Dynamics of Homemade Aortic Endografts: In Vivo Study in Humans with Computed Tomography Scanner Modeling

Degradation Phenomena on "Homemade" Explanted Aortic Textile Endografts

Objective

In the 1990s, the concept of “homemade” endografts (EGs) using commercially available materials was proposed in clinical practice for endovascular abdominal aortic repair (EVAR). The aim of this study was to analyse the ageing phenomena of these EGs in light of explant analyses.

Methods

The study focused on five explanted homemade EGs collected from 2012 to 2014. The explants were assessed in accordance with the ISO 9001/13485 certified standard protocol, which included naked eye evaluation, organic remnant cleaning, and microscopic and endoscopic examinations and analysis (magnification range from 20% to 200%). The observations report followed a classification based on 12 features assessing the fabric cover, the stitch filament, and the stents.

Results

The reasons for explantation were type 1 endoleak in three cases and aneurysm sac growth in two. The implantation duration ranged from 56 to 202 months. Sixty three per cent of the fabric surface lesions (holes and tears) were related to abrasion between the fabric and the stents. Up to 33% of the knots used to connect adjacent stents were broken on one EG. Other defects including running suture rupture and stent corrosion were also observed. The overall hole cumulated surface ranged from 0.377 mm² (56 month of implantation) up to 3.21 mm² (78 month of implantation).

Conclusion

In this study, various ageing phenomena on homemade textile EGs were identified and classified. The main damaging mechanisms were related to abrasion stress leading to tears and holes in the fabric, stitch ruptures, and detachment of stent segments responsible for serious EG deformations and further degradation.

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Main homemade endografts damaging mechanisms are related to abrasion stress (friction wear).

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Abrasion stent–metal, knot ruptures, and kinking phenomena were associated.

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Some damaging mechanisms were related to the creation technique (one piece stent skeleton).

Four-year results of the Bolton relay proximal scallop endograft in the management of thoracic and thoracoabdominal aortic pathology with unfavorable proximal landing zone

BACKGROUND

Thoracic endovascular aortic repair with a scallop design (scallop-TEVAR) is a useful treatment strategy to extend the proximal landing zone (PLZ), while maintaining perfusion to one or more of the supra-aortic trunks (SATs) when treating aortic pathology with an unfavorable PLZ. The durability of this approach with the Bolton Relay scallop endograft (Terumo Aortic, Sunrise, Fla) has not been established.

METHODS

A retrospective review of prospectively collected data on consecutive patients that received scallop-TEVAR in zones 0 to 2 at a tertiary aortic unit was undertaken. The main outcome was durability, characterized by survival estimates, freedom from reintervention to the thoracic aorta and PLZ, migration and aneurysm sac regression.

RESULTS

Between 2009 and 2019, 38 patients (71% male; median age, 70 years) underwent scallop-TEVAR for thoracic aortic pathology (n = 28, 74%) or as a part of thoracoabdominal aneurysm repair (n = 10 [26%]). The use of scallop-TEVAR significantly extended the PLZ (median, 5 mm preoperative PLZ vs 26 mm extended PLZ; P = .0001). A total of 41 SATs were perfused with a scallop, including the left subclavian artery (n = 25), left common carotid artery (n = 6), neo/innominate artery (n = 4), left subclavian artery, and vertebral artery (n = 1), innominate artery, and left common carotid artery (n = 2) in conjunction with 15 extra-anatomical bypasses. The PLZ was at Ishimaru zone 0 and 1 in 6 cases (16%), respectively, and zone 2 in 26 cases (68%). Technical success was 98%. The 30-day mortality was 5% (2/38; 1 death from myocardial infarction and 1 from multiorgan failure). A minor stroke occurred in three patients (8%) and temporary spinal cord ischemia in two patients (5%). The median follow-up was 4.5 years (range, 0-10.53 years) during which two patients (5%) developed type Ia endoleak and required intervention to the PLZ (one from device-related migration and one from disease progression). All-cause and aorta-related survival were 72% and 85% and freedom from thoracic and PLZ reintervention was 92% and 97%, respectively. There were no cases of early or late thoracic aortic rupture, retrograde type A aortic dissection or SAT occlusion.

CONCLUSIONS

Scallop-TEVAR offers a less invasive treatment option to extend the seal zone in selected patients with an unfavorable PLZ, allowing for a durable repair in terms of overall survival and reintervention. Periprocedural stroke remains a principle concern.