Transcatheter Aortic Valve Implantation in High-risk Patients with Severe Aortic Stenosis

Patricia Fonseca, Raphael Rosenhek, Vinayak Bapat, Markus Lins
European Cardiology, 2012;8(2):115–9
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Abstract

Aortic stenosis (AS) has become an increasingly prevalent condition in ageing Western populations. Symptomatic AS is associated with significant morbidity, high hospitalisation rates and reduction in quality of life and life-expectancy. A large number of patients with severe AS are not currently receiving proper treatment, with subsequent increased mortality. While surgical aortic valve replacement continues to be an effective treatment for these patients, transcatheter aortic valve implantation is a new alternative for those at high risk from surgery. Overall, valve replacement and implantation procedures have a significant impact on prognosis and quality of life in AS patients. Referring a patient to a centre that has a multidisciplinary heart team will ensure that all treatment options are fully explored and the best clinical outcomes are reached.
Keywords
Severe aortic stenosis, transcatheter aortic valve implantation, PARTNER trial (Placement of aortic transcatheter valve trial), balloon aortic valvuloplasty, surgical aortic valve replacement, transapical approach, transfemoral approach
Disclosure Patricia Fonseca is an employee at Touch Briefings.
Received: March 23, 2012 | Accepted April 17, 2012 | Citation European Cardiology, 2012;8(2):115–9
Correspondence: Patricia Fonseca, Touch Briefings, Saffron House, 6–10 Kirby Street, London, EC1N 8TS, UK. E: patricia.fonseca@touchbriefings.com
Support: The publication of this article was supported by Edwards Lifesciences.

Degenerative aortic stenosis (AS) is a chronic progressive valvular disease that affects approximately 1.4 % of individuals over 65 years and 4.6 % of patients older than 75 years in the US.1 While the prognosis of asymptomatic patients with severe AS is generally good, that of symptomatic patients is very poor, with an overall mortality of approximately 80 % at three years once the disease becomes symptomatic (post-mortem analysis including patients with traumatic heart disease).2 A retrospective study showed that the mortality in patients with mild-to-moderate AS was 80 % higher than that in age- and gender- matched control subjects, with a high rate of aortic valve replacement related to haemodynamic progression to severe stenosis observed in the AS patients during a five-year follow-up period.3 Up to one-third of apparently asymptomatic patients actually experience limiting symptoms during an exercise test.4

Until recently, the only effective treatment available for severe AS was surgical aortic valve replacement (SAVR). In the last decade, transcatheter aortic valve implantation (TAVI) has emerged as an effective alternative therapy for inoperable AS patients or those at high risk from surgery. Although SAVR has been shown to improve outcomes in symptomatic AS patients, older patients experience higher morbidity and operative mortality. Assessing the risks and being aware of the life-expectancy of the patient are crucial when choosing the optimal intervention.5

Operative mortality increases with age and is greatly dependent on symptomatic status and surgical therapy. For SAVR on its own, the overall mortality rate is 4.3 %, while it practically doubles for SAVR combined with coronary artery bypass grafting (CABG) (see Table 1). Renal failure, emergent status and New York Heart Association (NYHA) functional class IV are among the risk factors associated with higher operative mortality rates, which increase significantly for patients over 70 years of age who undergo SAVR (5.3 % for the 70–79 age group, 8.5 % for the 80–89 age group and 14.5 % for the 90–99 age group) (see Table 2).6

Undertreatment of Severe Aortic Stenosis – Extent of the Problem and Consequences

The European Society of Cardiology (ESC) guidelines recommend TAVI in patients with severe symptomatic AS requiring aortic valve replacement who are deemed inoperable or at high risk from surgery.7 While the European System for Cardiac Operative Risk Evaluation (EuroSCORE) still successfully discriminates high-risk patients undergoing SAVR, it has become increasingly uncalibrated with absolute risk, resulting in an overestimation of the 30-day mortality rate.8 The limitations of current risk scoring systems are mentioned in a recent ESC position paper on risk assessment before intervention in patients with valvular disease.5

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