The Preclinical Study Of A Novelly Designed Endovascular Patch Based On The Anatomical Features Of The Intimal Tear Of Type B Aortic Dissection

Objective:We measure the location,size and shape of intimal tear in three-dimensional models of type B aortic dissection(TBAD)using threshold segmentation and three-dimensional reconstruction.Based on the measurement,we categorized the intimal tears and designed a nickel-titanium woven endovascular patch for intimal tear closure.The safety and efficacy of endovascular patch were verified in a porcine intimal tear model of aortic dissection.Methods:We retrospectively enrolled 210 patients with TBAD from the database of ROBUST study.All the enrolled patients have CT angiopraphy from January 1 2008 to December 31 2016.We used 3 Medicine to segment and reconstruct the lumen of dissected aorta,and we used Geomagic wrap to reconstruct,size and categorize the intimal tear in three-dimensional models.Besides,we surgically construct arteriovenous fistulas between abdominal aorta and inferior vena cava to stimulate the blood flow between true lumen and false lumen of aortic dissection.The patches were used to seal the arteriovenous fistulas in porcine models.After the implantation of endovascular patch,we sacrificed animals in 1 month,3months,and 6 months respectively.DSA,CTA and histological evaluation were also employed at these time points.Results:(1)Category of intimal tear:we divided the location of intimal tears into aortic arch,visceral artery area,renal artery area and other area.According to the morphologic characteristics,intimal tears in aortic arch were divided into concave,convex,posterior,anterior and others;intimal tears around visceral artery were divided into visceral artery originated from false lumen,both false lumen and true lumen,and true lumen;intimal tears around renal arteries were divided into renal artery originated from false lumen and both false lumen and true lumen.(2)Size comparison of intimal tears:intimal tears in aortic arch>intimal tears in other area>intimal tears around visceral artery>intimal tears around renal artery(3)Technical success rate:the success rate of surgical construction of fistula was 100%,the success rate of endovascular patch implantation was 100%.(4)Safety evaluation:during the follow-up period of up to 6 months,no patches were found to detach,and no abdominal aorta and inferior vena cava rupture occurred.No bleeding and infarction were found in lung,liver,kidney,and spleen.(5)Efficacy evaluation:The arterial shunt was significantly reduced immediately after patch implantation,and a small amount of residual shunt was observed,and no shunt was observed in 1 months,3 months and 6 months follow-up angiography.Conclusion:Nickel-titanium wires woven patches are suitable for specific types of intimal tears.The technical operation of releasing the patch is easy to practice.The follow-up results showed a satisfactory safety and efficacy.However,this study is limited by a relative small sample size and no-control design.In my point of view,the endovascular patch needs further study before conducting clinical research.