Empirical Study Of Modular Branched Stent-graft To Reconstruct Aortic Arch In Canine By Endovascular Repair

Although EVR is one of the most important methods to treat aortic aneurysm and dissection, up to now, it is not an available method to reconstruct the aortic arch to cure the affections in ascending aorta and aortic arch. This is an empirical study to design a modular branched stent-graft system which is fit for the reconstruction of the aortic arch, to seek the method of EVR, to confirm the feasibility and availability of the aortic arch reconstruction in canine, and then to conduct the clinical design, manufacture and application. This experiment will benefit to the clinical application in following profile: design and manufacture of stent-graft system, alternative of interventional access and interventional method, observation and precaution of complication, observation of therapeutic efficacy et al. Objective:1. To design and manufacture the modular branched stent-graft system which is fit for the reconstruction of aortic arch in canine, to research the interventional method and its feasibility, the homodynamic change in ascending aorta and aortic arch after EVR, the therapeutic efficacy after EVR, and the pathological change of landing zone after EVR. 2. To provide the design proposal fitting for the clinical application, and to provide operational experience for clinical interventional operation.Methods:1. Measurement of data: Two 24 kg male hybrid canine were chosen. Angiography and anatomy were executed to measure the length and diameter of ascending aorta, aortic arch, and branch vessel of aortic arch respectively.2. Design and Manufacture of stent-grafts: According to the data collected, the shape and the qualification of the modular branched stent-grafts wereformulated. The stent-graft system includes 3 modules which stent is made of Ni-Ti alloy thread, and graft is made of e-PTFE. The shape of 1st and 2nd modular is branched, which are made of the main body, the shorter-grosser arm and the longer-slenderer arm. The 3rd modular is straight. During EVR, the main body of the 1 st modular anchors at ascending aorta, with its longer-slenderer at brachiocephalic trunk and shorter-grosser at arch of aorta; The main body of 2nd modular is inserted into the shorter-grosser branch of the 1st modular with its longer-slenderer branch at LSA and shorter-grosser at aortic arch. The 3rd modular is inserted to the shorter-grosser branch of the 2nd modular, and the distal profile of the 3rd anchors at descending aorta. The modular branched stent-graft system is produced by Shenzhen Lifetech Scientific Inc.3. Management and Observation of therapeutic effect: Ten hybrid canines (23.5-25.5kg ) were performed in this research. Bilateral subclavian arteries and half femoral artery were exposed. Under fluoroscope, the 3 modulars were inserted through RSA, LSA and femoral artery ordinally and respectively. Endoleak, migration, and pressure difference between ascending aorta and descending aorta were observed after EVR. Pathological change in aorta and endomembrane condition in graft was surveyed after EVR.Results:1. Eight of ten operations were completed successfully with two dogs died of obstruction of coronary artery and arteriorrhexis of LSA respectively during EVR. Mean blood loss was 90ml (50-450 ml) , mean operation time was 300 minutes(270—400minutes) , and mean dosage of contrast was 140ml.2. There were 3 deaths after EVR because of excessive loss of blood (1, 5h after EVR) and thrombogenesis in stent-graft (2, 3d-5d after EVR).3. In the eight successful operation cases, two proxmial type I endoleaks were observed, and no other type endoleak occurred. The shape and the localization of stent-grafts were fine, and the coronary artery and carotid artery were unobstructed during DSA after EVR.4. The mean differential pressure between ascending aorta and descending aorta was 6 mm Hg.5. Four months after EVR, regenerate endangium had been looked on the surface of e-PTFE at landing zone. Cellular proliferation of endangium mid-smooth muscle cell and monolayer endotheliocyte cytomorphosis on the surface of e-PTFE had been observed at the landing zone by pathological section.Conclusion:The designment of the reconstruction of aortic arch by modular branched stent-graft system is reasonable and feasible: Operation of intervention is convenient with microtrauma by using bilateral subclavian artery and half femoral artery as intervention access, and no special technique and equipment were needed. Brain blood-supply can be warranted during EVR, and blood-supply of extremity and organ is sufficient after EVR. The reconstruction of aortic arch in human being can be guided by this empirical study. More research is wanted before clinical application.