A Study On The Efficacy Of Shortening Or Avoiding Deep Hypothermic Circulatory Arrest During Total Aortic Arch Replacement

Aortic arch diseases are complex and diverse,such as acute aortic dissection and chronic aortic aneurysm.The special anatomical structure of the aortic arch exposes patients to various risks when undergoing aortic arch surgery.Besides the neurological risks directly related to the three branches of the arch,the risks of myocardial infarction,perioperative respiratory insufficiency and renal insufficiency are also common.The special pathological anatomy of certain aortic diseases and the special circulatory strategy that aortic arch surgery relies on may cause multiple vascular beds to be ischemia,which in turn leads to poor perfusion of the heart,brain,spinal cord,kidney,gastrointestinal tract and extremities.At first,surgeons performed aortic arch surgeries under deep hypothermic circulatory arrest.However,deep hypothermic circulatory arrest is considered to be a risk factor for a variety of surgical complications.Severe deep hypothermia and prolonged ischemia time cause renal insufficiency,platelet dysfunction bleeding,nervous system dysfunction,etc.Open aortic arch surgery has been developing toward higher temperatures and shorter circulatory arrest times.The application of selective cerebral perfusion provides strong protection to the central nervous system,which is the most concerned in aortic arch surgery.Aortic arch surgery tends to be performed at moderate hypothermia,which may reduce surgical complications resulted by deep hypothermic circulatory arrest.The aortic balloon occlusion(ABO)technique is an improvement on the classic total arch replacement with frozen elephant trunk(FET).The ABO technique makes full use of the hard elephant trunk.After the FET is implanted in the descending aorta,the aortic balloon blocks the descending aorta and the distal arch anastomosis is completed with lower body perfusion restored,then shortening the circulatory arrest time.Hybrid total aortic arch repair(HAR)is a perfect combination of open surgery and endovascular technology.HAR in this study refers to the type ? HAR,including ascending aorta replacement to create a new landing zone,arch vessel debranching and stent graft implantation.In type II HAR,aortic arch is clamped and transected between the left common carotid artery and the innominate artery,ensuring bilateral cerebral perfusion and lower body perfusion,and completely avoiding deep hypothermic circulatory arrest.The thesis contains two chapters,and each chapter contains two parts.The thesis mainly includes:the application of ABO technique and type ? HAR in a variety of aortic arch diseases,and the comparison between the two techniques and open total arch replacement.The summary of each part is now introduced as follows:Part 1 Aortic Balloon Occlusion Technique Combined with Total Arch Replacement and Frozen Elephant Trunk for Complex Aortic Arch PathologiesObjective To evaluate the safety and efficacy of aortic balloon occlusion technique combined with total arch replacement and frozen elephant trunk in the treatment of complex aortic arch lesions.Methods Between August 2017 and September 2018 in Fuwai Hospital,the clinical data of 100 patients undergoing aortic balloon occlusion technique combined with total arch replacement and frozen elephant trunk were retrospectively analyzed,and their early clinical results were analyzed.Results The average time of cardiopulmonary bypass in this group was(178.7 ± 43.7)min;the average time of cross clamp was(116.8 ± 31.8)min;the average time of circulatory arrest was(5.2± 3.1)min.The lowest nasopharyngeal temperature was(27.9 ± 1.0)?,the lowest bladder temperature was(29.2 ± 1.2)?.The average ICU stay time was(5.1 ±4.6)days,and the ventilation time was(37.5 ± 43.3)h.The average hospital stay was(14.2± 7.1)days.1 case died in the hospital due to multiple organ failure caused by acute liver failure,and 4 cases died within 30 days.Other postoperative complications included 3 cases of cerebral infarction,2 cases of paraplegia,1 case of low cardiac output syndrome assisted by intra-aortic balloon pump(IABP),and 5 cases of renal failure requiring continuous dialysis.There were 4 cases of re-sternotomy due to bleeding,3 cases of reintubation,1 case of recurrent laryngeal nerve injury,and 1 case of osteofascial compartment syndrome.Conclusions The aortic balloon occlusion technique combined with total arch replacement and frozen elephant trunk is safe and feasible when used in complex aortic arch lesions,and its organ protection still needs to be confirmed by a large sample of comparative studies.Part 2 Aortic Balloon Occlusion Technique versus Moderate Hypothermic Circulatory Arrest with Antegrade Cerebral PerfusionObjective The aim of this study is to evaluate the efficacy of aortic balloon occlusion(ABO)technique in total arch replacement and frozen elephant trunk(TAR and FET)for the treatment of acute type A aortic dissection(ATAAD).Methods We retrospectively reviewed the clinical data of patients with ATAAD who underwent TAR and FET between August 2017 and January 2019,ABO in 79 cases and MHCA/ACP in 109 cases.The primary endpoint is a composite of adverse outcomes(30-day mortality,stroke,spinal cord injury,renal failure necessitating hemodialysis at discharge,and cardiac dysfunction requiring IABP assistance).The secondary endpoint includes hepatic dysfunction,acute kidney injury(AKI)graded by a modified RIFLE(risk,injury,failure,loss of kidney function,and end-stage kidney disease)criteria,and ventilation time more than 24 hours.Results Circulatory arrest time was significantly decreased in ABO group(4.8 ± 1.2 min vs 18.4 ±3.1 min,P<0.001).The composite endpoint was comparable in the 2 groups(11.4%for ABO vs 13.8%for MHCA/ACP,P=0.631).In ABO group,fewer patients developed hepatic dysfunction(11.4%vs 28.4%,P=0.005)and high-grade AKI(Grade?&? AKI,22.8%vs 36.7%,P=0.041).There was no significant difference in the incidence of ventilatory time>24 hours between the two groups,but the average ventilation time in ABO group was significantly less than that of conventional surgery(31.4±32.3 h vs 45.7±43.6 h,P=0.017).Multivariate logistic analysis showed that ABO technique is protective factor for hepatic dysfunction(OR,0.218;95%CI,0.084-0.561:P=0.002),and Grade ?&? AKI(OR,0.432;95%CI,0.204-0.915;P=0.028)and ventilation time more than 24 hours(OR,0.455;95%CI,0.234-0.887;P=0.021).Conclusions ABO technique shortens the circulatory arrest time significantly in TAR and FET.Available clinical data suggested that it has certain protective effect on liver and kidney.Part 3 Hybrid Arch Repair for Complex Aortic Arch PathologiesObjective The hybrid arch repair(HAR)is an appealing surgical option in the management of aortic arch diseases.The aim is to evaluate the short and mid-term outcomes of type II HAR involving replacement of the ascending aorta,arch debranching,and zone 0 stent graft deployment in diverse arch pathologies.Methods 200 patients with various diffuse aortic pathologies involving the arch were enrolled between 2016 and 2019.Complex arch diseases included acute type A dissection(n=129,64.5%),acute type B dissection(n=16,8.0%),aortic arch aneurysm(n=42,21.0%)and penetrating arch ulcer(n=13,6.5%).Mortality,morbidity,survival and re-intervention were analyzed.Results The overall 30-day mortality rate was 8.0%(16/200).Stroke was present in 3.5%(7/200)of the general cohort and spinal cord injury was occurred in 3.0%(6/200).Multivariable logistic analysis showed that cardiac malperfusion and CPB time were the risk factors associated with 30-day mortality.The mean follow-up duration was 25.9 months(range 1-57.2 months),and the 3-year survival rate was 83.1%.On Cox regression analysis,age,diabetes,cardiac malperfusion and CPB time predicted short and mid-term overall mortality.A total of 3 patients required reintervention during the follow-up due to the thrombosis of epiaortic artificial vessels(n=1),anastomotic leak at the site of the proximal ascending aorta(n=1)and the type I endoleak(n=1).Conclusions Type II HAR was performed with satisfactory early and mid-term outcomes in complex aortic arch pathologies.Part 4:Hybrid Arch Repair versus Total Arch Replacement and Frozen Elephant TrunkObjective The aim of this study was to evaluate the objective outcomes of type ? hybrid arch repair(HAR)and total arch replacement with frozen elephant trunk(TAR with FET).Methods Data from 528 patients who underwent aortic arch repair from January 2017 to June 2019 were collected,which consisted of 175 type ? HAR and 353 TAR with FET.The propensity score-matched analysis identified a subgroup of 90 pairs.Perioperative data and mid-term follow-up results were assessed.Results There was no significant difference in the composite adverse events(type ? HAR,20.6%,36/175 vs TAR with FET,17.8%,63/353,P=0.450)which included 30-day mortality and other major complications.Multivariable logistic analysis of the 528 patients showed that the procedure type(type ? HAR or TAR with FET)was not associated with composite adverse events,30-day mortality or stroke.The 3-year survival rates were 84.8%in the type ? HAR group and 90.1%in the TAR with FET group(P=0.12).The 3-year reintervention-free rates in the type ? HAR and TAR with FET groups were 98.7%and 96.5%(P=0.22),respectively.After matching,no significant difference was found in the incidence of composite adverse events or the 3-year survival and reintervention-free rates.Conclusions No significant differences were found in the early and mid-term outcomes of type ? HAR and TAR with FET.The long-term outcomes remain to be investigated.Careful patient selection for individualized approaches is the key to taking full advantage of the two surgical procedures.