• Prosthetic heart valves

The wolf and the lamb shall feed together… (Isaiah 65:25)

Aortic sclerosis of different degrees of severity is found in about 26% of elderly subjects and a diagnosis of severe aortic stenosis affects 2–4% of adults aged >75 years.1 The extent of ageing of the population is expected to nearly double by 2025.2 Two per cent of patients with aortic stenosis are symptomatic and therefore require early treatment to avoid rapid clinical worsening of the disease and a high chance of dying within a short period.3

The ability to offer effective treatment for patients with valvular diseases is one of the triumphs of cardiac surgery and a reason for pride. Since the introduction of the first caged-ball valves in the 1960s, valve technology has significantly improved and surgeons can now choose among a variety of mechanical and biological prostheses. Operative mortality of aortic valve replacement (AVR) has drastically decreased in the past decade. However, it remains high in specific subsets of patients, including the very elderly. This paradoxically means that in the population with the highest prevalence of aortic valve disease the operation can often be fatal and therefore inadvisable. Importantly, about one-third of symptomatic patients with severe aortic stenosis are still today not treated because of the perceived increased risk of dying during, or as a consequence of, the procedure.4

The search for alternative, less invasive treatments to deal with this unmet clinical need, and therefore subject to lower periprocedural risk, finally culminated in the engineering of stent-based biological prostheses …