Effects Of Distal Tears On Aortic Remodeling After TEVAR For Stanford Type B Aortic Dissection In Sub-acute Period

Objective Aortic dissection(AD)refers to an intimal tear followed by blood surging antegrade and cleaving the intimal and medial layers of the aortic wall longitudinally.The aortic lumen separated into the true and false lumina.The incidence of which is increasing dramatically.Without timely treatment it will become lethal.However,the conventional thoracic endovascular repair(Thoracic Endovascular Aortic Repair,TEVAR)can only seal the proximal tear,while the distal one was left untreated.This study is to analyze the characteristics of distal tear in sub-acute Stanford type B aortic dissection underwent TEVAR and its effect on postoperative aortic remodeling.It may provide reference for intraoperative distal tear treatment and postoperative management in the future.Method Forty-three patients with Stanford type B aortic dissection treated by TEVAR in subacute stage,after which the distal tear remained unsealed,in Anhui Provincial Hospitals from July 2011 to April 2015 were retrospectively analyzed.The number of distal tears in all patients was calculated according to the preoperative aortic computed tomographic angiography(CTA).It was compared that how the cardiac beatings to fill the false lumen by contrast through the distal tears,blood pressure and reflex flow direction after TEVAR affected the aortic remodeling.During the follow-up period,the areas of true and false lumens at the level of left subclavian artery,pulmonary artery and celiac artery before and after TEVAR and the thrombosis of false lumen after TEVAR were observed.Result Total of 43 patients with sub-acute Stanford type B aortic dissection treated by TEVAR in subacute stage.Of them,male was in 32 cases and female in11.The age ranged from 32-72 years-old,averagely 63.42 years-old.Among them,38 patients have hypertension(38/43,88.37%).All procedures were completed successfully.One patient died in eight days.Two patients lost follow-up after the first visit in 1 month after the surgery.Three patients lost contact immediately after the surgery.The follow-up rate was 86.04%.(1)On preoperative CTA in 43 cases,total of 89 distal tears were observed,with an average of 2.07 tears per patient.The result showed that the majority of tears were distributed in the area from celiac artery to renal artery(45/89,50.56%).(2)Comparing two groups of patients with different reflux speed through distal tear,it revealed that aortic remodeling(false lumen shrinking and thrombosis)achieved better in the group that false lumen was filled by contrast in 2 or more than2 cardiac beatings than those in less than 2(p <0.05).(3)Comparing two groups of patients with different postoperative blood pressure control,the better postoperative blood pressure control(systolic blood pressure<140mm Hg and diastolic blood pressure <90mm Hg)resulted in significantly aortic remodeling(false lumen shrinking and thrombosis)superior to poorly blood pressure control group(p <0.05).(4)Comparing two groups of patients with different reflux directions,there is no statistical significance of the relationship between the directions of distal tear blood flow(bi-directional and unidirectional)and the formation of postoperative false lumen thrombosis at the pulmonary artery level(p = 0.74).Conclusion Patients with Stanford B type aortic dissection all had distal tears,which are mainly distributed in the area with large visceral branches(from celiac artery to the renal arteries).The blood flow directions in false lumen after stent implantation had no effect on aortic remodeling.High speed of distal tear reflux(false lumen was filled by contrast in less than 2 cardiac beatings)and postoperative poor blood pressure control(systolic blood pressure ? 140 mm Hg and(or)diastolic blood pressure ? 90 mm Hg)had negative impact on aortic remodeling.Therefore,the distal tears should be managed simultaneously(if technically possible)in the patients whose blood pressure may be controlled imperfect and the distal tear blood reflux speed is high.The blood pressure should be strictly controlled after surgery in the patients with hypertension if distal tears were not sealed,.