Context

Aortic stenosis is a common condition occurring in 2–4% of adults over the age of 65 years. This prevalence increases with age and it is estimated that up to 2.9% of adults between the ages of 75 and 86 years have severe aortic stenosis.1 Although the annual mortality for patients with asymptomatic stenosis is low (1%),2 once symptoms develop, the prognosis is poor. The mean survival after the onset of heart failure is 11 months, after syncope 27 months and after angina 45 months.3

Current guidelines recommend surgery for patients with severe aortic stenosis who have symptoms or in asymptomatic patients with a left ventricular ejection fraction <50%.4 However, up to 30% of patients with symptoms have numerous concurrent comorbidities and are considered to be too high risk for surgical intervention. Historically, these patients have been managed medically or occasionally with aortic valve balloon valvuloplasty. Transcatheter aortic valve implantation (TAVI) has now emerged as a viable alternative. Since its first description by Cribier and colleagues in 2002,5 in excess of 8000 procedures have been performed worldwide. Although the initial results have been encouraging in terms of procedural success, and both short- and medium-term mortality, this has been at the expense of a relative high 30-day or inhospital mortality of 10–22%. There has …