In hypertensive retinopathy, which vascular change is responsible for the development of arteriovenous nicking (Salus sign)?

Explanation

## Arteriovenous Nicking in Hypertensive Retinopathy **Key Point:** Arteriovenous (AV) nicking is a CHRONIC finding caused by arteriolar sclerosis and narrowing, not acute endothelial injury. The sclerotic arteriole compresses the underlying venule at the crossing point, creating the appearance of the vein being "nicked." ### Pathophysiology of AV Nicking 1. **Chronic hypertension** → sustained arteriolar wall stress 2. **Arteriolar medial hypertrophy and sclerosis** → vessel wall thickening and fibrosis 3. **Arteriolar narrowing** → reduced lumen diameter 4. **Mechanical compression** of venule at crossing point by the sclerotic arteriole 5. **Visual appearance:** Venule appears to be "nicked" or interrupted at the AV crossing **High-Yield:** AV nicking is a sign of **chronic hypertension** and indicates longstanding vascular remodeling, NOT acute hypertensive injury. It reflects structural changes in the arteriolar wall (medial hypertrophy, fibrosis, increased wall-to-lumen ratio). ### Distinction: Acute vs Chronic Hypertensive Retinopathy Findings | Finding | Acute/Severe | Chronic | Mechanism | |---------|--------------|---------|----------| | **Macular star exudates** | ✓ | — | Acute plasma leakage | | **Flame hemorrhages** | ✓ | — | Arteriolar necrosis, nerve fiber rupture | | **Cotton-wool spots** | ✓ | — | Nerve fiber layer infarction | | **AV nicking (Salus sign)** | — | ✓ | Chronic arteriolar sclerosis | | **Arteriolar narrowing** | — | ✓ | Chronic medial hypertrophy | | **Increased tortuosity** | — | ✓ | Chronic vascular remodeling | **Clinical Pearl:** The presence of AV nicking alone (without acute findings like macular star exudates or papilledema) indicates **chronic hypertension** and does NOT require emergency intervention. However, AV nicking + acute findings = **malignant hypertension** requiring urgent treatment. **Mnemonic:** **CHRONIC AV nicking** — Chronic Hypertension Reduces Organized Normal Intimal Caliber, causing Arteriolar-Venular nicking.