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)