Hypothermic circulatory arrest time affects neurological outcomes of frozen elephant trunk for acute type A aortic dissection: A systematic review and meta-analysis

Risk factors and prognosis of postoperative spinal cord injury in type A aortic dissection

OBJECTIVES

To investigate the risk factors and prognosis of spinal cord injury (SCI) after surgical procedure in type A aortic dissection (AAD).

METHODS

Between January 2013 and December 2021, a total of 1647 patients with AAD underwent surgical procedure. Postoperative SCI occurred in 58 patients, including 24 patients with paraplegia and 34 patients with paraparesis. Factors associated with SCI were identified through comparison between patients with and without SCI.

RESULTS

The mean age was 48.8 ± 10.8 years for patients with SCI and 50.1 ± 12.1 years for those without SCI (P = 0.43), with a comparable gender distribution. Median numbers of intercostal and lumbar arteries with involvement were significantly higher in the SCI group (both P < 0.001). The highest (P = 0.033) and lowest (P = 0.001) levels of intraoperative mean arterial pressure (MAP) were significantly lower in the SCI group. Multivariable analysis revealed the number of segmental arteries involved (odds ratio = 1.14, 95% CI 1.08-1.20, P = 0.000), and the duration of hypothermic circulatory arrest (HCA) (odds ratio  = 1.04, 95% CI 1.01-1.08, P = 0.042) was positively associated with the occurrence of SCI. Conversely, the lowest level of MAP was negatively associated with SCI (odds ratio = 0.98, 95% CI 0.96-0.99, P = 0.031). During the long-term follow-up, 14 patients with paraplegia needed a wheel chair, while only 1 patient with paraparesis needed one (P < 0.001).

CONCLUSIONS

The risk of postoperative SCI increases when AAD patients experience segmental arteries involved, longer HCA duration and decreased intraoperative MAP during operation.

Role of gender in short- and long-term outcomes after surgery for type A aortic dissection: analysis of a multicentre European registry

OBJECTIVES

Gender difference in the outcome after type A aortic dissection (TAAD) surgery remains an issue of ongoing debate. In this study, we aimed to evaluate the impact of gender on the short- and long-term outcome after surgery for TAAD.

METHODS

A multicentre European registry retrospectively included all consecutive TAAD surgery patients between 2005 and 2021 from 18 hospitals across 8 European countries. Early and late mortality, and cumulative incidence of aortic reoperation were compared between genders.

RESULTS

A total of 3902 patients underwent TAAD surgery, with 1185 (30.4%) being females. After propensity score matching, 766 pairs of males and females were compared. No statistical differences were detected in the early postoperative outcome between genders. Ten-year survival was comparable between genders (47.8% vs 47.1%; log-rank test, P = 0.679), as well as cumulative incidences of distal or proximal aortic reoperations. Ten-year relative survival compared to country-, year-, age- and sex-matched general population was higher among males (0.65) compared to females (0.58). The time-period subanalysis revealed advancements in surgical techniques in both genders over the years. However, an increase in stroke was observed over time for both populations, particularly among females.

CONCLUSIONS

The past 16 years have witnessed marked advancements in surgical techniques for TAAD in both males and females, achieving comparable early and late mortality rates. Despite these findings, late relative survival was still in favour of males.

Frozen elephant use in type a dissection: fundamentals, innovations, and pitfalls

INTRODUCTION

Type A acute aortic dissection (TA-AAD) is a great challenge for aortic surgeons. The establishment of a standardized surgical approach, particularly the determination of whether and when to address the aortic arch and the distal aorta in the same operation as the proximal aorta, is still unclear.

AREAS COVERED

Frozen elephant trunk (FET) has emerged as a valuable treatment for TA-AAD over the last decade. Here, we discuss the fundamentals and pitfalls of frozen elephant trunk procedures and present the latest innovations.

EXPERT OPINION

FET has the potential to simplify arch reconstruction in patients with complex arch tears and rupture, optimize perfusion in the distal true lumen for those with a compressed true lumen and malperfusion, address distal reentry tears, and promote false lumen thrombosis and late aortic remodeling. Nevertheless, FET is still associated with non-negligible mortality and morbidity rates. Patient selection, surgical expertise, and postoperative care remain crucial determinants in ensuring successful outcomes. Recent innovations in FET surgery involve the development of techniques to minimize or avoid hypothermic circulatory arrest and new FET devices with different arch branch configurations aiming to facilitate subsequent aortic reinterventions. We believe that both these advancements have the potential to improve patient outcomes.

Safety and effectiveness of the sutureless integrated stented graft prosthesis in an animal model

Background

Prolonged circulatory arrest time is an independent risk factor for postoperative adverse events of type A aortic dissection (TAAD) surgery. Further reduction of the circulatory arrest time is essential to improve surgical outcomes. This study aimed to evaluate the safety and effectiveness of the novel Sutureless Integrated Stented (SIS) graft prosthesis in an animal experiment.

Materials and methods

Straight type of the SIS graft prosthesis was implanted into the descending aorta of 10 adult male sheep, and the use of the device was scored on a scale of 1-10. Aortic digital subtraction angiography (DSA) was performed at 4, 14, and 26 weeks to investigate the prostheses. After 26 weeks, the animals were sacrificed for histological analysis.

Results

The immediate success rate of the surgery was 100 %, and the overall mean score of the use of the device was 9.65 ± 0.99. Three animals died from non-device-related causes during follow-up. Aortic DSA showed filling defects in 5 animals. Histological analysis revealed that all prostheses were intact. Except for 2 early deaths, the other 8 prostheses were endothelialized with mild inflammation, foreign body reactions, and intimal fibrosis. The mean cross-sectional area of the sutureless region was reduced by 26.4 % (range, 1.3-39.1 %).

Conclusions

The safety and effectiveness of the novel SIS graft prosthesis were acceptable, and the delivery system exhibited a promising performance. Using the SIS graft prosthesis in TAAD surgery was expected to simplify the procedures and shorten the circulatory arrest time. Further large-scale clinical trials are required to verify these findings.

Open aortic arch repair without circulatory arrest by frozen elephant trunk in Ishimaru zone 0

BACKGROUND

Open arch surgery is technically demanding for the surgeon and surgically and biologically invasive for the patient, requiring a variably long period of hypothermic circulatory arrest.

CASE PRESENTATION

Here we present a case of an elderly patient with chronic renal failure and multiple splanchnic artery disease successfully treated for a rupturing pseudoaneurysm of the aortic arch with a technique that we developed for particularly frail patients. The procedure includes: triple supra-aortic vessel perfusion; distal thoracic aorta antegrade perfusion; balloon endo-clamping of the descending aorta; and anastomosis of an off-the-shelf hybrid arch prosthesis in Ishimaru zone 0. These maneuvers allowed to maintain an extracorporeal circulation in the phase of distal anastomosis, instead of a period of circulatory arrest, employing just mild hypothermia: technical details are depicted and discussed also in comparison with other methods proposed in the literature.

CONCLUSIONS

Being able to take advantage of both open surgery advancements and endovascular methods is the key to cardiovascular surgery success today in front of complex pathologies of the aorta: increasing safety and reducing invasiveness of therapeutic options may progressively extend surgical candidacy to the frailest patients.

Frozen elephant trunk versus conventional proximal repair of acute aortic dissection type I

Objective

The extent of surgery and the role of the frozen elephant trunk (FET) for surgical repair of acute aortic dissection type I are still subjects of debate. The aim of the study is to evaluate the short- and long-term results of acute surgical repair of aortic dissection type I using the FET compared to standard proximal aortic repair.

Methods

Between October 2009 and December 2016, 172 patients underwent emergent surgery for acute type I aortic dissection at our center. Of these, n = 72 received a FET procedure, while the other 100 patients received a conventional proximal aortic repair. Results were compared between the two surgery groups. The primary endpoints included 30-day rates of mortality and neurologic deficit and follow-up rates of mortality and aortic-related reintervention.

Results

Demographic data were comparable between the groups, except for a higher proportion of men in the FET group (76.4% vs. 60.0%, p = 0.03). The median age was 62 years [IQR (20), p = 0.17], and the median log EuroSCORE was 38.6% [IQR (31.4), p = 0.21]. The mean follow-up time was 68.3 ± 33.8 months. Neither early (FET group 15.3% vs. proximal group 23.0%, p = 0.25) nor late (FET group 26.2% vs. proximal group 23.0%, p = 0.69) mortality showed significant differences between the groups. There were fewer strokes in the FET patients (FET group 2.8% vs. proximal group 11.0%, p = 0.04), and the rates of spinal cord injury were similar between the groups (FET group 4.2% vs. proximal group 2.0%, p = 0.41). Aortic-related reintervention rates did not differ between the groups (FET group 12.1% vs. proximal group 9.8%, p = 0.77).

Conclusion

Emergent FET repair for acute aortic dissection type I is safe and feasible when performed by experienced surgeons. The benefits of the FET procedure in the long term remain unclear. Prolonged follow-up data are needed.

Total aortic arch replacement without deep hypothermic circulatory arrest in type A aortic dissection: Left axillar artery for arterial cannulation

Objective

Total aortic arch replacement (TAR) necessitates hypothermic circulatory arrest (CA). The frozen elephant trunk technique (FET) additionally requires commercial hybrid grafts. Herein we describe a novel modified FET technique without CA using standard grafts thanks to left axillary artery (LAxA) cannulation in patients with acute type A aortic dissection.

Methods

LAxA anastomosis is made first using a homemade debranching graft, and cardiopulmonary bypass is initiated, followed by anastomoses of left common carotid and innominate arteries. The rest of the operation is performed with complete cerebral perfusion. Following replacement of ascending aorta/root, cardiac reperfusion is started using a root cannula which continues throughout the procedure. Distal arch anastomosis is performed clamp-on, allowing lower body perfusion via left subclavian artery. Lower body perfusion is interrupted for 5 to 8 minutes to deploy an endograft to complete a modified FET. Following cannulation of distal arch graft, perfusion of distal aorta is restarted, and all three grafts are incorporated to construct a neo-ascending aorta and arch.

Results

Between December 2018 and May 2022, 38 patients underwent TAR without operative mortality. Hospital mortality was %15.7, and spinal cord ischemia and stroke were not encountered in surviving patients. The mean lower body CA time was 7.2 ± 2.8 minutes.

Conclusions

TAR using standard endografts without CA is possible with LAxA cannulation. To perform a FET, only a short interruption of lower body circulation is sufficient to deploy an endograft, also improving hemostasis of distal anastomosis. Further studies are required with a higher number of patients to evaluate the efficiency of this novel technique.

Distal Aortic Progression After Hemiarch, Zones 1-3 Arch Replacement in Acute Type A Aortic Dissection

BACKGROUND

There is debate regarding aortic arch repair extent for acute type A aortic dissection (ATAAD) patients.

METHODS

From 1996 to 2021, 756 ATAAD patients underwent open arch replacement. The cohort was divided into hemiarch (n = 481), zone 1 (n = 65), zone 2 (n = 148), and zone 3 (n = 62) arch replacement groups. Cross-group comparison of aortic growth was modeled using data from interval postoperative computed tomography or magnetic resonance imaging of the distal aorta.

RESULTS

Demographics were not significantly different except the hemiarch group had more coronary artery disease and less stroke. Intraoperatively, zones 1, 2, and 3 had greater cardiopulmonary bypass, cross-clamp, and hypothermic circulatory arrest times and required more intraoperative blood transfusion than the hemiarch group. Perioperative outcomes were similar among groups except zone 3 had more reoperation for bleeding. Ten-year cumulative incidence of reoperation was hemiarch, 16.7%; zone 1, 16.3%; zone 2, 21.5%; and zone 3, 17.6% (P = .70). Ten-year survival was similar: hemiarch, 66%; zone 1, 60.3%; zone 2, 68.0%); and zone 3 66.1% (P = .20). Aortic arch, descending aorta, and abdominal aorta growth rates were not significantly different among groups over 10 years. In the whole cohort, the growth rate over time for aortic arch was 0.38 mm per year (P < .001), descending aorta 0.84 mm per year (P < .001), and abdominal aorta 0.69 mm per year (P < .001).

CONCLUSIONS

There was no significant difference in long-term survival, distal aorta growth, or reoperation rate for distal aortic aneurysm after hemiarch or zones 1, 2, or 3 arch replacement. Patient-specific arch replacement strategies may be used rather than defaulting to aggressive arch replacement for all ATAAD patients.

Acute Stanford Type A Aortic Dissection: A Review of Risk Factors and Outcomes

Acute aortic dissection (AAD) can be said to be a relatively uncommon emergency with fatal outcomes mainly due to delayed/missed diagnosis and treatment. Its ability to masquerade as other emergencies like acute coronary syndrome and pulmonary embolism makes the prognosis unfavorable in a significant proportion of patients. Patients have been seen to present to the accident and emergency department or outpatient setting with typical or atypical symptoms as we will discuss in this article. We have focused on indicators for risk and prognosis of acute Stanford type A aortic dissection in this traditional review. It is well known that despite recent developments and improvements in treatment modalities, AAD is still associated with a significant mortality rate and postoperative complications.

Combining aortic arch dissection stent implantation and root surgery for aortic dissection type A

BACKGROUND

Acute aortic dissection type A (AADA) is associated with high perioperative morbidity and mortality. A novel non-covered hybrid prosthesis (AMDS, CryoLife, Kennesaw, USA) can be easily implanted to stabilize the true lumen. However, the role of AMDS for patients requiring additional aortic root surgery has not been described.

METHODS

Between 2010 and 2020 a total of n = 370 patients underwent surgery for AADA in our department. Of those, n = 120 underwent treatment for aortic root in addition to proximal arch replacement without resection of the aorta beyond the innominate artery (Control, n = 111) and were compared to patients who received additional AMDS implantation (AMDS, n = 9).

RESULTS

Aortic valve repair was performed in 48.6% (Control) and in 55.6% of AMDS patients. Cardiopulmonary bypass (Control: 248 ± 76 min, AMDS: 313 ± 53 min, P < 0.01) time as well as circulatory arrest time of the lower body (Control: 30 ± 15 min, AMDS: 52 ± 12 min, P < 0.01) was prolonged in the AMDS group. Nevertheless, postoperative in-hospital morbidity such as dialysis (Control: 22.4%, AMDS: 11.1%, P = 0.68) and stroke (Control: 17.0%, AMDS: 22.2%, P = 0.65) were comparable. In-hospital death (Control: 21.8%, AMDS: 11.1%, P = 0.68) and the compound end-point MACCE (Control: 38.7%, AMDS: 44.4%, P = 0.74) did also not differ.

CONCLUSIONS

Addressing the arch by implantation of AMDS prolongs cardiopulmonary bypass and circulatory arrest time, however without relevant impairments of short-term outcome. Combining root surgery with replacement of the proximal aortic arch and AMDS implantation seems feasible and safe as it did not impair the early postoperative outcome.

Aortic arch repair: lessons learned over three decades at Baylor College of Medicine

The treatment of complex aortic arch disease continues to be among the most demanding cardiovascular operations, with a considerable risk of death and stroke. Since January 1990, our single-practice service has performed over 3000 repairs of the aortic arch. Our aim was to describe the progression of our technical approach to open aortic arch repair. Our center's surgical technique has evolved considerably over the last three decades. When it comes to initial arterial cannulation, we have shifted away from femoral artery cannulation to innominate and axillary artery cannulation. During difficult repairs, this transition has made it easier to use antegrade cerebral perfusion rather than retrograde cerebral perfusion, which was commonly used in the early days. Brain protection tactics during open aortic arch procedures have evolved from profound (≤14 °C) hypothermia during circulatory arrest to moderate (22-24 °C) hypothermia. Aortic arch repair is performed through a median sternotomy and may treat acute aortic dissection, chronic aortic dissection, or degenerative aneurysm. Reoperative repair - that necessitating redo sternotomy - is common in patients undergoing aortic arch repair. The majority of repairs will include varying portions of the ascending aorta and may involve the aortic valve or the aortic root. In some patients, repair may extend into the proximal descending thoracic aorta; this includes elephant trunk, frozen elephant trunk, and antegrade hybrid approaches.

Normothermic frozen elephant trunk: our experience and literature review

BACKGROUND AND OBJECTIVE

The frozen elephant trunk (FET) technique has undoubtable advantages in treating complex and extensive disease of the aortic arch and the thoracic descending aorta. Despite several improvements in cardiopulmonary bypass conduction and surgical strategy, operative times and the institution of systemic circulatory arrest remain the main determinants of early mortality, cerebral/spinal cord injury and visceral organs dysfunction. We have conducted this review to highlight the recent technical advances in arch and FET surgery aiming at the reduction/avoidance of systemic circulatory arrest, and their impact on early outcomes.

METHODS

A literature search (from origin to January 2022), limited to publications in English, was performed on online platforms and database (PubMed, Google, ResearchGate). After a further review of associated or similar papers, we found 4 experiences, described by 11 peer-reviewed published papers, which focused on minimising or avoiding systemic circulatory arrest during total arch replacement plus stenting of the descending thoracic aorta.

KEY CONTENT AND FINDINGS

Recent experiences reported the use of an antegrade endoaortic balloon, advanced and inflated into the stent graft, to provide an early systemic reperfusion soon after the deployment of the stented portion of the FET prosthesis and minimize the circulatory arrest time (down to a mean of 5 minutes), thus avoiding the need of moderate or deep hypothermia (mean systemic temperature 28-30 °C) while allowing a complete arch and FET repair. Our approach, based on off-pump retrograde vascular stent graft deployment in distal arch/descending thoracic aorta, and the use of a retrograde endoballoon, allows the repair of extensive aortic pathologies during uninterrupted normothermic cerebral and lower body perfusion.

CONCLUSIONS

The use of endoballoon occlusion has emerged in recent years as a safe and effective strategy to allow distal perfusion during FET repair. This technique minimizes or avoids the detrimental effects of hypothermia and systemic circulatory arrest and significantly reduces the operative times.

A Novel Sutureless Integrated Stented (SIS) Graft Prosthesis for Type A Aortic Dissection: A Pilot Study for a Prospective, Multicenter Clinical Trial

Aims

Various kinds of surgical strategies and prostheses have been advocated to improve short-term and long-term outcomes in type A aortic dissection (TAAD). Large-scale repair of the pathological aorta is hard to generalize due to complex procedures. We aimed to investigate the performance, effectiveness and safety of a novel Sutureless Integrated Stented (SIS) graft prosthesis in TAAD patients undergoing total arch replacement (TAR) and frozen elephant trunk (FET) implantation surgery.

Methods

All patients admitted to Fuwai Hospital were prospectively screened. Urgent or scheduled surgery was arranged for eligible patients. The primary endpoint was operative mortality. Key secondary endpoints included stroke, spinal cord injury, unexpected aortic reoperation, and 1-year survival. Discharged patients were followed up with computed tomography angiography and transthoracic echocardiography at 3 months, 6 months, and 1 year after surgery. Performance, effectiveness and safety analyses were performed in those patients.

Results

Between August 1 and September 3, 2020, ten TAAD patients were enrolled in this study and successfully implanted with the SIS graft prosthesis. The median (IQR) age was 56.50 (43.75, 66.75) years (range from 31 to 75), and seven patients were male (70.0%). All patients underwent ascending aorta replacement + TAR + FET and additional procedures when necessary. The median (IQR) operation time, cardiopulmonary bypass time and cross clamp time were 270.50 (218.50, 312.50), 110.00 (88.00, 125.75), 69.50 (51.25, 82.75) min, respectively. Of note, the median (IQR) circulatory arrest time was 9.00 (8.00, 9.00) min (range from 4 to 12). The median (IQR) lowest nasopharyngeal temperature was 26.75 (25.98, 27.67) °C. Follow-up was 100% completed. During the 1-year follow-up, no patients died, no severe adverse events occurred, and rate of freedom from aortic reintervention was 100%.

Conclusions

The SIS graft prosthesis was implanted in a novel sutureless way, which simplified the surgical procedure, shortened the circulatory arrest time and avoided deep hypothermia. The preliminary clinical outcomes and follow-up outcomes demonstrated the effectiveness and safety of this prosthesis. A large-scale trial is being conducted to further assess these findings.