Laser Generated In situ Fenestrations in Dacron Stent Grafts

In Situ Needle Fenestration during Thoracic Endovascular Aneurysm Repair: Successful Fenestration of Two Overlapping Thoracic Stent Grafts

Endovascular stent grafting is becoming more common in treating complex thoracic aortic aneurysms and dissections. When it becomes necessary to cover the supra-aortic vessels, maintaining blood supply through the supra-aortic branches can be achieved by performing in situ needle fenestration. We present a case of a 65-year-old man with a type B aortic dissection that extended from the origin of the left subclavian artery. A stent graft was inserted into the thoracic aorta distally of the origin of the left common carotid artery. Due to the stent graft moving distally and not adequately sealing the subclavian artery, a second stent graft was placed more proximally. Both stent grafts were successfully in situ fenestrated using a needle, and a stent graft was inserted into the subclavian artery. In conclusion, during thoracic endovascular aortic repair, in situ needle fenestration can be successfully carried out on two overlapping thoracic stent grafts.

In Situ Fenestration and Carotid-Subclavian Bypass for Left Subclavian Artery Revascularization During Thoracic Endovascular Aortic Repair

PURPOSE

To evaluate the safety and feasibility of left subclavian artery (LSA) revascularization techniques during thoracic endovascular aortic repair (TEVAR)-the in situ needle fenestration (ISNF) technique and the carotid-subclavian bypass (CS-Bp)-for complicated aortic pathologies.

METHODS

A retrospective single-center observational study was conducted to identify all patients with thoracic aortic pathologies who underwent TEVAR with LSA revascularization using either CS-Bp or ISNFs from January 2014 to December 2020.

RESULTS

One hundred and twelve consecutive patients who received TEVAR with LSA revascularization were included. Among them, 69 received CS-Bp and 43 received ISNF (29 using the Futhrough adjustable puncture needles, 14 using the binding stent-graft puncture systems). Technical success, defined as achieving aortic arch pathology exclusion and LSA preservation, was attained in 99.1% patients. Early mortality was 0.9%. Major adverse events within 30 days, including one cerebral hemorrhage, one cervical incision hemorrhage, one stroke and two paraplegia, were exclusively observed in the CS-Bp group. Immediate type I, II and III endoleaks occurred in 0%, 4.7% and 2.3% in the ISNF group, respectively, compared to 0%, 2.9% and 0% in the CS-Bp group.One hundred and eight (97.2%) patients were available for follow-up at a median 50 (maiximum of 103) months, revealing a LSA patency rates of 99.1%. Six patients died during follow-ups-five in the CS-Bp group and one in the ISNF group. Cause of death include one aortic-related stent-graft infection, three non-related and two with unknow causes. The survival exhibited no significantly different between the ISNF (97.7%) and CS-Bp (89.9%) groups (p = 0.22).

CONCLUSIONS

Both CS-Bp and ISNF are feasible techniques for LSA reconstruction in TEVAR. ISNF, whether using Futhrough or BPS, seems to be competitive with CS-Bp.

In Situ Laser Fenestration Technique: Bench-Testing of Aortic Endograft to Guide Clinical Practice

PURPOSE

In situ laser fenestration (ISLF) is a recently introduced technology that offers the potential to perform total endovascular treatment of aortic arch and thoracoabdominal aortic pathologies in the acute setting. This experiment's aim was to assess ISLF in some currently common aortic endografts and bridging stent-grafts.

MATERIALS AND METHODS

Three different aortic endografts were evaluated: (1) Zenith Alpha, (2) Zenith TX2, and (3) Conformable GORE TAG. Each endograft was submerged in 37°C saline to create fenestrations using the 308 nm CVX-300 Excimer Laser System fitted with a 2.3 mm diameter Turbo-Elite laser atherectomy catheter compatible with a 0.018″ guidewire. Three different 8 mm bridging stent-grafts were evaluated: (1) BeGraft peripheral, (2) BeGraft peripheral plus, and (3) GORE VIABAHN VBX Balloon Expandable. All bridging stent-grafts were deployed and exposed to different balloon sizes and pressures. The ISLFs and bridging stent-grafts were then evaluated for any tears, stenoses, and seal.

RESULTS

A laser fenestration was consistently rapidly obtained in the Zenith Alpha and the Zenith TX2 endografts while it proved difficult to achieve a timely fenestration in the C-TAG. No fabric tears were noted in the Zenith Alpha and Zenith TX2 when inflating Armada (Abbott) 8 mm balloon in the fenestrations with pressures up to 15 atmospheres (rated burst pressure) nor when flaring bridging stent-grafts with balloons up to 12 mm in diameter at 10 atmospheres, while major tears were frequently noted in the C-TAG when the Armada 8 mm balloons were inflated. BeGraft Peripheral and BeGraft Peripheral Plus were all firmly attached to the fenestrations showing good seal on manual testing, while every sixth VBX bridging stent-graft displayed poorer attachment to the fenestration before dilatation at high pressure. Commonly, significant stenoses remained in the bridging stent-grafts after dilatation at nominal pressure, which could only be eradicated with high-pressure balloons.

CONCLUSION

In this limited bench-test, Dacron endografts responded well to the ISLF technology. Satisfactory deployment of the bridging stent was noted only after inflation and/or flaring with high-pressure balloons. Further work with different types of commercially-available bridging stent-grafts and endografts to assess the durability of in situ fenestration (ISF) and bridging stents in ISF is recommended.

CLINICAL IMPACT

This report on experimental in situ laser fenestration provide important insights for clinicians considering using in situ laser fenestration of aortic stentgrafts in vivo. In particular, different laser settings were tested together with a selection of aortic stentgrafts. Also, the target pressure needed in PTA balloons to dilate the fenestrations and any subsequent tears in the fabric were noted. This was followed by deployment of assorted balloon-expandable stentgrafts with estimation of residual stenosis and seal.

Off-the-Shelf Single-Fenestrated Endograft for Emergent Juxtarenal and Pararenal Abdominal Aortic Aneurysm

INTRODUCTION

Endovascular solutions to emergent juxtarenal and pararenal abdominal aortic aneurysms (AAAs) are complicated. Endovascular aortic repair (EVAR) with in situ laser fenestration (ISLF) is promising but requires a period of visceral ischemia. With an off-the-shelf, single superior mesenteric artery (SMA)-fenestrated device mesenteric ischemia is avoided and renal ischemia decreased. The aim was to develop an optimized design of such an endograft suitable for >90% of juxtarenal and pararenal AAAs.

METHODS

Single-center analysis on 44 consecutive preoperative CTs for previously elective fenestrated EVARs for juxtarenal and pararenal aneurysms. Anatomical characteristics were analyzed to define: (1) shortest aortic coverage above SMA fenestration to achieve ≥4 cm seal; (2) feasibility of a scallop for the celiac artery; (3) shortest distance between the SMA and lowest renal, to facilitate renal ISLF in a straight endograft; (4) distance from the lowest renal to the aortic bifurcation, to allow an overlapping zone >40 mm with a bifurcated stent graft; (5) aortic diameter in the sealing zone, for optimal proximal stent graft diameter with 10% to 30% oversizing; (6) the final design was then tested on individual level.

RESULTS

(1) The stent graft needs to start 40 mm above the SMA fenestration to achieve a 4 cm sealing zone in >90% of cases. (2) A proximal sealing zone of 40 mm without a scallop covers 77% of celiac arteries. With an addition of a 20 mm deep, 20 mm wide scallop at 12:30, the stent graft still covers 27% of celiacs. This suggests that a scallop would not be practically feasible. (3) In >90% of cases, the lowest renal was <31 mm from the SMA, suggesting that the tapering should start 30 mm below the SMA. (4) The distance from the lowest renal to the aortic bifurcation ranged from 82 to 166 mm. This allows for a 20 mm tapering and 50 mm straight part in all cases. (5) The 5th and 95th percentile of the aortic diameter in the sealing zone was 22 and 31 mm, respectively. Thus, 2 different stent graft diameters (28 and 34 mm) would fit >90% of cases. (6) The final design was suitable in 91% cases.

CONCLUSIONS

Two sizes of a single-fenestrated aortic stent graft without scallop cover >90% of juxtarenal and pararenal anatomies.

CLINICAL IMPACT

Emergent juxta- and pararenal aortic aneurysms is a difficult clinical scenario that continuously challenges physicians. An endovascular option is in situ laser fenestrated endografts. One risk with these is the complete visceral ischemia occurring before the fenestrations are completed. An off-the-shelf single-fenestrated stent graft facilitates the treatment by removing the ischemia time for the SMA and reducing the ischemia time for the celiac and renal arteries thus decreasing the risk of visceral ischemia complications.

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.

A Systematic Review of Contemporary Outcomes from Aortic Arch In Situ Laser Fenestration During Thoracic Endovascular Aortic Repair

BACKGROUND

In situ laser fenestrated endovascular aortic repair (L-FEVAR) is a novel and creative solution for complex aortic pathologies in the urgent and emergency setting. Outcomes of this technique, however, are poorly reported. We sought to evaluate the efficacy, safety, and outcomes of L-FEVAR in aortic arch pathologies.

METHODS

A systematic literature review and analysis were conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses and Cochrane guidelines. A search was conducted using Google, PubMed, and Scopus to identify studies evaluating L-FEVAR. Two independent reviewers determined study inclusion. Case reports and series including < 10 patients were excluded. Reviewers also assessed the methodological quality and extracted data regarding outcomes. A meta-analysis of endoleak event rates was conducted using a fixed-effect model due to small sample size.

RESULTS

Eight studies met inclusion criteria between 2013 and 2021. Most studies were retrospective (87.5%) with median follow-up duration of 12.5 months (range 10-42). There were 440 patients included (range 15-148), mostly men (64%). Mean age was 61 years (range 53-68). Included patients were all symptomatic with L-FEVAR being technically successful in 93.3% of cases. The main indication for aortic arch intervention was aortic dissection. Single fenestrations occurred most frequently (68%), followed by triple (22%) then double fenestrations (9%). Meta-analysis of 8 studies (n = 440) demonstrated an endoleak event rate of 0.06 (95% confidence interval 0.04-0.09, P < 0.001) with no observed statistically significant heterogeneity of effects (Q = 7.91, P = 0.34). The median operative time was 162 min (range 53-252) with median length of stay of 10 days (range 7-17). Primary branch patency was 96.6%. Secondary patency rate was 97%. Pooled complication rates such as endoleak occurred in 4.8%, stroke in 2.0%, spinal cord ischemia in 0.2%, retrograde dissection in 0.9%, and 30-day death in 2.0%. Access complications occurred in 0.4%. Antiplatelet regimen was poorly reported in the study cohort.

CONCLUSIONS

In situ laser fenestration is a feasible, safe, and effective approach to treat aortic arch disease in patients who are unsuitable for open or custom-made endovascular means. High technical success and excellent short-term branch patency can be achieved. These single-institution series exhibit promising short-term outcomes. In a similar paradigm to investigational device exemptions studies for custom-made and physician modified endografts, these preliminary data make a persuasive argument for larger long-term multi-institutional prospective study of this promising 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).

Special Features of Polyester-Based Materials for Medical Applications

This article presents current possibilities of using polyester-based materials in hard and soft tissue engineering, wound dressings, surgical implants, vascular reconstructive surgery, ophthalmology, and other medical applications. The review summarizes the recent literature on the key features of processing methods and potential suitable combinations of polyester-based materials with improved physicochemical and biological properties that meet the specific requirements for selected medical fields. The polyester materials used in multiresistant infection prevention, including during the COVID-19 pandemic, as well as aspects covering environmental concerns, current risks and limitations, and potential future directions are also addressed. Depending on the different features of polyester types, as well as their specific medical applications, it can be generally estimated that 25–50% polyesters are used in the medical field, while an increase of at least 20% has been achieved since the COVID-19 pandemic started. The remaining percentage is provided by other types of natural or synthetic polymers; i.e., 25% polyolefins in personal protection equipment (PPE).

Midterm Outcomes of an Adjustable Puncture Device for In Situ Fenestration During Thoracic Endovascular Aortic Repair

OBJECTIVE

To evaluate the midterm outcomes of in situ fenestration (ISF) with an adjustable puncture device for aortic arch branch preservation during thoracic endovascular aortic repair (TEVAR).

METHODS

From October 2016 to April 2019, patients with complicated type B aortic dissection, thoracic aortic aneurysm > 5.5 cm in diameter, or aortic penetrating ulcer with a base > 20 mm or depth > 15 mm, who received TEVAR requiring a proximal sealing beyond zone 3 and underwent ISF using an adjustable puncture device, were included. After the procedure, patients were monitored at one, three, six, and 12 months, and annually thereafter. Peri-operative and follow up data were collected and analysed.

RESULTS

Fifty of 51 patients (98%) received successful ISFs. One, two, or three aortic arch branches were preserved in 44, six, and one patient, respectively. Intra-operatively, eight type Ia endoleaks and one type II endoleak were found on angiography. One patient died of cerebral hernia three days post-procedure from a severe stroke; one patient suffered from transient paraplegia but recovered in two weeks; one patient had a non-disabling stroke. The median follow up was 31 months (22.5 - 36.5 months). At six month follow up, all nine unmanaged endoleaks had disappeared. One new type Ia endoleak was identified in a patient at the one month follow up which resolved spontaneously one year later. All revascularised arteries were patent at the last follow up. No fractures, migrations, or bridging stent kinks were found.

CONCLUSION

In this largest mechanical based ISF study to date, an adjustable puncture device was shown to facilitate the procedure of ISF during endovascular repair of aortic diseases involving the aortic arch, with high success. The midterm outcome demonstrates the efficacy and safety of the device in assisting with preservation of aortic arch branches.

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.

A systematic review of experimental and clinical studies reporting on in situ laser fenestration of aortic endografts

OBJECTIVE

To summarize available in-situ laser fenestration (ISLF) literature, including experimental studies with their subsequent recommendations regarding optimal fenestration technique and fabric; as well as the short and mid-term results of clinical studies.

METHODS

A systematic review of English articles was performed in MEDLINE, the Cochrane Database and EMBASE, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines by two researchers. The search period was without starting date until the 31^st August 2020, and search terms included were in situ, laser, fenestration, and endograft. Quality assessment of the studies was performed using the Newcastle-Ottawa scale by two other independent researchers.

RESULTS

A total of 19 clinical studies were included, with a total of 428 patients (390 supra-aortic trunk ISLF, 38 visceral vessel ISLF). The technical success was 96.9% and 95.6% supra-aortic and visceral vessel ISLF, respectively. Most studies have less than 12-month follow-up, and the longest available follow-up (in one study) was 5-years for left-subclavian fenestration and 17-months for visceral vessel ISLF. Overall, the quality of the evaluated clinical studies was low. Six experimental studies were included, with the highest level of evidence suggesting fenestration of multifilament polyethylene terephthalate grafts, followed by dilation with either a 6- or 8-mm non-compliant balloon.

CONCLUSION

Experimental studies favour the use of multifilament polyethylene terephthalate , followed by dilation with non-compliant balloons as the most durable "in-vitro" technique for ISLF. Short-term outcomes for arch and visceral vessel revascularization are promising, with low rates of in-hospital mortality, stroke, and end-organ ischemia. Nonetheless, the long-term durability of ISLF is yet to be determined and they should be limited to selected symptomatic or urgent cases.

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.

Optimal In Situ Fenestration Technique With Laser Perforation and Balloon Dilation for Aortic Stent-Grafts

PURPOSE

To evaluate the response of various stent-grafts after laser fenestration and dilation with noncompliant balloons to determine the optimal therapeutic combination for this treatment technique.

MATERIALS AND METHODS

Five aortic stent-grafts were evaluated ex vivo: the Bolton RelayPlus, Jotec E-vita Thoracic 3G, Medtronic Valiant, Cook Zenith Alpha, and Vascutek Anaconda. Small holes were created using an excimer laser with the grafts submerged in saline. Five rows of 5 fenestrations were created, 4 holes in each row were dilated once with a 6-, 8-, 10-, or 12-mm-diameter noncompliant balloon to the specified nominal pressure (one hole served as the control). The saline solution from each stent-graft was collected and qualitatively analyzed for debris. The fenestrations were evaluated under light and scanning electron microscopes. The maximum diameter and area for each fenestration were measured. The direction and length of tears were assessed.

RESULTS

The fenestration was feasible and reproducible in all the stent-grafts. The mean area of fenestration ranged from 7.63±1.63 to 14.75±0.73 mm² when using balloons of 6- and 8-mm diameter, respectively. The 10- and 12-mm-diameter balloons caused a significant increase in area, variability, and tearing. The Anaconda graft tended to tear in the weft direction, while the other devices tore in the warp direction when using the 10- and 12-mm-diameter balloons. Dilation of the RelayPlus and Anaconda grafts with 6- and 8-mm-diameter balloons provided minimal tearing and precise fenestrations. Melted fiber remnants were observed after filtration of the saline solution for all devices.

CONCLUSION

Laser fenestration and dilation with noncompliant balloons is a relatively simple and reproducible option for revascularization in urgent, complex aortic endovascular repairs. In our model, large balloons (ie, >10 mm) increased the destruction and tearing of the fabric. The maximum dilation recommended is 6 to 8 mm to avoid significant tears. Development of stent-grafts or novel fabrics designed explicitly for fenestration is needed to reduce potential complications.

Midterm Results of Retrograde In Situ Needle Fenestration During Thoracic Endovascular Aortic Repair of Aortic Arch Pathologies

PURPOSE

To evaluate the safety and feasibility of the in situ needle fenestration (ISNF) technique for reconstruction of the left subclavian artery (LSA) during thoracic endovascular aortic repair (TEVAR) of complicated aortic arch pathologies.

MATERIALS AND METHODS

A retrospective review was conducted from January 2014 to December 2019 of 50 patients (mean age 60.2±11.1; 45 men) who underwent ISNF to revascularize the LSA during TEVAR. Twenty-one of the patients also required revascularization of the left common carotid artery (LCCA; n=19) and innominate artery (IA; n=2) using physician-modified in vitro fenestration. Overall, 73 supra-aortic branches were targeted for revascularization.

RESULTS

ISNF was successful in 48 patients (96%); one LSA could not be stented and a tortuous LSA prevented the needle from fenestrating the graft. No perioperative major adverse event occurred. There were no type I and 4 type III endoleaks (8%), 3 of which occurred among the first 20 cases. Types II and IV endoleaks were found in 3 (6%) and 6 (12%) cases, respectively; all disappeared during a median follow-up of 15 months (range 3-66). One death (2%) occurred within 12 months due to cerebral hemorrhage. Two patients (4%) required open reinterventions at 6 and 62 months.

CONCLUSION

ISNF for revascularization of the LSA during TEVAR seems to be feasible with acceptable midterm outcomes. The learning curve and evolving patient selection criteria affected technical success, complications, and the need for reinterventions. Long-term durability requires further evaluation.

Endovascular treatment for aortic arch pathologies: chimney, on-the-table fenestration, and in-situ fenestration techniques

Background

Revascularization of the supra-aortic major branches in thoracic endovascular aortic repair (TEVAR) is challenging owing to the complex anatomic configuration of aortic arch pathologies. This study aims to evaluate the feasibility, effectiveness, and safety of three major techniques—chimney, fenestrated, and in-situ fenestration—for patients with aortic arch pathologies.

Methods

A retrospective analysis was performed involving 234 patients with aortic arch lesions, who underwent TEVAR with adaptations in technique (chimney, fenestrated, or in-situ fenestration) between January 2016 and December 2017.

Results

One hundred and twenty-six patients underwent the chimney technique (98 single chimneys, 24 double chimneys, and four triple chimneys); one hundred and two patients (102/234) were treated with on-the-table fenestration technique (92 single fenestrations, nine double fenestrations, and one double fenestration plus innominate artery chimney); and the remaining six patients underwent in-situ needle fenestration technique. Overall, indications included aortic dissections (99/234), aortic arch aneurysms (60/234), penetrating aortic ulcers (72/234), and re-interventions (3/234). The technical success rates were 99.6%. There were five cases of early all-cause mortality. The patency rates of overall branches were 99.6%. There were 15 cases with type Ia endoleak—14 in the chimney group (11.1%) and one in the on-the-table fenestration group (1%). Five patients underwent re-interventions. The median follow-up time for all patients was 28 (range, 16–41) months.

Conclusions

Our experience suggests that chimney, on-the-table fenestration, and in-situ needle fenestration techniques are feasible, effective, and safe treatment options for aortic arch pathologies with encouraging mid-term results. Long-term durability concerns require further evaluation.

Novel EM Guided Endovascular Instrumentation for In Situ Endograft Fenestration

Objective: This work aims at providing novel endovascular instrumentation to overcome current technical limitations of in situ endograft fenestration including challenges in targeting the fenestration site under fluoroscopic control and supplying mechanical support during endograft perforation. Technology: Novel electromagnetically trackable instruments were developed to facilitate the navigation of the fenestration device and its stabilization at the target site. In vitro trials were performed to preliminary evaluate the proposed instrumentation for the antegrade in situ fenestration of an aortic endograft, using a laser guidewire designed ad hoc and the sharp end of a commercial endovascular guidewire. Results: In situ fenestration was successfully performed in 22 trials. A total of two laser tools were employed since an over bending of laser guidewire tip, due to its manufacturing, caused the damage of the sensor in the first device used. Conclusions: Preliminary in vitro trials demonstrate the feasibility of the proposed instrumentation which could widespread the procedure for in situ fenestration. The results obtained should be validated performing animal studies. Clinical Impact: The proposed instrumentation has the potential to expand indications for standard endovascular aneurysm repair to cases of acute syndromes.

Hemodynamic consequences of TEVAR with in situ double fenestrations of left carotid artery and left subclavian artery

The aortic major branches after thoracic endovascular aortic repair (TEVAR) could be preserved by in situ fenestration (ISF). This study aims to explore the hemodynamic consequences of ISF-TEVAR with double fenestrations. Two patients with aortic dissection and aneurysm, respectively, were treated by ISF-TEVAR and both the left carotid artery (LCA) and left subclavian artery (LSA) were reconstructed by fenestration technique. The blood was considered a non-Newtonian fluid and the Windkessel model was adopted at the aortic outlets. Simulations were performed in two postoperative models to analyze the effects of the double fenestration stents on the hemodynamics. The postoperative wall pressure of the LCA and LSA is relatively low and the pressure difference between the inner and outer walls of the protruding segment of the LSA stent is found. Acceleration occurs when blood flows around the fenestration stents and the shear-thinning rheological behavior is observed at the aortic arch. Moreover, regions susceptible to thrombosis are identified and the surface exposed to high relative residence time is located at the aortic arch after the LSA stent. The presence of the double fenestration stents has a profound impact on the postoperative hemodynamics, and the aortic arch and rebuilt branches should be closely watched during follow-up.

In situ laser fenestration for revascularization of aortic arch during treatment for iatrogenic type A aortic dissection

Background

Iatrogenic aortic dissection is a rare and fatal complication. Its treatment was challenging and controversial especially in patients with previous cardiac procedure. This study aimed to present the case of a patient with aortic dissection after previous open cardiac surgery who was successfully treated by in situ laser fenestration for revascularization of aortic arch.

Case presentation

A 65-year-old man suffered severe aortic and mitral valve regurgitation was treated by open cardiac aortic valve replacement (biological valve, Edwards) and mitral valve repair. During the sixth-month follow-up, computed tomography angiography (CTA) scan revealed an aortic dissection that extended from the ascending aorta to both femoral arteries. After stabilized by medical treatment, the patient was treated by endovascular stent-graft implantation and in situ laser (holmium laser, energy: 0 5 J, frequency: 5 Hz.) fenestration for revascularization of aortic arch in our one-stop hybrid operating room. The patient recovered without any clinical complication and was discharged 5 days after the procedure.

Conclusions

Our work suggested that in situ laser fenestration for revascularization of aortic arch is a feasible, effective, and safe treatment in patients with iatrogenic aortic dissection.

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.

In Situ Generated Medical Devices

Medical devices play a major role in all areas of modern medicine, largely contributing to the success of clinical procedures and to the health of patients worldwide. They span from simple commodity products such as gauzes and catheters, to highly advanced implants, e.g., heart valves and vascular grafts. In situ generated devices are an important family of devices that are formed at their site of clinical function that have distinct advantages. Among them, since they are formed within the body, they only require minimally invasive procedures, avoiding the pain and risks associated with open surgery. These devices also display enhanced conformability to local tissues and can reach sites that otherwise are inaccessible. This review aims at shedding light on the unique features of in situ generated devices and to underscore leading trends in the field, as they are reflected by key developments recently in the field over the last several years. Since the uniqueness of these devices stems from their in situ generation, the way they are formed is crucial. It is because of this fact that in this review, the medical devices are classified depending on whether their in situ generation entails chemical or physical phenomena.

Effects of in situ fenestration stent-graft of left subclavian artery on the hemodynamics after thoracic endovascular aortic repair

Objectives

The left subclavian artery during thoracic endovascular aortic repair could be reconstructed by in situ fenestration. This study aims to evaluate the effects of thoracic endovascular aortic repair with in situ fenestration thoracic endovascular aortic repair on the hemodynamics.

Methods

A male patient suffering from aortic dissection is treated by in situ fenestration thoracic endovascular aortic repair and the fenestration stent implanted in the left subclavian artery is partially protruding in the aortic arch for the stability. Two-phase non-Newtonian blood model is applied and three-element Windkessel model is implemented to reproduce physiological pressure waves. Simulations are carried out in three postoperative models to analyze different in situ fenestration thoracic endovascular aortic repair strategies; Case A: the protrusion length of fenestration stent is 23.2 mm representing the clinical postthoracic endovascular aortic repair aorta; Case B: the protrusion length is reduced by half simulating the improved surgery; Case C: the protruding portion is removed to simulate the ideal fenestration.

Results

In Case A, a pressure difference is found on the fenestration stent surface and a blood acceleration phenomenon around the stent is observed. Only 2.36% of the inlet blood flow is assigned to the left subclavian artery. In the improved surgery, the blood supply to the left subclavian artery is elevated to 4.01%. As for the ideal fenestration, a further improvement is observed (6.14%). Moreover, the aortic arch surface exposed to low time-averaged wall shear stress expands significantly when the protrusion length is shortened.

Conclusions

Overall, we conclude that appropriately shortening the protrusion length of the stent-graft may improve the efficacy of in situ fenestration thoracic endovascular aortic repair from the perspective of hemodynamics.

Case report of retrograde in situ fenestration of the thoracic stent graft with reentry device in a patient with aortobronchial fistula

RATIONALE

In situ fenestration may be necessary to preserve branch arteries during thoracic endovascular aortic repair (TEVAR) when there is an inadequate landing zone.

PATIENT CONCERNS

We report the case of a 74-year-old man presenting with recurrent hemoptysis.

DIAGNOSES

Based on computed tomography (CT) angiogram and bronchoscopy, diagnosis was aorto-bronchial fistula.

INTERVENTIONS

We performed retrograde in situ fenestration with reentry catheter (Pioneer Plus, Volcano Corporation, San Diego, CA) to preserve the left subclavian artery following TEVAR for aorto-bronchial fistula.

OUTCOMES

Following this procedure, the patient had a patent left subclavian artery and no evidence of endoleak. The patient had no further episodes of hemoptysis.

LESSONS

The retrograde in situ fenestration with reentry catheter strategy is an option for patients when carotid-subclavian bypass is deemed unsafe.

Endovascular repair of aortic arch intramural hematoma and penetrating ulcers with 810 nm in situ laser-assisted fenestration: Preliminary results of a single-center

PURPOSE

The aim of the present study was to report the clinical outcomes of the use of 810 nm in situ laser-generated fenestration (ISLF) for the treatment of aortic aneurysms (AAs) and intramural hematomas (IMHs) located in the aortic arch.

STUDY DESIGN AND METHODS

Between April 2014 and September 2017, 23 patients (15 men, mean age 66.0 years) with AAs (n = 12) or IMHs (n = 11) underwent thoracic endovascular aortic repair (TEVAR) with 810 nm ISLF of the arch. The primary outcomes of the safety assessment were the presence of endoleaks, mortality and morbidity, including adverse in situ fenestration-related, cardiovascular, and cerebral events.

RESULTS

Technical success was achieved in all cases. Urgent intervention was performed in 15 (65.2%) cases. Left subclavian artery (LSA) ISLF was applied in six patients, LSA and left common carotid artery (LCCA) ISLF in three patients, and total aortic arch vessel ISLF in two patients. One patient suffered minimal stroke after the procedure and recovered without permanent disability to the extremities in 2 weeks. There were no fenestration-related complications except in one patient with brachial artery access who suffered a hematoma and underwent incision repair at the puncture site. All fenestrations remained patent, and there were no endoleaks during a mean follow-up of 10.5 ± 5.7 (range: 2-21) months.

CONCLUSIONS

Complete or incomplete endovascular arch reconstruction by ISLF in arch diseases (AAs and IMHs) is feasible and reproducible with safe, effective, and favorable primary results and no need for customized endografts. Lasers Surg. Med. 50:837-843, 2018. © 2018 Wiley Periodicals, Inc.

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.

In Situ Laser Fenestration Is a Feasible Method for Revascularization of Aortic Arch During Thoracic Endovascular Aortic Repair

Background

Reconstruction of the aortic major branches during thoracic endovascular aortic repair is complicated because of the complex anatomic configuration and variation of the aortic arch. In situ laser fenestration has shown great potential for the revascularization of aortic branches. This study aims to evaluate the feasibility, effectiveness, and safety of in situ laser fenestration on the three branches of the aortic arch during thoracic endovascular aortic repair.

Methods and Results

Before clinical application, the polytetrafluoroethylene and Dacron grafts were fenestrated by an 810‐nm laser system ex vivo, which did not damage the bare metal portion of the endografts and created a clean fenestration while maintaining the integrity of the endografts. In vivo, 6 anesthetized female swine survived after this operation, including stent‐graft implantation in the aortic arches, laser fenestration, and conduit implantation through the innominate arteries and the left carotid arteries. Based on the animal experiments, in situ laser fenestration during thoracic endovascular aortic repair was successively performed on 24 patients (aged 33–86 years) with aortic artery diseases (dissection type A: n=4, type B: n=7, aneurysm: n=2, mural thrombus: n=7). Fenestration of 3 aortic branches was performed in 2 (8.3%) patients. Both the left carotid artery and the left subclavian artery were fenestrated in 6 (25%) patients. Only left subclavian artery fenestration surgery was done in 16 (66.7%) patients. Among these patients, 1 fenestration was abandoned secondary to an acute takeoff of the innominate artery in a type III aortic arch. The average operative time was 137±15 minutes. The technical success rate was 95.8% (n=23). No fenestration‐related complications or neurological morbidity occurred after this operation. During a mean postoperative 10‐month follow‐up (range: 2–17 months), 1 patient died of severe pneumonia, and all the left subclavian artery and carotid artery stents were patent with no fenestration‐related endoleaks upon computed tomography angiography images.

Conclusions

In situ laser fenestration is a feasible, effective, rapid, repeatable, and safe option for the reconstruction of aortic arch during thoracic endovascular aortic repair, which might be available to revascularize the 3 branches. However, follow‐up periods should be extended to evaluate the robustness of this technique.

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.