Comparison of perioperative costs with fast-track vs standard endovascular aneurysm repair.

BACKGROUND: Perioperative health care utilization and costs in patients undergoing elective fast-track vs standard endovascular aneurysm repair (EVAR) remain unclear. METHODS: The fast-track EVAR group included patients treated with a 14 Fr stent graft, bilateral percutaneous access, no general anesthesia or intensive care monitoring, and next-day hospital discharge. The standard EVAR group was identified from Medicare administrative claims using a matching algorithm to adjust for imbalances in patient characteristics. Hospital outcomes included operating room time, intensive care monitoring, hospital stay, secondary interventions, and major adverse events (MAEs). Perioperative outcomes occurring from hospital discharge to 30 days postdischarge included MAE, secondary interventions, and unrelated readmissions. RESULTS: Among 1000 matched patients (250 fast-track; 750 standard), hospital outcomes favored the fast-track EVAR group, including shorter operating room time (2.30 vs 2.83 hrs, P<0.001), shorter hospital stay (1.16 vs 1.69 d, P<0.001), less need for intensive care monitoring (4.4% vs 48.0%, P<0.001), and lower secondary intervention rate (0% vs 2.4%, P=0.01). Postdischarge outcomes also favored fast-track EVAR with a lower rate of MAE (0% vs 7.2%, P<0.001) and all-cause readmission (1.6% vs 6.8%, P=0.001). The total cost to the health care system during the perioperative period was $26,730 with fast-track EVAR vs $30,730 with standard EVAR. Total perioperative health care costs were $4000 (95% CI: $3130-$4830) lower with fast-track EVAR vs standard EVAR, with $2980 in savings to hospitals and $1030 savings to health care payers. CONCLUSION: A fast-track EVAR protocol using a 14 Fr stent graft resulted in shorter procedure time, lower intensive care utilization, faster discharge, lower incidence of MAE, lower readmission rates, and lower perioperative costs compared to standard EVAR.

Perioperative Outcomes From the Prospective Multicenter Least Invasive Fast-Track EVAR (LIFE) Registry.

PURPOSE: To determine the feasibility, perioperative resource utilization, and safety of a fast-track endovascular aneurysm repair (EVAR) protocol in well-selected patients. METHODS: Between October 2014 and May 2016, the LIFE (Least Invasive Fast-track EVAR) registry ( ClinicalTrials.gov identifier NCT02224794) enrolled 250 patients (mean age 73±8 years; 208 men) in a fast-track EVAR protocol comprised of bilateral percutaneous access using the 14-F Ovation stent-graft, no general anesthesia, no intensive care unit (ICU) admission, and next-day discharge. The primary endpoint was major adverse events (MAE) through 30 days. The target performance goal for the MAE endpoint was 10.4%. RESULTS: Vascular access, stent-graft delivery, and stent-graft deployment success were 100%. A total of 216 (86%) patients completed all elements of the fast-track EVAR protocol. Completion of individual elements was 98% for general anesthesia avoidance, 97% for bilateral percutaneous access, 96% for ICU avoidance, and 92% for next-day discharge. Perioperative outcomes included mean procedure time of 88 minutes, median blood loss of 50 mL, early oral nutrition (median 6 hours), early mobilization (median 8 hours), and short hospitalization (median 26 hours). Fast-track EVAR completers had shorter procedure time (p<0.001), less blood loss (p=0.04), faster return to oral nutrition (p<0.001) and ambulation (p<0.01), and shorter hospital stay (p<0.001). With 241 (96%) of the 250 patients returning for the 30-day follow-up, the MAE incidence was 0.4% (90% CI 0.1% to 1.8%), significantly less than the 10.4% performance goal (p<0.001). No aneurysm rupture, conversion to surgery, or aneurysm-related secondary procedure was reported. There were no type III endoleaks and 1 (0.4%) type I endoleak. Iliac limb occlusion was identified in 2 (0.8%) patients. The 30-day hospital readmission rate was 1.6% overall. CONCLUSION: A fast-track EVAR protocol was feasible in well-selected patients and resulted in efficient perioperative resource utilization with excellent safety and effectiveness.

Fast-track endovascular aortic repair: Interim report from the prospective LIFE registry.

OBJECTIVE: To assess the feasibility, safety, and clinical utility of a fast-track endovascular aneurysm repair (EVAR) protocol. BACKGROUND: Despite recent advances in EVAR technology and techniques, considerable opportunity exists to further improve EVAR efficiency and outcomes. METHODS: Eligible patients underwent elective EVAR with the Ovation Prime stent graft. Successful completion of the fast-track protocol required bilateral percutaneous access, avoidance of general anesthesia and intensive care unit admission, and next-day discharge. Patients were followed through 1-month post-treatment. RESULTS: Between October 2014 and September 2015, 129 patients were enrolled in the study. Vascular access, stent graft delivery, and stent graft deployment were successful in all patients. The fast-track EVAR protocol was successfully completed in 114 (88%) patients. Bilateral percutaneous access was achieved in 97% of cases. Comparing patients who completed fast-track requirements to those who failed at least one component, procedure time was 86 vs. 122 min, use of general anesthesia was 0% vs. 20%, need for intensive care unit stay was 0% vs. 13%, hospital stay was 1.1 vs. 2.1 days, and postoperative groin pain severity (0-10 scale) was 1.2 vs. 4.0. No type I or III endoleaks, serious device-related adverse events, AAA ruptures, surgical conversions, or AAA-related secondary procedures were reported. One (0.9%) patient in the fast-track group died from acute respiratory failure. CONCLUSIONS: Initial results from the LIFE study are encouraging and suggest that a fast-track protocol is feasible, safe, and may improve efficiency of healthcare resource allocation in select patients undergoing EVAR. © 2016 Wiley Periodicals, Inc.

Comparison of the boomerang wire vascular access management system versus manual compression alone during percutaneous diagnostic and interventional cardiovascular procedures: The boomerang™ wire vascular access management trial II.

OBJECTIVES: To evaluate the use of the Boomerang™ Wire as an adjunct to manual compression (MC) in patients requiring diagnostic (Dx) or interventional (Ix) percutaneous procedures. BACKGROUND: MC remains the standard of care for closure of femoral artery access sites. Adjunctive use of a device to facilitate closure, reduce time to hemostasis (TTH) and ambulation (TTA) without increasing complication rates could reduce costs and hospital resource demands. METHODS: The Boomerang™ Trial was a prospective, multicenter, randomized, controlled trial comparing use of the Boomerang™ wire, (Cardiva Medical, Sunnyvale, CA) in conjunction with MC versus MC alone to achieve hemostasis in Dx and Ix patients undergoing percutaneous procedures requiring femoral artery access. Endpoints included TTH, TTA, major, and minor access-site related complications. Subjects were randomized 3:1, Boomerang versus MC. RESULTS: No minor or major device-related adverse events were reported. Nondevice related complication rates were 3 (0.9%) in the Boomerang arm (n = 327) and 1 (0.8%) in MC arm (n = 123). Mean TTH for Boomerang vs. MC was 11.2 ± 4.3 vs. 23.2 ± 11 min for Dx (P < 0.0001) and 13.9 ± 5.4 vs. 38.4 ± 57.3 min for Ix patients (P < 0.0001). Mean TTA for Boomerang vs. MC was 3.3 ± 3.0 vs. 4.5 ± 2.0 hr (P < 0.0001)for Dx and 5.4 ± 3.3 vs. 6.8 ± 3.2 hr (P < 0.0001) for Ix patients. CONCLUSIONS: Boomerang™ use, in conjunction with MC, was associated with low rates of complications and demonstrated that Boomerang™ as an adjunct to MC can significantly decrease TTH and TTA after both Dx and Ix procedures. © 2015 Wiley Periodicals, Inc.

Endovascular management of recurrent adult coarctation of the aorta.

Traditional open surgical repair has proven to be an effective treatment for the management of primary and recurrent coarctation of the thoracic aorta. Potential complications at short-term and long-term follow-up have included recurrent coarctation, hypertension, premature coronary artery disease, cerebrovascular disease, and anastomotic pseudoaneurysm. Endovascular repair of recurrent coarctation of the thoracic aorta offers a less invasive treatment approach in potential high-risk surgical patients.

Is endovascular repair the new gold standard for primary adult coarctation?

OBJECTIVE: Primary adult aortic coarctation (PAAC) is an unusual cause of hypertension. The standard of care includes surgical repair, which can be associated with considerable morbidity and operative risk. Although balloon angioplasty has been successfully used in paediatric and adolescent patients with coarctation, little information exists regarding the endovascular repair of PAAC. This study examines the procedural safety and efficacy of endovascular repair of PAAC along with midterm outcomes. METHODS: Between January 2000 and July 2008, 16 patients underwent endovascular repair of PAAC. All patients were hypertensive with 13 patients (81.3%) receiving medical therapy. Symptoms included chest pain (n=11, 69%), progressive fatigue (n=5, 31%), exercise intolerance (n=4, 25%) and shortness of breath (n=3, 19%). Associated cardiac concerns included depressed ejection fraction (n=6, 38%), pulmonary hypertension (n=5, 31%), ascending aortic dilatation (n=5, 31%) and bicuspid aortic valve (n=4, 25%). Endovascular repair was achieved using a percutaneous femoral approach. Balloon angioplasty of the coarctation was performed prior to treatment using a balloon-expandable uncovered stent. Aortic diameters were assessed using intravascular ultrasound. Pre- and post-procedure pressure gradients were measured and success was determined as a residual pressure gradient across the treated aorta of less than 20 mmHg. RESULTS: The male:female (M:F) ratio was 9:7 with a mean age of 39.7 years. Procedural success was 100%. Mean pre-procedural aortic diameter was 8.4mm (3-14 mm) and mean post-procedural aortic diameter was 16.3mm (10-20mm) (p=0.04). The mean pre-procedural pressure gradient was 48.3 mmHg (25-100 mmHg) and the mean post-procedural pressure gradient was 0.5 mmHg (0-15 mmHg) (p=0.05). Twelve patients received one stent, two patients received two stents, one patient received three stents and one other patient received a thoracic stent graft. The rate of paraplegia was 0% with no blood transfusions, strokes or deaths. Follow-up ranged from 12 to 72 months (mean=22.8 months). One patient required re-intervention with an additional stent 14 months following the initial procedure and all the patients remain symptom-free. CONCLUSION: Endovascular repair of PAAC is safe and effective and compares favourably with open surgical repair. Midterm follow-up suggests that the treatment is durable and may be an alternative to surgical repair. Although this is the largest endovascular treatment series for PAAC reported to date, additional study and follow-up are needed.

"Cracking and paving": a novel technique to deliver a thoracic endograft despite ilio-femoral occlusive disease.

BACKGROUND: The use of endoluminal grafts to treat thoracic aortic aneurysms has been associated with a decreased morbidity and mortality compared with open thoracic aortic aneurysm repair. High-risk surgical patients with ilio-femoral occlusive disease may not be amenable to general anesthesia and the construction of a retroperitoneal conduit. METHODS AND RESULTS: We report the use of a novel technique consisting of cracking and paving of the ilio-femoral vessels with balloon angioplasty, followed by deployment of an endoconduit to deliver an endoluminal graft under local sedation to treat a high-risk 80-year-old patient with a thoracic aneurysm. CONCLUSION: High-risk surgical patients with iliofemoral disease can undergo endoluminal graft therapy to threat thoracic aortic aneurysms.

Treatment of type II endoleaks associated with left subclavian artery coverage during thoracic aortic stent grafting.

OBJECTIVE: Increasing experience with thoracic aortic stent grafts has led to a more aggressive approach to thoracic aortic pathologies in the distal aortic arch and proximal descending thoracic aorta. To increase the length of the proximal landing zone, it is sometimes necessary to cover the left subclavian artery with the thoracic stent-graft, introducing the risk of retrograde filling of the excluded aorta from the left subclavian artery. It is currently unclear how best to manage these patients to prevent persistent risk of aneurysm expansion or rupture. We report our experience with a minimally invasive endovascular repair of the covered left subclavian artery. METHODS: We reviewed prospectively gathered data on all investigational device exemption-approved patients undergoing thoracic aortic stent grafting at the Arizona Heart Institute from 2000 to 2006 (n = 289 patients). Patients had surveillance with a contrast-enhanced computed tomography scan on the first postoperative day and during follow-up at 1, 6, and 12 months. RESULTS: A total of 289 patients received thoracic stent grafts during the study: Medtronic Talent (Medtronic, Minneapolis, Minn) (n = 25) or Gore TAG (WL Gore & Associates Inc, Flagstaff, Ariz) (n = 261). The left subclavian artery was covered in 23% of patients (n = 66), of whom 17% had preoperative carotid-subclavian bypass (n = 11/66). Among patients with left subclavian artery coverage, the 30-day mortality was 6.1% (n = 4), procedure-related strokes developed in 3 patients (n = 3, 4.6%), and the incidence of left arm claudication was 7.6% (n = 5), necessitating postoperative carotid-subclavian bypass in 2 patients. Twelve patients (18%) had a type I (n = 6) or II (n = 7) endoleak. Coverage of the left subclavian artery accounted for 71% of the type II endoleaks (n = 5), whereas patent intercostals accounted for the rest (n = 2). Type II endoleaks associated with left subclavian artery coverage were successfully treated by retrograde coil embolization from the left brachial artery (n = 3) or left subclavian artery ligation (n = 1). CONCLUSION: Coverage of the left subclavian artery during thoracic aortic stent grafting is associated with a low incidence of arm complications and type II endoleaks. All type II endoleaks were successfully treated by retrograde coil embolization or ligation of the left subclavian artery. Successful treatment of endoleaks may reduce the risk of aneurysm expansion or rupture.

Intravascular ultrasound imaging as applied to the aorta: a new tool for the cardiovascular surgeon.

Intravascular ultrasound is a novel endovascular imaging technology that is useful as an imaging tool for diagnosis and treatment of arterial and venous pathologies. Intravascular ultrasound is particularly useful as a decision-making tool in the endovascular management of vascular pathologies. Recently the aorta has become increasingly amenable to endovascular technology, and with the advent of intravascular ultrasound detailed imaging, using intravascular ultrasound permits the diagnosis and endovascular management of various complex aortic pathologies affecting the abdominal and thoracic aorta. Various aortic pathologies including thoracic and abdominal aortic aneurysms, type B dissections, penetrating aortic ulcers, coarctation of the aorta, and many other aortic pathologies, which were once only amenable by open surgical repair are increasingly being managed with endoluminal technology. As experience develops with this technology, more complex aortic pathologies would become readily amenable to advanced endovascular interventions.

Endovascular repair of the thoracic aorta in octogenarians.

BACKGROUND: To evaluate the feasibility and safety of thoracic endografting in the octogenarian population. METHODS: Between February 2000 and August 2005, 249 patients with a mean age of 69+/-12.3 years (range 23-91) underwent thoracic endografting. Forty-four patients (27 males and 17 females) were octogenarians with a mean age of 84+/-2.7 years. Indications for intervention included: atherosclerotic aneurysms (26/44, 59%), acute and chronic dissections (9/44, 20.5%), penetrating aortic ulcers (6/44, 14%) and contained rupture (3/44, 7%). RESULTS: Endovascular repair was achieved in all octogenarian patients (44/44, 100%). Mean length of stay was 4.7+/-3.6 days. Two cardiac-related deaths and 1 retrograde dissection death occurred (3/44, 7%). Complications included hemiparesis (n=2) with full recovery at discharge, groin hematoma (n=1), pneumonia (n=2) and stroke (n=1) [6/44, 11%]. Endoleaks were diagnosed in 3 patients [3/44, 7%] (2 type I, 1 type II) at 30-day follow-up. Two patients developed an endoleak beyond 30 days [2/44, 5%] (1 type I, 1 type II). Two re-interventions were necessary at 30 days (1 type I, 1 type II). Mean follow-up was 22 months and there were no device migrations or aortic ruptures. No statistical differences in overall mortality were noted between octogenarians and non-octogenarians at 30 days (7% vs 6%, p=NS), 12 months (18% vs 13%, p=NS) and 24 months (27% vs 15%, p=NS). However, at 5 years post-procedure, octogenarians had a significantly higher overall mortality than non-octogenarians (32% vs 17%, p=0.038). CONCLUSIONS: Advanced age is not a contraindication to thoracic endografting with favorable short and mid-term outcomes compared to non-octogenarians.

Management of endoleaks associated with endovascular treatment of descending thoracic aortic diseases.

OBJECTIVE: Endoluminal grafting is emerging as a less invasive alternative to the treatment of descending thoracic aorta diseases. Endoleaks (continued pressurization of the treated aorta external to the endoluminal graft) are a potential complication. We reviewed our cumulative endovascular experience for descending thoracic aorta pathologies with respect to the management of endoleaks and associated patient outcomes. METHODS: As part of a single-site investigational device-exemption protocol, 249 patients (146 men, 103 women) with thoracic aortic diseases underwent attempted delivery of a TAG endoprosthesis (W. L. Gore & Associates, Flagstaff, Ariz) between February 2000 and August 2005. Indications for study enrollment included 111 atherosclerotic aneurysms (44.6%), 67 aortic dissections (26.9%), 27 penetrating aortic ulcers (10.8%), 14 contained ruptures (5.6%), 11 pseudoaneurysms (4.4%), 9 acute aortic transections (3.6%), 7 aortobronchial fistulas (2.8%), 2 endoleaks (0.8%) after prior thoracic endoluminal grafting, and 1 (0.4%) adult coarctation. Endoleak surveillance was performed using serial computed tomography scans. RESULTS: Mean patient age was 68 years (range, 23-91 years). Endoleak developed in 38 patients (15.3%): 15 distal type I (39.5%), 13 proximal type I (34.2%), 8 type II (21.1%) and 2 type III (5.3%). No surgical intervention was performed in 26 patients (68.4%), in which the endoleak spontaneously resolved in 14 (53.8%), 8 (30.8%) are being monitored and are asymptomatic, 3 (11.5%) died of unrelated causes, 2 (7.7%) withdrew from the study, and 1 (3.8%) was lost to follow-up. Twelve patients (31.6%) required reintervention using an additional endoluminal graft: 8 (66.7%) with a proximal type I endoleak, 2 (16.7%) with a distal type I endoleak, 1 (8.3%) with both distal type I and type III endoleaks, and 1 (8.3%) with a type III endoleak. Open conversions were necessary secondary to device deployment difficulties in two patients (0.8%), and due to expansion of a thoracoabdominal aneurysm and rupture of an aneurysm secondary to a type II endoleak in one patient (0.5%) each. CONCLUSION: Endoleaks are an infrequent, yet important, complication after thoracic endografting. Many endoleaks will resolve spontaneously, but some patients may require another endovascular intervention. Close surveillance is recommended for these patients; however, open conversion is rarely indicated. Because more diseases of the thoracic aorta are being treated using an endovascular approach, a standardized treatment algorithm is essential to safely and effectively manage associated endoleaks.

Retrograde type A dissection after endovascular stenting of the descending thoracic aorta. Is the risk real?

OBJECTIVE: Retrograde type A dissection during or after endoluminal graft repair of the descending thoracic aorta is a potentially lethal complication unique to thoracic endografting. Our aim is to increase its awareness and to review possible etiological factors. METHODS: Two hundred and eighty-seven patients with different thoracic aortic pathologies were treated with endovascular prostheses over the last 6 years (February 2000 to March 2006) under a single-site protocol. A retrospective review was conducted to identify any retrograde aortic dissections by both chart and film review. Factors that may have contributed to its formation were also documented. This population was analyzed for the complication of retrograde aortic dissection as well as the factors related to its occurrence. RESULTS: Seven patients (2.4%) with a gender distribution of three males and four females experienced a retrograde type A dissection within this sample at a median of 202 days. The mean age was 74 years (range 53-83). Aortic pathologies included aortic dissections (n=6) and thoracic aortic aneurysm (n=1). There were (n=3) 43% retrograde type A dissections identified within the perioperative period. Balloon angioplasty was performed in 71.4% (n=5). Two female patients (28.6%) had this event identified within their initial hospitalization with fatal consequences. Overall mortality was 57% (n=4) with extension of dissection the primary cause of death n=3 and open surgical repair (n=1) after an extension of retrograde dissection. CONCLUSIONS: Female gender, use of stent-grafts for dissection and possible aggressive balloon angioplasty may play a role in the cause of retrograde type A dissection. A close surveillance program is recommended when using thoracic endografts outside the recommended device instructions for use.

Endoluminal graft therapy for the treatment of an aorto-bronchial fistula: mid-term follow-up.

Open surgical repair of aorto bronchial fistulas is associated with a high morbidity and mortality. Endovascular stent graft as an alternative therapy, though limited, has produced acceptable initial results, but few reports of mid-term follow-up are available. We report the mid-term results with the use of an endograft to treat a patient with both an aorto bronchial fistula and a contained rupture of the thoracic aorta.

Customized endoluminal graft to treat a suspected saccular thoracoabdominal mycotic aneurysm.

Open surgical repair of mycotic aneurysm is associated with a high surgical morbidity and mortality. The role of endovascular graft repair of mycotic aneurysm remains controversial because the graft material remains in contact with possibly infected tissue. We report an endovascular technique of customizing an abdominal endoluminal graft component to treat a suspected saccular thoracoabdominal mycotic aneurysm involving the takeoff of the celiac trunk.

A novel approach for the endovascular repair of the small thoracic aorta: customizing off-the-shelf endoluminal grafts to treat a post-coarctation pseudoaneurysm.

Surgical repair of post-coarctation pseudoaneurysm is associated with high morbidity and mortality. Endovascular stent grafting is a minimally invasive approach to manage this condition. The small thoracic aorta provides a dilemma for endovascular stent grafting using available commercially available thoracic endografts. We describe a hybrid approach including a novel technique to customize various components of the abdominal endoluminal grafts to repair a post-coarctation pseudoaneurysm. The patient is doing well at 1-year follow-up with no endoleaks.

Use of the right brachio-femoral wire approach to manage a thoracic aortic aneurysm in an extremely angulated and tortuous aorta with an endoluminal stent graft.

The presence of a tortuous, elongated thoracic aorta and an angulated arch poses a technical challenge for the delivery of an endoluminal graft to the target site to exclude management of a thoracic aortic aneurysm. Despite the availability of a flexible delivery sheath system, adjunct techniques are necessary to deal with extremely tortuous thoracic aortas. The use of a brachio-femoral wire with tension applied at both ends is a useful technique to deliver an endoluminal graft in an angulated thoracic arch. We describe the use of a right brachio-femoral wire approach to treat a thoracic aortic aneurysm in a 75-year-old man with an elongated, tortuous and angulated arch aorta.

A novel technique of deployment of a thoracic endograft in the hybrid treatment of a patient with thoracoabdominal aneurysm.

Repair of thoracoabdominal aneurysm is associated with high morbidity and mortality. We describe a hybrid approach to repair a Crawford type III thoracoabdominal aneurysm with antegrade deployment of the endoluminal graft through a side limb of the bifurcated inflow conduit. The advantage of this technique includes avoidance of thoracotomy, left heat bypass, hypothermia, and aortic cross clamping.

Successful management of a combined ruptured Stanford type B aortic dissection and malperfusion syndrome with an endoluminal graft.

Thoracic endografting has been recently approved in the USA for the treatment of thoracic aortic aneurysms. The application of endoluminal graft therapy to treat acute type B dissection has been shown to be effective but is still not considered standard of care. We describe the use of an endoluminal graft to treat a patient with an acute type B dissection associated with malperfusion and thoracic aortic rupture.

Endovascular repair of an ascending aortic pseudoaneurysm with a septal occluder device: mid-term follow-up.

Ascending pseudoaneurysm is an infrequent complication of ascending aortic surgery. Redo operations are often associated with a high surgical morbidity and mortality. Endovascular management of ascending aortic pathologies with endoluminal graft therapies are challenging due to short landing zones and the fear of flow obstruction to the coronaries and brachiocephalic circulation. We report mid-term follow-up of the management of an ascending aortic pseudoaneurysm using a an Amplatz septal occluder (AGA Medical Corp, Golden Valley, MN) in a 51-year-old man considered at high risk for conventional open surgical repair.

Endovascular grafts for thoracic aortic pathologies.

Endovascular aortic repair (EVAR) is rapidly being adopted to capture a substantial proportion of surgical candidates with aneurysmal disease of the descending thoracic aorta. This new technique requires both special equipment (hybrid operating room, full range of catheterization tools) and additional technical skills, which an average cardiothoracic surgeon usually lacks, not being exposed to this particular training during his formative years. Presently, EVAR is applied to high-risk surgical candidates, its main advantages being the avoidance of cardiopulmonary bypass, minimal invasiveness (no large incisions) and often the ability to perform the procedure under local anesthesia. Early mortality in the author's (H.S.) institution is comparable to the best surgical results published, which is remarkable with respect to the high-risk patients. The techniques are rapidly being developed, with treatment of the aortic arch aneurysm employing transposition of supra-aortic arteries, and of the thoraco-abdominal aneurysms with branched grafts.