Graft Durability and Fatigue after In Situ Fenestration of Endovascular Stent Grafts Using Radiofrequency Puncture and Balloon Dilatation

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.

Comparison of the Snare Loop Technique and the Hungaroring Reinforcement for Physician-Modified Endograft Fenestrations-An In Vitro Study

BACKGROUND

We conducted an in vitro comparison of the snare loop reinforcement against a closed-loop reinforcement (Hungaroring) for physician-modified endograft (PMEG) fenestrations regarding preparation time and stability during flaring balloon dilatation.

MATERIALS AND METHODS

The time to complete a PMEG fenestration with reinforcement was measured and compared between the Hungaroring and snare loop groups. The number of stitches was counted. Each fenestration was dilated using a 10 mm high-pressure, non-compliant balloon up to 21 atm in pressure, and fluoroscopic images were taken. The presence of indentation on the oversized balloon at the level of the reinforcement was evaluated at each fenestration.

RESULTS

Five fenestrations were created in each group (n = 5) for a total of ten pieces. The completion time in the snare loop group was 1070 s (IQR:1010-1090) compared to 760 s (IQR:685-784) in the Hungaroring group (p = 0.008). Faster completion time was achieved by faster stitching (23.2 s/stitch (IQR 22.8-27.3) for the snare loop group and 17.3 s/stitch (IQR 17.3-20.1) for the Hungaroring group (p = 0.016). None of the fluoroscopic images of the snare loop reinforcement showed an indentation on the balloon during the overexpansion; on the contrary, the Hungaroring showed indentation in every case, even at 21 atm.

CONCLUSION

Fenestrations reinforced with Hungaroring can be completed significantly faster. Furthermore, the Hungaroring resists over-dilation even at high pressures, while snare loop reinforcements dilate at nominal pressure.

Early and midterm outcomes of in situ fenestration via adjustable puncture needle for Ankura aortic stent graft: A single-center experience

OBJECTIVES

An analysis was conducted to demonstrate early and midterm outcomes of using adjustable puncture needle-based in situ fenestration (ISF) technique for Ankura aortic stent graft to reconstruct the supra-arch branch in thoracic endovascular aortic repair (TEVAR).

METHODS

A retrospective analysis of 68 cases of aortic lesions with insufficient proximal anchoring area admitted to our department from March 2017 to December 2021 was performed. In situ fenestration thoracic endovascular repair (TEVAR) was performed at the same time during the operation. Among them, there were fifty-eight cases of thoracic aortic dissection, seven cases of thoracic aortic aneurysm, and three cases of thoracic aortic ulcer. Intraoperative adjustable puncture with needle was used for the Ankura aorta stent graft to perform ISF and reconstruction of the supra-arch branch.

RESULTS

The success rate of ISF was 94.1% (64/68). Only in four cases, attempts were made to create ISF in the left subclavian artery (LSA), and all the four were unsuccessful because of sharp and tortuosity angle. Among them, forty-four cases were only LSA fenestration, and one case was left common carotid artery (LCCA) fenestration + LSA embolism. LSA + left vertebral artery (LVA) fenestration was performed in two cases, LSA fenestration +LCCA chimney was performed in fourteen cases, LCCA + LSA fenestration + innominate artery (INA) chimney was performed in one case, and LCCA fenestration + INA chimney + LSA embolism was performed in two cases. The overall neurologic event rate was 3.1% (spinal cord ischemia 0, with stroke observed in two cases). Postoperatively, one patient (1.6%) died on the third day after TEVAR due to the retrograde dissections. There were four cases of endoleak (6.3%; three type I and one type II). The average follow-up was 29.2 ± 14.4 months, and no patient died during the follow-up period. Three cases of endoleak disappeared, and one case did not increase further. In addition, other two cases of retrograde dissections were observed at 3 and 5 months after TEVAR. Fortunately, they were scheduled for emergency surgery with ascending aorta replacement and improved well. There was only one case of LSA occlusion after ISF which was reconstructed by endovascular treatment. Two patients were found with distal stent graft-induced new entries (dSINE), and TEVAR was performed again during the follow-up period.

CONCLUSION

Early and midterm outcomes demonstrated that ISF via the adjustable puncture needle device for the Ankura aorta stent graft is a feasible and effective treatment method, which can achieve high technical success and satisfactory short-term results.

Stent-Graft Fabrics Incorporating a Specific Corona Ready to Fenestrate

In situ fenestration of endovascular stent-grafts has become a mainstream bailout technique to treat complex emergent aneurysms while maintaining native anatomical visceral and aortic arch blood supplies. Fabric tearing from creating the in situ fenestration using balloon angioplasty may extend beyond the intended diameter over time. Further tearing may result from the physiologic pulsatile motion at the branching site. A resultant endoleak at the fenestrated sites in stent-grafts could ultimately lead to re-pressurization of the aortic sac and, eventually, rupture. In an attempt to address this challenge, plain woven fabrics were designed. They hold a specific corona surrounding a square-shaped cluster with a plain weave fabric structure, a 2/2 twill, or a honeycomb. The corona was designed to stop potential further tearing of the fabric caused by the initial balloon angioplasty and stent or later post-implantation motion. The cluster within the corona was designed with relatively loose fabric structures (plain weave, 2/2 twill weave, and honeycomb) to facilitate the laser fenestration. Two commercial devices, Anaconda (Vascutek, Terumo Aortic) and Zenith TX2 (Cook), were selected as controls for comparison against this new design. All the specimens were characterized by morphology, thickness, and water permeability. The results demonstrated that all specimens with a low thickness and water permeability satisfied the requirements for a stent graft material that would be low profile and resistant to endoleaks. The in situ fenestrations were performed on all fabrics utilizing an Excimer laser followed by balloon angioplasty. The fabrics were further observed by light microscopy and scanning electron microscopy. The dimension of the fenestrated apertures was smaller than the balloon's diameter. The tearing was effectively confined within the corona. The clinical acceptability of this concept deserves additional bench testing and animal experimentation.

Midterm Outcomes of Antegrade In Situ Laser Fenestration of Polyester Endografts for Urgent Treatment of Aortic Pathologies Involving the Visceral and Renal Arteries

OBJECTIVE

Aortic endografting and antegrade in situ laser fenestration of visceral arteries (LFEVAR) may be considered as an alternative to open surgery for the emergency repair of complex abdominal aortic aneurysms (AAA) in fragile patients. The aim of this article was to evaluate the midterm results of LFEVAR performed with polyester endografts.

METHODS

From August 2015 to December 2020, all consecutive LFEVAR performed for non-deferrable treatment of complex AAA were analysed. Polyester endografts were deployed and subsequently fenestrated using an atherectomy laser probe; the fenestrations were enlarged using cutting and semicompliant balloons before implantation of balloon expandable bridging stents into the target vessels. Prospectively collected midterm survival, patency, and re-intervention rates were analysed.

RESULTS

Forty four procedures were performed for 11 type 1a endoleaks, five thoraco-abdominal aneurysms, 20 pararenal aneurysms, four segmental renal artery (RA) preservations, three anastomotic aneurysms, and one aortic dissection. One hundred and eight laser fenestrations were performed (26 for the superior mesenteric artery [SMA], 13 for the coeliac trunk, 33 and 31 for the right and left RA, respectively). The median ischaemia duration was 7, 48, 48, and 45 minutes, respectively. The technical success rate was 97%, with no open surgical conversions. The 30 day mortality was 4.5% (n = 2). No spinal cord ischaemia events were observed nor early stent related complications. Kaplan-Meier overall survival at two years was 73%, the aortic related re-intervention free survival was 70%, and the stent related re-intervention free survival was 90.6%. Four target vessel thromboses were detected, of which three were rescued. Three type IIIc endoleaks, one RA false aneurysm, and one SMA stenosis, required re-intervention during a median follow up of 24.7 months.

CONCLUSION

Antegrade LFEVAR is feasible, safe, and provides satisfactory early and midterm outcomes for non-deferrable treatment of aortic pathologies involving the visceral segment. Long term data are mandatory to confirm the usefulness of this promising off label technique.

Techniques of antegrade in situ laser fenestration for endovascular aortic repair of complex abdominal and thoracoabdominal aortic aneurysms

Antegrade in situ laser fenestration allows for incorporation of visceral and renal arteries during endovascular repair of complex abdominal and thoracoabdominal aortic aneurysms. This technique can be particularly useful for urgent and emergent cases and for centers without access to manufactured fenestrated-branched endovascular aneurysm repair devices. In the present report, we have described two techniques of antegrade in situ fenestration, the common pitfalls, and the anatomic considerations for each technique.

An autopsy case of retrograde in situ branched stent grafting for a complex aortic arch aneurysm

Although retrograde in situ branched stent grafting (RIBS) is one possible treatment option for thoracic aortic aneurysms, concerns exist regarding the durability of the stent graft (SG) at the junction between the main SG and the branched SG. We report on the autopsy results of a patient treated with RIBS for a complex aortic arch aneurysm. The patient had died of a nonaortic cause 14 months after the RIBS procedure. On computed tomography analysis and a leak test, the harvested SG was intact without any stent fracture, stenosis, or junctional leak at 1 atm water pressure (760 mm Hg).

Early Clinical Outcomes of Retrograde In-Situ Branched Stent Grafting for Complex Aortic Arch Aneurysms

OBJECTIVE

To evaluate the early outcomes of retrograde in-situ branched stent grafting (RIBS) using the gutter balloon technique for complex aortic arch aneurysms (CAAs).

METHODS

The RIBS technique is an in-situ needle fenestration procedure during thoracic endovascular aortic repair (TEVAR) with the reconstruction of cervical branches. The Double-RIBS (D-RIBS) for the reconstruction of the left common carotid artery and the brachiocephalic artery using the gutter balloon technique was performed in 30 high-risk patients. We describe the early clinical results of the D-RIBS technique for CAAs. Primary endpoints were technical success and 30-day mortality. Secondary endpoints were postoperative complications, rates of endoleaks, overall survival, aneurysm-related death, and re-interventions.

RESULTS

The mean age was 77.1±6.6 years and the mean maximum minor-axis aneurysmal diameter was 65.9±8.9 mm. Twenty six patients underwent D-RIBS for elective arch aortic aneurysm and four patients were for reintervention after Zone 2 TEVAR failure. Stent graft puncture was performed 60 times from the common carotid arteries and technical success was achieved in all cases (100%). Postoperative complications included cerebral infarction in 2 patients (6.7%), recurrent nerve palsy in one patient (3.3%). The 30-day mortality was 0%. During the median follow-up period of 14 months (6-56), overall survival at 12 months was 92.3% without any aneurysm-related death. Type 1b and type 2 endoleaks were observed in one each and no reintervention was encountered.

CONCLUSION

Early clinical outcomes of the D-RIBS for high-risk patients with CAAs are acceptable. The gutter balloon method enables safe and reliable fenestration. Further studies and dedicated devices are warranted.

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

BACKGROUND

To evaluate the quality of in vitro fenestrations during in situ fenestration (ISF) and investigate the differences between needle and laser puncture in current stent-grafts.

METHODS

An in vitro study evaluated the damage created by needle ISF on stent-graft fabrics versus laser ISF. Fenestrations were made in 5 different commercially available stent-grafts, including polyester stent-grafts (Relay, Valiant and Hercules) and expanded polytetrafluoroethylene (ePTFE) stent-grafts (TAG and Ankura). Each stent-graft received fenestration by needle and laser separately, followed by gradual dilation (4 mm, 6 mm, 8 mm, and 10 mm sequentially) of noncompliant balloons. Quantitative and qualitative evaluations including fenestration diameter, area, shape and margins were conducted using light microscopy and scanning electron microscope.

RESULTS

The primary fenestrations created by needle were slit-like with visible cut-off fibers in polyester stent-grafts and were almost circular with clear margins in ePTFE stent-grafts; those created by laser were squared or elliptical with ragged edges and burned fibers in all the stent-grafts. Fabric debris and toxic particles due to burning of the material were generated during laser-assisted fenestration. The Primary holes in polyester stent-grafts (Relay, Valiant and Hercules) by needle showed smaller area (0.05 mm² vs. 0.22 mm2, 0.52 mm² vs. 0.70 mm² and 0.28 mm² vs. 0.46 mm²; P < 0.01) and worse shape (0.93 vs. 2.46, 1.17 vs. 2.33 and 0.93 vs. 2.47; P < 0.01) than those by laser, while larger area (0.67 vs.0.43, 0.59 vs.0.45; P < 0.05), better shape (3.93 vs. 2.53, 3.90 vs. 2.93; P < 0.05) and better margin (3.83 vs. 2.47, 3.83 vs. 2.53; P < 0.05) in ePTFE stent-grafts (TAG and Ankrura). After gradual balloon dilation, the final holes showed no evident difference in maximal length, fenestration area, scores of shape and margin between the 2 ways of fenestration (P > 0.05). Ankura stent-graft showed the largest holes with best quality than the others.

CONCLUSIONS

The primary fenestrations were different between needle and laser puncture, laser induced fabric debris and toxic particles release should be cautiously considered. The final fenestrations were similar after gradual balloon dilation.

Endovascular In Situ Fenestration Technique of Aortic Arch Pathology: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this study was to evaluate the safety, applicability and outcomes of the endovascular in situ fenestration (ISF) technique for patients with aortic arch pathologies by performing a systematic review.

METHODS

We conducted a systematic search using the PubMed, Embase, and Cochrane databases to identify English language articles between January 2004 and March 2019 on the management of aortic arch pathologies using an in situ fenestration technique. Two independent observers selected studies for inclusion in the study, assessed the methodological quality of the included studies, and extracted the data. The studies included all investigated the clinical outcomes and postprocedural complications of using ISF techniques.

RESULTS

Seven studies reported on a total of 117 aortic arch pathologies patients. Including 52 dissection patients, 47 aneurysm patients, 18 intramural hematomas and penetrating ulcers patients. Needle fenestration and laser fenestration were performed in 62 and 45 patients respectively, and the rest 10 patients received radiofrequency fenestration. The follow-up period ranged from 1 to 55 months. The pooled technical success rates were 94% (95% confidence interval [CI]: 79-98%). The stroke rate was 6% (95% CI: 3-13%). The 30-day MAE was 11% (95% CI: 6-18%).

CONCLUSION

The results of the study showed that using the in-situ fenestration technique for treating patients with aortic arch pathologies produced encouraging mid-outcomes. Long-term outcomes remain undefined.

Experimental Analysis of the Quality of Needle-Assisted Fenestration in Aortic Stent-Grafts and the Differences Between Gradual and Rapid Balloon Dilation

Purpose: To report the findings of an in vitro experiment to evaluate the quality of needle fenestrations dilated by different size balloons in various stent-grafts and to investigate the differences between gradual and rapid dilation. Materials and Methods: Fenestrations were made using an 18-G needle in 5 different polyester or expanded polytetrafluoroethylene (ePTFE) stent-grafts: Relay, Valiant, Hercules, TAG, and Ankura. Each stent-graft received 2 groups of fenestrations: one was followed by gradual sequential dilation (4-, 6-, 8-, and 10-mm balloons) and the other by rapid dilation (4- and 10-mm balloons). The pressure was increased to 10 atmospheres or until the balloon was fully inflated with no waist. Quantitative and qualitative evaluations, including fenestration diameter, area, shape, and margins were conducted using light microscopy and scanning electron microscopy. Results: Relay had the strongest resistance to dilation and Ankura the slightest. The maximum length and area of holes expanded as the balloon diameter increased. The fenestrations in polyester devices were mostly elliptical or slit-like, with limited tears but extensive fibers visible in the margin, while ePTFE stent-grafts showed larger fenestration areas with clearer margins. Ankura showed the best quality of fenestrations, which were always circular or square without fabric tears, while the holes in the TAG were square or elliptical but sometimes had a slit after large balloon dilation (≥6 mm). The Relay, Valiant, Hercules, and Ankura devices showed no difference in maximum diameter, fenestration area, or scores of shape and margin (p>0.05). Rapid dilation in the TAG increased the rate of uncontrolled fabric tear, resulting in a larger final diameter (12.90 vs 10.82 mm, p=0.047), smaller area (30.46 vs 41.09 mm2, p=0.028), worse shape (0.75 vs 1.20, p=0.268), and worse margin (0.40 vs 1.00, p=0.174). Though the decreased fenestration shape and margin scores did not reach statistical significance, the trend for decline was more obvious than with the other devices. Conclusion: Materials and structures of the stent-grafts determine the quality of fenestrations dilated by different size balloons. The use of sequential vs rapid balloon dilation is also crucial for fashioning high-quality fenestrations and should be selected judiciously.

Indirect Burst Pressure Measurements for the Mechanical Assessment of Biological Vessels

IMPACT STATEMENT

Vascular tissue engineering (VTE) is a rapidly expanding field, with numerous approaches being explored both in preclinical and clinical settings. A pivotal factor in the development of VTE techniques is patient safety, notably with respect to the mechanical properties of the vessels. Of the mechanical properties, the bursting strength, representing the ability of a vessel to withstand the forces exerted on it by blood pressure, is the most important. The burst pressure is commonly assessed using one of three methods proposed by the ISO 7198. In this study, we evaluate the three burst pressure assessment methods exactly as they are presently in the field of VTE. We show that the indirect assessment methods, as they are presently used, provide inconsistent and therefore unreliable estimates of the true yield stress of a vessel.

Methods and clinical outcomes of in situ fenestration for aortic arch revascularization during thoracic endovascular aortic repair

OBJECTIVE

Despite endovascular advances in fenestrated and branched devices, thoracic endovascular aortic repair (TEVAR) for arch pathologies remains challenging. The aim of this study was to provide a contemporary review on the current evidence for in situ fenestration during TEVAR and to evaluate its short- and mid-term clinical outcome in the management of arch pathology.

METHODS

A systematic literature review on in situ fenestration of thoracic aortic stent-graft from January 2003 to September 2018 was performed under the instruction of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

RESULTS

Our initial search yielded 169 studies, of which 21 articles were relevant to the topic and were finally included. One hundred and forty-five in situ fenestration procedures in 99 patients were reviewed, involving 25 innominate arteries (17%), 33 left common carotid arteries (23%) and 87 left subclavian arteries (60%). Twelve patients (12/99, 12%) had two-vessel fenestration and three-vessel fenestration was performed in 17 patients (17/99, 17%). Technical success was achieved in 136 arteries (136/145, 93%). Talent/Valiant with monofilament twill woven polyester fabric was the most common (50/99, 51%) stent-graft used for fenestration. Three methods reported for in situ fenestration were needle, laser and radiofrequency. Needle was the most frequently used device for fenestration, which was performed in 60 patients (60/99, 61%). Three patients (3/99, 3%) died with 30 days, none were in situ fenestration TEVAR procedure-related. Perioperative complications including one (1%) retrograde type A aortic dissection, two (2%) type II endoleaks, and three (3%) strokes were reported. The pooled estimate for overall technical success, perioperative mortality and stroke was 88.3% (95% CI, 78.6%-93.9%), 5.9% (95% CI, 2.5%-13.4%) and 9.5% (95% CI, 4.1%-20.6%), respectively. Four patients (4/96, 4%) died during follow-up, none were aortic-related. All the fenestration bridging stents were reportedly patent, with only 1 (1/96, 1%) asymptomatic left subclavian stent stenosis. Two patients (2/96, 2%) with type II endoleak from left subclavian artery required secondary intervention.

CONCLUSION

In situ fenestration appeared to be a feasible and effective method to extend proximal landing zone during TEVAR. It had an acceptable short-term result with high technical success and low fenestration related morbidity. Long-term durability data were lacking, and there was no high level evidence to recommend the routine use of in situ fenestration TEVAR for the management of arch pathology.

Multicenter Analysis of Endovascular Aortic Arch In Situ Stent-Graft Fenestrations for Aortic Arch Pathologies

BACKGROUND

In situ fenestration of aortic stent grafts for treatment of aortic arch aneurysms is a new option for endovascular aortic arch repair. So far, only few reports have shown perioperative and short-term results of in situ fenestrations for aortic arch diseases. We present the multicenter experience with the aortic arch in situ fenestration technique documented in the AARCHIF registry for treatment of aortic arch aneurysms or localized type A aortic dissections and analyzed perioperative outcome and midterm follow-up.

METHODS

Patients with aortic arch pathologies treated by aortic arch in situ fenestration with proximal stent graft landing in aortic arch Ishimura zones 0 and 1 were included in the registry. Stent-graft in situ fenestrations were created using needles or radiofrequency or laser catheters and completed by implantation of covered connecting stent grafts. Single in situ fenestrations for the left subclavian artery (LSA) were excluded.

RESULTS

Between 06/2009 and 03/2017, twenty-five patients were treated by in situ stent-graft fenestrations for aortic arch pathologies at 9 institutions in 7 different countries, 3 of them as bailout procedures for stent-graft malplacement. In situ fenestrations were performed for the brachiocephalic trunk (n = 20), the left common carotid artery (n = 21) and the LSA (n = 9). Technical success for intended in situ fenestrations was 94.0% (47/50), with additional supraaortic bypass procedures performed in 14 patients. Perioperative mortality occurred in 1 (4.0%) patient, treated as a bailout procedure and 3 (12.0%) perioperative strokes were observed. One proximal aortic stent-graft nonalignment and 4 type III endoleaks, 2 early and 2 late, required reeintervention. During follow-up (1-118 months), the diameter of aortic arch aneurysms decreased from 61.5 ± 4.1 mm to 48.4 ± 3.2 mm (P = 0.02) and, so far, 6 patients died from diseases unrelated to their aortic arch pathologies with a mean survival time of 79.5 months and 3 endovascular reinterventions for distal aortic expansion were performed. Cerebrovascular event (n = 4) was the most relevant prognostic factor for mortality during midterm follow-up (P = 0.003).

CONCLUSIONS

The aortic arch in situ fenestration technique for endovascular aortic arch repair seems to be valuable treatment option for selected patients, although initial consideration of other treatment options is mandatory. Data about long-term durability are required.

Hybrid Aortic Arch Repairs

Hybrid aortic arch repair (HAAR) consists of thoracic stent-graft repair and procedures to maintain cerebral blood flow. Several hybrid techniques have been used, including arch artery debranching, parallel graft technique, fenestration or branching of endograft, or a combination of these. We provided an overview of HAAR by presenting literature reviews as well as our clinical experience. The experience consisted of 172 patients who had undergone HAAR. The 30-day mortality was 3% (5/172). Persistent neurologic deficits occurred in 7 patients (4%), respiratory failure in 5 (3%), de novo aortic dissection in 3 and spinal cord injury in 2. 17% of the patients experienced type Ia endoleak. Seventeen patients required redo thoracic endovascular aortic repair. Fifty-six late deaths occurred during the follow-up period, including aortic-related death in 9 patients. In conclusion, hybrid arch debranching repair should be performed for elderly or high-surgical-risk patients. However, refining techniques and device technology is likely to reduce late endograft-related events. (This is a translation of Jpn J Vasc Surg 2018; 27: 385-391.).

Treatment of Aortic Coarctation by Self-expanding Thoracic Endograft with Left Subclavian In Situ Laser Fenestration

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) with self-expanding endograft is increasingly used as a viable treatment option for adult aortic coarctation (AC).

METHODS

We hereby reported a 55-year-old gentleman with late presentation of AC, treated by a novel strategy with thoracic endograft and in situ laser fenestration for left subclavian artery (LSA) revascularization.

RESULTS

AC was incidentally discovered during coronary angiogram as an investigation for his angina pectoris. TEVAR with self-expanding endograft was chosen because preoperative computer tomography scan showed ectatic thoracic aorta and stenosis just distal to the LSA. The patient was planned for a timely second-stage aortic valve replacement and coronary artery bypass grafting using left internal mammary artery shortly after TEVAR, which required a patent LSA. The procedure was arranged semiurgently. A 34-mm thoracic tube endograft was placed across the coarctation with proximal landing distal to the left common carotid artery. In situ fenestration was created by laser catheter through retrograde left brachial access. The fenestration was then enlarged by balloon dilatation and bridged to the left subclavian origin with a 16-mm balloon-expandable covered stent.

CONCLUSIONS

TEVAR with in situ fenestration for LSA is a reliable choice for adult AC. The technique added to the armamentarium of treatment options.

Comparison of supra-arch in situ fenestration and chimney techniques for aortic dissection involving the left subclavian artery

Introduction

Endovascular intervention involving the aortic arch, particularly in thoracic aortic dissection, remains challenging and controversial at current time when there is no commercially suitable grafts on most of the international markets. This study compared two endovascular treatments that maintain left subclavian artery perfusion using two modified techniques for type-B aortic dissection patients.

Methods

Consecutive cases utilizing chimney or in situ fenestration techniques to preserve left subclavian artery in type B AD from 2006 to 2015 in our single institution were retrospectively reviewed. Statistical analyses were performed with Student t-test, Wilcoxon rank sum, and Fisher exact tests when appropriate. Significant statistical differences were determined with p < 0.05.

Results

A total of 85 cases, including 67 (79.8%) with chimney and 18 (21.2%) with in situ fenestration techniques were identified in this retrospective study. In chimney group, there were 18 (26.9%) acute, 29 (43.3%) sub-acute, and 20 (29.9%) chronic aortic dissections. We implanted 24 Zenith and 43 Talent aortic endografts along with 55 balloon-expandable bare stents and 12 self-expanding covered stents in chimney group. Whereas in in situ fenestration group, there were four (22.2%) acute, six (33.3%) subacute, and eight (44.5%) chronic aortic dissections, all of which received Zenith endografts with 11 balloon-expandable covered and seven self-expanding covered stents, respectively. Demographic variables were similarly distributed with 100% intraoperative technical overall success in both groups. Comparing to in situ fenestration group, chimney group has shorter procedural and fluoroscopy time, less blood loss, and contrast volume used. All patients were followed-up to 52 months (median 38, range 24–52). Overall group mortality is 3.6% (3/84). All deaths were from chimney group. There was no procedure-related stroke observed within the study series. Primary patency was maintained while aortic remodeling with complete false lumen was achieved in all patients except that there were three (4.55%) Type-I endoleak cases in early post-operative period and one (1.5%) stent compression at 3-months follow-up in chimney group. There were no stent-related complications observed in in situ fenestration group.

Conclusion

Although there were previous studies describing the similar techniques, this study appears to be the first study to compare in situ fenestration and chimney techniques for aortic dissection involving the left subclavian artery according to the MEDLINE search. Although we are unable to establish the superiority between two approaches due to small sample size and relative short period of follow-up, in situ fenestration may represent a more favorable option, especially among aortic dissections with short proximal landing zones in the study.

Anatomical repair for Kommerell diverticulum with deep site in-situ fenestration

An 83-year-old woman with a Kommerell diverticulum was treated by anatomical endovascular repair with a deep site in-situ fenestration instead of complex debranching techniques. The main component of the thoracic stent-graft was deployed just distal to the third cervical branch to completely exclude the Kommerell diverticulum. A deep site in-situ fenestration was made on the main component using a radiofrequency needle through the left subclavian artery, and a stent-graft was deployed to bridge the main component to the left subclavian artery. Six months postoperatively, the Kommerell diverticulum was completely excluded with excellent left subclavian artery patency.

A New Adjustable Puncture Device for In Situ Fenestration During Thoracic Endovascular Aortic Repair

Purpose: To describe a new adjustable puncture system for in situ fenestration in thoracic endovascular aortic repair (TEVAR). Technique: An adjustable puncture needle for use in conjunction with a steerable 8-F, 55-cm Fustar sheath is demonstrated in a 65-year-old man with acute complicated type B dissection involving the left subclavian artery (LSA). The puncture device features an inflatable balloon at the tip, a central lumen for 0.018-inch guidewires, and a 3-level puncture depth. After thoracic stent-graft deployment at zone 2, the needle/sheath combination was delivered from a left brachial artery access. The needle was adjusted perpendicular to the fabric of the stent-graft with the assistance of the steerable sheath. The balloon at the tip was inflated to center the needle, and the puncture depth was selected on the puncture needle system. Holding the sheath and puncture needle together, a hole was created in the graft fabric. The aperture was sequentially dilated to accommodate the mating stent selected to maintain perfusion to the LSA. This new device has been successfully applied in 6 patients treated with TEVAR for different arch pathologies. Conclusion: This new puncture device could assist in situ fenestration and improve the technical success rate.

Laser Fenestration of Aortic Stent-Grafts Followed by Noncompliant vs Cutting Balloon Dilation: A Scanning Electron Microscopy Study

Purpose: To examine the effects of in situ laser fenestration and subsequent balloon dilation (noncompliant vs cutting) on the graft fabric of 4 aortic stent-graft models. Method: In an in vitro setup, the Zenith TX2, Talent, Endurant, and Anaconda aortic stent-grafts (all made of polyester graft material) were subjected to laser fenestration with a 2.3-mm-diameter probe at low and high energy in a physiologic saline solution followed by balloon dilation of the hole. For the first series of tests, 6-mm-diameter noncompliant balloons were used and replaced for the second series by 6-mm-diameter cutting balloons. Each procedure was performed 5 times (5 fenestrations per balloon type). The fenestrations were examined visually and with light and scanning electron microscopy. Results: Each fenestration demonstrated various degrees of fraying and/or tearing regardless of the device. The monofilament twill weave of the Talent endograft tore in the warp direction up to 7.09±0.46 mm at high energy compared with 2.41±0.26 mm for the Endurant multifilament device. The fenestrations of the 3 endografts with multifilament weave (Zenith, Anaconda, and Endurant) showed more fraying; fenestration areas in the multifilament Endurant were >10 mm2 at low and high energy. The fenestrations were free of melted fibers, but minor blackening of the filaments was observed in all devices. Overall, the cutting balloons resulted in worse tearing and damage. Of note, the edges of the dilated laser-formed fenestrations of the Talent and the Endurant grafts demonstrated evidence of additional shredded yarns. Conclusion: In situ fenestration does not cause any melting of the polyester; however, the observed structural damage to the fabric construction must be carefully considered. Cutting balloons caused various levels of tearing compared to the noncompliant balloons and cannot be recommended for use in this application. Rather, noncompliant balloons should be employed, but only with endografts constructed from multifilament yarns. The use of in situ fenestration must be restricted to urgent and emergent cases until long-term durability can be determined.

A Comprehensive Review of In Situ Fenestration of Aortic Endografts

OBJECTIVE

Despite technical advances of fenestrated and branched endografts, endovascular exclusion of aneurysms involving renal, visceral, and/or supra-aortic branches remains a challenge. In situ fenestration (ISF) of standard endografts represents another endovascular means to maintain perfusion to such branches. This study aimed to review current indications, technical descriptions, and results of ISF.

METHOD

A review of the English language literature was performed in Medline databases, Cochrane Database, Web of Science, and Scopus using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Sixty-seven relevant papers were selected. Thirty-three papers were excluded, leaving 34 articles as the basis of the present review.

RESULTS

Most experimental papers evaluated ISF feasibility and assessed the consequences of ISF on graft fabric. Regarding clinical papers, 73 ISF procedures have been attempted in 58 patients, including 26 (45%) emergent and three (5%) bailout cases. Sixty-five (89%) ISF were located at the level of the arch, and eight (11%) in the abdominal aorta. Graft perforation was performed by physical, mechanical, or unspecified means in 33 (45%), 38 (52%), and two vessels (3%), respectively. ISF was technically successful in 68/73 (93%) arteries. At 30 days, two (3.4%) patients died in the setting of an aorto-bronchial fistula and an aorto-oesophageal fistula, respectively. No post-operative death, major complication, or endoleak was described as secondary to the ISF procedure. With follow-up between 0 and 72 months, four (6.9%) late deaths were noted, unrelated to the aorta. One (1.7%) LSA stent was stenosed without symptoms.

CONCLUSIONS

Although there may be publication bias, multiple techniques were described to perform ISF with satisfactory short-term results. Long-term data remain scarce. Aortic endograft ISF is an off-label procedure that should not be used outside emergent bailout techniques or investigational studies. A comparison with alternative techniques of preserving aortic side branches is needed.

Laser Generated In situ Fenestrations in Dacron Stent Grafts

OBJECTIVE/BACKGROUND

To evaluate if the creation of laser generated in situ fenestrations in polyester/Dacron stent grafts causes embolization.

METHODS

In seven pigs, Dacron stent grafts were implanted from the infrarenal aorta to the right iliac artery. Prior to placing the stent graft, a carotid artery protection filter, with a pore size of 70-200 μm, was placed in the proximal left common iliac artery. An excimer laser catheter was then advanced antegradely through the stent graft and positioned at the level of origin of the left iliac artery. A fenestration was then created with the laser probe. The carotid filter was retrieved and inspected macroscopically with magnifying glasses, for emboli and clot.

RESULTS

Seven pigs with a median weight of 90 kg (range 78-98 kg) were tested. The median operating time was 170 minutes. All laser fenestrations were successfully completed. No emboli or clot could be detected in the protection filters.

CONCLUSION

Creation of laser generated, in situ fenestrations do not produce macroscopically visible emboli/clot. This might indicate safe usage of laser created fenestrations for endovascular arch repair and left subclavian artery revascularization.

Radiofrequency In Situ Fenestration for Aortic Arch Vessels During Thoracic Endovascular Repair

Purpose: To report the first clinical application of a novel technique using radiofrequency puncture to create retrograde in situ fenestrations during thoracic endovascular aortic repair (TEVAR). Methods: Between June 2011 and December 2013, 40 TEVAR procedures were performed in our facility, including 10 cases in which in situ fenestration was planned. Two thoracic stent-graft models were deployed: the Valiant (n=5) and the Zenith TX2 (n=5). A 0.035-inch PowerWire radiofrequency guidewire delivered from a brachial approach was used to fenestrate the grafts covering a left subclavian artery (LSA) in 9 cases and a left common carotid artery in one. The fenestrations were serially dilated to 6 mm, and self-expanding Advanta V12 covered stents were positioned in the target arteries. Results: Technical success was achieved in 6 of the 10 planned cases. Of the remaining 4 cases, stent-grafts were deployed in zone 3 in 2 cases (one received a chimney to the LSA). Another stent-graft was deployed in zone 2 without endoleak after fenestration was abandoned (the LSA had good filling via the vertebral artery). In the last case, the fenestration was unsuccessful in double-layered (proximal extension overlap) stent-grafts; a carotid-axillary bypass was required. There were no fenestration-related complications, but overall surgical complications included a case of paraparesis that resolved following spinal drainage and a death from a preexisting aortoesophageal fistula. There were no postoperative strokes. All fenestrations remained patent, and there were no endoleaks at a mean 12-month follow-up (range 1–33). Conclusion: Radiofrequency puncture is a viable alternative to needle or laser punctures for in situ fenestration during TEVAR. Early clinical results suggest technical feasibility and acceptable early outcomes.

Transcaval access for TAVR across a polyester aortic graft

Transcaval access to the aorta allows transcatheter aortic valve replacement in patients without other good access options. The resulting aorto-caval fistula is closed with a nitinol cardiac occluder device. There is no experience traversing a synthetic aortic graft to perform transcaval access and closure. We describe a patient who underwent successful traversal of a polyester aortic graft using radiofrequency energy applied from the tip of a guidewire, to allow retrograde transcatheter aortic valve replacement from a femoral vein, along with details of our technique. The patient did well and was discharged home after 3 days. There was residual aorto-caval fistulous flow immediately after implantation of a polyester-seeded nitinol muscular ventricular septal defect occluder device, but this fistula spontaneously occluded within one month.