Cardiovascular system Flashcards
Pathophysiology of coronary artery disease
- Chronic endothelial injury due to HTN, diabetes, tobacco use etc.
- Fatty streak formation - lipids accumulate into smooth muscle cells
- Fibrous plaque - collagen covers the fatty streak leading to reduced blood flow due to narrowed lumen
- Complicated lesion - plaque rupture, thrombus formation or total occlusion of the vessel
Coronary artery disease non-modifiable risk factors
Age
Gender (men>women until 60)
Ethnicity
Genetic predisposition and family history
Coronary artery disease modifiable risk factors
Serum lipids: elevated triglycerides and LDL, decreased HDL
HTN
Tobacco use
Physical inactivity
Obesity
Coronary artery disease contributing modifiable risk factors
Diabetes mellitus
Fasting blood sugar > 6.4mmol/L
Psychological states
Homocysteine levels
Nursing management of coronary artery disease
Monitor blood pressure, heart rate and respirations every 5 minutes during anginal attack
Maintain continuous ECG monitoring
Pain assessment
Cardiac and resp assessments
Coronary artery disease diagnostic test
Cardiac CT scan
Prevention of coronary artery disease
Nutrition: eat more plant-based
Exercise: at least 150 mins of moderate intensity or 75 of vigorous activity each week
Tobacco: quit
Social determinants: housing, food security, transportation, self-image and culture
Aspirin: risk of bleeding
Pathophysiology of angina
When the demand for myocardial oxygen exceeds the ability of the coronary arteries to supply the heart with oxygen, myocardial ischaemia occurs
Angina is the clinical manifestation of reversible myocardial ischaemia
Stable versus unstable angina
Stable angina is chest pain that occurs intermittently with the same pattern of onset, duration and intensity of symptoms.
Unstable angina is chest pain that is new in onset or has a worsening pattern.
Stable angina usually occurs on exertion, while unstable angina can occur at rest.
Stable angina usually lasts for 3-5 minutes, while unstable angina is unpredictable and is an emergency.
What are the 3 conditions included in acute coronary syndrome?
- Unstable angina
- Non-ST elevation myocardial infarction
- ST elevation myocardial infarction
Acute coronary syndrome symptoms
Central chest pain
Pain may spread to back, jaw, shoulder, arm
Abdominal pain
SOB, sweating, nausea, palpitations and fainting
Acute coronary syndrome risk factors
Age
Family history
Smoking
Diabetes
HTN
High cholesterol
Obesity
Sedentary lifestyle
Unhealthy diets
Psychosocial stress
Acute coronary artery causes
- Formation of a blood clot in an artery already narrowed by an atherosclerotic plaque
- Coronary artery embolism
- Coronary spasm
- Coronary artery dissection
Which two markers are present in cardiac ischaemia?
- Troponin
- Creatine kinase
How do troponin levels indicate ischaemia?
Troponin is released into the bloodstream upon death of cardiac myocytes, occurs within 6 hours.
The amount of troponin is proportional to infarct size
ECG changes in unstable angina
Usually normal ECG. Sometimes transient ST depression
ECG changes in NSTEMI
ST depression
T-wave inversion
ST depression + T-wave inversion
ECG changes in STEMI
ST elevation
ST depression is opposite ECG leads
Which acute coronary syndromes cause increased troponin levels?
NSTEMI and STEMI as cardiac cell death occurs
Where is the infarction in a NSTEMI?
Limited to the inner layer of the ventricular wall
Where is the infarction in a STEMI?
Extends the entire thickness of the myocardium
Interventions for suspected acute coronary syndrome
- Antiplatelets (aspirin)
- Angina medications (GTN)
- Supplemental oxygen if required (only if hypoxic)
Interventions for confirmed acute coronary syndrome
- Anticoagulants
- Beta blockers
- ACE inhibitors
- Statins
STEMI interventions
Emergency (<90mins) percutaneous coronary intervention (PCI) to restore blood flow
If PCI is not available, fibrinolytic therapy is done
Coronary artery bypass graft (CABG)
