Experimental Analysis of In Situ Fenestration of Endovascular Stent-Grafts: Comparison between Needle and Laser Puncture

Effects of Long Term Fatigue Cycling on In Situ Fenestrations of Polyethylene Terephthalate and Expanded Polytetrafluorethylene Thoracic Aortic Stent grafts: An Experimental Study

OBJECTIVE

In this study, the long term durability of fenestrations after in situ fenestration (ISF) of five commercial thoracic aortic stent grafts was evaluated in an in vitro experiment after a simulated 10 year period.

METHODS

Five different thoracic aortic stent grafts (Relay, Valiant, Hercules, TAG, and Ankura, with a diameter of 34 mm) received both needle and laser ISF in vitro. A Viabahn (11 × 50 mm) was released in each fenestration as a bridging stent graft. Long term fatigue tests (simulating 10 years) of each of the fenestrated stent grafts were then conducted in a flow fatigue test system. The area, shape, margin, and the long and short axis of all the fenestrations were evaluated with light microscopy before and after the fatigue test. The leakage from the fenestration junction before and after the long term fatigue was also measured.

RESULTS

The experimental results showed no obvious difference between needle and laser fenestrations. The long axes of all the fenestrations remained unchanged, while the short axes increased after the fatigue test, which was significant in Relay, Valiant, and Hercules polyethylene terephthalate stent grafts. The shape scores of fenestrations improved after the fatigue test in Valiant and Hercules, remained unchanged in Relay and Ankura, and worsened in the TAG. After the fatigue cycling, the average leakage from the fenestration junction decreased in all the stent grafts, and the Ankura had the maximum decline rate.

CONCLUSION

The ISF technique was durable over a simulated 10 year period. The fenestrations were positively remodelled to be more circular, and the leakage from the junction decreased after long term fatigue testing.

TEVAR for aortic arch lesions combining physician-modified endograft and in-situ fenestration

BACKGROUND

The aim of this retrospective study was to investigate the outcomes of combining physician-modified endograft (PMEG) and in-situ fenestration (ISF) for aortic arch repair.

METHODS

A retrospective analysis was performed in 12 patients with aortic arch pathologies who underwent thoracic endovascular aortic repair with PMEG and ISF between June 2019 and February 2020.

RESULTS

Revascularizations of supra-aortic arteries were successfully performed in 91.7% patients (11/12). One patient with aberrant right subclavian artery was unsuccessful because of tortuosity and sharp angle. One patient received endovascular exclusion by Viabahn due to artery injury of the femoral access. During the follow-up (mean 22.7 months), one patient underwent Bentall surgery because of retrograde type A aortic dissection, and one patient received coils embolization due to occurrence of a type I endoleak. In addition, one patient died of myocardial infarction 13 months after surgery. Results obtained after computed tomography angiography confirmed patency of all the supra-aortic arteries.

CONCLUSIONS

Combining PMEG and ISF could be a feasible option for aortic arch lesions in selected patients. Long-term durability concerns require further evaluation.

Comparative effectiveness and safety of laser, needle, and "quick fenestrater" in in situ fenestration during thoracic endovascular aortic repair

Background

Special instruments are needed for the revascularization of aortic branches in in situ fenestration during thoracic endovascular aortic repair (TEVAR). This prospective study compared the effectiveness and safety of three currently used fenestraters: laser, needle, and Quick Fenestrater (QF).

Methods

In all, 101 patients who underwent TEVAR for aortic disease (dissection, n = 62; aneurysm, n = 16, or ulcer, n = 23) were enrolled. All patients were randomly assigned to three groups: 34 were assigned to laser fenestration, 36 to needle fenestration, and 31 to QF fenestration. The epidemiological data, treatment, imaging findings, and follow-up outcomes were analyzed using data from the medical records.

Results

The technical success rates of the laser, needle, and QF fenestration groups were 94.1%, 94.4%, and 100% (p > 0.05). After correction of mixed factors such as age and gender, it was showed the average operative time (Laser group: 130.01 ± 9.36 min/ Needle group: 149.80 ± 10.18 min vs. QF group: 101.10 ± 6.75 min, p < 0.001), fluoroscopy time (Laser group: 30.16 ± 9.81 min/ Needle group: 40.20 ± 9.91 min vs. QF group: 19.91 ± 5.42 min, p < 0.001), fenestration time (Laser group 5.50 ± 3.10 min / Needle group 3.50 ± 1.50 min vs. QF group 0.67 ± 0.06 min, p < 0.001), and guide wire passage time after fenestration (Laser group 5.10 ± 1.70 min / Needle group 4.28 ± 1.60 min vs. QF group 0.07 ± 0.01 min, p < 0.001) were all shorter with QF fenestration than with the other two tools. The overall perioperative complication rates of the laser, needle, and QF fenestration groups were 5.9%, 5.6%, and 0% (p > 0.05): One case of sheath thermal injury and one case of vertebral artery ischemia occurred in the laser fenestration group; one case each of access site hematoma and brachial artery thrombosis were reported in the needle fenestration group. 89 (88.1%, 89/101) patients were followed for a median of 12.6 ± 1.6 months. The overall postoperative complication rates of the laser, needle, and QF fenestration groups were 3.3%, 6.5%, and 0% (p > 0.05): In the laser fenestration group, there was one death due to postoperative ST-segment elevation myocardial infarction; in the needle fenestration group, one patient developed occlusion of the bridge stent; no complications occurred in the QF group.

Conclusion

All three fenestration methods were effective in reconstructing supra-arch artery during TEVAR. QF fenestration required less contrast agent, with a shorter surgery duration and fewer complications than laser and needle fenestration.

Parallel grafts and physician modified endografts for endovascular repair of the aortic arch

Aortic arch aneurysms are a challenging clinical problem especially in high-risk patients. Open aortic arch replacement, even in the best of centers, carries significant risk of stroke or death in this high-risk population. Many high-risk patients are deemed inoperable and not offered repair. Branched and fenestrated thoracic endografts are currently undergoing clinical trials in the United States but are not yet commercially available. Many elderly and frail patients have significant brachiocephalic occlusive disease or anatomy excluding them for consideration for such clinical trials. These patients also present with acute aortic syndromes requiring urgent or emergent repair and are unable to participate in clinical trials due to the time required to have such devices available. Alternative endovascular therapies, including parallel stent grafts (including Chimneys, Snorkels and Periscopes) and physician modified thoracic endografts, have been used to treat such high-risk patients combined with commercially available thoracic endovascular aneurysm repair (TEVAR) devices. This paper aims to review the techniques and current reported outcomes from parallel stent grafts and physician modified devices used to treat high risk patients undergoing repair for aortic arch pathologies.