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Department of Radiology
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Interventional Case Record
Interventional Case Record
Contributed by : Milan Talati
Contributed by : Milan Talati
Thoracic endovascular aortic repair (TEVAR) in a case of dissected thoracic aortic aneurysm with contained rupture.
Thoracic endovascular aortic repair (TEVAR) in a case of dissected thoracic aortic aneurysm with contained rupture.
Introduction:
Introduction:
The sine qua non of the classic aortic dissection is a tear in the intima that allows pulsatile blood to penetrate the vessel wall. A cleavage plane develops between the layers of the intima and media and allows a column of blood to form within the intramural space, composing the false lumen. The dissection may propagate in an antegrade or retrograde direction or in both directions. The location of the intimal tear usually occurs in a compromised region of the vessel with underlying mural degeneration. Common causes include long-standing hypertension, connective tissue disorders, and trauma. (1,2,3)
The sine qua non of the classic aortic dissection is a tear in the intima that allows pulsatile blood to penetrate the vessel wall. A cleavage plane develops between the layers of the intima and media and allows a column of blood to form within the intramural space, composing the false lumen. The dissection may propagate in an antegrade or retrograde direction or in both directions. The location of the intimal tear usually occurs in a compromised region of the vessel with underlying mural degeneration. Common causes include long-standing hypertension, connective tissue disorders, and trauma. (1,2,3)
It is important to differentiate the primary or entry intimal tear from the secondary or re-entry tear(s). Approximately two thirds of primary tears occur in the ascending aorta, with more than half of these located within the first 2 cm of the ascending aorta. The next most common site of the primary tear is the isthmus of the aorta just beyond the ligamentum arteriosum (4,5). These regions are presumably subjected to the greatest hemodynamic stress, which makes them more susceptible to injury. In either location, these tears are 5 times more likely to be transverse in orientation rather than longitudinal. Other sites of primary tears include the descending thoracic aorta, aortic arch, and abdominal aorta, with multiple primary tears seen in 8% of cases. (6).
It is important to differentiate the primary or entry intimal tear from the secondary or re-entry tear(s). Approximately two thirds of primary tears occur in the ascending aorta, with more than half of these located within the first 2 cm of the ascending aorta. The next most common site of the primary tear is the isthmus of the aorta just beyond the ligamentum arteriosum (4,5). These regions are presumably subjected to the greatest hemodynamic stress, which makes them more susceptible to injury. In either location, these tears are 5 times more likely to be transverse in orientation rather than longitudinal. Other sites of primary tears include the descending thoracic aorta, aortic arch, and abdominal aorta, with multiple primary tears seen in 8% of cases. (6).
Case presentation:
Case presentation:
A 65-years old man presented with history of backache, vomiting since four to five days. His pain was associated with breathlessness. The patient was known hypertensive since eight years and on regular medications for the same. There was no history of any past hospital admission. Clinical examination of his respiratory and cardiovascular system was normal. Chest radiograph was done and showed widening of mediastinum with unfolding of aorta, based on abnormal chest radiograph CT aortogram was performed. CT aortogram showed dissection with thrombosis of false lumen saccular outpouching arising from arch of aorta distal to the origin of left subclavian artery with mediastinal hematoma and contrast extravasation which gradually increased on delayed images (Fig 1a,1b)
A 65-years old man presented with history of backache, vomiting since four to five days. His pain was associated with breathlessness. The patient was known hypertensive since eight years and on regular medications for the same. There was no history of any past hospital admission. Clinical examination of his respiratory and cardiovascular system was normal. Chest radiograph was done and showed widening of mediastinum with unfolding of aorta, based on abnormal chest radiograph CT aortogram was performed. CT aortogram showed dissection with thrombosis of false lumen saccular outpouching arising from arch of aorta distal to the origin of left subclavian artery with mediastinal hematoma and contrast extravasation which gradually increased on delayed images (Fig 1a,1b)
Fig. 1 :
1a- Axial CT image of Aortogram (arterial phase) shows dissection and saccular aneurysm arising from arch of aorta distal to the origin of left subclavian artery with mediastinal hematoma.
1b- Axial CT image of Aortogram (delayed phase) shows contrast extravasation in the mediastinum with surrounding mediastinal hematoma.
1c- Axial CT image of Aortogram delayed phase shows extension of extravasated contrast up to the neck.
1d- MPR image showing a saccular outpouching arising from arch of aorta distal to the origin of left subclavian artery.
Fig. 2 2a- The saccular aneurysm with dissection is seen arising distal to left subclavian artery, however periaortic hematoma is seen extending upto its origin.
2b- Axial CTscan at the level of neck shows prominent right vertebral artery as compared to left.
The procedure was performed under general anaesthesia. Left Common femoral artery access was obtained with a 5F vascular sheath. A 5F marker pigtail catheter was positioned in the aortic arch with the help of a glide wire, and arch aortogram was obtained and findings confirmed. Subsequently, right common femoral artery arteriotomy was performed and a 5F sheath inserted, through which a Lunderquist wire was inserted up to the level of the aortic arch.
The procedure was performed under general anaesthesia. Left Common femoral artery access was obtained with a 5F vascular sheath. A 5F marker pigtail catheter was positioned in the aortic arch with the help of a glide wire, and arch aortogram was obtained and findings confirmed. Subsequently, right common femoral artery arteriotomy was performed and a 5F sheath inserted, through which a Lunderquist wire was inserted up to the level of the aortic arch.
A metallic stent graft (Ankura TAA, Lifetech) was then inserted on the wire and subsequently unloaded. Repeat aortogram showed adequate placement of the stent, with no filling of the aneurysmal sac and filling of left subclavian artery by steal of blood from right vertebral artery. The procedure was clinically uneventful. Vital monitoring done throughout the procedure was uneventful. Post procedure, patient tolerated the procedure well.
A metallic stent graft (Ankura TAA, Lifetech) was then inserted on the wire and subsequently unloaded. Repeat aortogram showed adequate placement of the stent, with no filling of the aneurysmal sac and filling of left subclavian artery by steal of blood from right vertebral artery. The procedure was clinically uneventful. Vital monitoring done throughout the procedure was uneventful. Post procedure, patient tolerated the procedure well.
Figure 3: 3a- Axial CT image of Aortogram arterial phase shows mediastinal hematoma.
3b- Axial CT image of Aortogram delayed phase shows progressive increased extravasated contrast.
Fig. 4, DSA image showing codominance of bilateral vertebral arteries.
Fig. 5: A,B,C- Axial CT image at the level above the arch, at the level of arch, at level below the arch, shows near complete resolution of mediastinal hematoma
Video 1: DSA of arch of aorta shows saccular aneurysm arising distal to left subclavian artery.
Video 2: DSA of arch of aorta post deployment of stent graft distal to the common origin of brachiocephalic artery and left common carotid artery shows isolation of aneurysm from the main circulation and retrograde filling of left subclavian artery from left vertebral artery.
Selective cannulation of inferior pancreatico-duodenal artery (IPD) was done and gram performed confirmed the findings (Video 4). So distal to proximal coiling across this defect in gastro-duodenal artery was performed using Terumo Progreat microcatheter (Video 5)(Video 6).
Selective cannulation of inferior pancreatico-duodenal artery (IPD) was done and gram performed confirmed the findings (Video 4). So distal to proximal coiling across this defect in gastro-duodenal artery was performed using Terumo Progreat microcatheter (Video 5)(Video 6).
Discussion:
Discussion:
Classification Systems of Aortic dissection:
Classification Systems of Aortic dissection:
The 2 most common anatomic classifications of aortic dissection are the DeBakey and Stanford classifications. Under the DeBakey system, type I dissection begins in the proximal aorta and involves both the ascending and descending thoracic aorta, type II dissection is confined to the ascending aorta, and type III is confined to the descending aorta. Under the Stanford system, type A dissection involves the ascending aorta, whereas type B dissection does not.
The 2 most common anatomic classifications of aortic dissection are the DeBakey and Stanford classifications. Under the DeBakey system, type I dissection begins in the proximal aorta and involves both the ascending and descending thoracic aorta, type II dissection is confined to the ascending aorta, and type III is confined to the descending aorta. Under the Stanford system, type A dissection involves the ascending aorta, whereas type B dissection does not.
The convenience and prognostic value of the Stanford system has resulted in its popular use; however, an important feature that is not distinguished in the Stanford system is the location of the primary tear. In a typical type A dissection, the primary tear is located in the ascending aorta, whereas in a retrograde type A dissection, the tear is located in the descending aorta. This detail has a profound influence on the current feasibility of stent-graft management. (7,8,9)
The convenience and prognostic value of the Stanford system has resulted in its popular use; however, an important feature that is not distinguished in the Stanford system is the location of the primary tear. In a typical type A dissection, the primary tear is located in the ascending aorta, whereas in a retrograde type A dissection, the tear is located in the descending aorta. This detail has a profound influence on the current feasibility of stent-graft management. (7,8,9)
Acute Type A Dissection:
Acute Type A Dissection:
Although shown to be superior to medical management alone, surgical management is still associated with alarmingly high rates of morbidity and mortality. In a review of 547 type A dissections, IRAD investigators demonstrated a hospital mortality rate of 27% for those patients treated surgically (10). In another IRAD report, surgical repair was associated with in-hospital mortality rates of 10% by 24 hours, 16% by 7 days, and nearly 20% by 14 days (11).5 Long-term survival for patients treated with surgery who were discharged alive has been shown to be 96% at 1 year and 91% at 3 years (11,12).
Although shown to be superior to medical management alone, surgical management is still associated with alarmingly high rates of morbidity and mortality. In a review of 547 type A dissections, IRAD investigators demonstrated a hospital mortality rate of 27% for those patients treated surgically (10). In another IRAD report, surgical repair was associated with in-hospital mortality rates of 10% by 24 hours, 16% by 7 days, and nearly 20% by 14 days (11).5 Long-term survival for patients treated with surgery who were discharged alive has been shown to be 96% at 1 year and 91% at 3 years (11,12).
Patients with retrograde type A dissection (DeBakey type IIId) represent an important subgroup that comprises 4% to 20% of all type A cases (13-15). In these individuals, the inciting primary tear is typically positioned in the distal arch, with retrograde extension of the dissection process to the ascending aorta. This poses a dilemma for surgical repair that involves either excision of the entry tear with replacement of both the ascending aorta and aortic arch, which is associated with high morbidity and mortality, or graft replacement of the ascending aorta alone without excision of the primary tear, which leaves the patient at risk of postoperative aortic rupture (15). Regardless, conventional therapy mandates immediate surgical repair in this patient subgroup.
Patients with retrograde type A dissection (DeBakey type IIId) represent an important subgroup that comprises 4% to 20% of all type A cases (13-15). In these individuals, the inciting primary tear is typically positioned in the distal arch, with retrograde extension of the dissection process to the ascending aorta. This poses a dilemma for surgical repair that involves either excision of the entry tear with replacement of both the ascending aorta and aortic arch, which is associated with high morbidity and mortality, or graft replacement of the ascending aorta alone without excision of the primary tear, which leaves the patient at risk of postoperative aortic rupture (15). Regardless, conventional therapy mandates immediate surgical repair in this patient subgroup.
Acute Type B Dissection
Acute Type B Dissection
Owing to the small risk of aortic rupture and sudden death and the high morbidity and mortality associated with surgical repair of the descending aorta, medical treatment alone is advocated for uncomplicated type B dissection. Surgery is typically reserved for complicated type B dissections. IRAD investigators reviewed 175 patients treated according to this complication-specific approach and identified in-house mortality rates of 11% and 31% for medical and surgical treatment, respectively. Patients who undergo surgery also have a high rate of morbidity; in particular, paraplegia has been reported in 1.5% to 19% despite advances in surgical technique(16). IRAD investigators also performed long-term evaluation of outcomes for patients discharged after hospital management of type B dissection. This analysis identified 3-year survival rates of 78% and 83% for patients treated medically and surgically, respectively (17,18)
Owing to the small risk of aortic rupture and sudden death and the high morbidity and mortality associated with surgical repair of the descending aorta, medical treatment alone is advocated for uncomplicated type B dissection. Surgery is typically reserved for complicated type B dissections. IRAD investigators reviewed 175 patients treated according to this complication-specific approach and identified in-house mortality rates of 11% and 31% for medical and surgical treatment, respectively. Patients who undergo surgery also have a high rate of morbidity; in particular, paraplegia has been reported in 1.5% to 19% despite advances in surgical technique(16). IRAD investigators also performed long-term evaluation of outcomes for patients discharged after hospital management of type B dissection. This analysis identified 3-year survival rates of 78% and 83% for patients treated medically and surgically, respectively (17,18)
Because medical therapy alone does not stop flow within the false lumen, 20% to 50% of patients who survive the acute phase develop aneurysmal dilatation of the false lumen within 1 to 5 years after onset (15-19). In this regard, the majority of late deaths that occur in patients with type B dissection initially managed by medical therapy are due to rupture, extension of dissection, and perioperative mortality of subsequent aortic or vascular surgeries. In fact, the long-term survival of patients with type B dissection remains worse than that of patients with type A dissection.
Because medical therapy alone does not stop flow within the false lumen, 20% to 50% of patients who survive the acute phase develop aneurysmal dilatation of the false lumen within 1 to 5 years after onset (15-19). In this regard, the majority of late deaths that occur in patients with type B dissection initially managed by medical therapy are due to rupture, extension of dissection, and perioperative mortality of subsequent aortic or vascular surgeries. In fact, the long-term survival of patients with type B dissection remains worse than that of patients with type A dissection.
Chronic Dissection
Chronic Dissection
Those patients who survive the acute stage of aortic dissection, which is associated with the greatest mortality, by definition have chronic dissection. The 30-day survival rate for this population is high at 90%, independent of whether they were managed medically or surgically. Medical therapy is therefore recommended for patients with both type A and type B chronic dissection. Surgery is reserved for those who develop an aneurysm, rupture, peripheral branch-vessel compromise, or other complications(18,20).
Those patients who survive the acute stage of aortic dissection, which is associated with the greatest mortality, by definition have chronic dissection. The 30-day survival rate for this population is high at 90%, independent of whether they were managed medically or surgically. Medical therapy is therefore recommended for patients with both type A and type B chronic dissection. Surgery is reserved for those who develop an aneurysm, rupture, peripheral branch-vessel compromise, or other complications(18,20).
Endovascular Management
Endovascular Management
Endovascular management of dissection comprises 3 major treatments: (1) aortic stent-graft placement, (2) dissection flap fenestration, and (3) branch-vessel stenting. Typically, 1 or more of these techniques is used to treat aortic dissection. In some cases, endovascular techniques may obviate the need for surgical management, whereas in other cases, endovascular techniques are complementary to surgical repair.
Endovascular management of dissection comprises 3 major treatments: (1) aortic stent-graft placement, (2) dissection flap fenestration, and (3) branch-vessel stenting. Typically, 1 or more of these techniques is used to treat aortic dissection. In some cases, endovascular techniques may obviate the need for surgical management, whereas in other cases, endovascular techniques are complementary to surgical repair.
Stent-Graft Technology:
Stent-Graft Technology:
The development of thoracic aortic stent grafts has largely followed in the footsteps of abdominal aortic stent-graft technology used primarily to treat abdominal aortic aneurysms. The earliest feasibility and safety studies of thoracic stent grafts were performed in 1992 to treat thoracic aortic aneurysms. Since then, the number of applications of this technology has grown rapidly to include the management of aortic dissection and dissection variants
The development of thoracic aortic stent grafts has largely followed in the footsteps of abdominal aortic stent-graft technology used primarily to treat abdominal aortic aneurysms. The earliest feasibility and safety studies of thoracic stent grafts were performed in 1992 to treat thoracic aortic aneurysms. Since then, the number of applications of this technology has grown rapidly to include the management of aortic dissection and dissection variants
Principles and Techniques of Endovascular Management
Principles and Techniques of Endovascular Management
Stent-Graft Management:
Stent-Graft Management:
The rationale of stent-graft management is 2-fold. First, in the acute phase, the use of stent grafts may prevent imminent aortic rupture and relieve dynamic branch-vessel obstruction. Second, stent-graft management may promote thrombosis of the thoracic false lumen and decrease the long-term morbidity associated with patency of the false lumen, including aneurysmal dilatation, late aortic rupture, and late mortality(9,16).
The rationale of stent-graft management is 2-fold. First, in the acute phase, the use of stent grafts may prevent imminent aortic rupture and relieve dynamic branch-vessel obstruction. Second, stent-graft management may promote thrombosis of the thoracic false lumen and decrease the long-term morbidity associated with patency of the false lumen, including aneurysmal dilatation, late aortic rupture, and late mortality(9,16).
Stent-graft treatment is predicated on the ability to cover the primary intimal tear and create a seal to stop the flow of blood entering the false lumen and prevent the transmission of systemic pressure across the major intimal defect. If the seal is adequate, cardiac output is redirected into the true lumen and rapid and the false lumen simultaneously decompresses (which relieves dynamic obstruction of branches supplied by a diminutive true lumen). As a result, within seconds, the true lumen diameter typically enlarges, with markedly improved flow. The immediate hemodynamic and morphological alterations may prevent imminent rupture and relieve aortic true-lumen collapse and branch-vessel ischemia(9).
Stent-graft treatment is predicated on the ability to cover the primary intimal tear and create a seal to stop the flow of blood entering the false lumen and prevent the transmission of systemic pressure across the major intimal defect. If the seal is adequate, cardiac output is redirected into the true lumen and rapid and the false lumen simultaneously decompresses (which relieves dynamic obstruction of branches supplied by a diminutive true lumen). As a result, within seconds, the true lumen diameter typically enlarges, with markedly improved flow. The immediate hemodynamic and morphological alterations may prevent imminent rupture and relieve aortic true-lumen collapse and branch-vessel ischemia(9).
Furthermore, stent-graft management of retrograde type A dissection and type B dissection has been shown to decrease flow in the false lumen and induce false-lumen thrombosis. Again, this is a critical point, because natural history studies of type B dissection have shown 20% to 50% of patients who receive medical therapy alone and survive the acute phase ultimately develop aneurysmal dilatation of the false lumen within 1 to 5 years (15,21,22). Even if complete thrombosis of the false lumen does not occur, it is likely that partial thrombosis and decreased flow will limit the progression to aneurysmal dilatation (9).
Furthermore, stent-graft management of retrograde type A dissection and type B dissection has been shown to decrease flow in the false lumen and induce false-lumen thrombosis. Again, this is a critical point, because natural history studies of type B dissection have shown 20% to 50% of patients who receive medical therapy alone and survive the acute phase ultimately develop aneurysmal dilatation of the false lumen within 1 to 5 years (15,21,22). Even if complete thrombosis of the false lumen does not occur, it is likely that partial thrombosis and decreased flow will limit the progression to aneurysmal dilatation (9).
To obliterate the primary tear, an adequate seal zone is required. One of the anatomic requirements is a proximal landing zone (relative to the primary tear) of at least 15 to 20 mm. The ideal landing zone should be uniform in shape and free of significant disease; however, this ideal is rarely met, because the position of the primary tear and its proximity to branch vessels usually requires device deployment within a dissected segment. A common dilemma is selection of the “correct” device dimension, because the true lumen is generally crescentic or elliptical in shape and a fraction of the overall transaortic diameter. Most operators base their selection on more than 1 measurement, the most compelling of which is the diameter of the nondissected aorta immediately proximal to the entry tear. In the setting of a classic entry location just distal to the left subclavian artery origin, the segment between the left carotid and left subclavian arteries is used. This is the best estimate of the original size of the involved aorta before dissection. This measurement is oversized by ≈10% and used to select the stent-graft diameter. The oversizing factor ensures secure anchoring and a tight circumferential seal.
To obliterate the primary tear, an adequate seal zone is required. One of the anatomic requirements is a proximal landing zone (relative to the primary tear) of at least 15 to 20 mm. The ideal landing zone should be uniform in shape and free of significant disease; however, this ideal is rarely met, because the position of the primary tear and its proximity to branch vessels usually requires device deployment within a dissected segment. A common dilemma is selection of the “correct” device dimension, because the true lumen is generally crescentic or elliptical in shape and a fraction of the overall transaortic diameter. Most operators base their selection on more than 1 measurement, the most compelling of which is the diameter of the nondissected aorta immediately proximal to the entry tear. In the setting of a classic entry location just distal to the left subclavian artery origin, the segment between the left carotid and left subclavian arteries is used. This is the best estimate of the original size of the involved aorta before dissection. This measurement is oversized by ≈10% and used to select the stent-graft diameter. The oversizing factor ensures secure anchoring and a tight circumferential seal.
Depending on the type and size of the stent graft, currently available devices will require delivery systems that are 20F to 24F in size. The iliofemoral arteries should be assessed routinely to ensure that an adequate intraluminal diameter to accommodate introduction of the device exists. Access usually involves surgical exposure of the common femoral artery. In the case of small or heavily calcified femoral arteries, surgical exposure of the iliac arteries or aorta with or without placement of a graft conduit may be required. Recently, in select patients, stent-graft procedures have been performed entirely percutaneously, with the puncture sites closed by commercially available suture-mediated access-closure devices(21,22). The obvious benefits of this approach over surgical exposure are the decreased time to recovery and possible reduced risk of infection, lymphocele, seroma, and postoperative scar.
Depending on the type and size of the stent graft, currently available devices will require delivery systems that are 20F to 24F in size. The iliofemoral arteries should be assessed routinely to ensure that an adequate intraluminal diameter to accommodate introduction of the device exists. Access usually involves surgical exposure of the common femoral artery. In the case of small or heavily calcified femoral arteries, surgical exposure of the iliac arteries or aorta with or without placement of a graft conduit may be required. Recently, in select patients, stent-graft procedures have been performed entirely percutaneously, with the puncture sites closed by commercially available suture-mediated access-closure devices(21,22). The obvious benefits of this approach over surgical exposure are the decreased time to recovery and possible reduced risk of infection, lymphocele, seroma, and postoperative scar.
We present a case of a dissecting saccular aneurysm from the distal aortic arch and the proximal descending aorta, managed by Endovascular Interventional techniques.
We present a case of a dissecting saccular aneurysm from the distal aortic arch and the proximal descending aorta, managed by Endovascular Interventional techniques.
The role of TEVAR in aortic aneurysms is to provide a durable conduit for aortic flow across the entire longitudinal extent of the aneurysm, resulting in aneurysm sac decompression, thrombus formation and eventual stabilization or regression in size. Usually performed in an emergency setting in a known or suspected rupture,
The role of TEVAR in aortic aneurysms is to provide a durable conduit for aortic flow across the entire longitudinal extent of the aneurysm, resulting in aneurysm sac decompression, thrombus formation and eventual stabilization or regression in size. Usually performed in an emergency setting in a known or suspected rupture,
TEVAR is also indicated for symptomatic aneurysms causing chest pain regardless of aneurysm diameter and in a rapidly expanding aneurysm (more than 1 cm growth in 12 months). Other indications for an elective TEVAR procedure include asymptomatic fusiform aneurysm with minimum orthogonal diameter of more than 5.5 cm or more than two times the diameter of adjacent nonaneurysmal aorta.
TEVAR is also indicated for symptomatic aneurysms causing chest pain regardless of aneurysm diameter and in a rapidly expanding aneurysm (more than 1 cm growth in 12 months). Other indications for an elective TEVAR procedure include asymptomatic fusiform aneurysm with minimum orthogonal diameter of more than 5.5 cm or more than two times the diameter of adjacent nonaneurysmal aorta.
Some guidelines have suggested that repair is appropriate for aneurysms as small as 5.5 cm, saccular aneurysms greater than 2 cm, or saccular aneurysms associated with a total aortic diameter greater than 5 cm. Major contraindication to TEVAR includes inadequate proximal or distal seal zones, tortuosity of the vessel, lack of vascular access options, or extremes of aortic diameter. The large diameter of the thoracic aorta compared to abdominal aorta necessitates larger endografts, and the degree of angulation requires a relatively long seal zone (2 cm). (20-22)
Some guidelines have suggested that repair is appropriate for aneurysms as small as 5.5 cm, saccular aneurysms greater than 2 cm, or saccular aneurysms associated with a total aortic diameter greater than 5 cm. Major contraindication to TEVAR includes inadequate proximal or distal seal zones, tortuosity of the vessel, lack of vascular access options, or extremes of aortic diameter. The large diameter of the thoracic aorta compared to abdominal aorta necessitates larger endografts, and the degree of angulation requires a relatively long seal zone (2 cm). (20-22)
Current-generation devices are all characterized by their improved flexibility, a design feature employed to allow for improved conformability to the aortic arch. Aortic arch debranching via ascending aortic-to-innominate and left common carotid artery bypass, carotid–carotid bypass, or left carotid-to-subclavian artery bypass may be required to obtain an adequate seal zone. Device diameters are generally oversized 10 to 20% relative to the native landing zone (3), If the distal landing zone is significantly smaller than the proximal, a tapered endograft can be used. Arterial access is preferably through the common femoral artery but may be via the external iliac or common iliac arteries or the distal infrarenal aorta. Paired intercostal branches are derived from the descending thoracic aorta and provide collateral flow to the anterior spinal cord via the artery of Adamkiewicz and other radicular branches. The degree of coverage of these branches must be assessed during TEVAR, as extensive coverage is a major risk factor for spinal cord ischemia and postoperative paraplegia. (23-24)
Current-generation devices are all characterized by their improved flexibility, a design feature employed to allow for improved conformability to the aortic arch. Aortic arch debranching via ascending aortic-to-innominate and left common carotid artery bypass, carotid–carotid bypass, or left carotid-to-subclavian artery bypass may be required to obtain an adequate seal zone. Device diameters are generally oversized 10 to 20% relative to the native landing zone (3), If the distal landing zone is significantly smaller than the proximal, a tapered endograft can be used. Arterial access is preferably through the common femoral artery but may be via the external iliac or common iliac arteries or the distal infrarenal aorta. Paired intercostal branches are derived from the descending thoracic aorta and provide collateral flow to the anterior spinal cord via the artery of Adamkiewicz and other radicular branches. The degree of coverage of these branches must be assessed during TEVAR, as extensive coverage is a major risk factor for spinal cord ischemia and postoperative paraplegia. (23-24)
Vascular access is typically achieved by surgical cutdown. If the LSCA is to be covered, a arterial line should be placed in the right radial artery. The procedure is typically performed under general anaesthesia. Common femoral artery contralateral to the previously determined site is cannulated. After placement of sheath, advance a marker pigtail catheter to the proximal aortic arch and then perform an initial aortogram with the fluoroscope angled in left anterior oblique projection. Arterial access is obtained at the planned endograft insertion site and once access is obtained anticoagulation is used for the duration of the procedure. The stent graft delivery system is then prepared. With continuous fluoroscopic guidance angled perpendicular to the proximal landing zone, the endograft delivery system is advanced to the target site over a guidewire- with the radiopaque marker guiding and help confirming the final positioning. After reconfirming the correct position, the device is deployed under continuous fluoroscopic view. (25-26)
Vascular access is typically achieved by surgical cutdown. If the LSCA is to be covered, a arterial line should be placed in the right radial artery. The procedure is typically performed under general anaesthesia. Common femoral artery contralateral to the previously determined site is cannulated. After placement of sheath, advance a marker pigtail catheter to the proximal aortic arch and then perform an initial aortogram with the fluoroscope angled in left anterior oblique projection. Arterial access is obtained at the planned endograft insertion site and once access is obtained anticoagulation is used for the duration of the procedure. The stent graft delivery system is then prepared. With continuous fluoroscopic guidance angled perpendicular to the proximal landing zone, the endograft delivery system is advanced to the target site over a guidewire- with the radiopaque marker guiding and help confirming the final positioning. After reconfirming the correct position, the device is deployed under continuous fluoroscopic view. (25-26)
Conclusion:
Conclusion:
Treatment options for repair of thoracic aortic aneurysm include thoracic endovascular aortic aneurysm repair (TEVAR) and open surgical repair. The perioperative 30-day mortality rate for TEVAR is significantly lower than for open repair.Nowadays TEVAR is preferred over surgical repair because it provides a less invasive alternative for low-risk patients, lower procedural morbidity and mortality, Decreased post procedure pain, complications, and shortened convalescence are other advantages. It is the procedure of choice for high-risk patients who are not surgical candidates and would otherwise have no therapeutic options for thoracic aortic aneurysm repair.
Treatment options for repair of thoracic aortic aneurysm include thoracic endovascular aortic aneurysm repair (TEVAR) and open surgical repair. The perioperative 30-day mortality rate for TEVAR is significantly lower than for open repair.Nowadays TEVAR is preferred over surgical repair because it provides a less invasive alternative for low-risk patients, lower procedural morbidity and mortality, Decreased post procedure pain, complications, and shortened convalescence are other advantages. It is the procedure of choice for high-risk patients who are not surgical candidates and would otherwise have no therapeutic options for thoracic aortic aneurysm repair.
References:
References:
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