Absence of proximal neck dilatation and graft migration after endovascular aneurysm repair with balloon-expandable stent-based endografts

OBJECTIVE: Proximal neck dilatation (PND) and/or endograft migration with the subsequent development of type I endoleak is a significant cause of late endograft failure after endovascular abdominal aortic aneurysm repair (EVAR). Although there are numerous reports examining PND in patients receiving endografts that use self-expanding stents (SES) for proximal fixation, there are no such reports for patients treated with endografts that use balloon-expanding stents (BES). The purpose of this study was to investigate PND and endograft migration after EVAR with BES endografts. METHODS: We retrospectively reviewed all charts and all serial computed tomographic scans available for patients who underwent EVAR with a BES endograft (surgeon-made, aortounifemoral polytetrafluoroethylene graft with a proximal Palmaz stent) between August 1997 and October 2002. Only patients with longer than a 12-month follow-up were analyzed. Neck diameter was measured at the level of the lowest renal artery and at 5 mm below it. PND was defined as neck enlargement of 2.5 mm or more. To assess endograft migration, the distance between the superior mesenteric artery and the cranial end of the BES was measured. Stent migration was defined as a change of 5 mm or more. RESULTS: A total of 77 patients received this device during the study period. The technical success rate was 99%. The 1-, 3-, and 5-year survival was 66%, 48%, and 29.5%, respectively. Complete serial computed tomographic scans were available in 41 of the 48 patients who survived 12 months or longer after the operation. The mean follow-up period for these patients was 31 months (range, 12-66 months). The maximum aneurysm diameter was either unchanged or decreased in 35 patients (85%). The immediate postoperative proximal neck diameter was 19 to 29 mm (median, 24 mm). This was unchanged at the latest follow-up. None of the patients had significant PND. The cranial end of the BES was located in the area between 14 mm proximal and 36 mm distal to the superior mesenteric artery (median, 6 mm). None of the patients developed significant endograft migration. CONCLUSIONS: Neither PND nor endograft migration was observed with the BES endograft. The nature of the SES may be responsible for the observed neck dilatation and device migration after EVAR with SES endografts. This study suggests that BES may be a better fixation method for EVAR.     

Mid- and long-term device migration after endovascular abdominal aortic aneurysm repair: a comparison of AneuRx and Zenith endografts

BACKGROUND: Freedom from migration is key to the durability of endovascular aneurysm repair (EVAR). This study evaluates the mid- and long-term incidence of migration with two different endografts. METHODS: Between September 1997 and June 2004, 235 patients were scheduled for EVAR with an AneuRx (Medtronic/AVE Inc.) or Zenith (Cook) endograft. Patients with fusiform, infrarenal aneurysms and a minimum 12 months of follow-up were analyzed, for a final cohort of 130 patients. Migration was assessed on axial computed tomography (CT) (2.5 to 3 mm cuts) as the distance from the most caudal renal artery to the first slice containing endograft (AneuRx) or to the top of the bare suprarenal stent (Zenith). Aortic neck diameters were measured at the most caudal renal artery. The initial postoperative CT scan was the baseline. Migration was defined by caudal movement of the endograft at two thresholds, > or =5 mm and > or =10 mm, or any migration with a related clinical event. RESULTS: Life-table analysis demonstrated AneuRx freedom from migration (> or =10 mm or clinical event) was 96.1%, 89.5%, 78.0%, and 72.0% at 1, 2, 3, and 4 years, respectively. Zenith freedom from migration was 100%, 97.6%, 97.6%, and 97.6% at 1, 2, 3, and 4 years, respectively (P = .01, log-rank test). The stricter 5-mm migration threshold found 67.4% of AneuRx and 90.1% of Zenith patients free from migration at 4 years of follow-up. Twelve out of 14 (85.7%) AneuRx patients (12/14) with migration (> or =10 mm or clinical event) underwent 14 related secondary procedures (13 endovascular, 1 open conversion). The single Zenith patient with migration (> or =10 mm) has not required adjuvant treatment. Mean follow-up was 39.0 +/- 2.3 months (AneuRx) and 30.8 +/- 1.9 months (Zenith, P = .01). Patients with and without migration did not differ in age, gender ratio, aneurysm diameter, and neck diameter. However, initial neck length was shorter in patients with migration (22.1 +/- 2.1 mm vs 31.2 +/- 1.2 mm, P = .02). A subset of patients (21.6%) experienced significant (defined as > or =3 mm) maximum aortic neck dilation. Of the AneuRx patients, > or =3 mm aortic neck dilation affected 30.8% of migrators vs 13.0% of nonmigrators (P = .20). CONCLUSIONS: Endograft migration is a time-dependent phenomenon affected by both device choice and aortic neck length. A great majority of patients (85.7%) with migration of the AneuRx device ultimately required treatment. A minority of patients experienced aortic neck dilation that could be considered clinically significant. Careful surveillance for migration is an essential component of long-term follow-up after EVAR.     

Aortic Neck Attachment Failure and the AneuRx Graft: Incidence, Treatment Options, and Early Results

Some investigators have reported that proximal attachment failure is a long-term complication of endovascular abdominal aortic aneurysm repair (EVAR) with the AneuRx (Medtronic, Santa Rosa, CA) device. We evaluated the need for an intervention in patients with suboptimal proximal fixation as well as the feasibility and early success of a variety of treatment strategies. From October 1999 to October 2003, we performed 365 EVARs using the AneuRx graft. At a mean follow-up of 23.7 ± 14.8 months, 20 patients (5.5%) with suboptimal outcomes (14 with a type I endoleak, one with a type III endoleak, and 5 with an inadequate seal zone <1 cm) were considered for treatment. Characteristics of each patient’’s aortic neck anatomy that could be associated with proximal attachment failure were evaluated. Eighteen patients (90%) underwent successful treatment (9 AneuRx cuffs, 6 Talent cuffs, 5 aortic stents, one redo endograft, and two surgical conversions) without major perioperative complications, one patient had a persistent type I endoleak despite endovascular treatment, and one patient refused treatment, ultimately leading to aneurysm rupture. There have been no further endoleaks or graft migrations noted since the secondary intervention at a mean follow-up of 13.9 ± 11.8 months. In our experience, proximal attachment failure associated with the AneuRx graft is relatively uncommon and usually associated with unfavorable neck anatomy. Despite this, most cases are treatable by endovascular means. Long-term follow-up is needed to assess the ultimate frequency of these combined device reconstructions.Presented at the spring meeting of the Peripheral Vascular Surgery Society, Anaheim, CA, June 5, 2004.     

Endovascular abdominal aortic aneurysm repair in patients with challenging anatomy: utility of the hybrid endograft

Commercially available aortic stent grafts differ in construction and clinical advantage such that creating hybrid endografts by combining components from different manufacturers is sometimes useful. We describe a multicenter experience using hybrid endografts to treat patients with challenging anatomy. Hospital records and office charts were reviewed from four institutions. Hybrid endografts were defined as those with two types of covered stents in continuity to treat an abdominal aortic aneurysm (AAA). Indications for hybrid grafts were defined by type of endoleak and whether an endoleak was expected or unexpected as determined by the preoperative radiographic evaluation. Endpoints include intraoperative endoleaks, late endoleaks, change in aneurysm size, and rupture. Hybrid endografts were used to treat AAA (endovascular aneurysm repair [EVAR]) in 90 patients, representing 7.9% of the total multicenter experience. In 7 patients (7.8%), a hybrid graft construction as a secondary procedure successfully corrected a type 1 endoleak. In the remaining 83 patients (92.2%), hybrid grafts were created at the time of original EVAR to treat expected challenging anatomy or unexpected endoleaks. Hybrid endografts corrected 88 (97.8%) type 1 endoleaks, but 2 patients (2.2%) persisted with a proximal type 1 leak requiring conversion. During follow-up of 1 to 24 months, computed tomography and ultrasound surveillance, available for 73 patients (81.1%), detected one unresolved distal type 1 (1.1%) and seven type 2 (7.8%) endoleaks. Aneurysm size decreased at least 0.5 cm in 23 of 50 patients (46.0%) at 6 months and in 19 of 31 patients (61.3%) at 12 months. Aneurysm size increased at least 0.5 cm in 4 of 50 patients (8.0%) at 6 months and in 1 of 31 patients (3.2%) at 12 months. There were no ruptures. Hybrid endografts have favorable early and intermediate results in the treatment of AAA. Long-term follow-up will be needed to confirm the absence of significant adverse biomaterial interaction and the effect on AAA exclusion. We advocate the use of hybrid endografts as endovascular therapy for patients whose anatomy may be unsuitable for a single endograft type.     

Double-barrel technique for preservation of aortic arch branches during thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) may involve either planned or inadvertent coverage of aortic branch vessels when stent grafts are implanted into the aortic arch. Vital branch vessels may be preserved by surgical debranching techniques or by placement of additional stents to maintain vessel patency. We report our experience with a double-barrel stent technique used to maintain aortic arch branch vessel patency during TEVAR. Seven patients underwent TEVAR using the double-barrel technique, with placement of branch stents into the innominate (n = 3), left common carotid (n = 3), and left subclavian (n = 1) arteries alongside an aortic stent graft. Gore TAG endografts were used in all cases, and either self-expanding stents (n = 6) or balloon-expandable (n = 1) stents were utilized to maintain patency of the arch branch vessels. In three cases the double-barrel stent technique was used to restore patency of an inadvertently covered left common carotid artery. Four planned cases involved endograft deployment proximally into the ascending aorta with placement of an innominate artery stent (n = 3) and coverage of the left subclavian artery with placement of a subclavian artery stent (n = 1). TEVAR using a double-barrel stent was technically successful with maintenance of branch vessel patency and absence of type I endoleak in all seven cases. One case of zone 0 endograft placement with an innominate stent was complicated by a left hemispheric stroke that was attributed to a technical problem with the carotid-carotid bypass. On follow-up of 2-18 months, all double-barrel branch stents and aortic endografts remained patent without endoleak, migration, or loss of device integrity. The double-barrel stent technique maintains aortic branch patency and provides additional stent-graft fixation length during TEVAR to treat aneurysms involving the aortic arch. Moreover, the technique uses commercially available devices and permits complete aortic arch coverage (zone 0) without a sternotomy. Although initial outcomes are encouraging, long-term durability remains unknown.     

Long-term postplacement cost comparison of AneuRx and Zenith endografts

Long-term postplacement costs increase the global cost of endovascular aneurysm repair (EVAR) by 44%. Secondary procedures and endoleaks significantly increase long-term expense. This study evaluates device-specific long-term postplacement costs using two different endografts. AneuRx and Zenith endografts were used to treat 250 patients with abdominal aortic aneurysms between December 1998 and June 2006 at a single institution. A relative value unit-based hospital cost accounting system was used to calculate both direct and indirect hospital departmental costs. Institutional overhead expenses, costs of professional services, and outpatient visits were also included in cost determinations. All costs were valued in 2006 dollars. To examine long-term costs, patients with <1 year follow-up were excluded. The initial 50 EVAR patients between December 1995 and 1998 were also excluded, to limit the effect of the learning curve on postplacement cost. The cumulative 5-year postplacement costs per patient were $12,465 (AneuRx) and $10,606 (Zenith, p = 0.22). Mean durations of follow-up were 38.5 +/- 5.2 months (AneuRx) and 32.8 +/- 3.8 months (Zenith, p = 0.12). For both devices, the largest cost components were secondary procedures (59.5% AneuRx vs. 56.4% Zenith) and radiologic studies (29.2% AneuRx vs. 34.9% Zenith). Freedom from secondary procedures (80% vs. 51%, p < 0.05) and endoleaks (83% vs. 58%, p = 0.05) was higher in patients treated with Zenith vs. AneuRx endografts, respectively. There was a reduction in secondary procedures and endoleaks in patients treated with Zenith compared to AneuRx. The corresponding 15% reduction in cost, however, was not statistically significant. Additional device-related cost reductions may be possible through improvements in device and technique and alterations in surveillance imaging.     

Device-specific aneurysm sac morphology after endovascular aneurysm repair: evaluation of contemporary graft materials

OBJECTIVE: This study analyzed device-specific aneurysm sac morphology after endovascular aneurysm repair (EVAR) with low-permeability devices. METHODS: Between September 2004 and May 2006, 122 patients were treated with EVAR. Three different devices were implanted: 47 Zenith (Cook, Indianapolis, Ind), 46 AneuRx (Medtronic, Santa Rosa, Calif) with Resilient Dacron Graft Material, and 29 Excluder (W. L. Gore & Associates, Flagstaff, Ariz) with low-porosity polytetrafluoroethylene (PTFE). Patients were followed up at 1, 6, and 12 months and then biannually with computed tomography (CT) angiography. Standard axial two-dimensional CT measurements were obtained and compared with preoperative imaging. The preoperative scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at follow-up. RESULTS: Patient age, sex, and preoperative aneurysm morphology were similar among groups. Patients receiving the Zenith endograft had a significantly larger neck diameter; however, there was no difference in the neck length between groups. The rate of type II endoleaks was similar for the Zenith (17%), AneuRx (17%), and Excluder (14%). At 1, 6, 12, and 18 months, all three grafts were associated with sac shrinkage. The resulting decreases in mean aneurysm size at 18 months and corresponding shrinkage were Zenith, 11%, 6.4 +/- 1.8 mm; AneuRx, 18.9%, 12.7 +/- 2.7 mm; and the Excluder, 5.5%, 3.3 +/- 0.9 (P < .05). The sac size in the 19 patients with a type II endoleak decreased 8.06% compared with a 15.43% decrease in sac size in patients without endoleak at 6 months. No significant sac expansion > or =5 mm has been observed among any of the groups to date. CONCLUSIONS: Sac regression with all devices appears to have been favorably influenced by the new generation of graft materials and is improved compared with published reports of older generation graft materials for the AneuRx and Excluder. However, there is a trend toward greater sac regression with devices using Dacron vs PTFE. The relationship of aneurysm morphology and long-term effects on aortic stent grafts is yet to be determined.     

Impact of endograft design and product line on the device cost of endovascular aneurysm repair

OBJECTIVE: Device cost is a substantial component of the overall cost of endovascular abdominal aneurysm repair (EVAR), and the four commercially available devices differ significantly in the cost of their basic configuration. This study examined the impact of three different endografts and their product lines on the overall cost of repair. METHODS: Implant records of 467 EVAR procedures performed during 2000 through 2006 were reviewed. The three devices used were the AneuRx in 178 (38.1%; Medtronic, Santa Rosa, Ca), the Excluder in 123 (26.3%; W. L. Gore & Associates, Flagstaff, Ariz), and the Zenith in 166 (35.5%; the Cook Zenith (Bloomington, Ind). The Powerlink device (Endologix, Irvine, Calif) was not studied. The specific device implanted was determined by its commercial availability at the time of repair, patient anatomy, and surgeon preference. Retail list prices were used for all calculations, and only devices used during the original repair were used for analysis. RESULTS: The device cost of the most basic configuration for repair (ie, 2 pieces for AneuRx and Excluder, 3 pieces for Zenith) differed by $3022 between the most expensive (Zenith) to the least expensive (AneuRx). However, the AneuRx system required the most number of extensions (1.90 +/- 1.25 per case; range, 0-7), whereas the Zenith required the fewest (0.21 +/- 0.51 per case; range, 0-3). When the costs of the extensions were added, the overall mean device costs per case were similar. CONCLUSION: The initial cost advantage of the AneuRx and Excluder endograft systems were offset by the more frequent need for proximal and distal extensions. The minimum device cost of a basic repair should not factor into the decision to select one specific device over another because additional devices may be required depending on the design and construction of the endograft system and the accuracy and reliability of their deployment mechanisms.     

Treatment of short-necked infrarenal aortic aneurysms with fenestrated stent-grafts: short-term results.

INTRODUCTION: A proximal neck of 15 mm length is usually required to allow endovascular repair of abdominal aortic aneurysms (EVAR). Many patients have been refused EVAR due to a short neck. By customising fenestrated grafts to the patients' anatomy, we can offer an endovascular solution, especially for patients who are unsuitable for open repair. METHODS: Eighteen patients were selected for fenestrated stent-grafting if they presented with an abdominal aneurysm of at least 55 mm in diameter, a short neck (less than 15 mm), plus contra-indications for open repair (cardiopulmonary impairment or a hostile abdomen). The stent-graft used was a customised fenestrated model based on the Cook Zenith composite system. We used additional stents to ensure apposition of the fenestrations with the side branches. RESULTS: All endovascular procedures were successful. Out of the 46 targeted side branches (10 superior mesenteric arteries, 36 renal arteries), 45 were patent at the end of the procedure. One accessory renal artery became occluded by the stent-graft. There was one possible proximal type I endoleak, which later proved to be a type II endoleak. There was no mortality, but complications occurred in six patients: two cardiac complications, three urinary complications and one occlusion of a renal artery. At follow-up (mean 9.4 months, range 1-18), there were no additional renal complications and all the remaining targeted vessels stayed patent. DISCUSSION: By customizing fenestrated stent-grafts, it is possible to position the first covered stent completely inside the proximal neck, thus achieving a more stable position. The additional side-stents may also contribute to a better fixation. This technique may become a valuable alternative for patients who are at high risk from open surgery.     

Aortic Aneurysm Sac Shrinkage after Endovascular Repair Is Device–dependent: A Comparison of Zenith and AneuRx Endografts

Aneurysm sac shrinkage after endovascular aneurysm repair (EAR) provides objective evidence of successful aneurysm exclusion and absence of endotension. Attainment of this outcome parameter may be device-dependent. In this study, 169 patients underwent EAR with an AneuRx (n = 118) or Zenith (n = 51) endograft at a single institution. A prospectively maintained database was examined for significant changes in aneurysm sac diameter (> or = 5 mm) on the basis of computed tomography (CT) measurements at 6 and 12 months follow-up. Significant aneurysm sac shrinkage (> or = 5 mm) occurred in 73.1 % (19/26) vs. 43.1% (28/65) of patients in the Zenith and AneuRx groups, respectively, at 12 months (p = 0.03). At 6 months follow-up, sac shrinkage rates were 51.4% (19/37) vs. 25.8% (16/62) in the Zenith and AneuRx groups, respectively (p = 0.04). Mean reduction of sac diameter at 12 months was -7.6 +/- 1.6 mm vs. -3.5 +/- 0.8 mm in the Zenith and AneuRx groups, respectively (p = 0.01). There was a trend toward fewer Type I and III endoleaks at 1 month in the Zenith group (0 vs. 8.3%) that did not achieve statistical significance (p = 0.067). The presence of any endoleak (> or = 1 month) was associated with reduced 12 month shrink rates from 47.1% (25/51) to 28% (4/14) in the AneuRx group (p = 0.35) and from 77.3% (17/22) to 50% (2/4) in the Zenith group (p = 0.25). Patients treated with the Zenith endograft demonstrated a significantly higher rate and amount of aneurysm sac shrinkage than patients treated with an AneuRx device. Endoleaks appeared to negatively influence shrink rates with both endografts.     

Renal interventions after abdominal aortic aneurysm repair using an aortic endograft with suprarenal fixation

BACKGROUND: Our aim was to determine whether suprarenal fixation in endografts compromises renal artery (RA) flow and whether subsequent RA intervention is precluded by the stent struts. METHODS: Prospectively acquired data from 104 patients with endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm using the Zenith endograft (Cook, Inc., Bloomington, IN) were analyzed. The Zenith device uses a 26-mm, uncovered, barbed Z stent for suprarenal function. RESULTS: No RA stenosis, occlusion, or infarction resulted from the suprarenal stent. In 3 of 104 (2.9%) patients, RA compromise (2 stenoses, 1 occlusion) was caused by impingement of graft material on the lowermost RA. The 2 RA stenoses were stented successfully at 1 and 7 months post-EVAR. Six of 104 (5.8%) patients developed late stenoses unrelated to the endograft: all were stented successfully from 19 to 36 months after EVAR. One patient with severe RA stenosis had balloon angioplasty pre-EVAR and then was stented electively 6 weeks post-EVAR. CONCLUSIONS: Our data show that the suprarenal fixation of the Zenith aortic endograft does not cause RA stenosis, occlusion, or infarction, nor does it preclude post-EVAR renal artery intervention.     

Use of proximal aortic cuffs as an adjunctive procedure during endovascular aortic aneurysm repair

The purpose of this study was to evaluate the incidence and durability of additional proximal cuffs during endovascular abdominal aortic aneurysm repair (EVAR). A retrospective review of 90 EVAR patients was conducted. Postoperative survival, proximal sealing zone-related complications, and secondary procedures were analyzed. Additional proximal cuffs were used in 11%. Their use did not affect postoperative survival (p = .58), type I endoleak rate (4.4%; p = .19), or the need for sealing zone-related secondary procedures (6.3%; p = .38) compared with patients without cuff placement but was related to a higher cumulative graft migration rate (2.2% overall p = .02). Two patients (2.5%; p = .79) underwent conversion to open surgery, both for proximal sealing zone-related complications. Application of proximal cuffs appears to be an effective intraoperative adjunctive procedure to achieve a proximal seal during EVAR, with favorable midterm results. However, the risk of late endograft migrations may be elevated in this group.     

EVAR reintervention management strategies in contemporary practice

It is known that following an endovascular aneurysm repair (EVAR) procedure, patients may experience endoleaks, device migration, stent fractures, graft deterioration, or aneurysm growth that might require a reintervention. In this review management strategies of reinterventions after EVAR in contemporary practice will be discussed. The current endovascular treatment options of Type I endoleak involve securing of the attachment site with percutaneous transluminal balloon angioplasty, stent-graft extension, or placement of a stent at the proximal attachment site. Moreover, the use of endostaples to secure the position of the proximal cuff to the primary endograft have been developed. Type II endoleaks can be managed conservatively if the aneurysm is shrinking or remains stable. Otherwise, reinterventions include transarterial embolization, translumbar embolization, transcaval embolization, direct thrombin injection, and endoscopic or open ligation of the lumbar and mesenteric arteries. There is little debate regarding the treatment of type III endoleaks, including deployement of additional stent graft components to bridge the defect. Endovascular treatment of endotension includes endovascular conversion stent or relining of the stent graft. Alternative options are puncture of the aneurysm sac and removal of the aneurysm sac content. In case of migration large balloon-expandable stents can be used to improve the seal between the components, or devices that deploy staples to secure endovascular grafts to the aortic wall to secure endovascular components together. In conclusion, the first treatment options for reinterventions after EVAR are catheter based nowadays.     

Intermediate Follow-Up after Endovascular Aneurysm Repair: Can We Forgo CT Scanning in Certain Patients?

Current recommendations for follow-up after endovascular repair of abdominal aortic aneurysms (EVAR) include yearly computed tomographic (CT) scans after the first year. We hypothesize that this is unnecessary for patients who have aneurysm sacs that are stable or shrinking at 1 year and no evidence of endoleak. To explore this hypothesis, we reviewed the records of all patients undergoing EVAR at our institution who were implanted with grafts that are currently commercially available and had a minimum of 18 months' follow-up. Of 415 patients who underwent EVAR over an 8-year period, 93 met the entry criteria. At a mean follow-up of approximately 3 years, secondary interventions were required in 13%, 39%, and 25% of patients undergoing EVAR with Zenith, AneuRx, and Excluder devices, respectively, and secondary interventions after the first year were required in 3%, 22%, and 8% of such grafts, respectively. Seventy-one patients (76%) had aneurysm sacs that were stable or shrinking at 1 year and no endoleak. Only two of these patients subsequently required reintervention. Both patients had AneuRx grafts, and both problems could have easily been identified without CT scanning. Our data support the hypothesis that patients who meet these criteria at 1 year are unlikely to have problems that cannot be identified by ultrasound and/or clinical evaluation alone and, thus, that CT scans are not necessary after this point, especially in patients with Zenith or reengineered Excluder devices.     

Does hostile neck anatomy preclude successful endovascular aortic aneurysm repair?

OBJECTIVES: Poor outcomes have been reported with endovascular aneurysm repair (EVAR) in patients with hostile neck anatomy. Unsupported endografts with active fixation may offer certain advantages in this situation. We compared EVAR results using the Ancure (Guidant) endograft in patients with and without hostile neck anatomy. METHODS: Records of EVAR patients from October 1999 to July 2002 at a tertiary care hospital were retrospectively reviewed from a division database. Patients with elective open abdominal aortic aneurysm (AAA) repair during the same period were reviewed to determine those unsuitable for EVAR. Hostile neck anatomy, assessed by computer tomography (CT) scans and angiograms, was defined as one or more of the following: (1) neck length 3 mm, (3) >2-mm reverse taper within 1 cm below the renal arteries, (4) neck thrombus > or =50% of circumference, and (5) angulation > or =60 degrees within 3 cm below renals. RESULTS: Three hundred and twenty-two patients underwent EVAR with an average follow-up of 18 months. Patients in Phase II trials (n = 41), repaired with other graft types (n = 48), or without complete anatomic records (n = 27) were excluded. Demographics and co-morbidities were similar in the 115 good-neck (GN) and 91 bad-neck (BN) patients except for age (mean, 72.9 years GN vs 75.7 BN; P = 0.13), gender (11% female GN vs 22% BN; P =.04); neck length (mean, 21.8 mm GN vs 14.4 mm BN: P <.001), and angulation (mean, 22 degrees GN vs 40 degrees BN; (P <.001). Perioperative mortality (0 GN vs 1.1% BN), late mortality (5.2% GN vs 4.4% BN), all endoleaks (19.1% GN vs 17.6% BN), proximal endoleaks (0.8% GN vs 2.1% BN), and graft migration (0 for both groups) did not reach statistical significance. Neck anatomy precluded EVAR in 106 of 165 (64%) patients with open AAA. CONCLUSIONS: Unsupported endografts with active fixation can yield excellent results in treating many medically compromised patients with hostile neck anatomy. Nonetheless, an unsuitable neck remains the most frequent cause for open abdominal AAA.     

Remodeling of the aortic neck with a balloon-expandable stent graft in patients with complicated neck morphology

Graft migration and other device-related problems are more frequent in abdominal aortic aneurysm (AAA) patients with a complicated neck. We wanted to evaluate the performance of a balloon-expandable stent graft in these cases. Complicated aortic neck morphology was defined as a combination of short (<15 mm) and angulated (>45 degrees) necks with or without circumferential thrombus. Severe aortic angulation was defined as less than 120 degrees. During a 24-month period, 18 consecutive patients with complicated neck anatomy were treated with the Vascular Innovations (VI)-Datascope balloon-expandable endograft. In two patients, a balloon-expandable cuff was implanted to remodel the neck prior to insertion of a bifurcated endograft (Excluder, W.L. Gore & Associates, Flagstaff, AZ). Demographic, procedural, and outcome data were collected prospectively and retrospectively analyzed. All patients had preoperative computed tomographic (CT) angiography to determine aortic neck angulation and were followed with duplex ultrasonography and CT every 3 and 6 months postoperatively to assess aortic neck and sac dilatation, as well as device migration. The VI-Datascope graft consists of an aortounifemoral polytetrafluoroethylene (PTFE) graft sutured to a proximal balloon-expandable stent. The length of the graft is 40 cm; thus, the distal end of the graft always protrudes through the ipsilateral arteriotomy and can be cut to an appropriate length for each patient. The covered portion of the graft was deployed just below the level of the lowest renal artery. The proximal bare metal stent was deployed in the suprarenal area. An endoluminal hand-sewn anastomosis was performed between the aortounifemoral limb and the distal external iliac or the common femoral arteries. An occluder device was placed in the contralateral common iliac artery to prevent retrograde perfusion of the aneurysm. A femorofemoral 8 mm Dacron graft bypass was then performed to establish flow to the contralateral extremity and pelvis. Using this approach, remodeling and straightening of angulated aortic neck morphology were achieved in all cases, including in 44% of patients with severe aortic neck angulation. The average follow-up period was 11.5 months (4-21 months). There was one early occlusion (<30 days after implantation) of the PTFE limb requiring thrombectomy and one late occlusion (6 months after implantation) requiring thrombectomy and implantation of a Viabahn stent graft (W.L. Gore & Associates). Scheduled CT scans did not show any graft migration or proximal neck dilatation. Neither neck dilatation nor endograft migration was observed with the balloon-expandable stent graft. In patients with complicated aortic neck morphology, balloon-expandable stent grafts such as the VI-Datascope graft provide more secure fixation and better long-term outcomes compared with the more commonly used self-expanding endografts.     

Fabric tears as a new cause of type III endoleak with Ancure endograft

PURPOSE: We present two case reports of type IIIb endoleak. One was due to fabric erosion caused by placement of a stent (Wallstent; W. L. Gore & Associates, Flagstaff, Ariz) after endovascular aneurysm repair; the other arose spontaneously. In both cases, an Ancure endograft (Guidant/EVT, Menlo Park, Calif) was placed. CASE REPORTS: In case 1, a large endoleak developed 36 months after uncomplicated endovascular treatment of an abdominal aortic aneurysm. In case 2, endoleak developed 30 months after a complicated procedure. In both cases, two Wallstents were used to treat type I endoleak and limb kinking in the first postoperative months. One type III endoleak was within the endograft at the level of the stents. CONCLUSION: To our knowledge, these are the first type III endoleaks reported in association with Ancure endografts. Placement of Wallstents inside endografts is of concern, and another indication for close monitoring during follow-up.     

Lessons learned from midterm follow-up of endovascular repair for traumatic rupture of the aortic isthmus

OBJECTIVE: The aim of this study was to evaluate the short- and midterm results following endovascular repair of a traumatic rupture of the aortic isthmus. METHODS: Between January 2001 and January 2007, 27 patients underwent endovascular repair for acute traumatic rupture of the aortic isthmus (8 women, 19 men, mean age 40.2 +/- 16.7 years [19-78]). All patients underwent a computed tomography scan resulting in the preoperative diagnosis of aortic disruptions. Twenty-one patients were treated within the first 5 days following diagnosis. Follow-up computed tomography scans were performed at 1 week, at 3 and 6 months, and annually thereafter. The median follow-up was 40 months. RESULTS: All endografts were successfully deployed (Excluder-TAG [16], Talent [10], Zenith [2]). Three patients required common iliac artery access. The morbidity rate was 14.8%: two cases of inadvertent coverage of supra-aortic trunks occurred peroperatively, a proximal type I endoleak was successfully treated by a proximal implantation of a second endograft, and one collapse of an endograft was successfully treated by open repair and explantation. No patient suffered transient or permanent paraplegia, cerebral complication, endograft migration, or secondary endoleak. The overall mortality rate was 3.7%. CONCLUSIONS: Short and midterm results following endovascular treatment for traumatic rupture of the aortic isthmus favor the proposition of endovascular repair as the first-line treatment in hemodynamically unstable patients. In hemodynamically stable patients, the preoperative morphological evaluations aim to assess aortic anatomy and thereby detect possible technical limitations (aortic diameter <20 mm, severe aortic isthmus angulation, short proximal aortic neck <20 mm, conical aorta). In the presence of any one of these technical restrictions, open surgical treatment should be discussed to avoid major per- or postoperative complications related to endovascular repair. Further studies and long-term survival studies are mandatory to determine the efficacy and durability of this technique.     

腹主动脉瘤腔内修复术中特殊近端锚定区的处理

目的探讨腹主动脉瘤腔内修复术（EVAR）中特殊近端锚定区的处理方法。方法1997年7月至2005年7月对41例特殊类型腹主动脉瘤（瘤颈过短、严重成角、严重钙化、附壁血栓、形态不规则等）的腔内修复术中，根据情况分别采用近端裸支架跨肾动脉技术、覆盖部分肾动脉并肾动脉支架成形技术、针对成角选择合理产品、近端裸支架内支撑技术、近端延长支架型血管内支撑技术、“凹口”状支架型血管保留肾动脉技术来处理特殊近端锚定区的病变。结果41例EVAR中原发性近端Ⅰ型内漏发生率17．1％（7／41），随诊发现原发性内漏4例自愈，3例转化为持续性内漏，另发现4例继发性内漏。术后30d近端Ⅰ型内漏发生率17.1％（7／41）。无中转开腹手术及术中瘤体破裂、肾梗死等情况发生。结论对特殊近端锚定区的病例，通过相关技术处理可以使之适合腔内治疗。     

Detection of endograft fractures with multidetector row computed tomography

Delayed endograft metallic strut failures detected in vivo with multidetector row computed tomography (MDCT) are reported in two patients who underwent endovascular abdominal aortic aneurysm repair with AneuRx and Talent endografts. In both instances, nitinol fractures were associated with proximal migration and type I endoleak. In both cases, the metallic strut fractures were detected with transverse sections from 16-channel MDCT angiograms and confirmed by using volume rendering. These cases highlight the previously unreported ability of thin-section, high-resolution MDCT angiography to detect endograft strut fractures.