Tissue Properties of the Fossa Ovalis as They Relate to Transseptal Punctures: A Translational Approach

OBJECTIVES: This study focused on how catheter size affects transseptal puncture, what transseptal indication means, and whether the swine model is predictive for humans. BACKGROUND: Transseptal puncture is a common procedure that gains access to the left atrium, allowing percutaneous mitral valve repair, left atrial appendage closure, and left-sided ablations. The basic approach has not changed in many years; however, the frequency of transseptal punctures and the size of devices are increasing with emerging treatments. METHODS: A broad range of devices (4 F to 18 F) were advanced through atrial septa of swine hearts; some devices were inserted in both swine and human hearts using 10 F catheters. RESULTS: Greater forces were required to puncture through the septa of human hearts compared to those of swine. Larger catheters used in swine hearts required greater force to advance them through the septa, causing greater dilation of tissue and sometimes tearing the floor of the fossa ovalis; analyses indicated an exponential increase in the size of the iatrogenic atrial septal defect. Specific tissue property testing of the septum primum showed that this tissue sheared at a lower exerted force in a superior to inferior direction. CONCLUSIONS: Results may provide physicians with important knowledge about what to expect when treating a possible iatrogenic atrial septal defect or help them understand the consequences of transseptal punctures. Comparative data between swine and human atrial septal tissue properties provide critical insights between the species and offer clinicians and device designers important information relative to differences in tissue behaviors.