Alpha-Gal Syndrome and Aortic Valve Replacement

Abstract

Background: Alpha-gal syndrome (AGS) is an IgE-mediated hypersensitivity response to galactose-alpha-1,3-galactose (alpha-gal), an oligosaccharide present in beef and pork. This complicates bioprosthetic heart valve selection, as both bovine and porcine valves contain alpha-gal, posing risks of allergic reaction and potentially accelerated structural valve degeneration.

Case summary: A 78-year-old man with AGS and severe symptomatic aortic stenosis underwent transcatheter aortic valve replacement with a porcine-derived Evolut FX 29-mm valve following multidisciplinary evaluation. Preoperative allergist-guided prophylaxis, including IgE risk stratification, antihistamines, and corticosteroids, enabled successful implantation without complications.

Discussion: Bioprosthetic valves may pose unique risks for individuals sensitized to alpha-gal, where an alpha-gal IgE to total IgE ratio ≤5% is a proposed threshold in which patients can be rechallenged with animal products. This case highlights the successful management of a slightly higher ratio.

Take-home message: The interplay between AGS, bioprosthetic valve selection, and structural valve durability necessitates an individualized approach to mitigate the hypersensitivity risks.

Keywords: Doppler ultrasound; aortic valve; cardiac risk; echocardiography; stenosis; valve replacement.