Introduction on Trans-catheter Aortic Valve Implantation Guidelines - Does the Latest Evidence Change our Views ?
Alain CribierÔÇÖs determination in the 1980s to provide a definitive solution for high-risk surgical candidates with severe aortic stenosis was met with significant resistance. However, over many years transcatheter aortic valve implantation (TAVI) was developed and refined, leading to the first human procedure in April 2002 in France. Since this first description by Cribier et al.,1 there are now more than 2,000 TAVIrelated articles in peer-reviewed journals. Currently, there are two main evices used in routine practice: the Sapien XT (Edwards Lifesciences, California, US), and the CoreValve (Medtronic Inc., Minneapolis, US), both of which consist of a trileaflet valve: the former delivered using a balloon expandable cobalt chromium open-cell stent and made from bovine pericardial tissue; the latter using a self-expandable nitinol stent and made from porcine tissue.
Valve disease strongly correlates with the phenomenon of population ageing.2 The UK over-65 population has increased by 1.7 million in the last 15 years and by projection it is estimated that by 2034, 23 % of the population will be aged 65 or over. Moreover, the 2010 to 2011 adult cardiac surgery audit has noted that the population of patients being put forward for cardiac surgery is increasingly high risk, where the overall predicted mortality of the population as assessed by the mean logistic European System for Cardiac Operative Risk Evaluation (euroSCORE) has increased from 3.7 % in 2001 to 4.6 % in 2010.3 The treatment of valvular heart disease will therefore continue to be an increasing burden on healthcare resources, with clinicians often facing a dilemma of suitability for surgical intervention.
The current recommendations from the British Cardiovascular Intervention Society (BCIS) and the Society of Cardiothoracic Surgeons (SCTS) are that TAVI should be reserved for patients who have been assessed by a multidisciplinary team (MDT) comprising two cardiac surgeons and two interventional cardiologists, and whose risk of open heart surgery is assessed to be too great (usually euroSCORE >20 and Society of Thoracic Surgeons (STS) score >10).4 Patients should have severe symptomatic aortic stenosis, and the procedure should be performed by an experienced team including interventional cardiologists, cardiac surgeons, cardiac anaesthetists and cardiac imaging specialists.5
TAVI has quickly evolved and programmes have grown considerably, and while TAVI is now considered a viable alternative to surgical aortic valve replacement (sAVR) where an open heart operation would be too precarious, careful consideration is required before proposing percutaneous valve implantation for a high-risk surgical patient. The longterm results are only beginning to emerge, and TAVI is not without risk.