Normothermic frozen elephant trunk: our experience and literature review

Effect of lower-body ischemia duration in aortic arch surgery under mild-to-moderate hypothermic circulatory arrest

Objectives

Aortic arch surgery is performed at increasingly higher circulatory arrest temperatures. This might affect visceral protection. We analyzed the effect of visceral ischemic time in arch surgery under mild-to-moderate hypothermia.

Methods

We divided the population into 3 groups: group 1 (visceral ischemic time ≤30 minutes), group 2 (31-60 minutes), and group 3 (>60 minutes). The link between visceral ischemic times and in-hospital outcomes, and visceral function biomarker levels were retrospectively analyzed through chi-square test, nonparametric analysis of variance, and cubic spline interpolation.

Results

From 1995 to 2023, 1325 patients underwent aortic arch surgery under circulatory arrest at our center. Mild-to-moderate hypothermia (nasopharyngeal temperature ≥25°) was used in 960 cases. There was no significant difference among the groups for in-hospital death (group 1 = 8.5%, group 2 = 13.2%, group 3 = 11.3%; P = .224), renal complications (group 1 = 13.0%, group 2 = 19.7%, group 3 = 22.6%; P = .056), and gastrointestinal complications (group 1 = 5%, group 2 = 5.5%, group 3 = 7.1%; P = .696). However, respiratory complications (group 1 = 19.4%, group 2 = 28.1%, group 3 = 21.4%; P = .027) and transient dialysis (group 1 = 2.8%, group 2 = 7.8%, group 3 = 11.3%; P = .011) were linked to longer visceral ischemic times. Groups 2 and 3 presented significantly higher levels of creatinine (P < .01), glutamic-oxaloacetic transaminase (P < .05), and glutamic pyruvic transaminase (24 and 48 hours postsurgery, P < .01). Cubic spline analysis showed that the incidence of renal complications reached a minimum at a low visceral ischemic time and then consistently increased. Respiratory complications showed a maximum incidence at approximately 50 minutes of visceral ischemic time and then subsequently decreased.

Conclusions

Mild-to-moderate hypothermia is a safe strategy for visceral organ protection regardless of visceral ischemic time. However, longer visceral ischemic times are linked to renal complications.

The Frozen Elephant Trunk Procedure-8 Years of Experience from Poland

Background: The frozen elephant trunk method combines the implantation of a Dacron prosthesis with a self-expanding stent graft, which allows for complex repairs of the aortic arch and thoracic aorta in one procedure. Despite the advantages of hybrid treatment for aortic arch aneurysms, in Poland, only a few such surgeries are performed annually compared to in Western countries. The aim of this study was to demonstrate the 8-year outcomes of treatment at the center where the Aortic Team operates, which is one of the centers in Poland with the most extensive experience in hybrid FET treatment. Methods: Patients who underwent frozen elephant trunk surgery for chronic and acute pathologies of the aortic arch and thoracic aorta between March 2016 and March 2024 were comprehensively analyzed retrospectively. Frozen elephant trunk procedures were performed under three consecutive clinical conditions: acute aortic dissection, chronic aortic dissection and redo surgery. Results: A total of 40 patients (median age: 60 years (53-66), 67.5% male) were admitted to our hospital and underwent an FET procedure. The median Euroscore II was 25.9% and the 30-day mortality was 7.5%. The 1-year and 5-year mortalities were the same, equal to 15%, with mortality cases observed only in the first and second groups of consecutive patients during the first two months of follow-up. Spinal cord injury was observed in 2.5% of patients. Conclusions: The FET technique can be successfully used to treat aortic aneurysms with optimal results and low complication rates. The surgery length, including the cardiopulmonary bypass and aortic cross-clamp times, decreased significantly with increasing experience.

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.

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.

Hybrid Treatment of Complex Diseases of the Aortic Arch and Descending Thoracic Aorta by Frozen Elephant Trunk Technique

The surgical management of acute and chronic complex diseases involving the aortic arch and the descending thoracic aorta remains challenging. Hybrid procedures associating total open arch replacement and stent-grafting of the proximal descending aorta were developed to allow a potential single-stage treatment, promote remodeling of the downstream aorta, and facilitate a potential second-stage thoracic endovascular aortic repair by providing an ideal landing zone. While these approaches initially used various homemade combinations of available conventional prostheses and stent-grafts, the so-called frozen elephant trunk technique emerged with the development of several custom-made hybrid prostheses. The aim of this study was to review the contemporary outcomes of this technique in the management of complex aortic diseases, with a special focus on procedural planning, organ protection and monitoring, refinements in surgical techniques, and long-term follow-up.

A Strategy for Minimizing Circulatory Arrest Duration in Complex Aortic Arch Procedures

Background and Objectives: Aortic arch pathologies represent a surgical challenge. The challenge is partly due to the necessity of complex cerebral, visceral, and myocardial protection measures. Aortic arch surgery generally requires a significant duration of circulatory arrest, which includes deep hypothermia levels with the associated sequelae. This retrospective observational study shows the feasibility of a strategy that reduces circulatory arrest duration and eliminates the need for deep hypothermia during the procedure. Materials and Methods: Between January 2022 and January 2023, 15 patients (n = 15) with type A aortic dissection underwent total arch replacement with a frozen elephant trunk. Cardiopulmonary bypass and organ perfusion were established via arterial lines in the right axillary artery and one of the femoral arteries. In the latter vessels, a y-branched arterial cannula was used (ThruPort^TM₎, allowing for endo-clamping of the stent part of the frozen elephant trunk with a balloon and subsequent perfusion of the lower body. Results: Applying this modified perfusion technique, circulatory arrest time could be reduced to a mean of 8.1 ± 4.2 min, and surgery was performed at a mean lowest body temperature of 28.9 ± 2.3 °C. The mean ICU and hospital stays were 18.3 ± 13.7 days and 23.8 ± 11.7 days, respectively. The rate for 30-day survival was 100%. Conclusions: By applying our modified perfusion technique, the circulatory arrest duration was below ten minutes. As a consequence, deep hypothermia could be avoided, and surgery could be performed at moderate hypothermia. Future studies will have to show whether these changes may be translated into a clinical benefit for our patients.