Outcomes of long versus short stent cronus hybrid prosthesis in type A aortic dissection: A single centre experience

Next-Generation Frozen Elephant Trunk Technique in the Era of Precision Medicine

The frozen elephant trunk (FET) technique can be applied to extensive aortic pathology, including lesions in the aortic arch and proximal descending thoracic aorta. FET is useful for tear-oriented surgery in dissections, managing malperfusion syndrome, and promoting positive aortic remodeling. Despite these benefits, complications such as distal stent-induced new entry and spinal cord ischemia can pose serious problems with the FET technique. To prevent these complications, careful sizing and planning of the FET are crucial. Additionally, since the FET technique involves total arch replacement, meticulous surgical skills are essential, particularly for young surgeons. In this article, we propose several techniques to simplify surgical procedures, which may lead to better outcomes for patients with extensive aortic pathology. In the era of precision medicine, the next-generation FET device could facilitate the treatment of complex aortic diseases through a patient-tailored approach.

The frozen elephant trunk: seeking a more definitive treatment for acute type A aortic dissection

OBJECTIVES

Conventional treatment for type A aortic dissection includes replacement of the ascending aorta with an open distal anastomosis in the hemiarch position. The frozen elephant trunk (FET) is a hybrid technique that extends the repair to the descending thoracic aorta. The goal is to improve resolution of malperfusion syndrome and to induce positive aortic remodelling and reduce the need for reintervention on the downstream aorta. We aim to summarize the data on the short and long-term outcomes of this technique.

METHODS

A thorough search of the literature was conducted isolating all articles dealing with aortic remodelling after the use of FET in case of type A acute aortic dissection. Keywords 'aortic dissection', 'frozen elephant trunk', 'aortic remodelling' and 'false lumen thrombosis' were used. Data for type B and chronic aortic dissections were excluded.

RESULTS

FET use favourably influences aortic remodelling. The main advantages lie in the exclusion of distal entry tears in either the aortic arch or descending aorta thus restoring antegrade blood flow in the true lumen and inducing false lumen thrombosis. False lumen thrombosis is not only induced at the level of the stent deployment but also lower in the distal descending aorta. Moreover, it offers an adequate landing zone in the mid-descending aorta for second-stage endovascular or open surgical aortic repair, if needed.

CONCLUSIONS

FET can be advantageous in the treatment of acute type A aortic dissection dealing with extended aortic pathology.

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.

Frozen Elephant Trunk for Aortic Dissection Using Different Hybrid Grafts: Preliminary Results from a Prospective Study

BACKGROUND

The frozen elephant trunk technique has become popular and led to an expansion of indications for surgery. Various hybrid grafts for the frozen elephant trunk are used, sometimes with significantly different features. The objective of this study was to compare early- and mid-term outcomes after the frozen elephant trunk for aortic dissection using different hybrid grafts.

METHODS

The prospective study included 45 patients with acute/chronic aortic dissections. The patients were randomized into two groups. Group 1 patients (n = 19) were implanted with a hybrid graft E-vita open plus (E-vita OP). Group 2 (n = 26) included patients who received a MedEng graft. The inclusion criteria were type A and type B acute and chronic aortic dissection. The exclusion criteria were as follows: hyperacute aortic dissection (less than 24 h), organ malperfusion, oncology, severe heart failure, stroke, and acute myocardial infarction. The primary endpoint was early- and mid-term mortality. The secondary endpoints were postoperative complications (stroke and spinal cord ischemia, myocardial infarction, respiratory failure, acute renal injury, and re-operation for bleeding).

RESULTS

The rate of stroke and spinal cord ischemia in the E-vita OP vs. MedEng groups was 11% vs. 4% (p = 0.565) and 11% vs. 0% (p = 0.173), respectively. The respiratory failure rate was comparable in both groups (p > 0.999). Acute kidney injury requiring hemodialysis and the need for re-sternotomy in the MedEng group vs. E-vita OP group was 31% vs. 16% (p = 0.309) and 15% vs. none (p = 0.126), respectively. Early mortality in the MedEng and E-vita OP groups did not differ (8% vs. 0, p = 0.501). The mid-term survival in the analyzed groups was 79% vs. 61%, (p = 0.079), respectively.

CONCLUSIONS

No statistically significant differences were observed between patients receiving frozen elephant trunk with the hybrid MedEng and E-vita OP grafts in regard to early mortality and morbidity. Mid-term survival was also non-significant between analyzed groups with a trend toward more favorable mortality in the MedEng group.

Aortic remodeling, distal stent-graft induced new entry and endoleak following frozen elephant trunk: A systematic review and meta-analysis

BACKGROUND

The introduction of the frozen elephant trunk (FET) technique for total arch replacement (TAR) has revolutionized the field of aortovascular surgery. However, although FET yields excellent results, the risk of certain complications requiring secondary intervention remains present, negating its one-step hybrid advantage over conventional techniques. This systematic review and meta-analysis sought to evaluate controversies regarding the incidence of FET-related complications, with a focus on aortic remodeling, distal stent-graft induced new entry (dSINE) and endoleak, in patients with type A aortic dissection (TAAD) and/or thoracic aortic aneurysm.

MATERIALS AND METHODS

A comprehensive literature search was conducted using multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE to identify evidence on TAR with FET in patients with TAAD and/or aneurysm. Studies published up until January 2022 were included, and after applying exclusion criteria, a total of 43 studies were extracted.

RESULTS

A total of 5068 patients who underwent FET procedure were included. The pooled estimates of dSINE and endoleak were 2% (95% confidence interval [CI] 0.01-0.06, I²  = 78%) and 3% (95% CI 0.01-0.11, I²  = 89%), respectively. The pooled rate of secondary thoracic endovascular aortic repair (TEVAR) post-FET was 7% (95% CI 0.05-0.12, I²  = 89%) while the pooled rate of false lumen thrombosis at the level of stent-graft was 91% (95% CI 0.75-0.97, I²  = 92%). After subgroup analysis, heterogeneity for distal stent-graft induced new entry (dSINE) and endoleak resolved among European patients, where Thoraflex Hybrid (THP) and E-Vita stent-grafts were used (both I²  = 0%). In addition, heterogeneity for secondary TEVAR after FET resolved among Asians receiving Cronus (I²  = 15.1%) and Frozenix stent-grafts (I²  = 1%).

CONCLUSION

Our results showed that the FET procedure in patients with TAAD and/or aneurysm is associated with excellent results, with a particularly low incidence of dSINE and endoleak as well as highly favorable aortic remodeling. However the type of stent-graft and the study location were sources of heterogeneity, emphasizing the need for multicenter studies directly comparing FET grafts. Finally, THP can be considered the primary FET device choice due to its superior results.