Updated clinical indications for transcatheter aortic valve implantation in patients with severe aortic stenosis: expert opinion of the Italian Society of Cardiology and GISE

The introduction of percutaneous treatment of severe aortic stenosis with transcatheter aortic valve implantation (TAVI) remains one of the greatest achievements of interventional cardiology. In fact, TAVI emerged as a better option than either medical therapy or balloon aortic valvuloplasty for patients who cannot undergo surgical aortic valve replacement (SAVR) or are at high surgical risk. Recently, increased operator experience and improved device systems have led to a worldwide trend toward the extension of TAVI to low-risk or intermediate-risk patients. In this expert opinion paper, we first discuss the basic pathophysiology of aortic stenosis in different settings then the key results of recent clinical investigations on TAVI in intermediate-risk aortic stenosis patients are summarized. Particular emphasis is placed on the results of the nordic aortic valve intervention, placement of aortic transcatheter valves (PARTNER) 2 and Surgical Replacement and Transcatheter Aortic Valve Implantation Randomized trials. The PARTNER 2 was the first large randomized trial that evaluated the outcome of TAVI in patients at intermediate risk. The PARTNER 2 data demonstrated that TAVI is a feasible and reasonable alternative to surgery in intermediate-risk patients (Society of Thoracic Surgeons 4-8%), especially if they are elderly or frail. There was a significant interaction between TAVI approach and mortality, with transfemoral TAVI showing superiority over SAVR. Moreover, we examine the complementary results of the recently concluded Surgical Replacement and Transcatheter Aortic Valve Implantation trial. This prospective randomized trial demonstrated that TAVI is comparable with surgery (primary end point 12.6% in the TAVI group vs. 14.0% in the SAVR group) in severe aortic stenosis patients deemed to be at intermediate risk. We review the most relevant clinical evidence deriving from nonrandomized studies and meta-analyses. Altogether, clinical outcome available data suggest that TAVI with a newer generation device might be the preferred treatment option in this patient subgroup. Finally, the differences between the latest European and American Guidelines on TAVI were reported and discussed. The conclusion of this expert opinion article is that TAVI, if feasible, is the treatment of choice in patients with prohibitive or high surgical risk and may lead to similar or lower early and midterm mortality rates compared with SAVR in intermediate-risk patients with severe aortic stenosis.