http://dqsendovascular.blogspot.kr/2012/10/evar-devices-summary.html
Several trials have compared endovascular aneurysm repair using a variety of endografts to open surgical repair for the treatment of infrarenal AAA.
The devices used in the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial included the Zenith® in 35 percent of EVAR patients, Talent™ in 28 percent, AneuRx® in 7 percent, Excluder® in 21 percent and other devices in the remaining 10 percent .
The endografts used in the EVAR1 and EVAR2 trials included Zenith® in 51 percent, Talent™ in 33 percent, Excluder® in 7 percent, AneuRx® in 4 percent, and Quantum in 3 percent .
Devices used in the OVER trial included the Excluder® in 37 percent, Zenith® in 39 percent, and AneuRx® in 21 percent .
These trials have consistently demonstrated significantly reduced perioperative morbidity and mortality (1 to 2 versus 3 to 5 percent) for endovascular compared with open surgical repair; however, long-term mortality is not significantly different. Endovascular repair is associated with a significantly greater number of graft-related secondary interventions, but the overall need for reintervention may be similar when all open surgical complications (eg, hernia, adhesiolysis for small bowel obstruction) are taken into account. The details of these trials and factors that enter into the decision to offer open versus endovascular management of elective and ruptured AAA repair are discussed elsewhere.
When aortic disease is more extensive and involves branch vessels, the complexity of the repair and risk of complications increases. Approaches to manage more complicated anatomy include debranching procedures and the use of fenestrated and branched endografts.
Debranching procedures involve ligation of an aortic branch that will be covered by the endograft and surgical revascularization (eg, carotid-subclavian bypass, hepatorenal bypass). The role of debranching in the treatment of aneurysmal disease is discussed elsewhere.
Fenestrated and branched grafts are available for clinical use in Europe, but are considered investigational devices in the United States and are still undergoing clinical trials. The Zenith® Fenestrated AAA Endovascular Graft is the most studied device. Several other device manufacturers are currently working on off-the-shelf designs of branched and fenestrated grafts with clinical trials underway.
Fenestrated grafts — The use of fenestrated-endovascular aneurysm repair (FEVAR) to manage more challenging aortic anatomy continues to evolve [40-51]. The Zenith® Fenestrated AAA Endovascular Graft is the most studied device. The device is similar in construction to the Zenith device discussed above with the addition of fabric openings (fenestrations) created in the graft based upon measurements obtained with high-resolution computed tomographic (CT) angiography. These grafts have been used primarily to manage juxtarenal abdominal aortic aneurysms (AAA).
A systematic review identified 11 studies describing a total of 660 procedures . Initial success in placing the graft was >99 percent. Target vessel perfusion ranged from 90.5 to 100 percent. Double fenestrations were more common than triple or quadruple fenestrations. The perioperative (30-day) mortality rate was 2 percent.
The largest of these studies evaluated the outcome of 134 patients following repair of juxtarenal abdominal aortic aneurysm treated with a Zenith® Fenestrated AAA Endovascular Graft at 16 French centers between May 2004 and January 2009 . A total of 403 visceral vessels were perfused through a fabric fenestration, including 265 renal arteries. The technical success of graft placement was 99.3 percent with one patient requiring open conversion. The success of target vessel revascularization was 99 percent. Perioperative mortality (30-day) was 2 percent. Dialysis was required in 4 percent of patients (transient in 3 percent and permanent in 1 percent). Endoleaks occurred in 12 percent of patients prior to discharge (one each type I and type III endoleak). Three patients had sac enlargement within the first year, associated with a persistent endoleak. No aneurysms ruptured or required open conversion during the follow-up period.
During follow-up, four renal artery occlusions were detected. A total of 12 procedure-related re-interventions were performed in 12 patients during follow-up, including 6 to correct endoleaks, and 5 to correct threatened visceral vessels. Longer-term mortality was 9 percent over the follow-up period but none of the deaths were related to the aneurysm repair. Actuarial survival at 12 and 24 months were 93 and 86 respectively. Aneurysm sac size decreased >5 mm in 52, 66, and 75 percent of patients at one, two, and three years, respectively.
Branched grafts — Branched grafts have a separate smaller side-arm graft sutured to the basic endovascular graft for deployment into a vessel to preserve flow into it. Another approach places a self-expanding stent-graft through the opening of a fenestrated graft. The Zenith® Fenestrated AAA Endovascular Graft (Cook Medical) is the primarily-studied device. (See 'Fenestrated grafts' above.)
Branched abdominal aortic grafts have been used in patients with suprarenal and juxtarenal aortic aneurysms, and common iliac artery aneurysms [53]. Initial experience with branched aortic grafts has shown similar perioperative mortality as conventional endovascular repair but the rate of aneurysm-repair-related mortality may be higher.
Branched grafts to the visceral vessels allow endovascular repair of more extensive aortic disease. The use of visceral branch devices in endovascular repair of abdominal aortic aneurysm is discussed elsewhere.
Iliac branched grafts are intended to preserve flow into the internal iliac artery during endovascular repair (abdominal aortic aneurysm or iliac artery aneurysm) that requires extension beyond the internal iliac artery orifice. The PRESERVE study will evaluate the safety and efficacy of the Zenith® Iliac Branch Device (Cook Medical). The use of iliac branch devices is discussed in detail elsewhere
There are no trials comparing specific aortic endografts for the treatment of abdominal aortic aneurysm (AAA). However, although the primary comparison in the endovascular aneurysm repair trials was between endovascular and open surgical repair, comparisons between the Talent™ and Zenith® devices in the EVAR trials failed to find significant device-specific differences .
Comparisons between different grafts have also been made in observational studies. One study that included 703 patients who underwent endovascular abdominal aortic aneurysm repair at a single institution over a six-year period found no significant differences for important outcomes. The devices used were Ancure (no longer available), AneuRx®, Excluder®, Talent™, and Zenith®. The outcomes included aneurysm-related death, conversion to open repair, need for secondary intervention, device migration, freedom from aortic rupture, and detection of Type I or III endoleaks [55]. Adhering to the device manufacturer’s criteria for anatomic suitability appears to be the more important issue.
Because the graft design doesn’t appear to have a major impact on outcomes of straightforward endovascular aneurysm repair, most operators choose one endograft for routine use, reserving others for one or more features that might be more suited to a specific patient [54,55]. The operator should become familiar with specific advantages inherent to endograft designs. A device with a lower profile is more advantageous in the patient with narrow access vessels, whereas a device with better conformability and active fixation would be more helpful in the patient with challenging aortic neck anatomy.
SUMMARY
Endovascular repair with abdominal endograft devices is used primarily to treat infrarenal abdominal aortic aneurysm. Endovascular aortic repair requires that specific anatomic criteria be fulfilled, and for those with appropriate anatomy, this technique has become a preferred approach and allows the treatment of patients who might not otherwise be candidates for aortic repair.
Endovascular aortic repair involves the insertion of endovascular graft components, usually via a femoral approach. The endovascular graft is constructed in vivo by the delivery and deployment of these components in an established order. Upon deployment, the endograft expands, contacting the aortic wall proximally and aorta or iliac vessels distally to exclude the native, dilated portion of the aortic wall from aortic blood flow and pressure.
Although there are significant variations in endovascular graft design, three types of components are common to all: the delivery system, main body device, and device extensions. Devices available in the United States to treat the abdominal aorta include the AneuRx®, Zenith®, Excluder®, AFX and Powerlink®, Talent™, and Endurant® grafts. The characteristics for each graft are described above. (See 'Abdominal devices' above.)
When aortic disease is more extensive and involves branch vessels, the complexity of the repair and risk of complications increases. Approaches to manage more complicated anatomy include debranching procedures and the use of fenestrated and branched endografts. These endografts preserve blood flow into specific aortic branches depending upon the level of repair, but are available only for investigational use in the United States.
Several trials have compared endovascular aneurysm repair with open surgical repair using a variety of endografts for the treatment of infrarenal abdominal aortic aneurysm. These trials have consistently demonstrated significantly reduced perioperative (30-day) morbidity and mortality (1 to 2 versus 3 to 5 percent) for endovascular compared with open surgical repair; however, long-term mortality is not significantly different. Secondary intervention is frequently needed in patients who receive an abdominal endograft. As such, these devices require lifelong surveillance; the long-term outcomes for these devices continue to be studied.
The few comparisons that are available for specific endograft designs for the treatment of abdominal aortic aneurysm (AAA) have found no significant differences between devices for important outcomes. Because the graft design doesn’t appear to have a major impact on the outcomes of straightforward endovascular aneurysm repair, most operators choose one endograft for routine use, reserving others for one or more features that might be better suited to a specific patient.
Several trials have compared endovascular aneurysm repair using a variety of endografts to open surgical repair for the treatment of infrarenal AAA.
These trials have consistently demonstrated significantly reduced perioperative morbidity and mortality (1 to 2 versus 3 to 5 percent) for endovascular compared with open surgical repair; however, long-term mortality is not significantly different. Endovascular repair is associated with a significantly greater number of graft-related secondary interventions, but the overall need for reintervention may be similar when all open surgical complications (eg, hernia, adhesiolysis for small bowel obstruction) are taken into account. The details of these trials and factors that enter into the decision to offer open versus endovascular management of elective and ruptured AAA repair are discussed elsewhere.
When aortic disease is more extensive and involves branch vessels, the complexity of the repair and risk of complications increases. Approaches to manage more complicated anatomy include debranching procedures and the use of fenestrated and branched endografts.
Debranching procedures involve ligation of an aortic branch that will be covered by the endograft and surgical revascularization (eg, carotid-subclavian bypass, hepatorenal bypass). The role of debranching in the treatment of aneurysmal disease is discussed elsewhere.
Fenestrated and branched grafts are available for clinical use in Europe, but are considered investigational devices in the United States and are still undergoing clinical trials. The Zenith® Fenestrated AAA Endovascular Graft is the most studied device. Several other device manufacturers are currently working on off-the-shelf designs of branched and fenestrated grafts with clinical trials underway.
Fenestrated grafts — The use of fenestrated-endovascular aneurysm repair (FEVAR) to manage more challenging aortic anatomy continues to evolve [40-51]. The Zenith® Fenestrated AAA Endovascular Graft is the most studied device. The device is similar in construction to the Zenith device discussed above with the addition of fabric openings (fenestrations) created in the graft based upon measurements obtained with high-resolution computed tomographic (CT) angiography. These grafts have been used primarily to manage juxtarenal abdominal aortic aneurysms (AAA).
A systematic review identified 11 studies describing a total of 660 procedures . Initial success in placing the graft was >99 percent. Target vessel perfusion ranged from 90.5 to 100 percent. Double fenestrations were more common than triple or quadruple fenestrations. The perioperative (30-day) mortality rate was 2 percent.
The largest of these studies evaluated the outcome of 134 patients following repair of juxtarenal abdominal aortic aneurysm treated with a Zenith® Fenestrated AAA Endovascular Graft at 16 French centers between May 2004 and January 2009 . A total of 403 visceral vessels were perfused through a fabric fenestration, including 265 renal arteries. The technical success of graft placement was 99.3 percent with one patient requiring open conversion. The success of target vessel revascularization was 99 percent. Perioperative mortality (30-day) was 2 percent. Dialysis was required in 4 percent of patients (transient in 3 percent and permanent in 1 percent). Endoleaks occurred in 12 percent of patients prior to discharge (one each type I and type III endoleak). Three patients had sac enlargement within the first year, associated with a persistent endoleak. No aneurysms ruptured or required open conversion during the follow-up period.
During follow-up, four renal artery occlusions were detected. A total of 12 procedure-related re-interventions were performed in 12 patients during follow-up, including 6 to correct endoleaks, and 5 to correct threatened visceral vessels. Longer-term mortality was 9 percent over the follow-up period but none of the deaths were related to the aneurysm repair. Actuarial survival at 12 and 24 months were 93 and 86 respectively. Aneurysm sac size decreased >5 mm in 52, 66, and 75 percent of patients at one, two, and three years, respectively.
Branched grafts — Branched grafts have a separate smaller side-arm graft sutured to the basic endovascular graft for deployment into a vessel to preserve flow into it. Another approach places a self-expanding stent-graft through the opening of a fenestrated graft. The Zenith® Fenestrated AAA Endovascular Graft (Cook Medical) is the primarily-studied device. (See 'Fenestrated grafts' above.)
Branched abdominal aortic grafts have been used in patients with suprarenal and juxtarenal aortic aneurysms, and common iliac artery aneurysms [53]. Initial experience with branched aortic grafts has shown similar perioperative mortality as conventional endovascular repair but the rate of aneurysm-repair-related mortality may be higher.
Branched grafts to the visceral vessels allow endovascular repair of more extensive aortic disease. The use of visceral branch devices in endovascular repair of abdominal aortic aneurysm is discussed elsewhere.
Iliac branched grafts are intended to preserve flow into the internal iliac artery during endovascular repair (abdominal aortic aneurysm or iliac artery aneurysm) that requires extension beyond the internal iliac artery orifice. The PRESERVE study will evaluate the safety and efficacy of the Zenith® Iliac Branch Device (Cook Medical). The use of iliac branch devices is discussed in detail elsewhere
There are no trials comparing specific aortic endografts for the treatment of abdominal aortic aneurysm (AAA). However, although the primary comparison in the endovascular aneurysm repair trials was between endovascular and open surgical repair, comparisons between the Talent™ and Zenith® devices in the EVAR trials failed to find significant device-specific differences .
Comparisons between different grafts have also been made in observational studies. One study that included 703 patients who underwent endovascular abdominal aortic aneurysm repair at a single institution over a six-year period found no significant differences for important outcomes. The devices used were Ancure (no longer available), AneuRx®, Excluder®, Talent™, and Zenith®. The outcomes included aneurysm-related death, conversion to open repair, need for secondary intervention, device migration, freedom from aortic rupture, and detection of Type I or III endoleaks [55]. Adhering to the device manufacturer’s criteria for anatomic suitability appears to be the more important issue.
Because the graft design doesn’t appear to have a major impact on outcomes of straightforward endovascular aneurysm repair, most operators choose one endograft for routine use, reserving others for one or more features that might be more suited to a specific patient [54,55]. The operator should become familiar with specific advantages inherent to endograft designs. A device with a lower profile is more advantageous in the patient with narrow access vessels, whereas a device with better conformability and active fixation would be more helpful in the patient with challenging aortic neck anatomy.
SUMMARY
Characteristics of abdominal endovascular devices
| Endograft | Materials graft/support | Suprarenal fixation | Active proximal fixation/hooks | Native aortic neck diameter (range in mm) | Native iliac diameter (range in mm) | Maximum bifurcated main body device/introducer sheath diameter (French, OD*) | Potential advantages |
| AneuRx® (Medtronic) | Polyester/nitinol | No | No | 20 to 26 | 8 to 22 | 21 | Hydrophilic delivery system |
| Endurant® (Medtronic) | Polyester/ electropolished nitinol | Yes | Yes | 19 to 32 | 8 to 25 | 20 | Indications include short (10 mm) aortic neck, angulated neck |
| Powerlink® (Endologix) | PTFE/cobalt chromium alloy | Yes | No | 18 to 32 | 10 to 23 | 17 | Anatomic fixation at iliac bifurcation, low profile |
| Excluder® (Gore) | PTFE/nitinol | No | Yes | 19 to 29 | 10 to 18.5 | 20 | C3 delivery system, ability to recapture and reposition body, delivery sheath with hemostatic seal |
| Talent® (Medtronic) | Polyester/nitinol | Yes | No | 18 to 32 | 8 to 22 | 24 | Indication for short (10 mm) aortic neck, angulated necks |
| Zenith® (Cook Medical) | Polyester/stainless steel | Yes | Yes | 18 to 32 | 8 to 20 | 26 | Spiral Z flexible limbs |
PTFE: polytetrafluoroethylene.
* OD: outer diameter.
* OD: outer diameter.
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