Raffa G.M.,Mediterranean Institute for Transplantation and Advanced Specialized Therapies ISMETT IRCCS |
Pasta S.,Mediterranean Institute for Transplantation and Advanced Specialized Therapies ISMETT IRCCS |
Gentile G.,Mediterranean Institute for Transplantation and Advanced Specialized Therapies ISMETT IRCCS |
Scardulla F.,University of Palermo |
And 4 more authors.
Journal of Biomechanics | Year: 2015
Hemodynamic alterations occur when the elephant trunk (ET) technique is adopted to treat extensive aortic aneurysms. In planning the 2nd stage operation to complete ET repair, surgeons must weigh an adequate recovery time after initial surgery against the risk of postoperative ET-related complications. The purpose of this study was to understand the mechanistic link between the flow alteration caused by the ET graft and the development of premature aortic rupture before the 2nd stage operation. Specifically, fluid-structure interaction (FSI) analysis was performed using the CT imaging data of aorta at different stages of ET repair, and then computational variables were compared to those observed in patients who underwent a prophylactic 2nd stage operation to complete aortic repair. Results show that intramural stress exerted near the distal ET anastomosis (IMS=37.5. kPa) at the time of urgent intervention was comparable to that of the extensive aortic aneurysm (IMS=47.4. kPa) at initial in-hospital admission, but was considerably higher than that occurring after the 1st stage procedure (IMS=3.5. kPa). Pressure index suggested higher peri-graft pressurization than aortic lumen pressure during diastole, imparting an apparent risk of aortic dilatation. These critical hemodynamic and structural parameters are related to the impending rupture of descending aorta observed clinically and can thus guide prophylactic intervention and optimal timing for the 2nd stage operation of a ET technique. © 2015 Elsevier Ltd.
PubMed | University of Southampton, Fondazione Ri.MED and Mediterranean Institute for Transplantation and Advanced Specialized Therapies ISMETT IRCCS
Type: | Journal: European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery | Year: 2016
We performed a pre-dissection computational fluid analysis of an ascending aortic aneurysm associated with unicuspid aortic valve. The analysis showed an abnormal helical flow pattern inside the aneurysm and an increased wall stress on the right postero-lateral wall of the ascending aorta. These values were largely higher than the theoretical cut-off for aortic wall dissection, their topographic distribution followed the intimal tear site as subsequently diagnosed by computed tomography scan and confirmed during the operation for dissection repair.