Patient-Specific Total Endovascular Aortic Arch Repair Using Custom Fenestration

0
0
0

Patient-Specific Total Endovascular Aortic Arch Repair Using Custom Fenestration of an Off-the-Shelf Thoracic Endovascular Aortic Repair Aortic-Stent

The management of aortic arch pathologies, including aneurysms and dissections, presents significant challenges due to the anatomical complexity and critical branching vessels. Traditional open surgical repair carries high morbidity and mortality risks, particularly in patients with comorbidities. Thoracic endovascular aortic repair (TEVAR) has emerged as a minimally invasive alternative, but its application in the aortic arch remains limited by the need to preserve blood flow to supra-aortic branches. Physician-modified fenestrated stent-grafts offer a promising solution, combining the economic advantages of off-the-shelf devices with the flexibility to address acute and complex cases. This article elaborates on the technical nuances of aligning fenestrations with aortic arch branches during TEVAR using a physician-modified triple-fenestrated stent-graft, illustrated through a clinical case.

Clinical Presentation and Preoperative Planning

A 64-year-old female presented with chronic type A aortic dissection extending from the aortic arch to both common iliac arteries. Imaging revealed that all major branches—innominate artery (IA), left common carotid artery (LCCA), left subclavian artery (LSA), celiac artery, superior mesenteric artery, and renal arteries—were perfused by the true lumen. The primary entry tear was located distal to the IA ostium. Preoperative planning emphasized precise measurement of anatomical features using computed tomography angiography (CTA) with 1 mm slice thickness. The Endosize workstation facilitated three-dimensional reconstruction, centerline-of-flow analysis, and multiplanar reformatting to determine:

  • Diameters of proximal and distal landing zones.
  • Optimal fluoroscopic projection angle (52° left anterior oblique).
  • Length of the aortic arch along the greater curvature.
  • Branch artery diameters and ostial distances along the greater curvature.
  • Clock-face orientation of branch ostia relative to the aortic lumen.

These measurements guided the design of fenestrations to align with the IA, LCCA, and LSA.

Device Selection and Modification

A 36 mm × 200 mm Valiant thoracic stent-graft (Medtronic Vascular) was selected for its partial deployment and re-sheathing capabilities. The proximal landing zone was positioned in the middle third of the ascending aorta (36 mm diameter), unaffected by the dissection. Fenestrations were created using a scalpel or electrosurgical device, avoiding stent struts to prevent endoleak or bridging stent compression. Rough fenestration edges were reinforced with hemstick sutures. Radiopaque markers and guidewire loops were used to intraoperatively localize fenestrations.

Key steps during modification included:

  1. Partial deployment of the stent-graft on the operating table.
  2. Addition of 1–2 distal stent segments to ensure fabric smoothness around fenestrations.
  3. Compression and re-sheathing of the modified stent-graft using two assistants: one secured the deployed portion with a 10-gauge wire, while another rotated the delivery handle to advance the sheath. The operator compressed the stent-graft incrementally to avoid rotation or displacement.

Operative Technique

Access and Positioning

A right femoral artery cutdown provided access for stent-graft delivery. The operating table was locked at 52° left anterior oblique to optimize branch vessel separation. Digital subtraction angiography (DSA) screen markers outlined the aortic arch and target vessels.

Distal Landing Zone Preparation

Given the 28 mm diameter of the distal landing zone (smaller than the 36 mm stent-graft), a 28 × 150 mm Valiant stent-graft was deployed distally as a restrictive scaffold, overlapping 4–5 cm with the proximal fenestrated device.

Fenestration Alignment Using Lu’s Direction-Turnover Technique

The fenestrated stent-graft was advanced over a stiff guidewire. The delivery system’s white marker (indicating the 6 o’clock position) was maintained perpendicular to the ground. As the stent-graft traversed the aortic arch’s greater curvature, the fenestrations rotated 180° to align with the 12 o’clock position—the anatomical orientation of branch ostia (Figure 1A). This maneuver ensured proper fenestration alignment without manual rotation.

Stent-Graft Deployment

The proximal bare stent was deployed first. The third stent segment’s distal end corresponded to the IA fenestration, aligned with the IA’s distal contour. Sequential deployment ensured IA, LCCA, and LSA alignment. Post-deployment angiography confirmed branch patency and false lumen exclusion.

Bridging Stent Implantation

  1. LCCA Fenestration: A 0.035-inch guidewire was passed through the fenestration into the LCCA. An 8 mm balloon expanded the fenestration, followed by deployment of an 8 × 50 mm Viabahn covered stent (Gore).
  2. LSA Fenestration: An 8 × 60 mm Fluency stent (C.R. Bard) was deployed without pre-dilation.
  3. IA Fenestration: A 16–13–80 mm Endurant Leg extension (Medtronic) was deployed, extending into the IA.

Postoperative Management and Follow-Up

Antiplatelet therapy (aspirin 100 mg/day) was initiated postoperatively. Three-year CTA demonstrated complete false lumen thrombosis, significant aortic remodeling, patent branch vessels, and no endoleak (Figure 1C). The aortic arch diameter decreased from 36 mm to 28 mm, and the distal landing zone remained stable.

Technical Considerations and Pitfalls

  1. Fenestration Design:

    • Avoid stent struts to prevent endoleak.
    • Use radiopaque markers (e.g., “8”-shaped wire loops) for intraoperative localization.
    • Ensure fenestration diameter matches bridging stent size (1:1 or slight oversizing).

  2. Resheathing Precautions:

    • Maintain segment distances; avoid compression-induced shortening.
    • Prevent rotation or forward sheath movement during re-sheathing.

  3. Bridging Stent Principles:

    • Insert 1 cm into the aortic lumen to prevent migration.
    • Post-dilate stenotic segments; avoid excessive dilation to reduce endoleak risk.

  4. Fluoroscopic Guidance:

    • Lock the operating table to maintain projection angle.
    • Use screen markers for real-time stent-graft positioning.

Advantages and Limitations

This technique enables total endovascular arch repair in emergencies, avoiding delays associated with custom devices. The Valiant stent-graft’s re-sheathing capability allows iterative adjustments, critical in complex anatomies. However, device selection is constrained by the need for partial deployment and re-sheathing features, excluding many commercial options. Additionally, the steep learning curve demands proficiency in fenestration modification, alignment techniques, and bridging stent deployment.

Conclusion

Patient-specific fenestrated TEVAR using physician-modified stent-grafts represents a viable option for aortic arch pathologies. Key success factors include meticulous preoperative imaging, adherence to Lu’s direction-turnover technique, and systematic bridging stent deployment. Three-year follow-up data demonstrate durable outcomes, underscoring the technique’s potential for broader adoption with appropriate training and device availability.

doi.org/10.1097/CM9.0000000000001438

Was this helpful?

0 / 0