Makindo Medical Notes

Related Subjects: |Atherosclerosis |Ischaemic heart disease |Assessing Chest Pain |ACS: general |ACS: NSTEMI |ACS: STEMI |Hypertension |Acute Heart Failure |Chronic Heart Failure |Cardiac Thrombolysis

In clinical practice, ~99% of coronary artery narrowing is due to atherosclerotic disease of the coronary vessels, which is why the terms Ischaemic Heart Disease (IHD) and atherosclerosis are often used synonymously. 🫀

ℹ️ About: Causes of Ischaemic Myocardium

• 💉 Coronary artery narrowing
  • Atherosclerosis ➝ obstructive or complicated plaques with thrombosis
  • Coronary artery spasm (Prinzmetal/variant angina)
  • Vasculitis (e.g. Kawasaki in children, Takayasu in adults)
• 💪 High wall stress impairing flow
  • Severe aortic stenosis ➝ increased LV afterload
  • Hypertrophic cardiomyopathy ➝ impaired relaxation + outflow obstruction

🧪 Atherosclerosis: Pathophysiology

• Earliest lesion = fatty streak, seen even in children and young adults.
• Progression ➝ lipid core (cholesterol, esters, foam cells, necrotic debris) + fibrous cap.
• Plaque can ulcerate or rupture ➝ exposes thrombogenic material ➝ local thrombosis and embolisation.
• Stable plaque = thick fibrous cap, slowly progressive narrowing, predictable angina.
• Unstable plaque = thin cap, prone to rupture ➝ ACS, MI, sudden death ⚡.
• Process typically affects medium-sized arteries (coronaries, carotids, renal, peripheral arteries).

📊 Risk Factors for Atherosclerosis

• 📈 Age – risk rises steeply with advancing age.
• ♂️ Male sex (premenopausal women relatively protected until menopause).
• 🚬 Smoking – strong, dose-dependent risk (pack-years correlate with burden).
• 💉 Hypertension – both systolic & diastolic increase risk of endothelial injury.
• 👨‍👩‍👧 Family history – especially premature CVD (<50 yrs in 1st-degree relatives).
• 🍬 Diabetes mellitus – accelerates atherogenesis (glycation, endothelial dysfunction).
• 🧪 Dyslipidaemia – high LDL/total cholesterol; low HDL is particularly adverse.
• 🧵 High fibrinogen, pro-coagulant states.
• 🏃 Physical inactivity, obesity (esp. central adiposity).
• 🍷 Alcohol – J-shaped curve: modest intake may be protective, excess harmful.

🩺 Clinical Manifestations of IHD

• Silent/asymptomatic (e.g. found post-mortem or on incidental ECG).
• Stable angina (predictable chest pain on exertion).
• Unstable angina (crescendo, rest pain).
• Non-ST elevation MI (NSTEMI).
• ST elevation MI (STEMI).
• Arrhythmias (e.g. VT, VF, AF secondary to atrial strain).
• Sudden cardiac death 💀.
• Ischaemic cardiomyopathy ➝ heart failure.

📋 Key Risk Factor Thresholds (UK Context)

💡 Teaching Pearl: The key concept is that atherosclerosis is a **systemic disease** — coronary events are often just one manifestation. Risk factor control (statins, smoking cessation, BP and diabetes control) is as important as revascularisation in reducing morbidity and mortality.