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)
| Risk Factor | Details |
|---|
| Age | Males >55 years; Females >65 years |
| Lipids |
- Total cholesterol >6.1 mmol/L
- LDL-cholesterol >4.0 mmol/L
- HDL-cholesterol: Males <1.0 mmol/L; Females <1.2 mmol/L
|
| Smoking | Risk proportionate to pack-years 🚬📉 |
| Family history | Premature CVD in 1st-degree relative <50 yrs |
| Other | Obesity (BMI ≥30), sedentary lifestyle |
💡 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.
