http://dqsendovascular.blogspot.kr/2012/10/tevar-devices-summary.html
Talent® Thoracic Stent-Graft System — The Talent® Thoracic Stent-Graft System (Medtronic) consists of two components. The stent-graft components are made of a woven polyester graft with an external self-expanding support structure of M-shaped nitinol stents and a longitudinal support bar throughout its length. The proximal component is a straight stent-graft with an uncovered stent proximally that allows placement across the left subclavian or carotid artery. The distal component can be a straight or tapered tubular graft and has a closed web design that is intended to assure fixation of the components in the region of overlap.
The proximal component is available in diameters ranging from 22 to 46 mm in lengths from 11.2 to 11.6 cm. The distal component is available in diameters ranging from 26 to 46 mm in lengths from 11.0 to 11.4 cm. The delivery sheath ranges from 22 to 25 French (7.33 to 8.33 mm) in diameter. The device is delivered through the Xcelerant delivery system (same as AneuRx® and Valiant™ grafts) which is a ratcheted system for controlled initial deployment to position of the device, and then a more rapid release of the remainder of the device to avoid a “windsock” effect. Once deployed, the device is self-expanding; subsequent ballooning of the device is an option.
The safety and efficacy of the Talent® Thoracic Stent-Graft System was evaluated in the VALOR I study which was a multicenter study that compared endovascular repair (n = 195) with retrospective open surgical data obtained from three centers (n = 189) [23]. An average of 2.7 stent-graft components was used per patient. Technical success was 99.5 percent for vessel access and endograft deployment at the intended site. Perioperative (30-day) mortality was 2.1 percent and major adverse events overall occurred in 41 percent of patients, with paraplegia in 1.5 percent; paraparesis in 7.2 percent; and stroke in 3.6 percent. At one-year follow-up, all-cause mortality was 16.1 percent and aneurysm-related mortality was 3.1 percent. Late complications included conversion to open surgery (0.5 percent), target aneurysm rupture (0.5 percent), stent graft migration >10 mm (3.9 percent), and endoleak (12.2 percent). Compared with open surgery, the Talent® Thoracic Stent-Graft was found to have significantly lower perioperative mortality (2 versus 8 percent), fewer perioperative major adverse events (41 versus 84.4 percent) and lower aneurysm-related mortality at one year (3.1 versus 11.6 percent).
The INSTEAD trial randomly assigned 597 patients with stable aortic dissection (>2 weeks) to elective aortic stent-grafting plus medical therapy or medical therapy alone [24]. The Talent® Thoracic Stent-Graft System was used in all cases. There was no significant difference in overall mortality between the groups at two years, with a cumulative survival rate of 95.6 percent for medical therapy alone compared with 88.9 percent for endovascular repair. No differences were seen in aorta-related death rates or the combined end-point of aorta-related death (rupture) and progression of disease. Three neurological events occurred in the endovascular repair group (one paraplegia, one stroke, and one transient paraparesis), compared with one case of paraparesis in the medical therapy alone group. Aortic remodeling with recovery of the true-lumen and thrombosis of the false-lumen was found in significantly more patients undergoing endovascular repair (91.3 versus 19.3 percent) compared with medical therapy alone. In spite of favorable aortic remodeling, no improvements were seen in two-year survival or adverse event rates, and the impact on long-term aneurysmal degeneration of the dissected aortic segment remains to be studied.
Valiant™ Thoracic Stent-Graft System — The Valiant™ Thoracic Stent-Graft System (Medtronic Vascular) is a third-generation device based upon the Talent® Thoracic Stent-Graft System. The Valiant™ graft has a modified proximal bare stent with eight shorter bare stents proximally compared with five longer bare stents found in the Talent® stent-graft. The longitudinal support bar of the Talent® device was removed to provide improved device flexibility for the Valiant™ device.
The graft is available in straight or tapered configurations with diameters ranging from 24 to 46 mm and lengths up to 22.7 cm. The device is also delivered through the Xcelerant delivery system.
The initial experience of the Valiant™ endograft was reported in a multicenter retrospective study of 180 patients [25]. A variety of indications were treated including thoracic aneurysms (n = 66), thoracoabdominal aneurysms (n = 22), acute aortic syndrome (n = 19), aneurysm degeneration of chronic aortic dissection (n = 52), and traumatic aortic dissection (n = 21). The perioperative (30-day) mortality for the series was 7.2 percent with perioperative morbidity that included stroke in 3.8 percent and paraplegia in 3.3 percent. Mortality rates differed significantly depending upon indications, with the highest rate for thoracoabdominal aneurysms at 27.3 percent and lowest (none) for acute traumatic rupture.
The VALOR II study has been completed using the Valiant stent-graft resulting in approval of the Captivia Delivery System for use in the United States. Commercial release is ongoing and the one-year results demonstrate safety and efficacy comparable with the Talent® stent-graft.
Investigational devices — Several devices for thoracic endovascular repair are investigational and not commercially available in the United States. These include the Bolton Relay™, the LeMaitre TAArget™, and the JOTEC E-Vita® stent-graft system. These are briefly reviewed below.
Relay™ — The Relay™ (Bolton Medical) device is composed of self-expanding nitinol stents sutured to a polyester fabric graft with a curved longitudinal nitinol wire intended to provide longitudinal strength. It has a proximal bare stent that remains constrained until the endograft is fully deployed. The safety and efficacy of this device has been demonstrated
The Relay™ device is available in straight and tapered configurations in diameters ranging from 22 to 46 mm and lengths from 10 to 25 cm. The delivery sheath ranges from 20 to 26 French (6.67 to 8.33 mm) in diameter depending upon the diameter of the device.
A study from the RESTORE registry, which is a multicenter, European, prospective clinical registry of patients who have undergone endovascular repair with the Relay™ device, found a technical success rate of 97.3 percent [27]. Among 150 patients evaluated, thoracic aortic aneurysm was treated in 64.7 percent of patients and dissections were treated in 19.3 percent. The perioperative (30-day) mortality rate was 10 percent. Perioperative morbidity included paraplegia in 3.3 percent, recovered paraparesis in 3.3 percent and stroke in 0.6 percent. The reintervention rate during two-year follow-up was 8.9 percent due to two stent graft migrations, three proximal type I endoleaks, four type III endoleaks and five distal type I endoleaks. No open conversions were needed during follow-up.
Another study of the RESTORE registry evaluated the performance of the Relay™ device in 91 patients with acute or chronic aortic dissections [28]. Most patients (84 percent) had descending thoracic aortic (type B) dissection, of which 61 were classified as chronic and 30 as acute. The overall technical success rate was 95 percent. Perioperative mortality (30-day) was 8 percent with greater mortality in acute (13 versus 5 percent) compared with chronic aortic dissections. Paraplegia, paraparesis, and stroke occurred in four, one, and two patients, respectively. Type I endoleak rate occurred in 7 percent of patients. The two-year survival rate was 83 percent.
TAArget™ — The TAArget™ (formerly called EndoFit, LeMaitre Vascular) thoracic stent graft consists of a nitinol skeleton of Z-shaped stents between two thin sheets of expanded polytetrafluoroethylene (ePTFE). The proximal graft is available with and without a bare stent and the device can be straight or tapered, allowing four different configurations which can be used alone or in combination.
The TAArget™ graft is available in diameters that range from 34 to 42 mm with lengths up to 20 cm. The device is deployed through a 22 or 24 French (7.33, 8 mm) sheath depending upon the diameter of the device.
In a study of 41 patients, indications for treatment were thoracic aneurysm (n = 24), acute contained aortic rupture (n = 5), aortic dissection (n = 6), penetrating atherosclerotic ulcers (n = 4), posttraumatic pseudoaneurysm (n = 1), and postcoarctation repair aneurysm (n = 1) [29]. The technical success rate was 100 percent. Perioperative mortality was 7.3 percent. One patient suffered from spinal cord ischemia with ongoing symptoms of lower extremity weakness. Three postoperative endoleaks were recorded, two type I endoleaks (one proximal and one distal) resolved spontaneously. A third patient with persistent type Ia endoleak required operative conversion at one year. Overall long-term mortality was 17 percent at two-year follow-up with aneurysm-related mortality of 11 percent.
A retrospective review of 46 patients with thoracic aortic aneurysm and 41 with thoracic aortic dissection evaluated the EndoFit graft [30]. Twenty percent of the cases were performed emergently and technical success was achieved in all the patients. Perioperative mortality (30-day) was 9.2 percent. Perioperative morbidity included neurological complications in 9.3 percent of patients, including five strokes (two fatal) and three cases of paraplegia. Five patients had immediate proximal type I endoleak; three were remedied with a proximal cuff, one was rescued with tri-lobe balloon, and one was left untreated. The mortality rate over an average follow-up of 15.2 months was 11.5 percent but was not felt to be related to the aneurysm or stent-graft. There were no conversions required during the follow-up period.
A registry to follow the acute and chronic treatment of type B aortic dissection using the TAArget™ graft has been established (DEDICATED registry) [31].
E-Vita® — The E-Vita® stent-graft system (JOTEC) is composed of a woven polyester graft with a nitinol spring support structure sutured to the interior surface without any form of continuous longitudinal support, making the graft very flexible.
The graft is available in 24 to 44 mm diameters in lengths of 13, 15, 17, and 23 cm. Multiple graft configurations are available, and can be used in combination (straight, tapered, open stent).
A review of 126 patients (71 percent men; age 64 [19 to 86] years) evaluated the performance of E-Vita® stent-graft in the treatment of type-B dissection (n = 56), thoracic aortic aneurysm (n = 25), penetrating aortic ulcer (n = 17), blunt thoracic injury (n = 10), mobile atheroma (n = 1), suture aneurysms (n = 7) and revision of prior endograft (n = 22) [32]. The procedure was emergent in 50 percent of the patients and the graft was successfully placed in 77 percent of patients. An average of 1.3 stents was implanted per patient with a mean covered aortic length of 20.4 cm. The overall perioperative mortality (30-day) was 12.3 percent (1.5 for elective and 22 percent for emergency procedures). Transient spinal cord dysfunction was observed in two cases. Stroke occurred in 2.8 percent.
There are no trials comparing the outcomes of specific endovascular stent-grafts to each other for the management of thoracic aortic pathology. It is unlikely that such studies will ever be performed.
Two studies have compared endovascular with open surgical repair of thoracic aortic aneurysm. These studies are discussed above and the implications of these results for the treatment of thoracic aortic aneurysm are discussed elsewhere.
Other studies comparing endovascular repair with open repair for the treatment of aortic dissection and traumatic aortic transection are also presented above.
When aortic disease is more extensive and involves branch vessels, the complexity and risks associated with endovascular repair increase. Approaches to address these issues include debranching procedures and the use of fenestrated and branched endografts.
Debranching procedures involve the ligation and surgical revascularization (eg, carotid-subclavian bypass) of an aortic branch that will be covered by the endograft. The role of debranching in the treatment of thoracic aneurysm is discussed elsewhere. Fenestrated grafts — The use of fenestrated-endovascular aneurysm repair (FEVAR) to manage more challenging aortic anatomy continues to evolve [33-44]. The Zenith® Fenestrated AAA Endovascular Graft (Cook Medical) is the primarily studied device. The Zenith® Fenestrated graft is still investigational in the United States and its use is limited to sites with an investigation device exemption (IDE).
Branched grafts have separate smaller side arm grafts 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. Branched grafts have been used in patients with thoracic or thoracoabdominal aneurysms, or thoracic dissection . Initial experience with branched aortic grafts has shown similar perioperative mortality as conventional endovascular repair, but the rate of aneurysm repair-related morbidity may be higher.
Aortic arch branch devices – Single and double branch thoracic aortic endografts are available primarily for investigational use (Cook Medical, Australia, Yu Heng Jia Scientific Technology Co., Beijing) . These grafts are intended to preserve flow into the innominate, carotid or subclavian artery during thoracic endograft placement. A separate access is needed to deploy the branch grafts.
Visceral devices – Branched grafts to the visceral vessels allow endovascular repair of more extensive aortic disease . The use of visceral branch devices is discussed elsewhere.Iliac devices – Iliac branched grafts are intended to preserve flow into the internal iliac artery during abdominal aortic or iliac aneurysm repair that requires extension beyond the internal iliac artery orifice. The PRESERVE-Zenith® Iliac Branch System clinical study (ClinicalTrials.gov identifier: NCT01208415) will evaluate the safety and efficacy of the Zenith® Iliac Branch Device
No one device is appropriate for all clinical indications or has been shown to be superior to any other device for the endovascular repair of the thoracic aorta. Most devices were originally designed for excluding thoracic aortic aneurysm and the evaluation of specific designs to manage acute aortic syndromes (aortic rupture, aortic dissection) is in early stages. With time, and with the addition of disease-specific endografts, a clear preference for one device over another may emerge.
SUMMARY
Endovascular repair of the thoracic aorta is becoming increasingly popular due to reduced perioperative morbidity and mortality compared with open surgical repair. Endovascular repair with stent-graft devices can be used to treat thoracic aortic aneurysm, aortic dissection, aortic rupture including traumatic rupture, penetrating aortic ulcer and nontraumatic aortic intramural hematoma. Endovascular aortic repair requires that specific anatomic criteria be fulfilled, and, for those with appropriate anatomy, this technique allows the treatment of patients who might not otherwise be candidates for aortic repair.
Endovascular aneurysm repair refers to the stepwise insertion of endovascular graft components, usually via a femoral approach. Although there are significant variations in endovascular graft design, three types of components are common to all: a delivery system, main body device, and graft extensions. Upon deployment, the endograft expands, contacting the thoracic aortic wall proximally and distally excluding the degenerated aortic wall from aortic blood pressure and flow.
When aortic disease is more extensive and involves branch vessels, the complexity and risks associated with endovascular repair increase. Approaches to address these issues include debranching procedures and the use of fenestrated and branched endografts. Advanced endovascular aortic devices are designed to allow perfusion into specific aortic branch arteries depending upon the level of repair
The indications for endovascular treatment of thoracic aortic pathologies are expanding, and the cases being treated are increasingly complex. Although graft design has evolved, an ideal graft suited to all circumstances is not available. A number of thoracic stent graft devices are available and include the TAG™, Zenith® Tx2®, Talent® Thoracic Stent-Graft System, and Valiant™ Thoracic Stent-Graft System. The Relay™, TAArget™, and E-Vita® grafts remain investigational in the United States.
There are no trials comparing the outcomes of specific endovascular stent-grafts to each other for the management of thoracic aortic pathology. The placement of aortic endovascular grafts is associated with device-related complications that can include component disconnect, stent-graft buckling and migration over time. In the thoracic aorta, secondary intervention is needed in 10 to 60 percent of patients, more commonly in patients undergoing endovascular repair of thoracic dissection. As such, these devices require lifelong surveillance; long-term outcomes continue to be studied.
Talent® Thoracic Stent-Graft System — The Talent® Thoracic Stent-Graft System (Medtronic) consists of two components. The stent-graft components are made of a woven polyester graft with an external self-expanding support structure of M-shaped nitinol stents and a longitudinal support bar throughout its length. The proximal component is a straight stent-graft with an uncovered stent proximally that allows placement across the left subclavian or carotid artery. The distal component can be a straight or tapered tubular graft and has a closed web design that is intended to assure fixation of the components in the region of overlap.
The proximal component is available in diameters ranging from 22 to 46 mm in lengths from 11.2 to 11.6 cm. The distal component is available in diameters ranging from 26 to 46 mm in lengths from 11.0 to 11.4 cm. The delivery sheath ranges from 22 to 25 French (7.33 to 8.33 mm) in diameter. The device is delivered through the Xcelerant delivery system (same as AneuRx® and Valiant™ grafts) which is a ratcheted system for controlled initial deployment to position of the device, and then a more rapid release of the remainder of the device to avoid a “windsock” effect. Once deployed, the device is self-expanding; subsequent ballooning of the device is an option.
The safety and efficacy of the Talent® Thoracic Stent-Graft System was evaluated in the VALOR I study which was a multicenter study that compared endovascular repair (n = 195) with retrospective open surgical data obtained from three centers (n = 189) [23]. An average of 2.7 stent-graft components was used per patient. Technical success was 99.5 percent for vessel access and endograft deployment at the intended site. Perioperative (30-day) mortality was 2.1 percent and major adverse events overall occurred in 41 percent of patients, with paraplegia in 1.5 percent; paraparesis in 7.2 percent; and stroke in 3.6 percent. At one-year follow-up, all-cause mortality was 16.1 percent and aneurysm-related mortality was 3.1 percent. Late complications included conversion to open surgery (0.5 percent), target aneurysm rupture (0.5 percent), stent graft migration >10 mm (3.9 percent), and endoleak (12.2 percent). Compared with open surgery, the Talent® Thoracic Stent-Graft was found to have significantly lower perioperative mortality (2 versus 8 percent), fewer perioperative major adverse events (41 versus 84.4 percent) and lower aneurysm-related mortality at one year (3.1 versus 11.6 percent).
The INSTEAD trial randomly assigned 597 patients with stable aortic dissection (>2 weeks) to elective aortic stent-grafting plus medical therapy or medical therapy alone [24]. The Talent® Thoracic Stent-Graft System was used in all cases. There was no significant difference in overall mortality between the groups at two years, with a cumulative survival rate of 95.6 percent for medical therapy alone compared with 88.9 percent for endovascular repair. No differences were seen in aorta-related death rates or the combined end-point of aorta-related death (rupture) and progression of disease. Three neurological events occurred in the endovascular repair group (one paraplegia, one stroke, and one transient paraparesis), compared with one case of paraparesis in the medical therapy alone group. Aortic remodeling with recovery of the true-lumen and thrombosis of the false-lumen was found in significantly more patients undergoing endovascular repair (91.3 versus 19.3 percent) compared with medical therapy alone. In spite of favorable aortic remodeling, no improvements were seen in two-year survival or adverse event rates, and the impact on long-term aneurysmal degeneration of the dissected aortic segment remains to be studied.
Valiant™ Thoracic Stent-Graft System — The Valiant™ Thoracic Stent-Graft System (Medtronic Vascular) is a third-generation device based upon the Talent® Thoracic Stent-Graft System. The Valiant™ graft has a modified proximal bare stent with eight shorter bare stents proximally compared with five longer bare stents found in the Talent® stent-graft. The longitudinal support bar of the Talent® device was removed to provide improved device flexibility for the Valiant™ device.
The graft is available in straight or tapered configurations with diameters ranging from 24 to 46 mm and lengths up to 22.7 cm. The device is also delivered through the Xcelerant delivery system.
The initial experience of the Valiant™ endograft was reported in a multicenter retrospective study of 180 patients [25]. A variety of indications were treated including thoracic aneurysms (n = 66), thoracoabdominal aneurysms (n = 22), acute aortic syndrome (n = 19), aneurysm degeneration of chronic aortic dissection (n = 52), and traumatic aortic dissection (n = 21). The perioperative (30-day) mortality for the series was 7.2 percent with perioperative morbidity that included stroke in 3.8 percent and paraplegia in 3.3 percent. Mortality rates differed significantly depending upon indications, with the highest rate for thoracoabdominal aneurysms at 27.3 percent and lowest (none) for acute traumatic rupture.
The VALOR II study has been completed using the Valiant stent-graft resulting in approval of the Captivia Delivery System for use in the United States. Commercial release is ongoing and the one-year results demonstrate safety and efficacy comparable with the Talent® stent-graft.
Investigational devices — Several devices for thoracic endovascular repair are investigational and not commercially available in the United States. These include the Bolton Relay™, the LeMaitre TAArget™, and the JOTEC E-Vita® stent-graft system. These are briefly reviewed below.
Relay™ — The Relay™ (Bolton Medical) device is composed of self-expanding nitinol stents sutured to a polyester fabric graft with a curved longitudinal nitinol wire intended to provide longitudinal strength. It has a proximal bare stent that remains constrained until the endograft is fully deployed. The safety and efficacy of this device has been demonstrated
The Relay™ device is available in straight and tapered configurations in diameters ranging from 22 to 46 mm and lengths from 10 to 25 cm. The delivery sheath ranges from 20 to 26 French (6.67 to 8.33 mm) in diameter depending upon the diameter of the device.
A study from the RESTORE registry, which is a multicenter, European, prospective clinical registry of patients who have undergone endovascular repair with the Relay™ device, found a technical success rate of 97.3 percent [27]. Among 150 patients evaluated, thoracic aortic aneurysm was treated in 64.7 percent of patients and dissections were treated in 19.3 percent. The perioperative (30-day) mortality rate was 10 percent. Perioperative morbidity included paraplegia in 3.3 percent, recovered paraparesis in 3.3 percent and stroke in 0.6 percent. The reintervention rate during two-year follow-up was 8.9 percent due to two stent graft migrations, three proximal type I endoleaks, four type III endoleaks and five distal type I endoleaks. No open conversions were needed during follow-up.
Another study of the RESTORE registry evaluated the performance of the Relay™ device in 91 patients with acute or chronic aortic dissections [28]. Most patients (84 percent) had descending thoracic aortic (type B) dissection, of which 61 were classified as chronic and 30 as acute. The overall technical success rate was 95 percent. Perioperative mortality (30-day) was 8 percent with greater mortality in acute (13 versus 5 percent) compared with chronic aortic dissections. Paraplegia, paraparesis, and stroke occurred in four, one, and two patients, respectively. Type I endoleak rate occurred in 7 percent of patients. The two-year survival rate was 83 percent.
TAArget™ — The TAArget™ (formerly called EndoFit, LeMaitre Vascular) thoracic stent graft consists of a nitinol skeleton of Z-shaped stents between two thin sheets of expanded polytetrafluoroethylene (ePTFE). The proximal graft is available with and without a bare stent and the device can be straight or tapered, allowing four different configurations which can be used alone or in combination.
The TAArget™ graft is available in diameters that range from 34 to 42 mm with lengths up to 20 cm. The device is deployed through a 22 or 24 French (7.33, 8 mm) sheath depending upon the diameter of the device.
In a study of 41 patients, indications for treatment were thoracic aneurysm (n = 24), acute contained aortic rupture (n = 5), aortic dissection (n = 6), penetrating atherosclerotic ulcers (n = 4), posttraumatic pseudoaneurysm (n = 1), and postcoarctation repair aneurysm (n = 1) [29]. The technical success rate was 100 percent. Perioperative mortality was 7.3 percent. One patient suffered from spinal cord ischemia with ongoing symptoms of lower extremity weakness. Three postoperative endoleaks were recorded, two type I endoleaks (one proximal and one distal) resolved spontaneously. A third patient with persistent type Ia endoleak required operative conversion at one year. Overall long-term mortality was 17 percent at two-year follow-up with aneurysm-related mortality of 11 percent.
A retrospective review of 46 patients with thoracic aortic aneurysm and 41 with thoracic aortic dissection evaluated the EndoFit graft [30]. Twenty percent of the cases were performed emergently and technical success was achieved in all the patients. Perioperative mortality (30-day) was 9.2 percent. Perioperative morbidity included neurological complications in 9.3 percent of patients, including five strokes (two fatal) and three cases of paraplegia. Five patients had immediate proximal type I endoleak; three were remedied with a proximal cuff, one was rescued with tri-lobe balloon, and one was left untreated. The mortality rate over an average follow-up of 15.2 months was 11.5 percent but was not felt to be related to the aneurysm or stent-graft. There were no conversions required during the follow-up period.
A registry to follow the acute and chronic treatment of type B aortic dissection using the TAArget™ graft has been established (DEDICATED registry) [31].
E-Vita® — The E-Vita® stent-graft system (JOTEC) is composed of a woven polyester graft with a nitinol spring support structure sutured to the interior surface without any form of continuous longitudinal support, making the graft very flexible.
The graft is available in 24 to 44 mm diameters in lengths of 13, 15, 17, and 23 cm. Multiple graft configurations are available, and can be used in combination (straight, tapered, open stent).
A review of 126 patients (71 percent men; age 64 [19 to 86] years) evaluated the performance of E-Vita® stent-graft in the treatment of type-B dissection (n = 56), thoracic aortic aneurysm (n = 25), penetrating aortic ulcer (n = 17), blunt thoracic injury (n = 10), mobile atheroma (n = 1), suture aneurysms (n = 7) and revision of prior endograft (n = 22) [32]. The procedure was emergent in 50 percent of the patients and the graft was successfully placed in 77 percent of patients. An average of 1.3 stents was implanted per patient with a mean covered aortic length of 20.4 cm. The overall perioperative mortality (30-day) was 12.3 percent (1.5 for elective and 22 percent for emergency procedures). Transient spinal cord dysfunction was observed in two cases. Stroke occurred in 2.8 percent.
There are no trials comparing the outcomes of specific endovascular stent-grafts to each other for the management of thoracic aortic pathology. It is unlikely that such studies will ever be performed.
Two studies have compared endovascular with open surgical repair of thoracic aortic aneurysm. These studies are discussed above and the implications of these results for the treatment of thoracic aortic aneurysm are discussed elsewhere.
Other studies comparing endovascular repair with open repair for the treatment of aortic dissection and traumatic aortic transection are also presented above.
When aortic disease is more extensive and involves branch vessels, the complexity and risks associated with endovascular repair increase. Approaches to address these issues include debranching procedures and the use of fenestrated and branched endografts.
Debranching procedures involve the ligation and surgical revascularization (eg, carotid-subclavian bypass) of an aortic branch that will be covered by the endograft. The role of debranching in the treatment of thoracic aneurysm is discussed elsewhere. Fenestrated grafts — The use of fenestrated-endovascular aneurysm repair (FEVAR) to manage more challenging aortic anatomy continues to evolve [33-44]. The Zenith® Fenestrated AAA Endovascular Graft (Cook Medical) is the primarily studied device. The Zenith® Fenestrated graft is still investigational in the United States and its use is limited to sites with an investigation device exemption (IDE).
Branched grafts have separate smaller side arm grafts 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. Branched grafts have been used in patients with thoracic or thoracoabdominal aneurysms, or thoracic dissection . Initial experience with branched aortic grafts has shown similar perioperative mortality as conventional endovascular repair, but the rate of aneurysm repair-related morbidity may be higher.
SUMMARY
No comments:
Post a Comment