Comparison of the conventional frozen elephant trunk implantation technique with a modified implantation technique in zone 1

Postoperative In-Stent Thrombus Formation Following Frozen Elephant Trunk Total Arch Repair

Objectives

Our aim was to investigate the occurrence and clinical consequence of postoperative in-stent thrombus formation following the frozen elephant trunk (FET) procedure.

Methods

Postoperative computed tomography angiography (CTA) scans of all 304 patients following the FET procedure between 04/2014 and 11/2021 were analysed retrospectively. Thrombus size and location were assessed in multiplanar reconstruction using IMPAX EE (Agfa HealthCare N.V., Morstel, Belgium) software. Patients’ characteristics and clinical outcomes were evaluated between patients with and without thrombus formation.

Results

During the study period, we detected a new postoperative in-stent thrombus in 19 patients (6%). These patients were significantly older (p = 0.009), predominantly female (p = 0.002) and were more commonly treated for aortic aneurysms (p = 0.001). In 15 patients (79%), the thrombi were located in the distal half of the FET stent-graft. Thrombus size was 18.9 mm (first quartile: 12.1; third quartile: 33.2). Distal embolisation occurred in 4 patients (21%) causing one in-hospital death caused by severe visceral ischaemia. Therapeutic anticoagulation was initiated in all patients. Overstenting with a conventional stent-graft placed within the FET stent-graft was the treatment in 2 patients (11%). Outcomes were comparable both groups. Female sex (p = 0.005; OR: 4.289) and an aortic aneurysm (p = 0.023; OR: 5.198) were identified as significant predictors for thrombus development.

Conclusion

Postoperative new thrombus formation within the FET stent-graft is a new, rare, but clinically highly relevant event. The embolisation of these thrombi can result in dismal postoperative outcomes. More research is therefore required to better identify patients at risk and improve perioperative treatment.

Taking the frozen elephant trunk technique to the next level by a stented side branch for a left subclavian artery connection: a feasibility study

OBJECTIVES

Our goal was to develop a modified frozen elephant trunk (FET) prosthesis with a stented left subclavian artery (LSA) side branch for LSA connection and to perform preclinical testing in a human cadaver model.

METHODS

We measured aortic diameters, distance between and diameters of supra-aortic vessels and the distance from the LSA offspring to the level of the left vertebral artery offspring in 70 patients. Based on these measurements, a novel FET prosthesis was developed (Cryolife/Jotec, Hechingen, Germany) featuring a stented side branch for an intrathoracic LSA connection. The feasibility and ease of implantation were tested in 2 human cadaver models at the Anatomical Institute of the Medical University Graz. A covered stent graft (Advanta V12™ by Atrium Medical Corp., Hudson, NH, USA) was used for an LSA extension.

RESULTS

Accurate deployment of the novel FET prosthesis with anatomical orientation of the stented side branch towards the LSA ostium followed by consecutive stent graft deployment was feasible in both cases. Proximalizing the distal anastomosis level from zone 3 to zone 1 not only diminished the complexity of the procedure but substantially facilitated the completion of the distal anastomosis. A 2.5-cm long extension stent graft was sufficient to seal to the LSA and to maintain left vertebral artery patency in both cases.

CONCLUSIONS

This initial study in human anatomical bodies could demonstrate the feasibility of implanting a newly designed FET prosthesis. This evolution of the FET technique has the potential to substantially ease total aortic arch replacement by proximalization of the distal anastomosis into zone 1 and by shortening spinal and lower body hypothermic circulatory arrest times via a stented side branch to the LSA. This direct connection enables early restoration of systemic perfusion.

Is total arch replacement associated with an increased risk after acute type A dissection?

Background

The surgical strategy for acute type A aortic dissection (AADA) usually consists of reconstruction of the tear-lesion in the affected part of the ascending aorta. The optimal strategy either to replace the ascending aorta (AAR) or to replace the ascending aorta and the total aortic arch (TAAR) is still under debate. Our study compares the 30-day mortality between AAR and TAAR in AADA surgery.

Methods

In this retrospective observational study, we analysed a total patient cohort of 339 patients who underwent surgery for AADA from January 2001 until December 2016. A propensity score-matched analysis between the AAR- and the TAAR-group with 43 patients for each subgroup was subsequently carried out. A multivariable analysis was performed to identify risk-factors for the 30-d-mortality. The 30-day mortality was defined as the primary end-point and long-term survival was the secondary endpoint.

Results

In 292 (86.1%) patients AAR and in 47 (13.9%) patients TAAR was performed for emergent AADA. Patients were older (P=0.049) in the AAR group. The median log Euro-SCORE was 25.5% (12.7; 41.7) for AAR and 19.7% (11.7; 32.2) for the TAAR patient cohort (P=0.12). Operative time, cardiopulmonary bypass- (CPB), cross-clamp- and ischemic time were significantly longer in the TAAR group (P<0.001). The overall 30-day mortality-rate was 17.7% (n=60) but was not significantly different between the two groups (P=0.27). Forty-nine (16.8%) patients died in the AAR and 11 patients (23.4%) in the TAAR group. After propensity-score matching, no difference in mortality was seen between the subgroups as well (P=0.44). Multivariable analysis identified the Euro-SCORE, long operation-time, postoperative dialysis and arrhythmia and administration of red blood cell concentrates as risk factors for 30-day mortality, but not for TAAR versus AAR.

Conclusions

The therapeutic goal in AADA surgery should be the complete restoration of the aorta to avoid further long-term complications and re-operations. Though 30-day mortality and postoperative co-morbidity for AAR are comparable to those in TAAR after treatment of AADA in our analysis, decision-making for the surgical strategy should weigh the operative risk of TAAR against the long-term outcome.