Historical Aspects and Evolution
`of Fenestrated and Branched
`Technology
`
`Blayne Roeder, David Hartley,
`and Michael Lawrence-Brown
`
`1
`
` Introduction
`
`Endovascular repair of aortic aneurysms (EVAR) has been
`disseminated worldwide since the first report by Juan Parodi
`in 1991 (Fig. 1.1). Since this initial disclosure, several inno-
`vators have worked on broadening the indications of EVAR
`to treat patients with complex anatomy. The Zenith AAA
`Endovascular Graft resulted from the collaboration of a
`global team of innovators. This team shared a common phi-
`losophy that the endovascular repair must seal in healthy
`aorta to provide a durable repair over the life of the patient.
`As a result of this philosophy, the Zenith was the first endo-
`vascular graft to incorporate proximal fixation and a modular
`three-piece system in combination with a delivery system
`that allowed for precise deployment. This enables the physi-
`cian to place the graft in a position that takes advantage of all
`the available healthy aortic seal zone possible, while active
`fixation acts to maintain the seal over a prolonged period,
`ultimately resulting in a durable endovascular repair.
`Subsequently, nearly every commercially available endovas-
`cular graft for abdominal aortic aneurysm (AAA) repair has
`evolved to incorporate proximal fixation, modularity, and
`delivery systems offering more control of graft placement.
`As experience grew in the early days of endovascular
`stent graft repair, it was quickly realized that not all patients
`were suitable candidates for standard infrarenal or thoracic
`endovascular grafts. These grafts were limited to the repair
`
`B. Roeder (*)
`Aortic Intervention, Cook Medical,
`750 Daniels Way, P.O. Box 489, Bloomington, IN 47402-0489,
`USA
`e-mail: Blayne.Roeder@CookMedical.com
`
`D. Hartley
`Radiology Department, Royal Perth Hospital,
`73 Sandpiper Island, Wannanup, WA 6210, Australia
`e-mail: david.hartley@cookmedical.com
`
`M. Lawrence-Brown
`Faculty of Health Sciences, Curtin University of Technology,
`Bentley Campus, Perth, WA 6845, Australia
`e-mail: mlabrown@iinet.net.au
`
`of lesions between the renal arteries and internal iliacs, or
`between the left subclavian and the celiac artery, where a
`suitable proximal and distal sealing zone remained without
`coverage of any major aortic branches. As disease encroached
`towards these branches, the options were to either compro-
`mise on the quality of the seal zones or incorporate the
`branches in order to have seal zones in healthy aorta. Driven
`by the aforementioned philosophy that the endovascular
`repair must land in a healthy segment of aorta to provide a
`durable repair, the group embarked upon developing the abil-
`ity to incorporate critical branches into the seal zone.
`Ultimately these developments resulted in the possibility of
`treating patients with branches in the seal zones and branches
`arising from the aneurysm itself, making repair of complex
`thoracoabdominal (TAAA) and arch pathologies possible.
`This chapter details the development of fenestrated and
`branched endografts from the first prototypes and clinical
`cases with simple fenestrated grafts in the late 1990s to the
`most recent developments where patients can be offered the
`possibility of endovascular treatment of the entire aorta from
`the sino-tubular junction to the internal and external iliacs.
`
` Development of the Zenith Fenestrated
`Graft
`
`The simplest structure that can be added to an endovascular
`graft to allow blood flow to a branch vessel is a fenestration
`(or hole) through the graft material. Challenges arise from
`the need to align the fenestration with the branch vessel
`during deployment, and in maintaining alignment with the
`vessel during the life of the endovascular repair, to ensure
`long-term branch patency. The need for three-dimensional
`precise alignment is the primary challenge in fenestrated
`endovascular repair when compared to infrarenal AAA
`repair. The Zenith AAA Endovascular Graft has a delivery
`system that allows for precise placement and proximal
` fixation to reduce migration and provide an ideal basis for
`incorporation of fenestrations.
`
`© Mayo Foundation for Medical Education and Research 2017
`G.S. Oderich (ed.), Endovascular Aortic Repair, DOI 10.1007/978-3-319-15192-2_1
`
`3
`
`MEDTRONIC 1124
`
`

`

`4
`
`B. Roeder et al.
`
`Australia and in the USA Roy Greenberg (2001) energetically
`took up the technology and, by the force of large numbers of
`cases, excellent data, and concise presentations, demonstrated
`to the world that it was a viable method of treatment. Michael
`Denton performed the first thoracoabdominal repair using the
`fenestrated endograft to incorporate the celiac axis and supe-
`rior mesenteric artery (Fig. 1.5). In the initial version of the
`device, two wires were used to constrain, and reduce the
`diameter of the device in its posterior wall. Today, fenestrated
`grafts with up to five fenestrations and scallops are routinely
`placed to treat short- neck AAA, juxtarenal AAA, pararenal
`AAA, and type IV TAAAs.
`The simple hole in the graft material evolved to include
`nitinol rings on the margins of the fenestration to make a
`more durable connection with the stent (Fig. 1.6a), and cov-
`ered balloon-expandable stents replaced bare stents (Fig. 1.6b)
`as they proved a more durable repair [2]. The use of covered
`stents also facilitated bridging small gaps between the endo-
`graft and aortic wall without the endoleak that would other-
`wise occur through the bare stent and into the aneurysm.
`As the technique developed, there were several deployment-
`related improvements that enhanced the Zenith system to bet-
`ter facilitate fenestrated endovascular repair. Gold radiopaque
`markers were added to demonstrate the margins of the fenes-
`tration under fluoroscopy and facilitate location and alignment
`of the fenestrations with their respective target arteries (see
`Fig. 1.6a). Diameter-reducing ties were added to partially con-
`strain the graft following release of the graft from the delivery
`sheath (Fig. 1.6c). In this way, some repositioning of the endo-
`vascular graft to perfectly align the fenestrations was possible.
`Further, the “composite” design wherein the body of the graft
`was manufactured in two parts, the proximal fenestrated com-
`ponent being a tube, and a separate distal component being
`bifurcated, simplifies the procedure by allowing alignment of
`the fenestrations during deployment of the proximal fenes-
`trated component independent of the positional requirements
`of the bifurcation. It is also perceived that the sliding connec-
`tion between the proximal and distal components reduces dis-
`placement forces applied to the fenestrations and connecting
`stents in the event of movement of the bifurcated component.
`These developments above are all features of the com-
`mercially available Zenith Fenestrated AAA Endovascular,
`which was CE marked in 2005 and following a prospective
`trial of 67 patients at 14 centers in the USA was approved by
`FDA in 2012. The trial reported 100 % technical success, and
`no aneurysm ruptures or conversions during a mean follow-
` up of 37 ± 17 months (range, 3–65 months), and patient sur-
`vival was 91 ± 4 % at 5 years [3]. Patient follow-up will
`continue through 5 years.
`Regardless of the clinical success of the fenestrated plat-
`form, the need to cannulate branch vessels through fenestra-
`tions in the graft and placement of stents through these
`
`Fig. 1.1 Parodi, Palmaz, and Barone from Argentina reported in 1991
`(Ann Vasc Surg 1991(6): 491–499) their initial animal experiments and
`clinical experience with endovascular aortic aneurysm repair. By per-
`mission of Mayo Foundation for Medical Education and Research. All
`rights reserved
`
`The first fenestrated repair was reported by Park in 1996
`using a device modification to incorporate an accessory renal
`artery in a patient with infrarenal aneurysm. In 1997, Dr. Tom
`Browne (Fig. 1.2) with the research team in Perth led by
`Michael Lawrence-Brown and David Hartley demonstrated
`deployment of an endovascular graft in an animal model in
`which a fenestration was aligned both longitudinally and
`rotationally to perfuse an aortic branch, which would other-
`wise have been covered [1]. This was achieved by deploying
`the fenestration over a balloon placed in the orifice of the tar-
`get vessel. The first successful clinical fenestrated endovascu-
`lar aneurysm repair (Fig. 1.3) was completed the next year by
`Dr. John Anderson in Adelaide, Australia. The first case was
`not aligned by stent in the fenestration. Later, John Anderson
`and the Perth team ensured long-term alignment by placing a
`balloon-expanded stent to hold tight the fenestration and tar-
`get orifice. The technique was quickly disseminated through
`workshops run in Perth to the rest of Australasia, Europe, and
`Southeast Asia. Wolf Stelter (1998) in Germany suggested a
`composite body to the stent graft with a tubular upper module
`and a separate distal bifurcated component (Fig. 1.4). The
`upper tubular module was adapted for the fenestrations in
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`5
`
`Fig. 1.2 The Perth research team
`of Tom Browne, David Hartley,
`and, led by, Michael Lawrence-
`Brown were instrumental in the
`initial animal experiments. The
`initial graft design was based on
`the Zenith Bifurcated Stent with
`suprarenal fixation. The
`fenestration was not reinforced and
`had radiopaque markers. Stent
`struts are noted across the
`fenestration, which at the time was
`not intended to be stented. The
`detailed designs and prototypes for
`the majority of the subsequent
`Cook production fenestrated and
`branched devices evolved out of the
`Perth R&D facility. By permission
`of Mayo Foundation for Medical
`Education and Research. All rights
`reserved
`
`fenestrations from a contralateral approach added additional
`challenge to the procedure over a standard infrarenal AAA
`repair. In addition, the need to place the stents from a contra-
`lateral approach limited applicability of the fenestrated tech-
`nique in patients without bilateral access. Towards these
`ends, and as suggested by Krassi Ivancev (Sweden), a novel
`preloaded delivery system (Fig. 1.7) was developed with its
`first use by Dr. Brendan Stanley in Perth, in May 2007,
`closely followed by Drs. Greenberg (USA), Ivancev
`(Sweden), Ferreira (Brazil), and Haulon (France), all of
`whom recognized the potential of the system to simplify pro-
`cedures and contributed to its development. Rather than rely-
`
`ing on contralateral access for targeting branch vessels, ports
`were added to the fenestrated delivery system to allow ipsi-
`lateral access with preloaded guide wires and sheaths for
`cannulation of target vessels and placement of the branch
`stents. The added inherent stability and control offered by
`the system simplifies vessel cannulation and placement of
`stents through the fenestrations.
`The preloaded delivery system facilitated the most recent
`evolution of fenestrated repair: an off-the-shelf device to
`treat short-neck AAA, juxta-renal AAA, and pararenal
`AAA. Planning, manufacturing, and delivery of a fenestrated
`device built for a specific patient can take several weeks.
`
`

`

`B. Roeder et al.
`
`6
`
`Fig. 1.3 The first clinical implant
`of a fenestrated stent using the
`Cook Zenith platform was
`performed by Dr. John Anderson in
`Adelaide, Australia. This
`illustration based on the actual case
`depicts a single left renal
`fenestration. The patient had been
`previously treated for a high-grade
`left renal stenosis by placement of
`a bare metal stent, which was
`carefully deployed inside the
`vessel. Note that the fenestration
`was non-reinforced and was not
`aligned by stent. By permission of
`Mayo Foundation for Medical
`Education and Research. All rights
`reserved
`
`This delay limits the potential for this technology in patients
`who experience a rupture, are symptomatic, or have a large
`aneurysm. The Zenith p-Branch is an off-the-shelf fenes-
`trated device. The device includes a large scallop for the
`celiac artery, a standard fenestration for the superior mesen-
`teric artery, and two pivot fenestrations for the renal arteries
`(Fig. 1.8). The device is deployed as a standard fenestrated
`graft, with focus on alignment of the SMA fenestration with
`its target. The dome-shaped pivot fenestrations are designed
`to allow for offset of the renal arteries from the renal fenes-
`trations. In this way, a singular device can be used to treat a
`range of patient anatomies. The additional stability and con-
`trol afforded by the preloaded fenestration delivery system,
`which is part of the p-Branch package, help to offset possible
`challenges in cannulation of renal arteries from the fenestra-
`tions. Tim Resch followed by Stephan Haulon completed the
`first p-Branch cases in 2011 [4, 5] and pre-approval clinical
`studies are currently under way (see Fig. 1.8).
`
` Preservation of Normal Anatomy
`
`Another key philosophy from surgery translated into endo-
`vascular techniques is the preservation of normal anatomy
`whenever possible. It is possible to restore blood flow to
`critical branches via surgical bypasses in combination with
`standard endovascular grafts that cover and occlude blood
`flow the native vessel ostia or via so-called parallel grafts.
`Although such “hybrid techniques” were a critical step in
`treating more patients by endovascular approaches, they
`most definitely do not preserve normal anatomy and hybrid
`techniques have the further downside of necessitating surgi-
`cal intervention in combination with the endovascular repair.
`Fenestrations are the foremost example of preservation of
`normal anatomy in endovascular aortic repair that incorpo-
`rate blood flow to branch vessels. In fenestrated repair, the
`structure of the combined endovascular graft and covered
`bridging stent placed in the branch vessel often replicates the
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`7
`
`Fig. 1.4 Progress in the design of the fenestrated graft is credited to
`Wolf Stelter in Germany who suggested the concept of a separate tubu-
`lar component with the fenestrations and a distal bifurcated component.
`Roy Greenberg in the USA is credited with applying the technology to
`wide clinical use, treating complex anatomy with multiple fenestrations
`
`and scallops in a large number of patients. The fenestrations at this
`point were not reinforced, but the design had evolved to avoid struts
`across the fenestrations, with the intention to align the fenestration to
`the target vessel with an “alignment” stent. By permission of Mayo
`Foundation for Medical Education and Research. All rights reserved
`
`native anatomy to within a millimeter or two. In some
`instances, blood flow may even be optimized as any stenosis
`in the orifice may be resolved by the stents. Angulation and
`tortuosity of branches may provide additional challenges to
`branch stent conformance to the anatomy leading to distor-
`tion at the junction of the stents with the arteries or kinking
`of the stents. In practice, additional self-expanding stents are
`often added to help address these transitions and to provide
`long-term branch patency. The transition at the end of the
`distal end of the connecting stent in the target vessels remains
`a challenge with some of these procedures.
`
` Directional Branches
`
`Endovascular branched grafts used to maintain blood flow to
`critical aortic branches were not an independent innovation
`but rather a continued evolution of previous designs. The
`Chuter unibody bifurcated abdominal aortic graft in 1993
`was the first example of a branch device, to preserve native
`anatomy and patency of both iliac arteries, when the com-
`mon practice at the time was to employ an aorto-uniiliac
`graft and a surgical fem-fem crossover procedure. This was
`followed by modular bifurcated branch devices with off-the-
`
`

`

`8
`
`Fig. 1.5 Michael Denton
`collaborated with initial experience
`using the fenestrated stent to treat a
`distal thoracoabdominal aneurysm.
`By permission of Mayo Foundation
`for Medical Education and
`Research. All rights reserved
`
`B. Roeder et al.
`
`shelf components to accommodate a wide range of iliac
`artery anatomy and simplified the procedure by allowing
`implantation in a staged fashion. When the use of fenestrated
`grafts to save renal arteries began in 1997, it was a small step
`forward to use a covered stent in the fenestration, and turn it
`into what was effectively a side branch.
`However, for the sake of clarity, branched endovascular
`grafts are now distinguished from their fenestrated counter-
`parts by having a tubular protrusion arising from the main
`lumen of the endovascular graft. The rationale for using such
`a connecting structure is that when self-expanding bridging
`stents are used to bridge the gap across an aneurysm space, it
`provides more surface area for seal and security. It can also
`direct the bridging stents, aligning them towards the target
`vessel in a direction that matches native anatomy, and allows
`more latitude in the positioning of these bridging stents.
`Initial development of branched endovascular grafts was
`focused in two areas: (1) a branch for the internal iliac artery
`in patients with iliac or aorto iliac aneurysms and (2) branches
`for the visceral vessels in patients with extensive TAAA.
`Today, branched stent grafts have evolved to include the treat-
`ment of aortic arch disease.
`
` Iliac Branch Device
`
`The first use of an iliac branch device to maintain flow to the
`internal iliac artery was performed successfully by Dr.
`
`Marcel Goodman in 2001 (Perth, WA). Professor Wolf
`Stelter (Frankfurt, Germany), also involved in the develop-
`ment of the iliac branch device (Fig. 1.9), completed the first
`large series of cases soon after that [6]. Initial attempts at
`iliac branch repair paralleled early approaches to complete
`infrarenal AAA repair with a unibody (single piece) bifur-
`cated endovascular prosthesis. Similar to the experience with
`AAA repair, the device implantation was simpler and the
`required device sizes required to treat varying patient anat-
`omy were reduced by a modular approach.
`Ultimately, the graft design was similar to that of a stan-
`dard iliac leg extension with a small branch added a few cen-
`timeters from the proximal end of the graft. Two unique
`versions of the device were developed. The first version had
`a straight branch that was designed to be used in combina-
`tion with a balloon-expandable covered stent to bridge to the
`internal iliac artery. The second version, pioneered by Roy
`Greenberg (see Fig. 1.9), had a helical branch that intended
`to align the branch with the internal iliac and use a self-
`expandable covered stent to connect to the internal iliac. The
`philosophy behind the helical device was to better manage
`the often angulated takeoff of the internal iliac and narrow-
`ing in the iliac bifurcation [7].
`The iliac branch device is intended to be the first compo-
`nent placed in the repair. The graft seals distally in the exter-
`nal iliac artery and can land proximally at or below the
`aortic bifurcation. A preloaded catheter facilitates place-
`ment of a femoral-to-femoral through-wire that further
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`9
`
`A third iliac branch device, the bi-branch was developed
`in collaboration with Dr. Stephen Cheng in Hong Kong and
`Roy Greenberg and is currently under clinical evaluation at
`the Cleveland Clinic (see Fig. 1.9). The device incorporates
`the branch for the internal iliac in the leg of a bifurcated
`prosthesis rather than in a leg extension. The repair is com-
`pleted with a proximal cuff landing below the renal arteries
`and a contralateral iliac leg extension. The concept was
`originally developed for use in patients with short common
`iliac arteries, because removal of two modular connections
`between the aortic graft bifurcation and the internal iliac
`branch shortened the overall length of the device. The device
`also found favor in use for preservation of internal iliac
`arteries in combination with other composite systems such
`as fenestrated or TAAA repairs. Preservation of internal
`iliac arteries is critical in TAAA repairs to minimize the risk
`of paraplegia.
`
` Thoracoabdominal Multibranch Repair
`
`Dr. Tim Chuter (Fig. 1.10) implanted the first multibranched
`device for TAAA repair [8]. The branched component had
`four branches (Fig. 1.10a), and was physician-manufactured
`and constructed of Z-stents sewn to Dacron fabric and
`remarkably similar to the design of visceral branched grafts
`manufactured today with two 8 mm braches for the SMA and
`celiac arteries and two 6 mm branches for the renal arteries.
`The first Cook-manufactured side branch was in the form
`of a short extension (Fig. 1.10b), only a few millimeters long,
`attached to the outside of a fenestration in a thoracoabdomi-
`nal fenestrated endovascular graft. This graft was placed by
`John Anderson in 2002. The axis of these early cuffs was
`orthogonal to the long axis of the graft but soon evolved in
`accordance with the principle of the Chuter design to have the
`cuffs arise from the graft at a lesser angle, nearly parallel to
`the graft itself (see Fig. 1.10b). In a further development of
`the original Chuter design, the side branches were manufac-
`tured to minimize profile, and strategically placed above each
`target vessel such that they could be cannulated and stents
`placed in an antegrade fashion (Fig. 1.10c). The graft evolved
`to its current design (t-Branch stent graft) with four direc-
`tional branches as an off-the-shelf alternative (Fig. 1.10d).
`An alternative configuration conceived and most com-
`monly used by Roy Greenberg had helical branches to pre-
`serve flow to the celiac and SMA and fenestrations with
`covered stents to provide flow to the renal arteries. Although
`use of helical branches in the treatment of TAAA is less
`common than straight branches, device strategies that pri-
`marily combine branches for the SMA and celiac and fenes-
`trations for the renal arteries are commonplace today.
`Key design principles for the ideal branch are as follows: the
`branches should be short in length, long-overlap is essential for
`a stable repair and long-term durability, and the trajectory of
`
`Fig. 1.6 Evolution of the Zenith fenestrated graft included the addition
`of a nitinol-reinforced ring and gold radiopaque markers (a), the use of
`covered stents to replace bare metal stents for alignment of fenestra-
`tions (b), and diameter-reducing ties (c). By permission of Mayo
`Foundation for Medical Education and Research. All rights reserved
`
`facilitates access to the branch, stability during cannulation
`of the internal iliac artery, and placement of the bridging
`stent from a contralateral approach. The repair is completed
`with a bifurcated device deployed above the iliac branch
`device and short limb connecting the short limb of the bifur-
`cated device to the proximal end of the iliac device prosthe-
`sis. The Zenith Branch Endovascular Graft was CE marked
`in 2006 with the helical version approved in 2007. The piv-
`otal US trial completed enrollment in early 2015. FDA
`approval is expected in 2016.
`
`

`

`10
`
`B. Roeder et al.
`
`Fig. 1.7 Development of the preloaded delivery system to facilitate
`fenestrated repair was first suggested by Ivancev, and became a collabo-
`ration of multiple investigators including Drs. Stanley (Australia),
`
`Greenberg (USA), Ivancev (Sweden), Haulon (France), and Ferreira
`(Brazil). By permission of Mayo Foundation for Medical Education
`and Research. All rights reserved
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`11
`
`Fig. 1.8 The p-Branch fenestrated
`graft evolved as an off-the-shelf
`alternative to treat juxta-renal
`abdominal aortic aneurysms. The
`device has a double-wide scallop
`for the celiac axis, a fenestration
`for the superior mesenteric artery,
`and two pivot fenestrations for the
`renal arteries. The initial clinical
`experience was by Tim Resch in
`Sweden and Stephan Haulon in
`France. By permission of Mayo
`Foundation for Medical Education
`and Research. All rights reserved
`
`the branch as it arises from the graft should be aligned with the
`target vessel. In this way, angulation of the branch stent and
`tendency towards kink is greatly reduced. Regardless of branch
`configuration, these principles provide a solid foundation for
`design of fenestrated and branched endovascular repairs.
`In theory, endovascular branches spanning an aneurysmal
`space allow some flexibility in offset of the branch from the
`target vessel. Taking advantage of this property, Tim Chuter’s
`suggestion to the research team in 2008 proposed a standard-
`ized design for a TAAA branched graft [9]. This analysis deter-
`
`mined that a majority of patient’s visceral vessel anatomy could
`be accommodated with a single four-branch configuration,
`something that could potentially be available off the shelf.
`Ultimately the Zenith t-Branch, an off-the-shelf four- branch
`device to treat TAAA was CE marked in 2012 (see Fig. 1.10d).
`In spite of the availability of an off-the-shelf solution, a
`significant portion of endovascular TAAA repairs are still
`completed using grafts manufactured for specific patients.
`Advantages to this approach include tailoring branch and
`potentially fenestration locations and branch graft dimensions
`
`

`

`B. Roeder et al.
`
`12
`
`Fig. 1.9 Evolution of endovascular
`repair to extend the landing zone
`into the external iliac artery
`required creation of an iliac branch
`device. The initial case by Marcel
`Goodman (Australia) and a larger
`clinical experience by Wolf Stelter
`(Germany) using the prototype
`depicted in the illustration, which
`evolved later into the straight iliac
`branch device currently utilized.
`The helical branch pioneered by
`Roy Greenberg later evolved into a
`bifurcated-bifurcated device with a
`helical branch. By permission of
`Mayo Foundation for Medical
`Education and Research. All rights
`reserved
`
`to fit an individual patient’s anatomy. Branches can even be
`included that have an upwards orientation if such a design will
`be a better match for the target vessel anatomy. Branch/fenes-
`tration locations that accurately match a patient’s anatomy
`have the potential to simplify deployment and improve out-
`comes. Custom tailoring of graft dimensions may also reduce
`
`the number of components required for the repair and limit the
`amount of coverage in the thoracic aorta. For these reasons,
`device usage for TAAA repair remains a split between off-the-
`shelf designs and grafts built for a specific patient.
`The first low-profile TAAA repair was completed in early
`2011 by Tim Chuter at the University of California, San
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`13
`
`Fig. 1.10 Tim Chuter is credited for the development and first clinical
`use of a multibranched thoracoabdominal device. The illustration
`depicts evolution of the device based on photographs of the first implant
`
`(a), first versions of a manufactured device (b, c), and current off-the-
`shelf t-branch stent graft (d). By permission of Mayo Foundation for
`Medical Education and Research. All rights reserved
`
`Francisco. The graft had four downward-facing branches sim-
`ilar to the Zenith t-Branch. Delivery sheath profile was reduced
`by 4 Fr from 22Fr to 18Fr. Low-profile systems may provide
`the biggest benefit in the thoracic aorta as graft delivery sys-
`tems are often larger to begin with and TAAA occur at a higher
`rate in women who often present with access challenges.
`
` Arch Branch Device
`
`As with short-necked infrarenal aortic aneurysms, where
`fenestrations and scallops were used to move the seal to a
`more proximal region, the same concept was applied in
`thoracic grafts, with scallops and fenestrations used to
`extend the sealing zone proximally to the level of the
`innominate, left common carotid and left subclavian arter-
`ies (Fig. 1.11a). The first clinical case performed by Dr.
`Peter Mossop and Ian Nixon in Melbourne, Australia,
`occurred in 2000 and had a fenestration to preserve the flow
`in a left subclavian artery.
`This approach required extreme accuracy in deployment to
`align fenestrations and scallops with target vessels. Deployment
`of the graft in the arch from a femoral approach makes precise
`positioning a challenge. Preloaded catheters were used to assist
`
`in alignment of fenestrations and scallops to the vessels, but
`this technique still provided a challenge especially in difficult
`anatomy, even for very skilled operators.
`The first case of a branched endovascular graft involving
`all of the branches in the arch was described by Tim Chuter
`in 2003 [10]. This approach relied on debranching of the
`arch,
`including carotid-carotid and carotid-subclavian
`bypasses. The branch graft was delivered through the right
`carotid artery and sealed proximally in the ascending aorta
`and in the innominate trunk (Fig. 1.11b). A single large-
`diameter branch directed to the distal arch. A standard tho-
`racic graft delivered from a femoral approach, landing in this
`branch, completed the repair. A primary limitation of this
`technique was the requirement of a large-caliber delivery
`sheath for the branch graft through the right carotid artery.
`Early endovascular approaches described above and
`experience from hybrid techniques where cervical deb-
`ranching and a bypass arising from the ascending aorta
`are used in combination with standard thoracic endograft
`sealing proximally in the distal ascending aorta provided
`the initial experience with endografts in the ascending
`aorta and arch. Combined, these techniques clearly dem-
`onstrated the potential benefits but also the primary
`challenges associated with arch endovascular repair:
`
`

`

`14
`
`B. Roeder et al.
`
`Fig. 1.11 Evolution of the arch branch device from initial experience
`using fenestrations and scallops (a) to the first full arch repair by Tim
`Chuter (b). The first clinical use of the third-generation device with
`
`diamond-shaped fenestrations is credited to Cherrie Abraham (c). By
`permission of Mayo Foundation for Medical Education and Research.
`All rights reserved
`
`

`

`1 Historical Aspects and Evolution of Fenestrated and Branched Technology
`
`15
`
`accuracy in landing, conformance to the aorta, access
`challenges, morbidity from surgical bypasses, mortality,
`and stroke.
`In late 2009, the first multibranched graft for a total
`arch repair was implanted by Cherrie Abraham (Fig. 1.11c)
`in Montreal, Canada, who also described the initial expe-
`rience with the technique [11]. Cases soon followed using
`a slightly modified design including completely internal
`cuffs and branches with Tim Chuter, Roy Greenberg,
`Krassi Ivancev, Stephan Haulon, and Brendan Stanley
`contributing to the design. The graft is intended to land in
`the ascending aorta and eliminates the need for precise
`positioning with respect to the branches of the arch.
`Moreover, the introducer is designed to rotationally align
`the branches to the outer curve of the arch. The branches
`are internal to the endograft and incorporate a wide, dia-
`mond-shaped opening to facilitate retrograde cannulation.
`Although it was initially applied to patients with arch
`aneurysms, the technique has found applicability in
`patients with chronic type A dissection [12]. Patients with
`prior surgical repair of the ascending aorta often present
`with the need to repair the remainder of the arch. The sur-
`gical graft provides an excellent landing zone for an endo-
`vascular repair. Iterative improvements are still under
`way. One such modification to the delivery system allows
`treatment of patients with a mechanical aortic valve [13].
`Results with the latest versions have been generally better
`than previous approaches, but clinical evaluation is still
`under way [14].
`
` Dissemination of the Technique
`
`It is important to note the significance of a global, collab-
`orative, multidisciplinary team to translate their philoso-
`phies, ideas, and technologies into viable new devices and
`therapies for patients. The original collaborators were not
`from a single specialty. Many of the innovators undertook
`multidisciplinary training programs in vascular surgery
`and interventional radiology. One example of many is the
`Malmo experience where Krassi Ivancev contributed his
`enthusiasm and interventional radiology skills and knowl-
`edge together with the vascular surgery specialty to form
`a multidisciplinary endovascular unit. A me