A novel insight into the role of entry tears in type B aortic dissection: pressure measurements in an in vitro model

Introduction: Predicting aortic growth in acute type B dissection is fundamental in planning interventions. Several factors are considered to be growth predictors in the literature and, among them, size and location of entry tears have been recognized to particularly influence the false lumen pressure. In this study, we develop an in vitro setting to analyze the actual impact of size and location of the entry tears on false lumen pressure, in the absence of other confounding factors such as the deformability of the aortic wall. Methods: We formalize some indexes that synthetically describe the false lumen pressure with respect to the true lumen pressure. Then, we experimentally derive their values in several configurations of the in vitro setting, and we look for trends in the indexes with respect to the size and location of entry tears. Results: Results show that the tears have a relevant impact on the false lumen pressure, but that their size and location alone are not enough to explain the phenomena observed in vivo. Conclusions: To predict the behavior of acute type B dissection, we therefore recommend not limiting to size and location, as many effects may derive from the interactions between these parameters and other patient characteristics.