19 February 2020
Vol 12, Issue 531

About The Cover

Cover image expansion

ONLINE COVER Adaptable with Age. This illustration shows cross sections of hearts with replacement pulmonary valves (white). As the size of the heart increases during developmental growth (left to right, following the white curve in background), the valve is expanded. Children with congenital heart valve disease often undergo multiple surgeries because replacement valves do not accommodate heart growth. To reduce open-heart surgical burden, Hofferberth et al. developed a geometrically adaptable bileaflet prosthetic valve that mimics human venous valves. The polymer-based valves could be mechanically expanded using a balloon catheter, facilitating unidirectional fluid flow without leakage in vitro and blood flow when implanted in growing lambs for 10 weeks. This nonliving valve design could support somatic growth. [CREDIT: SOPHIE C. HOFFERBERTH, LARA TOMHOLT, JAMES C. WEAVER]