Bioartificial Hearts, Assist Devices, and Myocardium: New Developments

The rising prevalence of heart failure, global donor heart shortages, and limitations of current assist devices have driven innovation in bioartificial hearts (BAHs) and cardiac constructs. This systematic review aims to give an overview of new developments in BAHs, engineered myocardium, and biohybrid ventricular assist devices research, evaluating their clinical readiness and outcomes while addressing strengths and limitations. Significant variability in study designs and outcomes highlights both advancements and ongoing challenges in this field. Although the development of BAHs and larger cardiac tissue constructs remains in preclinical stages, progress has been achieved in the development of cardiac patches, with 2 approved for clinical use. Several critical challenges continue to hinder the successful clinical translation of bioengineered cardiac solutions. Achieving meaningful myocardial contraction remains a complex task, as well as ensuring adequate vascularization and electrical integration. Biocompatibility limits the progression of bioengineered cardiac constructs toward clinical applications. Innovations in 3-dimensional bioprinting, shape-memory materials, adhesives, microfabrication techniques, and soft and stretchable bioelectronics are driving advancements in this field. However, outcomes regarding hemodynamic performance of BAHs or constructs are marginal at best. Cardiac patches show promising results in preclinical studies, with the paracrine effect of the patches being the most plausible explanation of these results. Importantly, from very little clinical experience thus far, we cannot conclude that cardiac patches have any beneficial effects nor that they are safe. The path toward developing a fully functional BAH or even parts of a functional myocardium appears to be long, complex, and perhaps even unattainable.