<B>degenerative calcific aortic stenosis </B>

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degenerative calcific aortic stenosis

Etiology:

• Unknown. Diseases of the aged of unkown cause are often loosely labelled "degenerative". May be related to "calcification of the mitral valve ring". See microscopic description.
• Aortic stenosis (AS) may be congenital.
• Congenital bicuspid aortic valve not inherently stenotic but may become stenotic in aged with fibrous thickening and calcification.
• AS may result from rheumatic pancarditis, with regurgitation as well, and with associated mitral.stenosis and/or regurgitation.

Pathogenesis:

• Unknown. No one knows whether this represents a disease process, or a "wear and tear" change of aging.
• Noteworthy that the same status applies to "calcification of the mitral valve ring", which is sometimes associated with degenerative calcific AS.

Epidemiology:

• 1/4 of cases of chronic valvular heart disease are due to AS. 4/5 of adults with clinically manifest AS are male.
• 10% of cases of AS in adults are due to rheumatic fever. AS secondary to congenital bicuspid aortic valve becomes symptomatic primarily in 6th and 7th decades. Acquired AS on prior presumably normal valves become symptomatic primarily in 8th and 9th decades (Robbins).

General Gross Description:

• Valve cusps are thickened and deformed by nodular confluent rock hard masses of calcified matter.
• Commissures remain separate, but cusps are rigid, and obstruct outflow area to a degree equal to the sum of their fixed surfaces areas.
• To be distinguished from healed rheumatic aortic valvulitis with stenosis, wherein obstruction is due to fusion of the commissures with uniform fibrous thickening of the cusps, and with late non-deforming dystrophic calcification.
• Both forms of stenosis cause massive left ventricular hypertrophy.

General Microscopic Description:

• Fields of proteinaceous amorphous matter with extensive variable patterns of calcification. Uncalcified matter is acellular and not atheromatous without neutral fats or cholesterol esters. Adjoining tissues show foci of chronic inflammatory response.
• Identical pathology is seen in "calcification of the mitral valve ring", which enlarges annulus, at tmes causing stenosis by forming a rigid circular shelf < 2+ cm thick under the leaflets.

Clinical Correlations:

• Clinically manifest in 5th to 7th decades.
• Asymtomatic until outflow obstruction reduces orifice to 1/3 (1 cm square) of its normal area, associated with left ventricular hypertrophy.
• Main symptoms are exertional dyspnea, angina pectoris, and syncope on effort, even in the absence of significant coronary arteriosclerosis.
• Left ventricular failure may progress to pulmonary hypertension with right heart failure. Sudden death seen in 10 to 20% of cases.

References:
•1. Robbins Pathological Basis of Disease, 5th Edition pp. 544-545. •2. Harrison's Principles of Internal Medicine, 13th Edition, pp. 1059-1060.