Paris, France, 21 May 2019. Recent findings on transcatheter aortic valve implantation (TAVI) constitute a paradigm shift that will affect the care of patients with severe, symptomatic aortic stenosis in several ways. Prof Stephan Windecker, Director Cardiovascular Centre Bern, Switzerland, will present a PCR Statement on evolving indications for TAVI in patients with severe symptomatic aortic stenosis at EuroPCR on 23 May at 14:45.
Aortic stenosis is in most cases a degenerative disease, causing calcification and immobility of the aortic valve leaflets that in turn leads to left ventricular outflow obstruction. Severe, symptomatic aortic stenosis is the most common heart valve lesion leading to intervention in Europe and the US. Affected patients suffer from symptoms including heart failure, syncope and angina, and have a dismal prognosis if left untreated. There is no effective medical treatment, and the only intervention is replacement of the diseased valve by means of surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI). The latter less invasive treatment has resulted in an unprecedented effort to conduct a series of high quality randomized clinical trials (RCTs) in a field devoid of randomized evidence prior to the advent of TAVI.
Previously accumulated evidence among patients with severe aortic stenosis, who are at extreme (inoperable), high- and intermediate-surgical risk was summarised in the 2017 ESC/EACTS Guidelines on the management of valvular heart disease (Baumgartner H et al. EHJ 2017)1. In these guidelines, TAVI was recommended as therapy of choice among patients at extreme-risk (inoperable) and as treatment alternative to SAVR among patients at increased surgical risk with the decision made by the Heart Team according to individual patient characteristics, and TAVI being favoured in elderly patients suitable for transfemoral access, while SAVR remained the standard of care among patients at low surgical risk.
Recently, the results of two additional RCTs comparing TAVI with SAVR extend the available evidence to patients at low surgical risk. In the PARTNER 3 trial, TAVI with use of the balloon-expandable Edwards Sapien S3 prosthesis compared with SAVR was associated with a lower risk of the primary composite endpoint of death, stroke and rehospitalization at 1 year among low surgical risk patients (mean age 74±6 years, STS score 1.9±0.7%) (Mack M et al. NEJM 2019). In the EVOLUT Low Risk trial, TAVI with use of the self-expanding supra-annular CoreValve/Evolut prosthesis compared with SAVR was non-inferior with respect to the primary composite endpoint of death and disabling stroke and superior for heart failure rehospitalization at 2 years among patients at low surgical risk (mean age 74±6 years, STS score 1.9±0.7%) (Popma J et al. NEJM 2019). These trials included patients, who were anatomically good candidates for TAVI.
An updated meta-analysis of seven RCTs comparing TAVI and SAVR among 8,020 patients with severe, symptomatic aortic stenosis reported a lower risk of all-cause mortality (12% relative risk reduction) and stroke (19% relative risk reduction), irrespective of underlying surgical risk throughout two years of follow-up (Siontis G et al. EHJ 2019).
In aggregate, the available evidence from the low surgical risk trials and meta-analyses can be summarized as follows:
- TAVI is superior to SAVR at two years with respect to patient-oriented endpoints including
- TAVI is associated with improved health care resource utilisation owing to
- shorter interventions without need for general anaesthesia, cardiopulmonary bypass and intensive care unit monitoring
- shorter hospitalisation duration
- reduced need for rehabilitation services
- faster recovery and more rapid restoration of daily life activities and quality of life
- notwithstanding, the cost-effectiveness of TAVI requires further study in view of the current cost of transcatheter heart valves
These findings constitute a paradigm shift that will affect the care of patients with severe, symptomatic aortic stenosis in several ways:
- The favourable outcomes of TAVI are consistent across the entire risk spectrum suggesting that surgical risk estimation is no longer the basis to guide the choice between TAVI and SAVR
- Instead, the Heart Team will weigh clinical and anatomic characteristics to identify the best treatment option for individual patients with transfemoral TAVI replacing SAVR as default therapy in more patients
- Prosthetic valve selection will be determined by life expectancy and durability with surgically implanted mechanical valve prostheses being favoured in younger patients (<50 years of age), and bio protheses (TAVI or SAVR) being favoured in older individuals (>65 years of age)
Future research will need to address remaining uncertainties and options for further improvement in outcomes:
- Evaluation of TAVI in younger patients (<70 years)
- Assessment of long-term durability using predefined clinical and echocardiographic assessment
- Evaluation of TAVI in patients with bicuspid aortic valve disease
- Evaluation of TAVI in patients with concomitant coronary artery disease
- Continued measures to reduce the need for permanent pacemaker implantation
- Definition of the optimal short and long-term antithrombotic treatment therapy
- TAVI in asymptomatic patients with severe aortic stenosis