Trade in the hammer for a power driver-perspectives on the frozen elephant trunk repair for aortic arch disease

Kinking of Frozen Elephant Trunk Hybrid Prostheses: Incidence, Mechanism, and Management

Introduction

Kinking of the Frozen Elephant Trunk (FET) stent graft is one of the most devastating complications of the FET procedure. It can present post-operatively with reduced arterial pressures in the lower limbs and intermittent claudication. However, it can also be visualized intra-operatively by the surgeons. Unresolved kinking of the stent graft can result in intraluminal thrombus formation and subsequent multi-organ septic emboli.

Aims

The main scope of this review is to collate, summarize and present all the evidence in the literature on kinking of FET stent grafts.

Methods

We carried out a comprehensive literature search on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the incidence, mechanism, and management of FET graft kinking.

Results

Incidence of kinking is variable, ranging from 0% to 8% in the literature, with varying rates associated with each stent graft type. The Thoraflex Hybrid^TM prosthesis seemed to be the most commonly used and superior graft, and out of all the 15 cases of kinking reported in the literature, 5 (33.3%) were associated with just the Frozenix graft which had the highest incidence. There are multiple theories regarding the mechanism of kinking, including the direction of blood flow, the length of the stent grafts used, and the position of the prosthesis in relation to the flexure of the aorta. Multiple reparative management techniques have been suggested in the literature and include total endovascular repair, open repair, balloon dilatation, and deploying a second stent graft.

Conclusion

Graft kinking is one of the most critical complications of the FET technique. Its life-threatening sequelae warrant appropriate follow-up of these patients post-operatively, in addition to time management if kinking is suspected. Given the limited evidence in the literature, future studies should incorporate graft kinking into their outcomes reporting.

Repeat Surgery in Chronic Aortic Dissection: A New Technique without Touching the Native Aorta

BACKGROUND

 Repeat surgery of the chronically dissected aorta following repair of a Type-A acute aortic dissection (AAD) still represents a challenge. The proposed surgical options are as follows: (1) staged procedure with elephant trunk (ET) technique, (2) traditional frozen elephant trunk (FET) intervention, and (3) beating heart cerebral vessel debranching followed by thoracic endovascular aortic repair (TEVAR). However, a marked enlargement of the proximal descending thoracic aorta might make it difficult to perform FET/ET intervention. Furthermore, because in conventional surgery for AAD, a prosthetic graft replacement is generally limited to the ascending aorta, and in repeat surgery, this short Dacron graft rarely provides enough room to allow a beating heart cerebral vessel debranching and obtaining a reliable landing zone for the implantation of a firmly anchored stent graft.

METHODS

 We retrospectively reviewed all the five consecutive patients treated in our institution, between 2014 and 2017, for chronic aortic dissection after successful surgical treatment of acute Type-A aortic dissection with graft replacement limited to the ascending aorta. The five patients underwent repair utilizing a modified FET technique with total aortic arch and upper descending aorta exclusion without touching the native dissected aorta.

RESULTS

 No early- or midterm mortality was observed. Mean time interval between the initial and the reoperative procedure was 26 months (range, 3-80 months). No patient had a minor/major neurologic event. Mean circulatory arrest time was 16 minutes (range, 11-25 minutes). Mean follow-up time was 22 months (range, 9-42 months).

CONCLUSIONS

 We report our initial experience with a modified FET technique realized by anastomosing the stent graft with the previously implanted ascending aortic graft in Hishimaru's zone 0 and by rerouting all cerebral vessels without "touching" the native chronically dissected aorta. A larger number of patients and a longer follow-up will be required to confirm these initial encouraging results.

Zone zero hybrid arch exclusion versus open total arch replacement

Open total aortic arch replacement is one of the most technically demanding operations in cardiothoracic surgery, requiring operator expertise and intraoperative and postoperative teamwork. Despite current advancements in the field of open aortic surgery with regard to intraoperative brain protection and postoperative care, the morbidity and mortality associated with open total arch operations varies. Endovascular and hybrid procedures involving the use of zone 0 as a landing zone allow fair comparison between open total arch and hybrid operations. Hybrid procedures involving all of the other landing zones [1-4] should not be compared with open total arch replacement, as the extent of the pathology is different.