Aortic valve treatment: from the first aortic valve replacement to the last decade of revolution

The first aortic valve replacement (AVR) from a human patient performed in 1962 marked the beginning of an evidencebased journey of openheart surgery for aortic valve stenosis (AVS). Surgical aortic valve replacement (SAVR) has long been the standard treatment to reduce symptoms and improve survival in patients with severe AVS through multiple trials, with an established durability beyond 10 years and low mortality rate in the absence of serious comorbidities. Nevertheless, over the last two decades, we have witnessed a rapidly evolving evidence basis for the treatment of AVS since the first human transcatheter aortic valve implantation (TAVI) by Alain Cribier in 2002. TAVI has established itself as a datadriven preferred treatment option for patients deemed to be at excessive or high risk of conventional SAVR. Technological innovations in valve design, refinement in implantation techniques and increased operator experience, along with the evolving evidence basis, have contributed to the expansion of the therapeutic indication to include intermediaterisk and lowsurgical risk patients. This evolution of practice is reflected in current guidelines; the 2021 European Guidelines on the Management of Valvular Heart Disease recommend TAVI over SAVR in older patients (≥75) or those with a high surgical risk. In contrast, SAVR is favoured in younger patients (<75) with low surgical risk. In other patients, SAVR or TAVI remain treatment options dependent on heart team evaluation. Similarly, the 2020 American Heart Association guidelines favour TAVI in patients ≥80 years or in younger patients with a life expectancy of less than 10 years, or patients with a high surgical risk. SAVR is recommended in younger patients (age less than 65) or in patients with a life expectancy of longer than 20 years. It is on the basis of such recommendations and technological innovations that TAVI now exceeds SAVR as a treatment modality for AVS in many European countries and North America, although its exact penetrance varies, depending on the means by which individual healthcare systems are funded, populationlevel demographics and differences in investment into new technologies at the national level. While broader TAVI adoption in certain healthcare systems like in the UK may have had a significant financial impact considering that a costeffectiveness analysis conducted by the National Institute for Health and Care Excellence favoured the surgical procedure in patients at intermediate or high operative risk at any age, even in such healthcare system its adoption has continued to increase. In their Heart paper, Graversen et al present contemporary nationwide data on clinical practice patterns of firsttime AVR for AVS in Denmark between 2008 and 2020. Their data show a 39% increase in AVR procedures from 174.7 per 1 million inhabitants in 2008 to 242.5 per 1 million inhabitants in 2020 (p trend <0.001), significantly driven by an upward trend in TAVI procedures from 10.0 per 1 million inhabitants in 2008 to 155 per 1 million 183 inhabitants in 2020 (p trend <0.001). The steady and steep upturn in annual rate of all AVRs over time reflects not only an increased awareness of the safety and efficacy of the TAVI procedure but also a paradigm shift in the approach of the elderly patient with AVS. With the undeniably less invasive nature of the TAVI procedure and no upper age limit suggested by either European or North American guidelines, the indication for AVRs has expanded to patients who were previously medically managed. In line with similar trends in other European countries, TAVI has rapidly broadened across the entire operative risk spectrum, accounting for >90% of all isolated AVRs in 2020 among the elderly (≥75 years) in the Danish registry. In the reported analysis, median age decreased significantly over time for both surgical bioprostheses and mechanical prostheses, whereas median age in the TAVI group remained stable over time, the latter reflecting the expanding indication for TAVI to younger patients. Notably, TAVI exceeded the use of isolated SAVR in patients with aged between 70 years and 74 years in 2020, beyond the cutoff indicated by the current European guidelines. As the indication for TAVI procedure has been expanding to younger patients, heart team decision making should recognise the potential need for multiple aortic valve interventions over a lifetime. Despite the significant downward trend in SAVR procedure during the study period, surgical bioprostheses outscored mechanical bioprostheses and TAVI in the <70year group of patients, leaving the option for future valveinvalve procedures in case of valve deterioration.