Devices for thoracic endovascular aortic repair of type B aortic dissection: is there any chance for Marfan syndrome?

ABSTRACT

Introduction

Type B aortic dissection (TBAD) is a threatening event that may lead to death for aortic rupture or multivisceral malperfusion in the acute phase and offers a poor prognosis for long term survivors. Thoracic endovascular aortic repair (TEVAR) has become the preferential therapy in acute and chronic complicated cases for its less invasivity compared to open surgery. However TEVAR is still encumbered by a significant number of reinterventions, caused by aortic neck aneurysmal degeneration, endoleaks and stent-graft induced new entry (SINE). This is even more true in patients with particularly fragile aortic wall like Marfan Syndrome (MS) in contrast to the excellent results of elective open surgery.

Areas covered

This review analyzes the current available TEVAR devices and techniques in TBAD and their technological advancements, especially those most suitable to TBAD anatomy, according to current literature.

Expert opinion

The continuous technological evolution of materials and device solutions ensures solid results of TEVAR in acute TBAD and may also potentially overcome some of the limitations of endovascular devices in this setting, paving the way for safer and more durable results and allowing for expanded indications in the future, even in the delicate population of collagenopathies, especially in MS.

KEYWORDS:

• Aortic dissection
• conformability
• device
• endovascular treatment
• false lumen
• Marfan Syndrome
• remodeling
• TEVAR
• thoracic endografts

Article highlights

• Thoracic endovascular aortic repair (TEVAR) has emerged as a first-line therapy in selected patients presenting with acute, subacute or chronic complicated type B aortic dissection (TBAD) due to the limited invasiveness compared to open surgery.

• Despite optimal early results, TEVAR long term outcome in TBAD is still affected by a significant number of reinterventions, because of the challenging anatomy and physiopathology of aortic dissection. The inherent aortic neck fragility is responsible for severe complication like retrograde type A dissection, aortic neck degeneration and endoleaks. Thoracic false lumen reperfusion from distal re-entry tears contribute to late false lumen aneurysmal evolution even after successful TEVAR.

• The limits of the first generation devices, designed to fit for aortic aneurysms, have led all the companies involved with aortic Stent-graft (SG) production to develop new devices dedicated to the treatment of TBAD

  1. The Valiant Navion device (Medtronic, Minneapolis, MN) has enhanced aortic conformability through the new design with overlapping proximal support stents, the multifilament plot, the stents length reduction.

  2. The Relay NBS device (Terumo Aortic, Sunrise FL, USA) probably provides the softest apposition to the aortic neck with the crown shaped sealing main support stent and the exclusive deployment mechanism.

  3. The C-TAG device (W.L. Gore, Flagstaff, AZ) has strongly enhanced its conformability through its renewed PTFE frame. The new Active control system ensure a proper SG aortic alignment.

  4. The Zenith Dissection Endovascular System (Cook Medical Inc, Bloomington, In) was the first device designed to treat aortic dissection. A modular system with a proximal endograft (The Zenith Dissection Endovascular Graft) and a distal bare metal stent component, (the Zenith Dissection Endovascular Stent).

  5. The new E-nya device (Cryolife Jotec, Hechingen, Germany) has a specific configuration designed for TBAD with enhanced proximal configuration without exposed stent peaks and new more conformable fabric.

• The anatomical complexity of aortic dissection has also favoured the development of new techniques:

  1. The PETTICOAT and STABILISE, described in literature, favour a more extensive aortic remodeling after standard TEVAR, expanding the treatment distally using bare metal stents. The STABILISE also involves ballooning of the bare stent, which is not recommended in the IFU.

  2. Several less invasive alternative therapies have also evolved using custom-made devices as Candy Plug or Nickerbocker techniques, described in literature or different common products to induce false lumen embolization.

  3. Fenestrated and branched endovascular aortic repair may treat very complex cases unfit for open surgery and standard TEVAR, representing a totally endovascular approach.

• The issues posed by aortic dissection to TEVAR are more evident in patients affected by collagenopathies like Marfan Syndrome (MS). Current available evidence suggests very poor results of TEVAR in Marfan patients and surgery is the preferred therapy.

• Marfan patients are often subjected to multiple aortic surgery and their natural history may be affected by an increasing invasivity and morbidity burden. The new devices dissection-specific design may also pave the way for a less invasive approach in Marfan patients.

• The forthcoming prospective trials evaluating the performance of the new low profile devices (Valiant Navion and Relay NBS PRO) in TBAD treatment as well as the increasing registry data from C-TAG will tell us more about the future of TEVAR in this context.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This paper was not funded.