whether there is reduced oxygen-rich blood flow to the heart tissue during physical activity and to determine what parts of the heart are affected by decreased blood flow
Stress Testing and Nuclear imaging
can be combined such as thallium and technetium studies, to further evaluate perfusion to the heart
Treatment: Medications Goal
for CAD are often prescribed with the goals of stopping the aggregation of blood components to the injured endothelium, controlling factors that led to damage of the endothelium, N=and relieving symptoms
Medications for patients with Stable Angina at low risk for ACS
-Aspirin and Nitroglycerin along with medications to reduce risk factors such as, anti-hypertensives, antidiabetic agents, and cholesterol lowering medication
>Aspirin prevents thrombus formation in the coronary artery
>Nitroglycerin, a vasodilator, is used to manage anginal episodes
Aspirin
prevents thrombus formation in the coronary arteries
Nitroglycerin
a vasodilator, is used to manage anginal episodes
- can be administered as sublingual tabs, a spray or powder, intravenously, transdermal patches, ointment, or by mouth with extended-release (XR) tablets
- during anginal episodes, sublingual and IV routes are preferred to restore blood flow promptly
- BP should be monitored carefully do to adverse reactions of hypotension
- headaches can also occur but treated with non-opioid analgesics like acetaminophen
Treatment of ACS (acute coronary syndrome)
aspirin, supplemental oxygen, nitroglycerin, and morphine and can be referred by the acronym MONA
-beta blockers, additional anticoagulants, and possibly calcium channel blockers are also prescribed
What can be given for Angina pain for patients not responsive to Nitroglycerin?
morphine, but its use can be associated with hypotension, nausea, and vomiting
Safety Alert: NItroglycerin
effective treatment for Angina
- be instructed to take this medication as prescribed, typically one tablet or spray under the tongue not to exceed 3 doses taken 5 minutes apart
- if the symptom of angina is not relieved with three doses or if the pain worsens, they should be instructed to call emergency personnel
- co-administration with sildenafil (Revatio, Viagra) increases risk of hypotension
Treatment: Percutaneous transluminal coronary angioplasty (PTCA)
procedure most commonly performed to relieve symptoms caused by atherosclerotic changes in the coronary vessel
- after the patient receives monitored anesthesia care (MAC), a catheter with a small balloon on its tip is advanced under fluoroscopy through a suitable artery (femoral or radial), to the area with atherosclerotic plaque
- the balloon is inflated and deflated to open the lumen of the artery (patients may experience chest pain due to vessel occlusion)
- once lumen is open, a stent may be advanced to the location to hold the artery open and maintain adequate blood flow; stent options include bare metal stents (BMS), drug-eluting stents (DES) to prevent clots, or the newer bioabsorbable stents
- patients frequently return from the procedure with a vascular closure device such as a angioseal, applied to the access site to maintain hemostasis; allows early ambulation
If no closure device is applied to the access site after percutaneous transluminal coronary angioplasty (PTCA), how long do patients need to be on bedrest until homeostasis is achieved?
6 to 8 hours
Genetic Connections: Pharmacogenetics and Anticoagulants after PTCA
anticoagulants such as warfarin or clopidogrel are prescribed after percutaneous transluminal coronary angioplasty
- patient responses to doses can vary greatly; some require low doses for therapeutic level while others require higher doses
- Pharmacogenetics: study of how a persons genes affect responses to medications
ex: some patients are fast metabolizers which increase risk of clotting and the need for higher or more frequent doses; slow metabolizers have a increased of bleeding and require lower or less frequent doses
Medications for Coronary Artery Disease
- Statins: reduce cholesterol and increase clearance of LDL from the blood
- Beta Blockers: inhibits the sympathetic nervous system response to physical activity which decreases cardiac workload and oxygen consumption
- Calcium channel blockers: lowers BP and increases blood flow to the coronaries, used when cant tolerate beta blockers, prevents coronary artery spasms in prinzmetals angina
- Aspirin
- Vasodilator: nitroglycerin
- anticoagulants
- ACE inhibitors and ARBS: reduced BP and decreases workload and oxygen demands; beneficial in patient with HTN, diabetes, renal disease, and HF
More invasive surgical Treatment
Coronary Artery Bypass Grafting (CABG)
- blockages in coronary arteries are bypassed using other arteries from the chest or arm or veins from the legs
- patients undergo general anesthesia
- large incision through sternum is made, and a cardiopulmonary bypass (CPB) is begun through large catheters in the vena cava or right atrium and aorta; a CPB provides continuous gas exchange and perfusion while the heart is stopped to provide a still, bloodless field for surgery.
- then arteries or veins being used as bypasses are surgically attached to the diseased coronary artery, creating an alternate path for blood to flow around the blockage
- sent to critical care unit for intensive monitoring and care
Lifestyle Management
- Diet and Physical activity
- maintain a healthy body weight or BMI
- smoking cessation
- refraining from excessive alcohol use
- cardiac rehabilitation
Diet
low in saturated fat and sodium as well as high in fruits, whole grains, vegetables
Cardiac Rehabilitation
supervised program of education, counseling, and supervised physical activity
- begins before discharge and continues in outpatient setting
- participation can improve morbidity and mortality, reduce angina episodes, and decrease rehospitalization
Complications of CAD
- acute coronary syndrome, which includes unstable angina and MI
- dysrhythmias and HF
- higher rates of adverse outcomes in women
Nursing Management: Assessment of clinical manifestations
careful assessment of chest pain and other manifestations of CAD is required to identify those patients with CAD and those patients who have stable angina that may progress to ACS
- clinical manifestations are the result of the imbalance of oxygen supply and demand to the myocardial tissue
- epigastric discomfort
- nausea and vomiting
- diaphoresis
- syncope
- SOB
- pain between shoulders/ jawline
Nursing DIagnosis
-decreased tissue perfusion r/t inadequate blood flow secondary to the presence of plaque within the coronary arteries and microvascular dysfunction
Nursing Interventions: Assessment
- Vital Signs
- Pain assessment using provoking factors, quality, region/radiation, severity, time (PQRST)
- electrocardiogram and continuous cardiac monitoring
- physical assessment
- patient history
- recreational drug use
- depression screening
- laboratory values; cardiac biomarkers troponin, CK/ CK-MB, creatinine, blood urea nitrogen, glycosylated hemoglobin (HgbA1c), lipid profiles
Assessment: Vital Signs
tachycardia ad tachypnea can be manifestations of cardiac ischemia
- hypertension is a CAD risk factor
- Nitroglycerin and morphine administration can result in hypotension
Assessment: Pain assessment utilizing provoking factors, quality, region/radiation, severity, time (PQRST)
angina can be non-specific in some patients; establishing location and quality can aid in the diagnosis of cardiac chest pain and disease progression
-headache can result from Nitroglycerin administration
Assessment: Electrocardiogram and continuous cardiac monitoring
depressed ST segment or flat or inverted T waves are indicative of ischemia
- ST elevations are indicative of acute injury
- cardiac dysrhythmias may result from ischemia or infarction
Assessment: Physical assessment
pallor, clamminess, nausea, vomiting, SOB, and diaphoresis may indicate cardiac ischemia
-Xanthomas (papules or nodules of the skin or mucous membranes that contain lipids) are associated with hypercholesterolemia
Assessment: Patient History
evaluate CAD risk factors and anginal patterns
- fatigue and weakness may be indicative of CAD
- identify potential noncardiac causes of chest pain, such as GERD or respiratory disorders
Assessment: Recreational Drug Use
illicit drug use (cocaine) can cause vasospasm, obstructing blood flow and causing symptoms that resemble CAD
Assessment: Laboratory Values: Cardiac Biomarkers
Troponin, Creatinine-kinase (CK), CK-MB
cardiac enzymes and troponin levels rise when the heart sustains an acute injury– can help differentiate between angina and MI pain
Assessment: Laboratory Values: Creatinine, Blood Urea Nitrogen (BUN)
assess renal function
-the contrast dye used during heart catheterization is nephrotoxic
Assessment: Laboratory Values: Glycosylated hemoglobin (HgbA1c)
hyperglycemia occurs with diabetes and is a risk factor for CAD
Assessment: Laboratory Values: Lipid Profiles
Cholesterol, triglycerides, LDL, HDL
-assess for hyperlipidemia, a risk factor for CAD development (high level of fats)
Nursing Interventions: Actions
- administer oxygen to keep oxygen saturation greater than 93%
- obtain ECG with the occurrence of chest pain
- administer nitroglycerin as ordered
- administer aspirin as ordered
- administer morphine as ordered if nitroglycerin does not relieve pain
- administer beta blockers/ calcium channel blockers as ordered
- administer statin medications as ordered
Nursing Interventions: Actions: administer oxygen to keep oxygen saturation greater than 93%
supplemental oxygen optimizes oxygen delivery to the myocardium
-cardiac dysrhythmias, especially tachycardia, and anxiety increase myocardial oxygen consumption
Nursing Interventions: Actions: Obtain ECG with the occurrence of chest pain
evaluates new anginal episode for evidence of ischemia or injury
-in cases of acute chest pain, an ECG within 10 minutes is recommended
Nursing Interventions: Actions: administer nitroglycerin as ordered
vasodilator; dilates the coronary arteries to improve flow to the heart and relieve pain
Nursing Interventions: Actions: administer aspirin as ordered
prevents platelet aggregation
Nursing Intervention: Actions: administer morphine as ordered if nitroglycerin does not relieve pain
minimizes pain and decreases the workload on the heart
-monitor for adverse effects of hypotension, nausea, vomiting, and respiratory depression
Nursing Interventions: Actions: administer beta blockers/ calcium channel blockers as ordered
inhibit cardiac response to physical activity, decrease oxygen consumption; may consider holding prior to exercise test
Nursing Interventions: Actions: administer statin medications as ordered
reduce cholesterol level and decrease the risk of increase plaque formation
Actions After PCI
- report and treat chest pain immediately (re-occlusion, vasospasm, or stenosis can result in ischemia)
- administer additional anti-coagulants (prevents vessel occlusion by thrombus)
- maintain fluids through catheterization sheaths if left in place (allows for immediate coronary access if return to cath lab is needed)
- maintaining bedrest and compression devices at the catheter insertion site (promotes homeostasis and prevents bleeding)
Teaching
- medication regimen
- angina management
- bleeding precaution if on anticoagulants
- risk factor reduction strategies: physical activity, blood pressure management, healthy diet/ weight loss, smoking cessation, decreased alcohol consumption, control of glucose
- when to call providers or emergency service
- encourage cardiac rehab for ACS patients after PCI or CABG
Teaching: angina management
if angina occurs during activity (stable angina), stop activity and take dose of nitroglycerin
- tabs can cause tingling or taste bitter when placed under the tongue
- not to exceed three doses 5 minutes apart
- caution about use of medication in the setting of lightheadedness or dizziness because this can be indicative of hypotension
Teaching: bleeding precautions if on anticoagulants
avoiding activities that have a high injury or fall risk, using a soft toothbrush and electric razor, and using caution with sharp objects
Teaching: When to call provider or emergency services
unrelieved chest pain— chest pain at rest requires early intervention
-for PCI patients; uncontrolled bleeding, swelling, redness, purulent discharge, nd pain at the insertion site or fever need prompt treatment
Evaluating care outcomes
- complying with prescribed medical therapy
- maintaining a healthy diet
- limiting alcohol
- engaging in regular exercise
- achieving desired activity levels and meeting self-care needs with minimal or no pain indicate achievement of care goals
- important that patient understands the disease process, the medications used to treat it, and when to call 911
