Total arch replacement and frozen elephant trunk for acute type A aortic dissection

Double-branched stent graft and four-stage deployment in total arch repair: safety and feasibility evaluation in porcine models

OBJECTIVES

The primary objective of this research was to evaluate the safety and feasibility of an innovative double-branched stent graft system employing four-stage deployment technology for aortic arch repair in porcine models.

METHODS

The double-branched stent graft system consisted of a proximal polyester artificial blood vessel, the main and double-branched stent grafts and a delivery system. We utilized 12 healthy pigs as experimental animals (6 per group). Postimplantation, samples were collected at 90 and 180 days after the operations. Preoperative and postoperative imaging and intraoperative arterial blood gas analyses were performed. After the pigs were euthanized, the implanted product, surrounding tissue and major organs were collected for pathological analysis.

RESULTS

The technical success rate of the stent graft implants was 100% (12/12). All animals survived to the experimental end point. Perioperative assessments showed intact stent grafts, and imaging features at the end of the follow-up period revealed neither endoleak nor device migration. No major adverse cardiovascular events were observed during the postoperative follow-up period. Pathological examinations confirmed the satisfactory biocompatibility of the stent graft.

CONCLUSIONS

This innovative double-branched stent graft system with four-stage deployment technology was affirmed as a safe and feasible option for aortic arch repair in accordance with our preclinical evaluation with porcine models.

Risk factors and early outcomes of prolonged mechanical ventilation following redo aortic arch surgery: A retrospective study

BACKGROUND

Redo aortic arch surgery is complex and associated with higher risks and mortality. Prolonged mechanical ventilation (PMV) after cardiac surgery is linked to early adverse outcomes and increased costs.

OBJECTIVES

Identify specific risk factors and early complications associated with PMV following redo aortic arch surgery.

METHODS

Retrospective study at Fuwai Hospital involving 203 patients. Data on patient characteristics, intraoperative factors, and outcomes were analyzed.

RESULTS

A total of 203 patients were included, with 42.4 % requiring PMV. PMV patients had longer ICU stays (P < 0.001), lower discharge ADL scores (P < 0.001), and higher hospitalization costs (P < 0.001). While there was no significant difference in-hospital mortality between the two groups, the long-term survival rate in the PMV group was lower than that in the non-PMV group (P = 0.029). Multivariate analysis identified longer cardiopulmonary bypass time (OR 1.008, 95% CI, 1.002 - 1.014, P = 0.006), elevated intraoperative red blood cell transfusion(OR 1.214, 95% CI, 1.057 - 1.393, P = 0.006), higher PEEP (OR 1.296, 95% CI 1.089 - 1.542, P = 0.003), and total arch replacement (OR 3.241, 95% CI 1.392 - 7.543, P = 0.006) as independent risk factors for PMV.

CONCLUSION

PMV following redo aortic arch surgery is linked to early adverse outcomes, increased healthcare costs, and reduced long-term survival, with longer cardiopulmonary bypass times, elevated intraoperative red blood cell transfusion, higher PEEP, and total arch replacement as independent risk factors.

Aortic arch branch-prioritized reconstruction for type A aortic dissection surgery

Background

Acute Stanford type A aortic dissection (STAAD) is a fatal condition requiring urgent surgical intervention. Owing to the complexity of the surgical process, various complications, such as neurological disorders, are common. In this study, we prioritized the reconstruction of aortic arch branches during surgery and investigated the association between prioritizing the branches and the postoperative outcomes of patients with STAAD.

Methods

Ninety-seven patients were included in the observational study and underwent total arch replacement and frozen elephant trunk technique between January 2018 and June 2021. Of these, 35 patients underwent the branch-priority technique, and 62 patients underwent the classic technique. By analyzing the perioperative outcomes, we compared the differences between the two techniques.

Results

The branch priority group had significantly shorter cardiopulmonary bypass and ventilator times and earlier postoperative wake-up times than the classic group. Additionally, the ICU stay time was shorter, with a significant decrease in neurological complications and 24 h drainage in the branch priority group compared to the classic group.

Conclusion

The branch priority technique can effectively provide better brain protection, resulting in earlier awakening of patients after surgery, reduced neurological complications, shorter ventilation time and decreased ICU hospitalization time. Therefore, it is recommended for use in aortic dissection surgeries.

Which Gelatin and Antibiotic Should Be Chosen to Seal a Woven Vascular Graft?

Among the vascular prostheses used for aortic replacement, 95% are woven or knitted grafts from polyester fibers. Such grafts require sealing, for which gelatin (Gel) is most often used. Sometimes antibiotics are added to the sealant. We used gelatin type A (GelA) or type B (GelB), containing one of the three antibiotics (Rifampicin, Ceftriaxone, or Vancomycin) in the sealant films. Our goal was to study the effect of these combinations on the mechanical and antibacterial properties and the cytocompatibility of the grafts. The mechanical characteristics were evaluated using water permeability and kinking radius. Antibacterial properties were studied using the disk diffusion method. Cytocompatibility with EA.hy926 endothelial cells was assessed via indirect cytotoxicity, cell adhesion, and viability upon direct contact with the samples (3, 7, and 14 days). Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to visualize the cells in the deep layers of the graft wall. "GelA + Vancomycin" and "GelB + vancomycin" grafts showed similar good mechanical characteristics (permeability~10 mL/min/cm2, kinking radius 21 mm) and antibacterial properties (inhibition zones for Staphilococcus aureus~15 mm, for Enterococcus faecalis~12 mm). The other samples did not exhibit any antibacterial properties. The cytocompatibility was good in all the tested groups, but endothelial cells exhibited the ability to self-organize capillary-like structures only when interacting with the "GelB + antibiotics" coatings. Based on the results obtained, we consider "GelB + vancomycin" sealant to be the most promising.

Overview of acute type A dissection in Japan

Acute type A aortic dissection is a relatively uncommon but devastating disease and usually requires emergency surgery. Based on the several database projects, a large amount of perioperative patient data has now been accumulated and is expected to be useful in clinical practice. Especially in Japan, the number of surgeries for acute type A aortic dissection has been gradually increasing recently, and the overall mortality rate has stabilized at less than 10%. One of the keys to further improvement in outcomes will be to improve the results of aortic root replacement. In addition, strategies need to be established for very elderly patients, comatose patients, and patients with malperfusion as preoperative conditions. The use of a relatively new device, the frozen elephant trunk, is also increasing and might be changing the surgical outcome. In this report, we describe the current status of acute type A aortic dissection in Japan, with reference to recent guidelines and literature.

Late outcomes of the frozen elephant trunk technique for acute and chronic aortic dissection: the angle change of the FROZENIX by "spring-back" force

OBJECTIVES

To evaluate the outcomes of total arch replacement using the frozen elephant trunk technique with a FROZENIX^® J Graft for patients with either acute or chronic aortic dissection, and to evaluate the late-phase outcomes.

METHODS

Between January 2015 and December 2020, we used the frozen elephant trunk technique in 47 patients with acute aortic dissection and 12 patients with chronic aortic dissection. The primary endpoints were 30-day mortality, late aorta-related death and late aortic events. The secondary endpoints included early surgical complications and any aortic events (e.g. stent graft-induced new entry, frozen elephant trunk angle change).

RESULTS

In the acute group, there were no aorta-related deaths, although 13 patients (27.7%) experienced an aortic event; stent graft-induced new entry occurred in 6 patients (12.8%). In the chronic group, 1 patient (9.1%) experienced aorta-related death, and 9 (81.8%) experienced an aortic event; stent graft-induced new entry occurred in 4 patients (36.4%). During the late phase after surgery, there was a significant increase in the frozen elephant trunk angle in both groups. In the AAD group, both the FET angle and spring-back angle were significantly enlarged in the late phase. There were no significant differences between groups in the degree of angle change, the overall survival, or aortic event-free survival.

CONCLUSIONS

Total arch replacement using the frozen elephant trunk technique affords good early-stage results for both acute and chronic aortic dissection. During follow-up, careful monitoring for aortic events and appropriate therapeutic interventions are required. If surgeons are to use this device, they must have a thorough understanding of its spring back force and other features.

Zone proximalization in frozen elephant trunk: what is the optimal zone for open intervention? A systematic review and meta-analysis

INTRODUCTION

The treatment of complex aortic lesions involving the ascending, arch, and proximal descending aorta, remains challenging for surgeons despite the evolution of surgical techniques and aortic prostheses over decades. The frozen elephant trunk (FET) approach offers a one-stage repair of this entity of aortic pathologies. The main scope of this systematic review and meta-analysis is to evaluate the clinical outcomes and effectiveness of FET.

EVIDENCE ACQUISITION

In a systematic review, multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE were searched from inception to June 2021 to identify relevant studies reporting on outcomes of total arch replacement (TAR) with FET.

EVIDENCE SYNTHESIS

Eighty-five studies met inclusion criteria, encompassing 10960 patients. Meta-analysis was conducted using the R-studio (RStudio, Boston, MA, USA) and STATA software (StataCorp LLC, College Station, TX, USA). The pooled in-hospital mortality rate was 7% (95% CI 0.05-0.09; I²=76%) and 12% for renal failure (95% CI 0.09-0.15; I²=88%), while the rates for paraplegia and cerebrovascular accidents were 3% (95% CI 0.02-0.04; I²=0%) and 6% (95% CI 0.05-0.08; I²=73%), respectively. Lower heterogeneity was attained after the stratification by the aortic pathologies, except for the renal failure. The distal anastomosis of the stent in zone 2 was significantly correlated with a lower renal failure development compared to zone 3 (odds ratio 0.52; 95% CI 0.33-0.82; P=0.069; I²=0%).

CONCLUSIONS

Our results indicate that the morbidities and mortality following TAR with FET were acceptable. We also associated the distal anastomosis in zone 2 with fewer renal failure development compared to that in zone 3.

Serum Myoglobin Is Associated With Postoperative Acute Kidney Injury in Stanford Type A Aortic Dissection

Background

The correlation between rhabdomyolysis and postoperative acute kidney injury has been reported in several surgical procedures. As a good predictor of rhabdomyolysis-related acute kidney injury, an elevated serum myoglobin level was often observed after total aortic arch replacement combined with frozen elephant trunk implantation. However, the correlation between serum myoglobin and acute kidney injury in such patients had not been established.

Methods

Totally 398 stanford type A aortic dissection patients who underwent total aortic arch replacement combined with frozen elephant trunk implantation were enrolled in this retrospective study. The correlations between serum myoglobin and acute kidney injury as well as the 30-day mortality were assessed.

Results

Overall, 268(67.3%) patients had acute kidney injury (KDIGO stage 1 or higher) and 75(18.8%) had severe acute kidney injury (KDIGO stage 2&3). Patients who developed acute kidney injury had higher level of perioperative serum myoglobin than patients without acute kidney injury. After adjusting for known acute kidney injury risk factors, logarithmically transformed preoperative serum myoglobin [OR = 1.58 (95% CI, 1.26–1.95), P < 0.001] and postoperative day 1 serum myoglobin [OR = 3.47 (95%CI, 2.27–5.29), P < 0.001] were associated with severe acute kidney injury. These correlation persisted after adjustment for decline in filtration via change in serum creatinine (ΔCr) and biomarkers of cardiac and kidney injury, including N-terminal prohormone of brain natriuretic peptide, cardiac troponin I, creatine kinase-MB, serum creatinine and Cystatin C. Compared with the clinical model, sMb considerably improved the risk discrimination and reclassification for AKI.

Conclusion

For stanford type A aortic dissection patients underwent total aortic arch replacement with frozen elephant trunk implantation, serum myoglobin can improve postoperative acute kidney injury risk classification. Rhabdomyolysis may be an important supplement to the existing knowledge on the mechanism of acute kidney injury.

Incidence of Distal Stent Graft Induced New Entry vs. Aortic Remodeling Associated With Frozen Elephant Trunk

Background

The introduction of the frozen elephant trunk (FET) technique for total arch replacement (TAR) has revolutionized the field of aortivascular surgery by allowing hybrid repair of complex aortic pathologies in a single step through combining an open surgical approach with an endovascular one. FET has been associated with favorable aortic remodeling, however, its is also associated with development of distal stent graft induced new entry (dSINE) tears postoperatively. The rate of aortic remodeling and the incidence of dSINE have been linked together, in addition, there seems to be a relationship between these two variables and FET insetion length as well as graft size.

Aims

The scope of this review is to highlight the rate of aortic remodeling as well the incidence of dSINE associated with different FET devices available commercially. This review also aimed to investigate the relationship between aortic remodeling, dSINE, FET insertion length and FET graft size.

Methods

We conducted a comprehensive literature search using multiple electronic databases including PubMed, Ovid, Scopus and Embase in order to collate all research evidence on the above mentioned variables.

Results

Thoraflex™ Hybrid Plexus seems to yield optimum aortic remodeling by promoting maximum false thrombosis as well true lumen expansion. Thoraflex Hybrid™ is also associated with the lowest incidence of dSINE post-FET relative to the other FET devices on the market. Aortic remodeling and dSINE do influence each other and are both linked with FET graft length and size.

Conclusion

The FET technique for TAR shows excellent aortic remodeling but is associated with a considerable risk of dSINE development. However, Thoraflex™ Hybrid has demonstrated itself to be the superior FET device on the aortic arch prostheses market. Since aortic remodeling, dSINE, FET insertion length and stent graft size are all interconnect, the choice of FET device length and size must be made with great care for optimum results.

Update in aortic dissection

New concepts regarding the diagnosis, classification, and treatment of aortic dissection have been recently developed. The aim of this paper is to describe the current state of knowledge on this subject and discuss any controversies surrounding it. Novel findings in the patho mechanisms of aortic dissection have evolved focusing on the indications for preventive surgery, biomarkers, and four-dimensional (4D)-flow magnetic resonance imaging. New classifications of aortic dissections have been proposed (TEM, STS/SVS). Finally, recent treatment improvements in aortic dissection treatment options have been presented, i.e., the frozen elephant trunk approach, thoracic endovascular repair, and the endo-Bentall concept as a future option.

Endovascular rescue for malpositioned frozen elephant trunk into the false lumen

We describe a case of frozen elephant trunk deployment unintentionally malpositioned into the false lumen. An 83-year-old man underwent total arch repair with a frozen elephant trunk for type A acute aortic dissection complicated by mesenteric malperfusion. However, intraoperative transesophageal echocardiography showed expansion of the false lumen in the descending aorta, suggesting a malpositioned frozen elephant trunk into the false lumen. Endovascular fenestration of the dissecting flap and subsequent endograft deployment from the inside of the malpositioned frozen elephant trunk graft to the true lumen of the descending aorta was successfully performed under intravascular ultrasound guidance.