What are the causes of aortic stenosis and structural heart disease?

Causes of Aortic Stenosis and Structural Heart Disease

Primary Causes of Aortic Stenosis

The most common cause of aortic stenosis in developed countries today is calcific degenerative disease, which has replaced rheumatic fever as the predominant etiology, particularly affecting patients in their eighth decade of life. 1

Degenerative/Calcific Aortic Stenosis

• Calcified degenerative stenosis represents an active inflammatory process with features similar to atherosclerosis, now accounting for the majority of cases in developed nations 1
• This pathology is often associated with congenital abnormalities of the aortic valve, especially bicuspid aortic valve, particularly when aortic stenosis presents in younger patients 2
• The age at onset of severe obstruction has shifted from the sixth decade 50 years ago to the eighth decade currently due to this etiologic change 1

Congenital Causes

• Bicuspid aortic valve is a major congenital cause, frequently leading to premature calcification and stenosis 2
• Congenital aortic valve abnormalities account for cases presenting earlier in life 2
• Supravalvular aortic stenosis occurs due to loss-of-function mutation of the elastin gene on chromosome 7q11.23, frequently associated with Williams-Beuren syndrome 2

Rheumatic Disease

• Rheumatic fever remains a cause of aortic stenosis, though now less common in developed countries than historically 2
• Rheumatic lesions typically affect multiple valves and may present with mixed stenotic and regurgitant pathology 2

Causes of Aortic Regurgitation (Another Form of Structural Heart Disease)

Valvular Causes

• Congenital bicuspid aortic valve is a common cause of aortic regurgitation 2
• Rheumatic disease affecting valve leaflets 2
• Infective endocarditis causing valve destruction 2
• Calcific degeneration of valve leaflets 2
• Myxomatous degeneration of the aortic valve 2

Aortic Root and Ascending Aorta Pathology

• Idiopathic dilatation of the aorta 2
• Aortic dissection of the ascending aorta 2
• Marfan syndrome causing aortic root dilatation 2
• Systemic arterial hypertension leading to aortic root changes 2

Less Common Causes

• Ankylosing spondylitis 2
• Syphilitic aortitis 2
• Rheumatoid arthritis 2
• Giant cell aortitis 2
• Ehlers-Danlos syndrome 2
• Osteogenesis imperfecta 2
• Reiter's syndrome 2
• Traumatic injuries to the aortic valve 2
• Anorectic drugs (recently reported) 2

Associated Structural Abnormalities

• Discrete subaortic stenosis with secondary aortic regurgitation 2
• Ventricular septal defects with prolapse of an aortic cusp 2

Clinical Context and Epidemiology

• Aortic stenosis affects 3% of persons older than 65 years, making it the most important cardiac valve disease in developed countries 3
• Aortic stenosis is the most prevalent structural heart disease affecting primarily older adults in their last decade of life 4
• The shift from rheumatic to degenerative etiology reflects improved public health measures and population aging in developed nations 1

Important Clinical Pitfalls

• Bicuspid aortic valve requires particular attention as it predisposes to both stenosis and regurgitation, and is associated with aortic root dilatation requiring surveillance 2
• In patients with Williams-Beuren syndrome, supravalvular aortic stenosis may be accompanied by coronary ostial stenosis, increasing risk of sudden cardiac death and anesthesia complications 2
• The presence of concomitant coronary artery disease is common in elderly patients with degenerative aortic stenosis due to shared pathophysiological processes 5, 6