Outcomes of original and low-permeability Gore Excluder endoprosthesis for endovascular abdominal aortic aneurysm repair

OBJECTIVE: Because of concern about the percentage of enlarging abdominal aortic aneurysms (AAAs) after endovascular repair with the Excluder device (W.L. Gore & Assoc, Inc, Sunnyvale, Calif), the graft material was modified to reduce its permeability and released for commercial use in mid-2004. We studied all AAA repairs with Excluder endografts performed at our institution, including the original-permeability (OP) version (n = 99) and the low-permeability (LP) version (n = 48). METHODS: All patients were followed up with serial computed tomography (CT) angiography and three-dimensional (3D) reconstruction. Morphologic measurements, including AAA diameter and 3D volume, were prospectively entered into a database to evaluate changes in AAA size over time. Owing to the length of available follow-up for the LP version, the primary end point was AAA size change at 6 and 12 months, evaluated by Mann-Whitney U test for unpaired samples. RESULTS: Preoperative and postoperative anatomy was similar in the two groups, including AAA diameter (OP, 5.6 +/- 1 cm; LP, 5.8 +/- 2 cm; P = .3), aortic neck length (OP, 21 +/- 1 mm; LP, 22 +/- 2 mm; P = .9), postoperative aortic seal zone (OP, 18 +/- 1 mm; LP, 16 +/- 1 mm, P > .1) and iliac seal zone (OP, 33 +/- 1 mm, LP 31 +/- 1 mm, P = .2). The rate of sac shrinkage differed significantly. Orthogonal diameter measurements showed a significant difference in the rate of shrinkage by 12 months postoperatively (OP, -2.1 +/- 1 mm; LP, -5.1 +/- 1 mm; P = .01). By 3D volume, the rate of shrinkage was considerably different between the two groups at both 6 and 12 months (12 months: OP, -6% +/- 1%; LP, -20 +/- 4%; P = .0006). There was no enlargement by diameter in either group at 6 or 12 months postoperative. By standard volume criteria, however, 12 of 99 patients in the OP group and one of 48 patients in the LP group had significant AAA enlargement < or =12 months (P = .04). Of these, four of 12 patients in the OP group had enlargement without apparent endoleak, even on delayed-contrast CT. The remainder had persistent type II endoleaks (8/12 in the OP group and 1/1 in the LP group). Multivariate analysis revealed graft permeability (P < .0001) and endoleak (P < .0001) as independent factors in aneurysm size change. In the OP group long-term, the average AAA enlarged at later time points compared with the prior scan: 24 months, -0.2%; 36 months, +0.2%; 48 months, +2%; and 60 months, +2% (P < .0002). CONCLUSIONS: In early follow-up, the low-permeability Excluder device is associated with a significantly greater aneurysm shrinkage rate than the original version. Clinically important enlargement also appears significantly different within 1 year of implantation. Despite these promising results, longer follow-up is needed to determine whether these differences will persist.     

The effect of endograft relining on sac expansion after endovascular aneurysm repair with the original-permeability Gore Excluder abdominal aortic aneurysm endoprosthesis

OBJECTIVE: Endovascular abdominal aortic aneurysm repair (EVAR) with the original-permeability Excluder (W.L. Gore & Associates, Flagstaff, Ariz) has been associated with postoperative sac expansion in the absence of endoleak. In these cases, we have performed an endovascular revision, relining the original endograft with another Excluder, in an effort to arrest sac expansion by reducing permeability. We have studied these cases to determine the effect of relining on aneurysm expansion. METHODS: Patients who demonstrated sac expansion (>or=5 mm diameter, >or=5% three-dimensional volume) after EVAR with the original Excluder were evaluated. Between 1999 and 2004, the original-permeability endoprosthesis was used in 97 patients who underwent EVAR for asymptomatic abdominal aortic aneurysm (AAA). Sac expansion occurred in 24 patients, of which multiple imaging modalities showed 12 had expansion without demonstrable endoleak. Nine of the 12 have had endovascular relining, and five of these nine have >6 months follow-up to form the primary basis for this report. RESULTS: AAA size was stable or smaller in the first 6 months after the original EVAR for all patients. Once expansion began (typically in the time frame of 6 to 12 months), multimodality imaging showed no aneurysm spontaneously decreased in size without intervention, despite the absence of endoleak (n = 12). Expansion exceeded clinically significant thresholds at 30 months (mean) by diameter criteria and 22 months (mean) by three-dimensional volume criteria for the five patients with >6 months follow-up after relining. Endovascular relining was performed at a mean of 36 months, with a mean hospital stay of 1 day, and no morbidity or mortality. Over the entire duration of expansion (mean, 26 months), aneurysms expanded by 6.0 +/- 1 mm/year diameter and by 12% +/- 2%/year by three-dimensional volume. At a mean of 16 months follow-up after relining with another Excluder, the mean diameter decrease was 2.0 mm/year (P < .03) and the mean volume decrease was 2.6%/year (P < .01). After relining, all AAAs were smaller by diameter or volume, or both, exceeding thresholds defining shrinkage in two of the five with >6 months follow-up after relining. There was no rupture, migration, endoleak, conversion to open repair, or aneurysm-related death in any patient. CONCLUSIONS: It appears from the initial follow-up that AAA expansion owing to permeability issues after EVAR with the original Excluder can be arrested by endovascular relining with a low-permeability Excluder endoprosthesis.     

The Gore Excluder endograft device for the treatment of abdominal aortic aneurysms

Open surgical repair on abdominal aortic aneurysms has been performed for many years with good RESULTS: Despite the many advances in medical care, the procedure is still associated with many complications. The Gore Excluder endograft is a third-generation endograft that became the third commercially available endograft approved in the United States. Data from multiple trials have compared the use of the Excluder endograft to open repair and have shown favorable RESULTS: This review shall summarize the clinical use of the Excluder endograft from its initial clinical trial in 1998 to its current commercial use.     

Secondary conversion of the Gore Excluder to operative abdominal aortic aneurysm repair

OBJECTIVE: Reports continue to document the occurrence of major adverse events after endovascular aortic aneurysm repair. Although many of these problems can be successfully managed through endovascular salvage, operative conversion with explantation of the endoprosthesis remains necessary in some patients. We report herein a review of all patients initially enrolled in multicenter US clinical trials of the Excluder endograft who underwent secondary conversion to open surgical repair. METHODS: Clinical data and relevant medical records of patients enrolled in phase I and II multicenter US clinical trials of the Excluder endograft were retrospectively reviewed for adverse events and further narrowed to those patients who underwent secondary operative conversion. Hospital records, operative and anesthesia reports, and all imaging studies were analyzed at initial implantation and at the time of subsequent open surgical repair. RESULTS: Late open conversion was performed in 16 (2.7%) of the 594 patients enrolled in the Excluder clinical trials. Presumed endotension accounted for 8 of 16 of secondary conversions. In two of these patients, however, an endoleak was identified at the time of open surgical repair. Of the remaining eight patients, two underwent conversion for device infection, five for persistent endoleak, and one for aneurysm rupture. The overall 30-day mortality was 6.25% (1/16), with one death occurring in a patient with a ruptured aneurysm. Of patients who underwent conversion because of endotension, the maximal abdominal aortic aneurysm diameter (mean +/- SD) at the time of initial implantation and subsequent graft removal was 61 +/- 11 mm and 70 +/- 10 mm, respectively. The mean time to open conversion for treatment of endotension was 37 +/- 12 months (range, 20-50 months; median, 42 months). Freedom from conversion was 98.6% and 96.7% at 24 and 48 months, respectively. CONCLUSIONS: Endotension in the absence of a demonstrable endoleak has been a major indication for late surgical conversion in patients treated with the Excluder endograft. Given the potential presence of an undetected endoleak and the possible effects of progressive sac enlargement on long-term device stability, continued close surveillance of patients with assumed endotension is required. Should changes in device design eliminate endotension, a further reduction in the already low incidence of late open conversion of the Excluder endograft can be anticipated.     

Early experience with the bifurcated Excluder endoprosthesis for treatment of the abdominal aortic aneurysm

PURPOSE: This report describes our initial experience with the modular, bifurcated Excluder endoprosthesis and its safety and efficacy in the primary endovascular repair of infrarenal abdominal aortic aneurysms (AAAs). METHODS: AAAs (mean diameter, 58.2 +/- 14.3 mm) were repaired in 19 patients with this device between March 1999 and January 2000. The mean age of patients was 71.8 +/- 8.4 years (range, 57-86 years). This modular device was inserted through an 18F introducer sheath placed in one femoral artery, and the contralateral artery was cannulated with a 12F introducer sheath. All procedures were performed in a standard operating room with angiographic capabilities. RESULTS: Endograft deployment was successful in all patients. The average surgical time was 135 +/- 37 minutes, with a mean blood loss of 229 +/- 138 mL. In eight patients, the use of either aortic or iliac extenders was required for enhanced sealing or additional length. An external iliac artery dissection occurring at the time of endograft insertion was successfully treated with a Wallstent. Type II leaks initially found to be present by means of intraoperative completion angiography had spontaneously thrombosed by the 1-month follow-up computed tomography scan. There was one perioperative death (5.3%). Complications included superficial wound infections (n = 3) and a nonfatal myocardial infarction (n = 1). The mean length of hospital stay was 2.9 +/- 1.2 days, and only six patients required intensive care. Endoleaks were seen in four patients (21%) by means of the 30-day computed tomography scan; three of these endoleaks had spontaneously sealed at the time of the 6-month follow-up examination (5.5% 6-month endoleak rate). Aneurysm size did not increase in the patients with leaks. CONCLUSION: The Excluder endoprosthesis was an effective means of excluding an infrarenal AAA from the systemic circulation in this selected group of patients. The smaller sheath sizes may increase the pool of potential candidates. Further study of this device is warranted, and continued assessment of the long-term durability of the device will be necessary.     

Late abdominal aortic aneurysm enlargement after endovascular repair with the Excluder device

OBJECTIVES: Behavior of the abdominal aortic aneurysm (AAA) sac after endovascular abdominal aortic aneurysm repair (EVAR) is graft-dependent. The Excluder endograft has been associated with less sac regression than some other stent grafts. Long-term follow-up has not been reported. METHODS: Between May 1999 and July 2002, 50 patients underwent EVAR with the Excluder bifurcated endoprosthesis. These patients were followed up prospectively with computed tomography (CT) at 1, 6, and 12 months and yearly thereafter. One immediate conversion to open surgery and three deaths occurred within 6 months. One additional patient was lost to follow-up. The remaining 45 patients, 35 men and 10 women, were followed up for at least 1 year, and form the basis for this report. Their mean age was 73 +/- 5.5 years. The minor axis diameter at the largest area of the AAA on CT examination was compared with the baseline measurement at 1 month and to the smallest size previously recorded during follow-up. Change in sac size of 5 mm or greater was considered significant. Mean follow-up was 2.7 +/- 1.2 years (range, 1-4 years). Nominal variables were compared with the chi(2) test, and continuous variables with the Student t test. RESULTS: A significant decrease in average AAA sac diameter was observed at 6-month, 1-year, and 2-year follow-up. These differences were lost by the 3-year evaluation, because of delayed sac growth (n = 9) and re-expansion of once shrunken aneurysms (n = 3). The probability of freedom from sac growth or re-expansion at 4 years was only 43%. At last follow-up, sac expansion occurred in the absence of active endoleak in nine patients. Type II endoleak was associated with sac expansion in three patients (P =.003), resulting in one conversion to open surgery after the 4-year follow-up. No graft migrations, AAA ruptures, or aneurysm-related deaths were noted. CONCLUSIONS: Late aneurysm sac growth or re-expansion after EVAR with the Excluder device is common, even in the absence of endoleak. Although the incidence of important clinical sequelae is low at this point, the incidence of aneurysm expansion should be taken into consideration during the risk-benefit assessment before EVAR repair with the Excluder device.     

Prediction of altered endograft path during endovascular abdominal aortic aneurysm repair with the Gore Excluder

OBJECTIVE: During endovascular abdominal aortic aneurysm (AAA) repair (EVAR), the rapid deployment of the Gore Excluder endograft may be associated with anatomic shortening of the endograft path. This shortened path may result in coverage of the hypogastric artery origin or overly conservative graft length selection that may lead to unnecessary extensions. We quantified the degree of path alteration with this endograft and developed an algorithm to predict it. METHODS: Preoperative and postoperative three-dimensional (3D) computed tomographic (CT) scans were evaluated for 50 consecutive patients with Gore Excluder endografts by using 21 anatomic measurements and 6 calculated indices. Measurements were evaluated as if only 3D lumen centerline measurements were available, rather than complete 3D computer-aided measurement and "virtual graft" simulation. Tortuosity was quantitated from the renal artery to the hypogastric origin, using the difference between a straight line and the lumen centerline. RESULTS: The endograft was deployed successfully in all cases. The graft end points were typically quite close to the preoperative plan: mean renal artery-to-graft distance was within 2.0 +/- .5 mm, and the limb end point-to-hypogastric origin differed by an average of only 1.8 +/- 1.6 mm. Although accurate in most cases, the actual graft path shortened 1 cm or more relative to the centerline in 11% of limbs. On univariate analysis, determinants of alteration of >1 cm in the graft deployment path were (1) aortoiliac tortuosity (renal-to-hypogastric artery, P < .002), (2) the degree of planned graft rotation (73% of cases altered >10 mm were in the rotated position, P < .05), and (3) the insertion side (73% of alterations >or=10 mm were ipsilateral to the main device, P < .05). On multivariate analysis, the renal-to-hypogastric artery tortuosity index (RHTI) was significant ( P < .004), and device type and rotation approached significance ( P < .08). We developed a classification scheme based on RHTI to predict the risk of alteration of the graft path >or=1 cm (low risk, 0%; medium risk, 10%; high risk, 25%) and an algorithm to predict the degree of alteration of the anatomy that reduced the number of cases shortening >or=1 cm to zero. CONCLUSIONS: The graft deployment path will be altered significantly in a minority of cases with the Gore Excluder endograft, but this can cause hypogastric occlusion or other problems. Anatomic shortening is predictable from morphologic features such as tortuosity, graft insertion side, and rotation. We developed an algorithm based on a tortuosity index that quantitates the risk and degree of shortening associated with endograft deployment.     

Three-dimensional analysis of enlarging aneurysms after endovascular abdominal aortic aneurysm repair in the Gore Excluder Pivotal clinical trial

OBJECTIVE: Recent reports have raised concern about the percentage of enlarging abdominal aortic aneurysms (AAAs) after endovascular repair with the Gore Excluder device. As part of the investigation into this issue, a morphologic analysis was performed on enlarging aneurysms in the Excluder Pivotal clinical trial. METHODS: Computed tomographic scans were evaluated on all patients identified with enlarging aneurysms (5-mm increase by Core laboratory or site) and at least 4 years of follow-up in the Excluder Pivotal clinical trial. Three-dimensional reconstruction, a set of 24 standard morphologic measurements, and analysis of potential enlargement mechanisms were performed. RESULTS: Of 112 trial patients with 4 years of follow-up, 38 AAAs (34%) were identified as enlarging. Data were obtained from 196 computed tomographic scans (the mean interval was 47 months from first to last scan). Of the 158 scans with a prior scan for comparison, 41% demonstrated growth relative to the initial scan by diameter criteria, but 79% demonstrated growth relative to the initial scan by 3-dimensional volume criteria (P < .0001 vs diameter; chi2 analysis). This difference was most evident at early time points: at 1 year, diameter criteria indicated that 8% of these AAAs were enlarging, but 56% were already enlarging by volume criteria. On average, enlargement was detected by volume 18 months before it was detected by diameter (P < .0001), and at a smaller diameter (55 +/- 1 mm vs 60 +/- 1 mm; P < .0001). Only 19% of scans (39% of patients) had apparent endoleaks. Scans with apparent endoleaks demonstrated a greater interval rate of growth as compared with those without apparent endoleak (3.6 +/- 0.8 mm vs 1.9 +/- 0.3 mm [P < .02] by diameter; 23 +/- 4 cm3 vs 11 +/- 1 cm3 [P < .001] by volume). Although the etiology of enlargement may be endotension or device permeability in up to 74% of patients, other potential causes of aneurysm enlargement included neck apposition length less than 15 mm (15 patients; 39%), large aortic diameter relative to device (18%), large iliac diameter (5%), and iliac apposition length less than 15 mm (20%). Multiple potential etiologies of enlargement were present in 53% of AAAs. CONCLUSIONS: The etiology of aneurysm enlargement in the Excluder Pivotal trial is likely multifactorial, including endoleak, inadequate attachment site length, and endotension or device permeability. Even by conservative criteria, a substantial percentage of aneurysm growth with the original device is likely due to material permeability. Three-dimensional volume criteria detected aneurysm enlargement more frequently, at a smaller diameter, and on average 18 months sooner than standard diameter criteria, thus suggesting a role in further investigation of this issue.     

Sac enlargement due to seroma after endovascular abdominal aortic aneurysm repair with the Endologix PowerLink device

A patient who had undergone endovascular repair of an abdominal aortic aneurysm with the Endologix PowerLink bifurcated system presented with delayed aortic aneurysm enlargement due to assumed endotension. He was treated with aortic sac evacuation and wrapping of the endograft. This is the first report of endotension and aneurysm sac enlargement after implantation of the PowerLink endograft.     

Ten-year outcome analysis of the Italian Excluder Registry with the Gore Excluder endograft for infrarenal abdominal aortic aneurysms

Objective

The objective of this study was to report the 10-year outcomes of the multicenter Italian Excluder Registry for elective endovascular aneurysm repair (EVAR).

Endoluminal stent grafting of the thoracic aorta: initial experience with the Gore Excluder

PURPOSE: The purpose of this study was to describe our experience with endoluminal graft repair of a variety of thoracic aorta pathologies with a commercially developed device currently under investigation. Our patient population included patients eligible for open surgical repair and those with prohibitive surgical risk. METHODS: From February 2000 to February 2001, endovascular stent-graft repair of the thoracic aorta was performed in 46 patients (mean age, 70 years; 29 male and 17 female patients) with the Gore Excluder. Twenty-three patients (50%) had atherosclerotic aneurysms, 14 patients (30%) had dissections, three patients (7%) had aortobronchial fistulas, three patients (7%) had pseudoaneurysms, two patients (4%) had traumatic ruptures, and one patient (2%) had a ruptured aortic ulcer. Patient characteristics, procedural variables, outcome, and complications were recorded. All patients were followed with chest computed tomographic scans at 1, 3, 6, and 12 months. Follow-up period ranged from 1 month to 15 months, with a mean of 8.5 months. RESULTS: All the procedures were technically successful. There were no conversions. Average duration of the procedure was 120 minutes. Average length of stay was 6 days, but most patients (64%) left the hospital within 4 days after endoluminal grafting. The overall morbidity rate was 23%. Two patients (4%) had endoleaks that necessitated a second procedure for successful repair. Two patients (4%) died in the immediate postoperative period. There were no cases of paraplegia. At follow-up examination, one patient had an endoleak found the day after the procedure and another patient had an endoleak 6 months after the procedure. Both cases were treated successfully with additional stent-grafts. There were no cases of migration. One patient died of a myocardial infarction 6 months after graft placement. In patients treated for aneurysm (n = 23), the aneurysm diameter ranged from 5.0 to 9.5 cm (mean, 6.8 cm). Residual sac measurements were obtained at 1, 6, and 12 months, with mean sac reductions of 0.59 cm, 0.77 cm, and 0.85 cm, respectively. In three cases, the sac remained unchanged, without evidence of endoleak. CONCLUSION: Thoracic endoluminal grafting with the Gore Excluder is a safe and feasible alternative to open graft repair and can be performed successfully with good results. Early data suggest an endoluminal approach to these disease entities may be favorable over classical resection and graft replacement.     

Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms

OBJECTIVES: Report the results of a phase II multicenter, prospective trial comparing endovascular treatment of descending thoracic aneurysm (TEVAR) with the TAG device to surgical controls after 5 years of follow-up. METHODS: The Gore TAG trial compared the TAG endograft patients (n = 140) with standard open surgical controls (n = 94) with enrollment from September of 1999 to May of 2001. An additional 51 patients were enrolled in 2003 after revision of the endograft. Follow-up consisted of patient visits, computed tomography (CT) scans and x-rays at 1, 6, and 12 months and yearly. Significant sac size change was defined as >or=5 mm increase or decrease from the 1 month baseline measurement. Migration was defined as >or=10 mm cranial or caudal movement of the device inside the aorta. Significance was determined as P 相似文献   

Long-term results after standard endovascular aneurysm repair with the Endurant and Excluder stent grafts

ObjectiveMany endografts are currently available for standard endovascular repair of infrarenal abdominal aortic aneurysms. Comparison of long-term outcomes between devices might aid in this decision process, but comparative data are scarce. The purpose of this study was to report long-term clinical outcomes of two commercially available endoprosthesis, the Endurant (Medtronic Vascular, Inc, Minneapolis, Minn) and the Excluder (W. L. Gore & Associates, Flagstaff, Ariz) stent grafts.MethodsPatients undergoing standard endovascular repair from July 2004 to December 2011 in a single institution with the Endurant or the Low-Porosity Excluder endografts were eligible. Only patients treated for intact degenerative abdominal infrarenal aneurysms were included. All measurements were performed on center-lumen line reconstructions obtained on dedicated software. The primary end point was primary clinical success, defined as clinical success without the need for an additional or secondary surgical or endovascular procedure. Neck-related events (a composite of type IA endoleak, neck-related secondary intervention, or migration of >5 mm), neck morphology changes, renal function, and overall survival were secondary end points.ResultsThe study included 277 patients (156 Endurants; 121 Excluders). The median follow-up was 5.8 years (range, 0.1-12.4 years) and did not differ between groups (P = .18). Patients treated with the Endurant stent graft had wider (neck diameter of >28 mm, 27.3% vs 1.7% [P < .001]; neck diameter of 27 mm, [interquartile range (IQR), 24-29 mm] for Endurant and 24 mm [IQR, 22-25 mm] for Excluder; P < .001) and more angulated necks (β-angle of >60°, 26.7% vs 12.5%; P = .004). Oversizing was greater in the Endurant group (16% [IQR, 12%-22%] vs 13% [IQR, 8%-17%], respectively; P < .001). Patients were treated outside device instructions for use regarding proximal neck: 16.7% in the Endurant and 17.3% in the Excluder group (P = .720). The 7-year primary clinical success was 54.7% for the Endurant and 58.1% for the Excluder groups (P = .53). Freedom from neck-related events at 7 years was 76.7% for the Endurant and 78.8% for Excluder group (P = .94). The Endurant stent graft (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.3-5.8; P = .009) was an independent predictor of significant renal function decline. Neck dilatation was greater in Endurant-implanted patients (13% [95% CI, 2%-22%] vs 4% [95% CI, 0%-10%]; P < .001). Overall survival at 7 years was 61.4% in the Endurant and 50.3% (n = 50; standard error, 0.047) in the Excluder group (P = .39).ConclusionsThis study reveals that durable and sustainable results can be obtained with either of these late generation devices. This finding suggests that careful planning and a tailored device selection taking into account the patient's anatomy are more relevant determinants than the graft model itself to obtain clinical success. The Endurant endoprosthesis seems to be associated with a higher rate of neck dilatation and faster decrease in the estimated glomerular filtration rate, but further studies with longer follow-up are necessary to determine the clinical relevance of these findings.     

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.