## Degenerative Aortic Valve Stenosis — Pathology **Key Point:** Degenerative (calcific) aortic stenosis is characterized by lipid accumulation, calcification, and fibrosis of the valve cusps, leading to progressive narrowing of the aortic orifice. ### Pathological Progression ```mermaid flowchart TD A[Aortic valve stress]:::outcome --> B[Endothelial injury]:::outcome B --> C[Lipid accumulation]:::outcome C --> D[Calcification begins]:::outcome D --> E[Fibrosis and stenosis]:::outcome E --> F[Aortic stenosis]:::urgent ``` ### Histological Features of Degenerative AS | Feature | Details | |---------|----------| | **Lipid deposition** | Cholesterol and lipid accumulation in valve cusps (similar to atherosclerosis) | | **Calcification** | Dystrophic calcium deposition (not metastatic) | | **Fibrosis** | Collagen deposition and remodeling | | **Inflammation** | Minimal; not a primary feature (unlike rheumatic stenosis) | | **Vegetation** | Absent (unlike infective endocarditis) | **High-Yield:** Degenerative AS is the **most common cause of aortic stenosis in developed countries** and increasingly in India. It is a **lipid-driven, calcification-mediated process**, NOT inflammatory. **Clinical Pearl:** Risk factors mirror atherosclerosis: age, hypertension, hyperlipidemia, chronic kidney disease, and male sex. The process is accelerated in bicuspid aortic valves. **Mnemonic:** **CALC** = CALcification with Lipid deposition and Collagen fibrosis (degenerative AS). 
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