Transcatheter aortic valve implantation (TAVI) improves one-year mortality and hospitalisation rates in patients with aortic stenosis who are unfit for surgery. The PARTNER study is the first trial to assess the impact of this new procedure. The non-surgical study cohort comprised 358 patients from 21 centres, mainly in North America, randomised to either TAVI or standard (non-surgical) care. There were two primary endpoints: one-year all cause mortality and a composite endpoint of one-year all cause mortality or repeat hospitalisation. 'Severe aortic stenosis is becoming increasingly prevalent with an aging population. The only effective treatment has been valve replacement and no drug intervention has been shown to reduce progression. Significant comorbidities greatly increase the risk of surgery in this population. The recent development of a transcatheter aortic valve prosthesis has provided a real alternative to surgery in patients with severe aortic stenosis felt to be too great a risk for open surgery. Overall these are very impressive results with only five patients needing to be treated to prevent one death.'