Acute Coronary Syndromes Flashcards
What is atherosclerosis?
The build-up of fatty plaques in the walls of arteries.
It is the pathology responsible for acute coronary syndromes, peripheral arterial disease, AAA, and ischaemic strokes.
What are risk factors for atherosclerosis?
Smoking
Hypertension
Obesity
Hypercholesterolaemia
Male gender
Family history
Age
Diabetes
Alcohol (as this raises BP)
What are the pathological stages involved in atherosclerosis?
- Primary endothelial injury.
- LDL taken from the blood into the tunica intima of the artery - it is oxidised.
- Macrophages migrate to these oxidised LDL, forming foam cells, which in turn creates the fatty streak.
- Activated macrophages release cytokines and growth factors (e.g., PDGF) which cause proliferation of the smooth muscle layer and deposition of collagen
- Plaque enlarges, compromising blood flow (e.g. angina/PAD)
- Progresses further, where clot can now block entire arterial lumen, initiating a clotting cascade - patient has an MI.
What causes stable angina?
Narrowing of the coronary arteries, reducing blood flow to the myocardium.
Symptoms appear during times of exercise as there is insufficient blood flow to meet the demands of the heart.
How is stable angina diagnosed?
It is a clinical diagnosis.
May use ECG or CT angiography to aid this.
How is stable angina treated?
Lifestyle interventions
GTN spray (for symptomatic relief)
Beta-blocker or CCB
What conditions are classified as the acute coronary syndromes?
STEMI
NSTEMI
Unstable angina
What is the mechanism responsible for an ACS?
Rupture/Erosion of the fibrous cap covering an atherosclerotic lesion.
What is the risk of MI in the 30 days following onset of unstable angina?
Around 50%.
In which leads would an infarction of the LCA show elevation in a STEMI?
Leads I, aVL, and V3-V6.
In which leads would an infarction of the LAD show elevation in a STEMI?
Leads V1-V4.
Which artery is said to be anterolateral?
Left coronary artery (LCA).
Which artery is said to be anterior?
Left anterior descending (LAD).
In which leads would an infarction of the circumflex show elevation in a STEMI?
Leads I, aVL, and V5-V6.
What artery is said to be lateral?
Circumflex