Precision alignment in minimalist fenestrated thoracic endovascular aortic repair: a novel physician-modified technique involving self-aligning Relay nonbare stent grafts for thoracic aortic endovascular repair

Introduction

Thoracic endovascular aortic repair (TEVAR) has emerged as the preferred intervention for acute aortic syndrome of the descending aorta (1-3). However, the endovascular management of aortic diseases involving the aortic arch continues to present unique anatomical challenges, particularly regarding branch vessel preservation. Although fenestrated TEVAR (f-TEVAR) with customized stent grafts has achieved promising mid-term outcomes, its widespread adoption remains limited by technical complexities in fenestration alignment and device modification (4,5). This paper introduces a novel minimalist approach involving the physician-modified Relay nonbare stent (NBS) graft system (Terumo Aortic, Sunrise, FL, USA), which capitalizes on the device’s intrinsic self-alignment properties to overcome traditional technical barriers. The success of our technique demonstrates how strategic device selection combined with procedural simplification can achieve optimal outcomes in complex arch diseases. We present this article in accordance with the STROCSS reporting checklist (available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-163/rc).

Methods

This study analyzed the medical records of 148 patients with aortic diseases undergoing thoracic endovascular aortic repair (f-TEVAR) between January and December 2023. Patients were diagnosed through contrast-enhanced computed tomography angiography (CTA) and classified according to the Society for Vascular Surgery (SVS)/Society of Thoracic Surgeons (STS) guidelines (2). The exclusion criteria were as follow: adequate proximal landing zones (PLZs) (≥20 mm), PLZ localization in zone 0 (sinotubular junction to the origin of the brachiocephalic artery), connective tissue disorders, and incomplete CTA datasets. After screening, 33 patients with an insufficient healthy PLZ were included in the final analysis. All the minimalist f-TEVARs were performed with Relay NBS grafts.

The technical success, stent-graft modification time, fluoroscopy time, procedure time, endoleak rate, procedure-related complications, length of stay, and 30-day and late mortality were assessed retrospectively.

Technical protocol of fenestration

Preoperative planning included electrocardiography-gated high-resolution aortic CTA (slice thickness 0.63 mm). Multiphase reconstructions enabled comprehensive analysis of the aortic/branch lumen diameters, arch morphology classification, branch ostium angulation and clock-face positioning, aortic segment lengths, and spatial interbranch relationships.

The Relay NBS grafts proprietary self-alignment technology ensures precise arch conformation through a precurved inner catheter matching the anatomical curvature, S-bar reinforcement along the greater curve, and a 12 o’clock alignment marker at the outer curvature. This integrated system automatically orients the stent graft’s black midline marker to the aortic arch’s superior aspect, enabling accurate fenestration positioning based on preoperative measurements. A customized fenestration template was generated for procedural guidance.

Following angiographic confirmation of anatomical parameters, stent-graft customization proceeded in the catheterization laboratory. The proximal inner sheath was advanced beyond the outer primary sheath after shipping retainer removal (Figure 1A), with the first-stage stent deployment exposing the modification zones (Figure 1B). Preplanned window positions were marked with sterile surgical rulers and skin markers, which was followed by the precise creation of the fenestration via low-temperature radiofrequency punch devices (Figure 1C). The NBS system’s inherent alignment accuracy eliminated the need for supplemental marker sutures.

Figure 1 The process of stent-graft modification. (A) The proximal portion of the inner sheath is pushed out. (B) The first one or two segments of the stent graft are released. (C) The fenestra is cut with a low-temperature punch. (D) The stent is compressed with silk thread and retrieved into the inner sheath. The arrow shows the closing process. (E) The outer sheath is advanced to repossess the inner sheath. The arrow shows the closing process. (F) The original markers are confirmed at the initial position under fluoroscopy.

The dual-sheath NBS delivery system (soft inner and rigid outer configuration) facilitated safe recapture through silk ligature-mediated stent compression during inner sheath retraction (Figure 1D) and continuous thread tension-guided outer sheath repositioning (Figure 1E). Fluoroscopy confirmed the 12/6 o’clock marker alignment to ensure preserved spatial orientation postresheathing. The original markers were confirmed at the initial position under fluoroscopy (Figure 1F).

All minimalist f-TEVAR procedures involved local anesthesia with bilateral femoral access via ProGlid preclosure (Abbott Laboratories, Chicago, IL, USA). Mandatory 12 o’clock flush port alignment during introducer insertion (Figure 2A) ensured proper device orientation. Critical deployment steps included left anterior oblique projection-guided D-shaped marker alignment along the aortic greater curvature, continuous advancement of the deployment grip until proximal markers reached the planned landing zone (Figure 2B,2C), and positioning of the fenestrations at predefined anatomical targets through use of the integrated self-orientation system (Figure 2D). The stent graft was deployed in a single continuous motion (Figure 2E), followed by retrograde [left subclavian artery (LSA)] or antegrade left common carotid artery (LCCA) fenestration cannulation.

Figure 2 The process of stent-graft implantation. (A) With flush port of the device pointing to the 12 o’clock, the stent-graft is inserted. (B) The D-shape marker on the inner sheath located at the aortic great curve is verified. (C) The inner sheath is pushed forward until the stent graft’s proximal markers reach the proximal landing zone. (D) The self-alignment mechanism of the NBS graft system make the proximal markers reach the 12 and 6 o’clock position of the aortic arch. The 12 and 6 o’clock positions are marked in arrows and circles. (E) The stent graft is released with one quick and continuous motion. NBS, nonbare stent.

Postdeployment assessment included completion angiography to evaluate endograft apposition, branch perfusion, and endoleak presence and was supplemented by transfenestration pressure-gradient measurements. An illustrative clinical case demonstrating the full procedural workflow is presented in Figure 3.

Figure 3 A case of minimalist TEVAR. (A) The aortic CTA showed a false aneurysm (blue arrow) with inadequate landing zone to the LSA. (B) The fenestration plan graph after an accurate measurement. (C) The fenestration (red arrow) of the stent graft. (D) Angiography revealed the aneurysm. (E) Angiography after fenestration stent-graft deployment showed that the aneurysm was occluded and the LSA was clear. (F) The postoperative CTA indicated a satisfactory result. CTA, computed tomography angiography; LSA, left subclavian artery; TEVAR, thoracic endovascular aortic repair.

Follow-up

Survival and clinical assessment data were collected through outpatient visits and telephone interviews. Patients underwent CTA at 1, 6, and 12 months postoperation, and annually thereafter. Patients’ baseline demographic characteristics, comorbidities, preoperative imaging features, details of procedures, and follow-up outcomes were collected and analyzed.

Statistical analysis

Statistical analysis was performed with SPSS version 23.0 (IBM Corp., Armonk, NY, USA). All sample sizes were combined with clinical data. Continuous variables are expressed as the mean ± standard deviation (SD). A two-sided P value <0.05 was considered statistically significant. Kaplan-Meier survival analysis was subsequently conducted, with comparisons made using the log-rank test, and Kaplan-Meier curves were generated via GraphPad Prism version 9.2.0 (Dotmatics, Boston, MA, USA).

Ethical consideration

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments and approved by the institutional ethics board of Beijing Anzhen Hospital, Capital Medical University (approval No. 2025137X). Informed consent was obtained from all participants.

Results

The study cohort comprised 33 patients (75.8% male; mean age 63.2±1.8 years) undergoing physician-modified f-TEVAR (Figure 4). Comorbidities included hypertension (84.8%), hypercholesterolemia (54.5%), diabetes mellitus (27.3%), coronary artery disease (33.3%), previous stroke (21.2%), and previous cardiac surgery (9.1%) (Table 1).

Figure 4 Flowchart of patient selection. CTA, computed tomography angiography; f-TEVAR, fenestrated thoracic endovascular aortic repair.

Aortic diseases included penetrating aortic ulcers (n=14, 42.4%), type-B dissections (n=9, 27.3%), non-A non-B dissections (n=61, 8.2%), and aneurysms (n=4, 12.1%). The arch morphology distribution was as follows: type I, 36.4% (n=12); type II, 30.3% (n=10); and type III, 33.3% (n=11). Anatomical variations included bicarotid trunk (n=6, 18.2%) and isolated left vertebral artery (n=2, 6.1%). The mean distance from the LSA to the target lesion was 2.4±3.3 mm (Table 2).

All procedures were successfully completed in the catheterization laboratory under local anesthesia. Deployed stent grafts had a mean proximal diameter of 34 mm (range, 30–35 mm) and a length of 204 mm (range, 164–209 mm). In this study, 41 fenestrations were created across 33 patients. Each fenestration diameter was precisely matched to the diameter of its target vessel, as determined by preoperative centerline CTA measurements. Fenestration configurations targeted the LSA alone (n=25, 75.7%), the LSA and LCCA combined (n=6, 18.2%), and the LSA-isolated left vertebral artery (n=2, 6.1%). Postintervention landing zone length increased significantly to 22.5±0.8 mm. Procedural metrics included a mean modification time of 6.8±1.8 minutes, a total operative time of 57.9±13.1 minutes, and a fluoroscopy duration of 8.2±3.9 minutes.

Technical success was achieved in all cases with complete aortic pathology exclusion and preserved supra-aortic branch patency. Bird-beak configuration occurred in 27.3% (n=9) of cases, but no immediate endoleaks, retrograde type A dissections, spinal cord ischemia, or procedure-related mortality were observed. Two patients required intraoperative salvage bridging via the VBX stent (W.L. Gore & Associates, Newark, DE, USA) for incidentally detected transfenestration pressure gradients (>20 mmHg) despite angiographic branch patency. These were classified as unplanned reinterventions. The postoperative freedom from reintervention rate was 93.9% (31/33). The mean hospitalization duration was 3.6±1.1 days, and there were no in-hospital mortality or neurological complications (Table 3).

Over a mean follow-up of 12.6±3.7 months, all patients remained free of spinal cord ischemia, cerebrovascular events, myocardial infarction, and renal dysfunction. Surveillance CTA confirmed stent-graft integrity without endoleaks, retrograde dissections, or stent-induced new entries. All supra-aortic branches remained patent without stenosis, occlusion, thrombosis, or kinking requiring reintervention. Kaplan-Meier analysis (Figure 5) revealed no significant difference in the reintervention rates between lesions involving the aortic lesser curvature (Group A) and those involving the greater curvature (Group B) (log-rank P=0.47).

Figure 5 Kaplan-Meier curve of the reintervention rate. (A) Follow-up results after f-TEVAR with no reintervention. The dashed lines are the 95% confidence intervals. (B) Comparison of reinterventions in lesions between the lesser curve (Group A) and the greater curve (Group B). f-TEVAR, fenestrated thoracic endovascular aortic repair.

Discussion

This study includes three critical findings related to the innovation of aortic arch repair: First, our physician-modified minimalist approach and standardized protocol incorporating the Relay NBS, a proprietary self-alignment system, achieved 100% technical success, eliminating the need for traditional manual orientation adjustments. Second, unprecedented procedural efficiency was demonstrated, with a stent modification time of <7 minutes and a total intervention time of <60 minutes. Third, the minimalist f-TEVAR for aortic pathologies involving arch branches had a good safety and efficacy profile, confirming its clinical applicability.

Endovascular reconstruction of supra-aortic branch vessels is the primary method for treating aortic arch diseases (6-9). Its advantages include a low rate of mortality, stroke, and endoleak. Compared to other aortic arch reconstruction methods, such as branched stents (10,11), hybrid surgery (12-14), in situ fenestration (7,15,16), and parallel stent techniques (17), the simplified physician-modified fenestration technique with NBS grafts offers distinct advantages. These include precise alignment, reduced operative time, rapid postoperative recovery, and decreased surgical risk and are not accompanied by an increase in procedural risk or stroke incidence. Unlike hybrid surgeries, the minimalist f-TEVAR does not require general anesthesia and its associated risks, providing a safer alternative. The technique provides two critical advantages related to the limitations of conventional endovascular repair: (I) it circumvents the LCCA-LSA distance requirement for single-branch endografts, successfully treating patients with complex anatomies (LCCA-LSA distance <5 mm). (II) It reduces type Ia endoleak incidence as compared to the chimney techniques. By combining preoperative computed tomography (CT)-guided planning with device-specific curvature memory, our method achieves immediate branch alignment without balloon molding or postdeployment stenting.

Our study cohort included patients with complex aortic pathologies—dissections, penetrating ulcers, and aneurysms—with inadequate PLZs, necessitating devices capable of balancing conformability and radial force. Despite these anatomical challenges, the Relay NBS graft demonstrated favorable clinical outcomes without major complications. Two cases required bailout branch via VBX stent for compromised LSA perfusion secondary to intraoperative graft migration and type II endoleaks. Notably, the device’s proximal nonbare design eliminated retrograde type A dissection risk, enabling safe deployment in high-risk zones 1–2. The intrinsic rotational alignment mechanism ensured precise fenestration orientation, achieving 100% first-attempt branch cannulation success despite complex arch angulation. The self-alignment mechanism of the Relay NBS graft eliminates the need for manual rotational adjustments, thereby reducing the intraoperative stroke risk associated with graft manipulation. In our cohort, no procedure-related stroke occurred, yielding a stroke rate equal to or lower than the 2.8–5.4% reported in conventional fenestration cohorts (7,18). This difference may be partly attributable to the relatively small sample size of our study but also to the mechanistic advantage of avoiding graft rotation. Crucially, the platform’s controlled deployment mechanics prevented significant migration events, with aorto-graft apposition being maintained even in severely angulated landing zones. For cases deemed unsuitable for branched endografts due to LCCA-LSA distances <5 mm or hostile arch morphology, this technique provided a reliable endovascular alternative with midterm patency rates equivalent to those of surgical bypass (98.4% vs. 98.9% at 12 months).

Our analysis revealed that 75% (25/33) of lesions involved the aortic arch’s lesser curvature—a distribution pattern associated with a 42–58% incidence of bird-beak configurations and endoleaks in TEVAR procedures (18-20). This anatomical predisposition stems from complex hemodynamic forces and the asymmetric wall apposition at the inner curve, which is compounded by the variability in arch morphology and landing zone angulation. Although a previous study reported higher complication rates in lesser curvature deployments (21), in our cohort, the clinical outcomes were similar between curvature subgroups, suggesting the NBS system’s self-adapting curvature compensation effectively neutralizes traditional inner-curve disadvantages. However, due to the limited sample size, we were unable to perform subgroup analyses to further elucidate the advantages of this technique for lesser curvature lesions.

This study involved several inherent limitations characteristic of retrospective analyses. First, the midterm follow-up period and modest cohort size may limit the generalizability to other populations with complex arch anatomies. Second, the sample constraints precluded powered comparative analyses of curvature-specific outcomes, despite 75% of lesions involving the lesser curvature—a subgroup historically associated with higher complication risks. Third, as we exclusively used the Relay NBS platform, the device-specific outcomes may not be generalizable to other fenestration techniques employing different stent-graft architectures. Most critically, the nonrandomized, single-arm design precludes causal inferences regarding technique superiority over conventional approaches. Future multicenter studies examining ≥5-year outcomes and randomized trials comparing fenestration strategies are needed to validate these preliminary findings.

Conclusions

The minimalist f-TEVAR protocol incorporating the NBS graft represents a reproducible, patient-specific solution for aortic arch pathologies, providing precise branch alignment with streamlined procedural efficiency. Its self-aligning design and simplified modification workflow address those anatomical challenges that have traditionally limited endovascular repair, particularly in cases with complex branching geometry. The outcomes of this preliminary study suggest favorable safety and technical reliability, but larger cohorts and extended follow-up are required to validate its long-term efficacy.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROCSS reporting checklist. Available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-163/rc

Data Sharing Statement: Available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-163/dss

Peer Review File: Available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-163/prf

Funding: This work was supported by the Doctor Research Foundation of Suzhou Hospital Affiliated Nanjing Medical University (project No. Szslyyrc202501030).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-163/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the institutional ethics board of Beijing Anzhen Hospital, Capital Medical University (approval No. 2025137X) and informed consent was obtained from all individual participants.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Upchurch GR Jr, Escobar GA, Azizzadeh A, et al. Society for Vascular Surgery clinical practice guidelines of thoracic endovascular aortic repair for descending thoracic aortic aneurysms. J Vasc Surg 2021;73:55S-83S. [Crossref] [PubMed]
2. Lombardi JV, Hughes GC, Appoo JJ, et al. Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) reporting standards for type B aortic dissections. J Vasc Surg 2020;71:723-47. [Crossref] [PubMed]
3. Czerny M, Grabenwöger M, Berger T, et al. EACTS/STS Guidelines for diagnosing and treating acute and chronic syndromes of the aortic organ. Eur J Cardiothorac Surg 2024;65:ezad426. [Crossref] [PubMed]
4. Saccenti L, Kobeiter H, Tacher V. Is In Situ Fenestration the Future of Complex TEVAR? Cardiovasc Intervent Radiol 2024;47:728-9. [Crossref] [PubMed]
5. Raulli SJ, Gomes VC, Parodi FE, et al. Five-year outcomes of fenestrated and branched endovascular repair of complex aortic aneurysms based on aneurysm extent. J Vasc Surg 2024;80:302-10. [Crossref] [PubMed]
6. Chen CW, Hu J, Li YY, et al. The outcomes of aortic arch repair between open surgical repair and debranching endovascular hybrid surgical repair: A systematic review and meta-analysis. J Vasc Surg 2024;79:1510-24. [Crossref] [PubMed]
7. Boufi M, Alexandru G, Tarzi M, et al. Systematic Review and Meta-Analysis of Ex-Situ and In-Situ Fenestrated Stent-Grafts for Endovascular Repair of Aortic Arch Pathologies. J Endovasc Ther 2024;31:1041-51. [Crossref] [PubMed]
8. Yordanov MD, Oberhuber A, Ibrahim A. Physician-Modified TEVAR versus Hybrid Repair of the Proximal Descending Thoracic Aorta. J Clin Med 2022;11:3455. [Crossref] [PubMed]
9. Czerny M, Berger T, Kondov S, et al. Results of endovascular aortic arch repair using the Relay Branch system. Eur J Cardiothorac Surg 2021;60:662-8. [Crossref] [PubMed]
10. Fang C, Wang C, Liu K, et al. Early Outcomes of Left Subclavian Artery Revascularization Using Castor Single-Branched Stent-Graft in the Treatment of Type B Aortic Dissection or Intramural Hematoma. Ann Thorac Cardiovasc Surg 2021;27:251-9. [Crossref] [PubMed]
11. Jing Z, Lu Q, Feng J, et al. Endovascular Repair of Aortic Dissection Involving the Left Subclavian Artery by Castor Stent Graft: A Multicentre Prospective Trial. Eur J Vasc Endovasc Surg 2020;60:854-61. [Crossref] [PubMed]
12. Liu D, Luo H, Lin S, et al. Comparison of the efficacy and safety of thoracic endovascular aortic repair with open surgical repair and optimal medical therapy for acute type B aortic dissection: A systematic review and meta-analysis. Int J Surg 2020;83:53-61. [Crossref] [PubMed]
13. Cheng Z, Liu Y, Ma X. Comparative Analysis of Endovascular Repair of Single-Branched Stent-Graft and Hybrid Procedure for Patients With Type B Acute Aortic Dissection Involving the Left Subclavian Artery. J Endovasc Ther 2024;31:892-900. [Crossref] [PubMed]
14. D'Oria M, Kärkkäinen JM, Tenorio ER, et al. Perioperative Outcomes of Carotid-Subclavian Bypass or Transposition versus Endovascular Techniques for Left Subclavian Artery Revascularization during Nontraumatic Zone 2 Thoracic Endovascular Aortic Repair in the Vascular Quality Initiative. Ann Vasc Surg 2020;69:17-26. [Crossref] [PubMed]
15. Reyes Valdivia A, Pitoulias G, Pitoulias A, et al. Systematic Review on the Use of Physician-Modified Endografts for the Treatment of Aortic Arch Diseases. Ann Vasc Surg 2020;69:418-25. [Crossref] [PubMed]
16. Zhao Z, Qin J, Yin M, et al. In Situ Laser Stent Graft Fenestration of the Left Subclavian Artery during Thoracic Endovascular Repair of Type B Aortic Dissection with Limited Proximal Landing Zones: 5-Year Outcomes. J Vasc Interv Radiol 2020;31:1321-7. [Crossref] [PubMed]
17. Chang H, Jin D, Wang Y, et al. Chimney Technique and Single-Branched Stent Graft for the Left Subclavian Artery Preservation During Zone 2 Thoracic Endovascular Aortic Repair for Type B Acute Aortic Syndromes. J Endovasc Ther 2023;30:849-58. [Crossref] [PubMed]
18. Li X, Zhang L, Song C, et al. Outcomes of Total Endovascular Aortic Arch Repair with Surgeon-Modified Fenestrated Stent-Grafts on Zone 0 Landing for Aortic Arch Pathologies. J Endovasc Ther 2022;29:109-16. [Crossref] [PubMed]
19. Gonzalez-Urquijo M, Fumagal González GA, Cárdenas Castro HM, et al. Analysis of Aortic Arch Hemodynamics With Simulated Bird's Beak Effects. Vasc Endovascular Surg 2024;58:595-601. [Crossref] [PubMed]
20. Kudo T, Kuratani T, Shimamura K, et al. Type 1a endoleak following Zone 1 and Zone 2 thoracic endovascular aortic repair: effect of bird-beak configuration. Eur J Cardiothorac Surg 2017;52:718-24. [Crossref] [PubMed]
21. Boufi M, Guivier-Curien C, Deplano V, et al. Risk Factor Analysis of Bird Beak Occurrence after Thoracic Endovascular Aortic Repair. Eur J Vasc Endovasc Surg 2015;50:37-43. [Crossref] [PubMed]

(English Language Editor: J. Gray)