Degenerative calcific aortic stenosis: a natural history.

Aortic stenosis (AS) is the consequence of active valve remodelling, which can be easily diagnosed, but for which no preventive strategy is available. It is the most common valve disease in Western countries, where its prevalence increases with age, reaching about 3% after the age of 75. The burden of AS is high and is expected to double within the next 50 years. Surgery is recommended in patients with severe symptomatic AS. In practice, however, surgery is often denied to the elderly owing to extensive comorbidities or 'frailty' and, as a consequence, decision-making is not always consistent with risk-benefit analysis. These findings highlight the need for less invasive approaches in high-risk patients and account for the rapid development of transcatheter aortic valve implantation (TAVI). Preliminary analyses suggest that in-hospital costs of TAVI compare favourably with the costs of surgery. Cost-effectiveness analyses are needed but should be interpreted with caution, given the discrepancies in analyses concerning surgery.