Frozen versus conventional elephant trunk technique: application in clinical practice

Abstract

SummaryTreating complex aortic arch disease with proximal and distal aortic segment involvement is challenging. In recent years, different surgical and endovascular techniques have been applied in a single or multiple-stage approach with the aim to cure and simplify these conditions. The first procedure available for this purpose was the conventional elephant trunk technique. Its recent evolution is the frozen elephant trunk, which treats the descending thoracic aorta using the antegrade release of a self-expandable stent graft. In the following review article, we analyse the advantages and drawbacks of both techniques from clinical and practical perspectives.

Long-term survival and related outcomes for hybrid versus traditional arch repair—a meta-analysis

“…For the classic/conventional Elephant Trunk procedure, the graft is invaginated, positioned in the distal aorta and the folded end anastomosed to the open section of distal aorta. The inside fold is then everted and anastomosed with the proximal aorta-the distal end of the graft is left free-floating in the descending aorta to be secured during a second-stage procedure (10,16,17). If the second stage involves securing the trunk via endovascular intervention, then the procedure is considered to be a hybrid repair (rather than traditional repair) (10,18,19 Areas of the aorta affected by pathology and targeted as landing-zones for endovascular stents were defined according to the zone definitions established by Mitchell, Ishimaru and colleagues (22).…”

“…The inside fold is then everted and anastomosed with the proximal aorta-the distal end of the graft is left free-floating in the descending aorta to be secured during a second-stage procedure (10,16,17). If the second stage involves securing the trunk via endovascular intervention, then the procedure is considered to be a hybrid repair (rather than traditional repair) (10,18,19 Areas of the aorta affected by pathology and targeted as landing-zones for endovascular stents were defined according to the zone definitions established by Mitchell, Ishimaru and colleagues (22). Hybrid arch repair was classified according to definitions used by Bavaria and colleagues (3): hybrid type I repair: aortic arch vessels are de-branched and re-implanted on the healthy native proximal aorta, with a subsequent endovascular stent graft then placed to cover the diseased aorta; hybrid type II repair: the proximal ascending aorta is resected and replaced by a prosthetic graft, followed by arch vessel de-branching and re-implantation on the prosthetic graft, and completed by an endovascular stent inserted to cover the distal portion of the diseased aorta; hybrid type III repair: a socalled 'frozen' or stented elephant trunk is deployed during conventional arch replacement to facilitate concomitant aortic arch and proximal descending aneurysmal repair in a single stage.…”

“…Recent systematic reviews and meta-analyses have examined these series and present differences in short-term outcomes between open and hybrid aortic arch repair (HAR) techniques (10)(11)(12) and for hybrid techniques generally (13,14). This review aims to examine long-term survival outcomes from comparative studies and to conduct a metaanalysis of short-term outcomes.…”

Commentary: Despite global warming, frozen has its place

“…The use of cerebrospinal fluid drainage is not explicitly endorsed by the European position paper 6 ; however, it may help reduce the rate of postoperative paraplegia, which is a well-established risk of FET approaches to aortic arch repair. [8][9][10] Leone and colleagues 7 also described in detail the difference in operative strategies between the European centers of interest, Bologna University and Hannover medical school. For instance, Bologna University provided antegrade cerebral perfusion by using a variety of cannulation sites (such as the right axillary, femoral, innominate, or right carotid arteries) as well as direct cannulation of the ascending aorta, whereas Hannover Medical School commonly provided bilateral antegrade cerebral perfusion using the left carotid and innominate arteries.…”

Commentary: Does the risk of paraplegia leave you cold?

“…Aortic arch repair has substantially changed in recent decades-temperature targets during hypothermic circulatory arrest have risen, the use of antegrade cerebral perfusion is widespread, cannulation sites have shifted away from the femoral artery, debranching techniques for the brachiocephalic arteries have been adopted, and more. [2][3][4][5] Although this evolution of approach has reduced the risk of postoperative death and stroke for many patients, it is commonly accepted that both repair in the setting of acute type A aortic dissection and extended repair increase operative risk. 5,6 To reduce operative risk in the setting of acute type A aortic dissection, many aortic centers tend to limit repair to partial arch replacement; however, the use of frozen elephant trunk approaches holds the promise of a long-term benefit by facilitating remodeling of the false lumen and subsequently reducing the possibility of late dilatation of the chronically dissected distal aorta that often necessitates further repair.…”