The Strategy Study Of Endovascular Treatment Of Aortic Dissection Involving Distal Aortic Arch

Section IThe characteristics of risk factors of aortic dissection involving distal aortic archBackgroundAortic dissection essentially features a tear in the intimal layer,followed by the formation and propagation of a subintimal hematoma.The dissecting hematoma commonly occupies up to 50%and,occasionally,100%of the aortic circumference,leading to the development of a false lumen or double-barreled aorta.This can reduce the flow of blood to any of the major arteries arising from the aorta.If the dissection involves the pericardial space,cardiac tamponade can result.The Etiology of aortic dissection has not yet fully understood,especially for patients with aortic dissection involving the aortic arch.The normal aorta contains collagen,elastin,and smooth muscle cells,which help contribute to the layers of the aorta,the intima,the media,and the adventitia.Any disease that weakens the strength of the aortic wall will predispose one to aortic dissection.Research has shown that genetic factors and environmental factors are involved in the pathogenesis of aortic dissection for other types of aortic dissection,The risk factors of the aortic dissection involving the aortic arch remains to be further defined.Objective:To analyze the characteristics of risk factors of aortic dissection involving distal aortic arch so as to determinate their value in the clinic diagnosis.Methods:A case-control study was conducted on 58 cases(inclusion criteria were as follows:1)presence of aortic dissection involving distal aortic arch;2)complete computed tomography angiography(CTA)data)with aortic dissection involving distal aortic arch in to in our center and 58 healthy control cases(without aortic dissection)in same period.The data of demography(age and sex),bad life habits(history of smoking or drinking),comorbidity(hypertension,coronary heart disease,diabetes mellitus,chronic obstructive pulmonary disease,peripheral vascular disease,cerebrovascular disease and renal dysfunction)and laboratory examination(hyperuricemia and hyperlipemia)was recorded.Risk factors and pathogenesis of aortic dissection involving distal aortic arch were analyzed.Binomial logistic regression analysis was used to determine the independent factors associated with aortic remodeling.Results:1.This study included 58patients,45 males and 13 females,aged 59±12.Fifty patients had comorbidity hypertension,12 patients had a coronary heart disease,5 patients had a diabetes mellitus,3 patients had a chronic obstructive pulmonary disease,18 patients had a peripheral vascular disease,5 patients had a cerebrovascular disease,and 2 patients had a renal dysfunction,only one patient had a previous heart surgery.Eighteen patients had a hyperuricemia and 34 patients had a hyperlipemia in laboratory examination.2.The proportion of male and hypertension,blood concentration of uric acid and serum lipid were significantly higher in patients with aortic dissection involving distal aortic arch than in control cases.Multivariate unconditional Logistic regression indicated that the proportion of male,hypertension,hyperuricemia and hyperlipemia were independent risks of aortic dissection involving distal aortic arch.ConclusionsThe proportion of male,hypertension,hyperuricemia and hyperlipemia may be risks of patients with aortic dissection involving distal aortic arch.Section IIThe advantages and disadvantages of various endovascular repair methods for the treatment of dissection involving distal aortic arch.BackgroundTEVAR has made great progress in last two decades,which avoid conventional surgical repair of aneurysms involving the aortic arch.This invasive procedure requires arch replacement with cardiopulmonary bypass and deep hypotermic circulatory arrest and is accompanied by significant in-hospital mortality rates that in large reported series exceed 20%.Furthermore,this procedure is associated with high rate of transient or permanent neurologic deficits,whose rates range between 3%and 17%.The hybrid repair of the aortic arch that combines the endovascular and open repair has evolved as an alternative treatment in selected high-risk surgical patients,but it has not been validated as a treatment option.Although it offers better results compared with open surgery,it is still associated to high rates of mortality and morbidity compared with total thoracic endovascular aneurysm repair(TEVAR).When the aortic arch is involved,the lesion may be involved or adjacent to the branch of the aortic arch.Enough anchor zone is necessary to ensure the proximal aortic stent anchoring area,otherwise it is easy to appear the complications.When the aortic dissection,involving the aortic arch,it is difficult to implement total thoracic endovascular aneurysm repair,and then produced a variety of methods to extend the aortic anchoring zone.The main methods to reconstruct the branch of the aortic arch include the Window technology,the Chimney technology,branched aortic arch covered stent graft and the hybrid repair and so on,The use of these techniques were reported,but these technical was mainly used for the treatment of aortic arch aneurysm,the effect for these new technical methods in the treat of aortic dissection involving the aortic arch still needs to be further defined.Objective:To evaluate the advantages and disadvantages of various endovascular repair methods for the treatment of dissection involving distal aortic arch.Methods:From January 2005 to July 2016,58 patients were included in this study,TEVAR were performed in 45 patients.All cases had an accurate assessment via a preoperative CTA scans.The intimal flap,the site of tear,origins of aortic branches was measured by CTA.All patients were examined in vascular diameters,intima-media thickness,blood stream velocities and plaques with color Ultrasonography.We evaluated the hemodynamics of the circle of Willis using magnetic resonance angiography(MRA),if necessary.The clinical data of 45 patients with aortic dissection involving distal aortic arch from were analyzed retrospectively.All the patients were treated endourologically.According to the morphology of aortic dissection,the following methods were used:directly coverage the orifice of left subclavian artery(LSA),chimney technique,fenestrated grafts,and neck vascular bypass surgery.Present the primary technical success rate,early and medium postoperativc complications.After discharge.all patients with hypertension required treatment of antihypertension medications to maintain blood pressure.Patients were monitored with CTA examinations during the follow-up period.Results:1.This study included 45 patients,35 males and 10 females,aged 56±8 years.Thirty-eight patients had a hypertension,5 had a pleural effusion,2 patients had a chronic obstructive pulmonary disease,2 patients had a cerebrovascular disease,and 2 patients had a renal dysfunction.Thirty-five patients’ intimal tear were just beyond the left subclavian artery and 7 were between the left common carotid and left subclavian artery.2.Among them,the primary technical success rate was 100%.Thirty-four cases received LSA coverage,among which 3 cases with type I endoleak,6 cases with type II endoleak,and 2 cases were improved through left subclavian artery embolism.After surgery,1 case with lower limbs paraplegia,1 case with steal blood syndrome,2 cases with upper limb ischemia.After conservative treatment,the above symptoms were all improved.Chimney technique was performed in 5 cases,among which 2 cases occurred endoleak.Window technique was performed in 4 cases.Left common carotid artery and arteria subclavia were reconstructed in 2 cases through neck vascular bypass surgery.3.No perioperative death occurred.The 30-day mortality rate was 2.2%(1 out of 45).The patient died because of a retrograde type adissection.Two patients were lost to follow-up,the mean follow-up time was 22±5 months.After long-term follow-up,all the brachial stent-grafts were patent.Most endoleak were disappeared gradually,endoleak still existed in 3 cases with no change of tumor diameter.ConclusionsEndovascular treatment is a safe and effective method for aortic dissection involving distal aortic arch;in the meantime,strict preoperative evaluation and suitable operation method are also important.Section ⅢThe risk factors associated with adverse aortic remodeling after thoracic endovascular aortic repairBackgroundThoracic endovascular aortic repair(TEVAR)has become the primary management for aortic dissections involving distal aortic arch..The principle of TEVAR is to cover the proximal major aortic entry tear with a stent graft.Coverage of the tear redirects blood flow into the true lumen and thus potentially resolves mal-perfusion and reduces the risk of rupture of the false lumen.Closure of the primary tear also facilitates thrombosis and subsequent regression of the false lumen and re-expansion of the true lumen,a late effect known as aortic remodeling.Aortic remodeling,i.e.,complete thrombosis and resolution of the false lumen,is considered to be the ideal morphological change in the aorta after TEVAR,and is associated,with improved long-term outcomes.A study with a minimum follow-up of 5 ycars showed that thoracic false lumen thrombosis occurred in 90%of TEVAR-treated patients,and only 22%of medically treated patients with type Baortic dissections,and false lumen thrombosis was associated with stabilization of aortic diameters,less aneurysmal expansion,and fewer cardiovascular events.However,complete aortic remodeling including abdominal aortic portion does not occur in all cases,and failure to achieve remodeling at 6 months post-TEVAR is a significant risk factor for late aortic events.The predisposing factors associated with aortic remodeling were still unknown,the further study is neededObjective:To determine the risk factors associated with adverse aortic remodeling after thoracic endovascular aortic repair(TEVAR)in these patients.Methods:1.The clinical data of 40 patients after endovascular treatment were analyzed to determine the independent factors associated with aortic remodeling after endovascular.2.Inclusion criteria were as follows:1)presence of aortic dissection involving distal aortic arch;2)presence of a preoperative false lumen without thrombus;3)complete computed tomography angiography(CTA)data,including data obtained during diagnosis,and for at least 6 months of postoperative follow-up.3.Exclusion criteria were as follows:1)presence of Marfan syndrome;2)descending aortic intramural hematoma;4.Patients were divided into two groups according to the presence of complete thrombosis in the false lumen after TEVAR.The data of demography,bad life habits,comorbidity and radiological information were recorded.Results:Among them,2 patients were lost to follow-up,1 patients died after treatment,and 2 patients don’t have complete computed tomography angiography data.Twenty-eight males and 12 females、aged 56±10 years were included in this study.Eighteen patients had a history of smoking,15 patients had a history of drinking.34 patients had a hypertension,10 patients had a coronary heart disease,5 patients had a diabetes mellitus,18 patients had a peripheral vascular disease,4 patients had a cerebrovascular disease,and 2 patients had a renal dysfunction.True-lumen and false-lumen volumes were increased(P<0.05)and decreased(P<0.05)after surgery,respectively.Therefore,the remodeling index increased after surgery 0.69±0.2 to11.8±0.7,P<0.05).Remodeling index and true-lumen volume were higher in the favorable aortic remodeling group compared to the adverse aortic remodeling group(P<0.05);while the false-lumen volume was lower in the favorable aortic remodeling group.A branch originating from the false lumen,the presence of multiple tears,hypertension,and age affected aortic remodeling(P<0.05).These variables were analyzed simultaneously using binomial logistic regression,and the results suggested that a branch originating from the false lumen(OR=11.458,95%CL:1.109-118.414,P=0.041)and the presence of multiple tears(OR=11.458,95%CL:1.109-118.414,P=0.041)were independent risk factors for adverse aortic remodeling.ConclusionsBranch originating from the false lumen,the presence of multiple tears,hypertension,and age affected aortic remodeling.Multivariate analyses revealed that a branch originating from the false lumen and the presence of multiple tears were determined to be independent risk factors for unfavorable aortic remodeling after TEVAR in patients with aortic dissection involving distal aortic arch.