A Comparative Study Of Fenestration Technique With Chimneytechnique For Aortic Arch Endovascular Repair

Objectives To evaluate the efficacy,safety and differences of fenestrated and chimney stent grafts in treating aortic arch lesions and to discuss endovascular strategy in the arch.Methods A retrospective study was carried out in patients with aortic arch lesions who treated with fenestrated or chimney stent grafts at the Department of Vascular Surgery,Nanjing Drum Tower Hospital,from May 2016 to Aug 2019.Totally 94 cases were included and divided into three groups by different surgery methods,In situ fenestration(ISF)Group,Physician modification Group and Chimney Group.General characteristics such as age,sex,diagnosis,comorbidities and zone of lesion site were collected.Operation time,hospital stay and perioperative complication rates were analyzed.Follow-up mainly focused on endoleak,reintervention,branch stent graft restenosis or occlusion.The data were processed by SPSS and then to make comparisons.Results There was no significant differences in sex,age,diagnosis,comorbidities and zone of lesion site(P > 0.05).(1)In ISF group,technique success was 100%.The average operation time was 243.06±154.1 min and the average hospital stay was 19.1±8.2 day.The incidence of perioperative complications was 27.8%,including bleeding(n=2),stroke(n=1),SCI(n=1),and hydropericardium(n=1).The average follow-up period was 17.6±3.9 months.2 type Ⅲ endoleaks occurred,giving 11.1% endoleak rate,which gradually disappeared during the period without reintervention.There was no branch stent graft restenosis or occlusion.One patient with stroke recovered during follow-up without permanent sequelae.(2)In physician modification group,technique success was also 100%.The average operation time was 182.4±93.7 min and the average hospital stay was 17.2±7.2 day.The incidence of perioperative complications was 7.3%,including stroke(n=1),creatinine elevation(n=1)and left lower limb artery embolism(n=1).The average follow-up period was 10.3±4.3 months.6 patients developed endoleaks,including 1 type Ⅰ,4 type Ⅲ and 1 type Ⅳ.Endoleak rate was 14.6%.Type Ⅰ and type Ⅳ patients underwent another repair afterwards,leading to7.3% reintervention rate.One stroke patient only partially recovered.(3)In chimney group,technique success was 97.1%.One serious type Ⅰ endoleak happened after the implantation and addressed by deploying another cuff at the proximal part of the arch.The average operation time was 100.1±48.1 min and the average hospital stay was 17.6±5.3 day.The incidence of perioperative complications was 2.9% due to common femoral artery injury(n=1).The average follow-up time was 23.6±10.1 months.8 endoleaks occurred,6 type Ⅰendoleaks and 2 type Ⅱ endoleaks.Endoleak rate was 22.9%.1 type Ⅰ endoleak and 1 typeⅡ endoleak received reintervention.Another 3 patients had distal intimal tear and underwent additional treatment.Reintervention rate was 14.3% in total.6(17.1%)chimney stent grafts was compressed during the follow-up and another 2 occlusion occurred.1 patient died in this group because of dissecting aneurysm,giving 2.9% mortality rate.There was no significant difference in success rate among three groups(P > 0.05).Both ISF group and physician modification group showed significant longer operation time before and after PSM(P<0.05).Perioperative complication rate was found higher in ISF group than in chimney group(P=0.014)but after PSM there was no significant difference between these two techniques(P>0.05).Physician modification group had shorter follow-up period(P<0.05).Branch vessel stent grafts restenosis rate was proved to be prominent in chimney group.These two techniques did not differ in reintervention rate and mortality rate(P=0.007).Although there was no statistic discrepancy in endoleak rates(P > 0.05),chimney group revealed noteworthy type I endoleak rate(P=0.044).Conclusions Fenestration and chimney techniques showed no significant difference in midterm outcomes of treating aortic arch lesions.Both techniques provide optimal alternatives to patients who are deemed unsuitable for open surgery.Both ISF and physician modified stent grafts revealed longer operation time than chimney technique.ISF had shorter preparation time than physician modified stent grafts,so it can be carried out quickly,but it showed higher incidence of perioperative complications,so it can be used in emergent cases or as a remedy when other procedures failed.Physician modified stent graft tended to be more difficult with long preparation duration,but it had relatively low perioperative complication rate and branch stent grafts remained patent in the medium term.Operation time is still needed to be shortened in order to decrease the risk of complications.Chimney technique was proved to be simplified with shorter operation time than fenestration technique and low incidence of perioperative complications.But the type I endoleak rate and branch vessel stent grafts restenosis rate were notably higher than fenestration technique.As a result,necessary measures should be taken to lower endoleak rate and all patients should be under strict surveillance so that reintervention can be conducted in time.Long term efficacy and discrepancy of these two methods still need large sample randomized clinical study to confirm.