EComment. A novel lower age threshold for use of biological valves

Abstract

The publication by Niclauss et al. [1] highlights a subject with conflicting results in the literature: the determination of a lower age limit for bioprosthetic valves in the aortic position. They concluded that biological aortic valve replacement could be an alternative treatment option for patients between 56 and 60 years old at the time of surgery. Nevertheless, biological aortic valves in patients younger than 60 years old is still a matter of ongoing debates, and the debate has gained renewed impetus with the advent of transcatheter aortic valve implantation and the feasibility of valve-in-valve procedures [2]. Moreover, valve-related complications in this patient population have not been clearly investigated. It is noteworthy that in two recently published studies, mechanical valves among younger patients were shown to have more superior clinical outcomes compared to bioprostheses. Badhwar et al. [3], who conducted a prospective study on 172 propensity-matched patients, demonstrated a significantly lower mortality rate in patients with mechanical prostheses after 4 years of follow-up. Of note, patients with bileaflet mechanical prostheses enrolled in the above-mentioned study were monitored at low international normalized ratio thresholds using point-of-care home monitoring. The merits of mechanical aortic valve have been reiterated by the study of Weber et al. [4]. They selected a cohort of 103 patients younger than 60 years old with the Perimount Carpentier-Edwards pericardial tissue valve and compared them with a propensity matched group of 103 patients with mechanical bileaflet aortic valve over a period of 10 years. Surprisingly, valve-related event rates were similar in both groups; however, survival was significantly reduced in patients with bioprostheses (90% vs 98%). One possible explanation speculated by the authors was the protective role of oral anticoagulation in patients with mechanical valves. The current guidelines from major international cardiovascular societies propose that both valve types are acceptable in patients aged between 60 and 65 years at the time of surgery. However, there is still insufficient evidence to recommend biological valves for patients younger than 60 years, other than in patients who have major medical contraindications to anticoagulant therapy. Conflict of interest: none declared.