Calcific Aortic Stenosis: A Review
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Importance: Calcific aortic stenosis (AS) restricts the aortic valve opening during systole due to calcification and fibrosis of either a congenital bicuspid or a normal trileaflet aortic valve. In the US, AS affects 1% to 2% of adults older than 65 years and approximately 12% of adults older than 75 years. Worldwide, AS leads to more than 100 000 deaths annually.
Observations: Calcific AS is characterized by aortic valve leaflet lipid infiltration and inflammation with subsequent fibrosis and calcification. Symptoms due to severe AS, such as exercise intolerance, exertional dyspnea, and syncope, are associated with a 1-year mortality rate of up to 50% without aortic valve replacement. Echocardiography can detect AS and measure the severity of aortic valve dysfunction. Although progression rates vary, once aortic velocity is higher than 2 m/s, progression to severe AS occurs typically within 10 years. Severe AS is defined by an aortic velocity 4 m/s or higher, a mean gradient 40 mm Hg or higher, or a valve area less than or equal to 1.0 cm2. Management of mild to moderate AS and asymptomatic severe AS consists of patient education about the typical progression of disease; clinical and echocardiographic surveillance at intervals of 3 to 5 years for mild AS, 1 to 2 years for moderate AS, and 6 to 12 months for severe AS; and treatment of hypertension, hyperlipidemia, and cigarette smoking as indicated. When a patient with severe AS develops symptoms, surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) is recommended, which restores an average life expectancy; in patients aged older than 70 years with a low surgical risk, 10-year all-cause mortality was 62.7% with TAVI and 64.0% with SAVR. TAVI is associated with decreased length of hospitalization, more rapid return to normal activities, and less pain compared with SAVR. However, evidence supporting TAVI for patients aged younger than 65 years and long-term outcomes of TAVI are less well defined than for SAVR. For patients with symptomatic severe AS, the 2020 American College of Cardiology/American Heart Association guideline recommends SAVR for individuals aged 65 years and younger, SAVR or TAVI for those aged 66 to 79 years, and TAVI for individuals aged 80 years and older or those with an estimated surgical mortality of 8% or higher.
Conclusions: Calcific AS is a common chronic progressive condition among older adults and is diagnosed via echocardiography. Symptomatic patients with severe AS have a mortality rate of up to 50% after 1 year, but treatment with SAVR or TAVI reduces mortality to that of age-matched control patients. The type and timing of valve replacement should be built on evidence-based guidelines, shared decision-making, and involvement of a multidisciplinary heart valve team.
