The evolution of polyurethane heart valve replacements: How chemistry translates to the clinic

Current heart valve replacements (HVRs) fail to comprehensively capture the physiological behavior of native heart valve tissues, allowing the burden of valvular heart disease to persist after surgical intervention. Through extensive research and clinical experience, it has become evident that material selection is central to the success of HVRs. One outstanding candidate material for next-generation HVRs is polyurethane. These polymers exhibit a unique segmented chemical structure that can imitate the mechanical strength and elasticity of soft biological tissues. Consequently, polyurethanes have long been investigated as HVR materials, however, progression to clinical utility has historically been impaired by the material's susceptibility to biodegradation and calcification. This review presents a concise and critical analysis of past and recent investigations to elucidate the contemporary potential of polyurethane HVRs. Importantly, the overwhelming clinical failure of past prototypes necessitated a detailed examination to validate any further use of polyurethanes in HVR development. Recently, advancements in polyurethane chemistry have contributed towards addressing the shortcomings of polyurethane HVRs, encouraging progress towards clinical translation.