## Most Common Site of Coronary Atherosclerosis **Key Point:** The left anterior descending (LAD) artery is the most frequently affected coronary vessel in atherosclerotic coronary artery disease, accounting for approximately 40–50% of significant stenoses. ### Anatomical and Hemodynamic Basis The LAD is preferentially affected due to: 1. **Highest blood flow** — carries the largest volume of blood among coronary arteries, resulting in greater shear stress and endothelial injury 2. **Longer course** — extends from the left main coronary artery to the apex, providing a longer segment for plaque formation 3. **Bifurcation points** — multiple branch points (diagonal and septal branches) create zones of disturbed flow where atherosclerosis preferentially develops ### Frequency of Involvement by Vessel | Coronary Artery | Frequency of Significant Stenosis | Typical Presentation | | --- | --- | --- | | LAD | 40–50% | Anterior wall MI, angina | | RCA | 30–40% | Inferior wall MI, RV involvement | | LCx | 20–30% | Lateral wall MI, posterolateral ischemia | | LM | < 5% | Acute global ischemia, cardiogenic shock | **High-Yield:** In angiographic studies, LAD stenosis is the single most common finding. RCA involvement is nearly as frequent, but LAD alone is more prevalent. ### Clinical Pearl LAD occlusion carries the worst prognosis among single-vessel disease because it supplies the largest territory of left ventricular myocardium (anterior wall, anterior septum, and apex). LAD-territory infarcts have the highest in-hospital mortality. **Mnemonic:** **LAD = Largest Area Delivered** — the LAD supplies the largest myocardial territory and hence experiences the most atherosclerotic burden.
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