The pericardium
The cardiac pericardium is a multilayer tissue that envelops the heart. Physiologic roles of the pericardium include: (1) protecting the heart, (2) creating a compartment for containing the pericardial fluid, and (3) providing this compartment for optimizing cardiac movements and functionality within the thoracic cavity. Compared to other cardiothoracic tissues, the pericardium exhibits material properties that vary based on location within the greater pericardial sac. These properties are a result of varied collagen fiber alignments, collagen densities throughout the pericardial sac, and overall cardiac health. Initiatives to better understand the tensile properties of human and large mammalian pericardium have driven both therapies and medical device manufacturing. Recent therapeutic approaches have been directed to exploit the space that exists between the pericardium and the epicardial surface of the heart. New devices and techniques are continually being developed to access this space with minimally invasive approaches. The pharmacokinetics of many drugs may be greatly enhanced if the drug is delivered into the pericardium. Advancements in transcatheter bioprosthetic heart valves have also motivated studies to better translate the biomechanical properties of large mammalian pericardium into more efficient heart valve designs. Developing preclinical research methods to better test and analyze native and treated pericardium will in turn improve the performances of bioprosthetic pericardial implanted devices and the quality of life of implant recipients. Therefore, as the complexities of implantable pericardial devices and pericardial access therapies increase, it remains crucial to better understand the properties of pericardium from both humans and commonly used animal models and tissues.
