What are the characteristics of the ideal endovascular graft for abdominal aortic aneurysm exclusion?

Can Magnetic Resonance Imaging Be the Key Technique to Visualize and Investigate Endovascular Biomaterials?

OBJECTIVE

Magnetic resonance imaging (MRI) is an established modality in clinical use but may be potentially underutilized to visualize and investigate biomaterials. As its use is totally contraindicated only for ferromagnetic devices, it was employed to visualize deployment, biofonctionality, healing, and biodurability of a commercially available endovascular device, namely the Medtronic-AVE AneuRx. The quality of the observations coupled with the absence of ionizing radiations are likely to make this technique an attractive imaging modality in the future.

METHOD

The potential benefits of the MRI technique were investigated in a GE Vectra-MR 0.5T MRI for the Medtronic-AVE AneuRx endovascular prosthesis, under different conditions: undeployed i.e., inserted in the delivery cartridge as received from the manufacturer (step 1), deployed in a mock glass-aneurysm tube (step 2), and as a pathological explant harvested at the autopsy of a patient (step 3). The device was submitted to X-rays for examination in addition to MRI. At step 3, the device was further investigated with light microscopy and scanning electron microscopy (SEM) together with X-ray diffraction.

RESULTS

The device which was inserted and pleated in the delivery cartridge did not demonstrate any significant observation either in MRI or in X-rays. When it was deployed in the mock aneurysmal glass tube, light artefacts were associated with the T2 weighed FSE images around the Nitinol whereas X-rays gave images of indisputable interest. Similar results were noted using the explanted device. Very high contrasts were obtained with T1 whereas T2 images were almost defect free. The X-rays allowed to accurate imaging of the Nitinol skeleton but were poor to discriminate between the different tissues. Pathology observations using light microscopy were not really challenged, as the magnetic resonance imaging was performed using a 0.5T machine.

DISCUSSION

The benefits of magnetic resonance imaging as a quality control technique to examine an endovascular device within its cartridge remains ill defined. Similarly, the role of conventional X-rays is unknown. The observation of devices fully deployed in a mock aneurysmal glass-tube under MRI are potentially useful but X-rays images allowed better definition. The MRI examination of the explanted device does permit observations related to the healing of the device that might be obtained in vivo and, thus offers new avenues for the follow-up of implanted devices. The pathological investigations brought additional informations about the tissues and the corrosion of the Nitinol. However, it is unlikely that MRI will permit detailed analysis of the biomaterials and in particular the corrosion process of the stents.

CONCLUSION

These early observations of the follow-up of devices using MRI warrant further investigation. The absence of ionizing radiation with MRI makes this technique particularly attractive. As there is no emission of ionizing radiation associated with magnetic resonance, it is recommended that further investigation using this environment friendly technique for the follow-up of devices made of biomaterials that are MRI compatible.

Durability of renal artery stents in patients with transrenal abdominal aortic endografts

OBJECTIVE

The management of renal artery stenosis in patients with abdominal aortic aneurysms continues to be complex and technically challenging despite advances in endovascular therapy. There is growing concern about the durability of renal artery stents in the setting of transrenal abdominal aortic endografts. This study reports a single-center experience of renal artery stenting with transrenal abdominal aortic endografts for patients with renal artery stenosis.

METHODS

All patients undergoing endovascular abdominal aortic aneurysm repair preceded or followed by renal artery stent placement between January 1999 and December 2005 were retrospectively reviewed from a prospectively gathered endovascular database. Patients were surveyed after renal stent procedures with multidetector computed tomography angiography or duplex sonography. The surveillance data were analyzed for primary patency of the renal artery stent at 6 months, incidence of complications, need for secondary interventions, and changes in creatinine clearance (CrCl).

RESULTS

Sixty-two renal artery stents were placed in 56 patients (44 men, 12 women) with a mean age of 77.3 years (range, 61 to 94 years). Forty-one were placed before the endograft procedure, eight were placed during the endograft procedure, and 13 were placed postoperatively. There were no major or minor complications related to the renal artery stent procedures. Transrenal aortic endografts were used in 44 of the 56 patients, and 12 had devices with infrarenal fixation. The mean follow-up was 18.5 months (range, 1 to 73 months). The 6-month primary patency, which could be evaluated for 51 renal artery stents, was 97.4% (37/38) in patients with transrenal fixation and 84.6% (11/13) in patients with infrarenal fixation. The overall rate of in-stent restenosis was 8.5% (4/47) in the transrenal fixation group and 20.0% (3/15) in the infrarenal fixation group. The overall occlusion rate was 2.1% (1/47) in the transrenal fixation group and 0% (0/15) in infrarenal fixation group. Five (83.3%) of six patients underwent successful treatment of in-stent restenosis with placement of a new stent in all five cases. CrCl decreased in the total group by 4.2 +/- 11.8 mL/min, by 4.7 +/- 12.0 mL/min in patients with transrenal fixation, and by 2.2 +/- 11.0 mL/min in patients with infrarenal fixation.

CONCLUSION

The presence of a transrenal aortic endograft did not affect the outcome of the renal artery revascularization procedure in this cohort. Renal artery stenting in the presence of transrenal abdominal aortic endografts appears to be a safe procedure without adverse effect on renal artery stent patency or renal function.

Review of Interventional Repair for Abdominal Aortic Aneurysm

Abdominal aortic aneurysm is associated with high mortality rate. For over 50 years, open surgical repair was the standard approach for large aneurysms. However, over the past decade, endovascular aneurysm repair (EVAR) has emerged as a viable alternative. EVAR is associated with lower operative and short-term morbidity and mortality and similar long-term survival (up to 4 years) compared with surgical repair. Endoleak remains a significant limitation associated with aneurysm expansion and reintervention. With newer, more versatile endograft designs, improvements in durability, and better surveillance techniques, the utilization of EVAR is likely to continue to expand.

Polymethylmethacrylate (PMMA) as an embedding medium preserving tissues and foreign materials encroaching in endovascular devices

Problems of displacement, poor healing, degradation of the polymers and corrosion of the metallic frame in endovascular devices still require in-depth investigations. As the tissues and the foreign materials are in close contact, it is of paramount importance to efficiently investigate the interfaces between them. Inclusion in polymethymethacrylate (PMMA) permits us to obtain thin slides and preserve the capacity to perform the appropriate stainings. An AneuRx prosthesis was harvested in bloc with the surrounding tissues at the autopsy of a patient 25 months post deployment in a 5.7 cm diameter AAA and sectioned in the direction of the blood flow in two halves. A cross-section of the encapsulated distal segment together with the surrounding aneuryshmal sac was embedded in polymethylmethacrylate (PMMA). Further to complete polymerization, slices of the specimen were cut on a precision banding saw under coolant. They were affixed onto methacrylate slides with a UV cured adhesive. Binding and polishing were done on a numeric grinder and slices 25 to 30 microm in thickness were stained with toluidine blue prior to observation in light microscopy. Additional slices were prepared for scanning electron microscopy and X-ray energy dispersive spectrometry for determination of the elemental composition of the Nitinol stent. The aortic wall did not demonstrate complete integrity along with its circumference. Some areas of rupture were noted. The content of the sac was heavily shrunk and was mostly acellular. The walls of the device were very well encapsulated. The PMMA embedding permitted the polyester wall, the Nitinol wire and the collagen to keep in close contact. Scanning electron microscopy involved backscattered electrons and confirmed the corrosion the Nitinol wire at the boundary with living tissues. Based upon the results obtained, we believe that PMMA embedding is the most appropriate method to process endovascular devices for histological and material investigation. Needless to say, that paraffin embedding would have not been feasible for such a big size specimen involving different materials.

Endograft technology: highlights of the past 10 years

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

The value of intraoperative intravascular ultrasound for determining stent graft size (excluding abdominal aortic aneurysm) with a modular system

Since the introduction of endovascular stent grafts at our institution we have used intraoperative intravascular ultrasound (IVUS) to definitively determine stent graft size. In this study, expected stent graft size, based on preoperative helical CT scan measurements, was compared with the actual final size, based on intraoperative IVUS measurements. Between December 1996 and January 1998, 54 patients were treated with an AneuRxTM bifurcated stent graft. Preoperatively all patients underwent angiography and helical CT scanning. Expected stent graft size was determined according to these measurements. The final stent graft size was based on IVUS measurements acquired during the procedure. Differences in expected and final size were compared and follow-up endoleaks were also noted. Differences in diameter measurements between CT and IVUS were compared using the paired Student's t-test. Differences in expected and chosen stent graft length were compared using the McNemar's test for paired proportions of binomial outcomes. Our results showed that helical CT scanning overestimates diameter and underestimates length. This underestimation of length is explained by the tortuosity of the aorta and iliac arteries while using axial slices of the CT scan. The last-minute corrections based on the intraoperative IVUS measurements did not result in a high incidence of endoleaks at fixation zones. In our opinion, the possibility of making final corrections in the choice of diameter or length of the stent graft is the additional value of intraoperative IVUS.

Anatomical importance of infrarenal aortic branches in conventional and endovascular surgery: a review

Minimally invasive or catheter-directed, endoluminal stent-graft treatment of abdominal aortic aneurysms (AAA) is a novel and important advance in the armamentarium of the vascular surgeon and interventional therapist. Provided adequate training is available, infrastructure is optimal, and patient selection correct, successful exclusion of AAA can safely and effectively be achieved with low morbidity and mortality by this lesser invasive technique. An important Achilles heel of endovascular repair (EVR) of AAA is back bleeding or endoleak formation due to incomplete sealing or bridging of aortic branches ostia by endoluminal stents. Significant, recurrent, and persistent retroleaks, a topic of clinical interest, are related to either incompletely sealed-off inferior mesenteric and/or lumbar arteries. The optimal method to diagnose and manage these endoleaks is currently in a state of evolution. In the process of stent-graft treatment of AAA, other important aortic branches are also bridged that may potentially present with the sequelae of peripheral ischemia. This review re-emphasizes the anatomical and clinical importance of abdominal aortic branches relevant to conventional aortic surgery and EVR of AAA.

Mechanisms of heparin transport through expanded poly(tetrafluoroethylene) vascular grafts

Thrombosis and neointimal hyperplasia limit the utility of small-caliber artificial vascular grafts. Surface modifications and adjunctive pharmacological therapy might mediate these complications. We examined the mechanisms by which a model vasoactive compound, heparin, transverses porous graft materials and how material modifications alters this drug's transport. The effective permeance of [(3)H]heparin was measured after application of a uniform concentration of drug to either the internal or external surface of the graft and in the presence or absence of pressure-driven physiologic hydraulic flows. Transgraft permeance was equivalent to those observed in normal arteries and, while enhanced by convection, was mediated in major part by diffusion. Peclet numbers under the various conditions examined ranged from 0.05 to 1.2, indicating that diffusive forces were equal to or exceeded convective forces in governing transmural heparin motion. Heparin traversed the graft even when applied from the outer perivascular surface, against adverse hydraulic flows. Modifications of the grafts that included a yarn barrier of spun poly(tetrafluoroethylene) or chemical modification of surface tension energy altered permeances as well. A unifying model for interpretation of these data incorporates the concept of entrapped air and surface tension energy in the graft. These characterizations allow for the design of vascular grafts that are optimized for pharmacotherapy to help prolong graft patency, especially in small-caliber vascular beds.

A fenestrated covered suprarenal aortic stent

OBJECTIVE

to address the clinical problem of inadequate neck length of abdominal aortic aneurysms in endoluminal surgery.

DESIGN

a covered suprarenal aortic stent was designed with a fenestration to preserve blood flow in a targeted renal artery.

METHOD AND MATERIAL

a Dacron-covered stent was accurately cut to size with a fenestration according to pre-imaging studies.

RESULTS

the stent was successfully deployed in canine models, preserving the visceral and renal artery of interest.

CONCLUSION

by accurately placing a covered stent in the aorta and preserving the blood flow to its branches, it may be possible to extend the indications for endoluminal aortic aneurysm grafting.

Mid-term fixation stability of the EndoVascular Technologies endograft. EVT Investigators

AIM OF THE STUDY

to determine the positional stability of the EndoVascular Technologies (EVT) endograft after endovascular aneurysm repair during morphologic changes of the abdominal aorta during follow-up.

PATIENTS AND METHODS

all patients treated worldwide with an EVT endograft with an adequate postoperative and at least 12 months postoperative CT scan were included (n=125). Endograft migration was investigated by recording the position of the endograft attachment systems relative to the renal arteries and the aortic or iliac bifurcations. The vertical body axis served as a scale to quantify migration. Aortic cross-sectional areas were measured in the suprarenal aorta and in the proximal and distal aneurysm necks. Length changes of the infrarenal aorta during follow-up were measured, comparing the distance between the left renal artery and the aortic bifurcation.

RESULTS

the median follow-up was 24 months (range 12-48 months). Graft migration was identified in 4 out of 125 patients (3%). Significant infrarenal aortic dilation was observed at the proximal and distal aneurysm neck during follow-up. However, aortic neck dilation was not associated with endograft migration. The length of the infrarenal aorta did not change significantly after endovascular repair.

CONCLUSION

fixation by stents containing hooks of the EVT design appear to be effective in preventing migration of endografts with an unsupported trunk for up to four years. A stable position was maintained in spite of changes in cross-sectional areas of the aneurysm neck.

Special iliac artery considerations during aneurysm endografting

BACKGROUND

The feasibility of endograft exclusion of abdominal aortic aneurysms (AAA) has been established. However, the technical challenges of graft delivery through tortuous or diseased iliac arteries and the treatment of associated iliac aneurysmal disease have received little attention.

METHODS

Over 19 months, 74 patients underwent endoluminal repair of AAA and/or iliac artery aneurysms. Iliac anatomy that required special consideration during endografting was reviewed.

RESULTS

Of the 74 patients, 35 (47%) had iliac anatomy that required special attention. Thirteen patients (18%) had aneurysmal involvement of a common iliac artery. Eleven of these patients required endograft extension into the external iliac artery (EIA) and hypogastric coil embolization due to the proximity of the aneurysm to the hypogastric origin. Eleven patients with ectatic, nonaneurysmal iliac arteries required aortic cuffs to achieve a distal seal in these oversized vessels. Iliac artery tortuosity or stenosis were complicating factors in 27 of the 74 patients (36%), requiring the use of brachial guidewire tension in 2 patients to facilitate tracking of the delivery device. Five patients with severely splayed aortic bifurcations required crossed placement of the iliac limbs to prevent kinking of the endograft. Occlusive atherosclerotic disease of the EIA mandated preprocedural dilatation and stenting in 3 patients and postprocedural surgical EIA reconstruction in another 5 patients. Three patients who underwent successful endograft placement required subsequent endovascular repair of traumatized EIAs.

CONCLUSIONS

Iliac artery anatomy plays a significant role in the endoluminal treatment of infrarenal abdominal aortic aneurysms, complicating the procedure in up to 47% of patients with otherwise suitable anatomy. A variety of supplemental procedures, both surgical and endovascular, may be required to facilitate endograft placement. A special understanding of these constraints and proper planning is required for optimal therapy.

Accurate assessment of abdominal aortic aneurysm with intravascular ultrasound scanning: validation with computed tomographic angiography

PURPOSE

The purpose of this study was to assess the accuracy of intravascular ultrasound (IVUS) parameters of abdominal aortic aneurysm, used for endovascular grafting, in comparison with computed tomographic angiography (CTA).

METHODS

This study was designed as a descriptive study. Between March 1997 and March 1998, 16 patients with abdominal aortic aneurysms were studied with angiography, IVUS (12.5 MHz), and CTA. The length of the aneurysm and the length and lumen diameter of the proximal and distal neck obtained with IVUS were compared with the data obtained with CTA. The measurements with IVUS were repeated by a second observer to assess the reproducibility. Tomographic IVUS images were reconstructed into a longitudinal format.

RESULTS

IVUS results identified 31 of 32 renal arteries and four of five accessory renal arteries. A comparison of the length measurements of the aneurysm and the proximal and distal neck obtained with IVUS and CTA revealed a correlation of 0.99 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate the length as compared with the CTA results (0.48 +/- 0.52 cm; P <.001). A comparison of the lumen diameter measurements of the proximal and distal neck derived from IVUS and CTA showed a correlation of 0.93 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate aneurysm neck diameter as compared with CTA results (0.68 +/- 1.76 mm; P =.006). Interobserver agreement of IVUS length and diameter measurements showed a good correlation (r = 1.0; P <.001), with coefficients of variation of 3% and 2%, respectively, and no significant differences (0.0 +/- 0.16 cm and 0.06 +/- 0.36 mm, respectively). The longitudinal IVUS images displayed the important vascular structures and improved the spatial insight in aneurysmal anatomy.

CONCLUSION

Intravascular ultrasound scanning results provided accurate and reproducible measurements of abdominal aortic aneurysm. The longitudinal reconstruction of IVUS images provided additional knowledge on the anatomy of the aneurysm and its proximal and distal neck.

Endovascular abdominal aortic aneurysm repair with percutaneous transfemoral prostheses deployment under local anaesthesia. Initial experience with a new, simple-to-use tubular and bifurcated device in the first 27 cases

BACKGROUND

Modification of endografts are required to simplify and improve the safety of the endovascular management of abdominal aortic aneurysms (AAA).

OBJECTIVES

The aim of this study is to evaluate the efficacy of a new custom-made, tubular and bifurcated device.

MATERIALS AND METHODS

The graft consisted of a continuous, self-expanding, stainless steel, Z-stent structure, covered with a thin wall PTFE tube. Bifurcated grafts were constructed in vivo from three PTFE tubes with a continuous Z-stent structure. Twenty-seven high risk patients with a mean age of 74 (62-86) years and AAA, mean diameter 5.9 cm, were treated in the last 26 months. Tube grafts were deployed in 13 aortic and one iliac cases, bifurcated grafts in nine cases and aorto-uni-iliac grafts with femorofemoral bypass in four cases. Grafts were deployed percutaneously under local anaesthesia. Patients were followed with contrast CT periodically.

RESULTS

All grafts were deployed. There were no open conversions or other major complications. There were nine proximal and one distal postoperative endoleak. Four sealed spontaneously, three were treated successfully with endovascular techniques and three are under surveillance. In the 7 (2-23) months follow-up, one patient died due to heart failure 3 months post-procedure.

CONCLUSIONS

Local anaesthesia and percutaneous graft introduction simplify and improve the efficacy of the procedure. Continuous aortic graft support provides stability and reduces the risk of migration. PTFE is a flexible, low-profile material for use in endovascular stent-grafts. The bifurcation concept used offers a simple technique for bifurcated grafts.

AneuRx stent graft versus open surgical repair of abdominal aortic aneurysms: multicenter prospective clinical trial

The results of a prospective, nonrandomized, multicenter clinical trial that compared endovascular stent graft exclusion of abdominal aortic aneurysms with open surgical repair are presented. During an 18-month period, 250 patients with infrarenal aneurysms underwent treatment at 12 study sites-190 patients underwent endovascular repair using the Medtronic AneuRx stent graft (Sunnyvale, Calif), and 60 underwent open surgical repair. There was no significant difference in operative mortality rates between the groups. The patients who underwent stent grafting had significant reductions in blood loss, time to extubation, and days in the intensive care unit and in the hospital, with an earlier return to function. The major morbidity rate was reduced from 23% in the surgery group to 12% (P <. 05) in the stent graft group. There was no difference in the combined morbidity/mortality rates between the two groups. Primary technical success at the time of discharge for the patients with stent grafts was 77%, largely as a result of a 21% endoleak rate. At 1 month, the endoleak rate had decreased to 9%. There was no difference in the primary or secondary procedure success rates at 30 days between the surgery and stent graft groups. The primary graft patency rate at 6 months was 98% in the surgery group and 97% in the stent graft group. The aneurysm exclusion rate at 1 month and 6 months was 100% in patients who underwent surgery and 91% in patients who underwent stent grafting. Stent graft migration occurred in three patients and resulted in late endoleaks; each endoleak was corrected by means of endovascular placement of a stent graft extender cuff. There have been no aneurysm ruptures and no surgical conversions to open repair in the stent graft group. Stent graft repair compares favorably with open surgical repair, with a reduced morbidity rate, shortened hospital stays, and satisfactory short term outcomes.

Endovascular grafting for abdominal aortic aneurysms

Despite the initial success of endovascular grafts in a very difficult patient population, many problems remain. These procedures are often time-consuming and quite complicated, requiring the close cooperation of an experienced team of vascular surgeons and interventional radiologists. Access may be difficult through occluded, stenotic, and tortuous vessels. Inadequate graft deployment may result in arterial rupture or graft migration, which could potentially lead to acute occlusion of the renal or iliac arteries. Occlusion of the inferior mesenteric artery may result in ischemic colitis. Also, endovascular grafts may fail to exclude an aneurysm from systemic arterial blood pressure, not protecting the patient against impending rupture, and embolization and thrombosis are ever-present dangers. Concerns have been raised regarding radiation exposure and intravenous contrast loads used during these procedures. Clearly, more experience must be gained and technologic advancements made before the use of these devices becomes commonplace, something that may not be too far off in the future.

Experience with the Stentor endograft at four Italian centers

PURPOSE

To report the outcome of an Italian multicenter trial of endovascular abdominal aortic aneurysm (AAA) exclusion using the Stentor device.

METHODS

Between April 1995 and July 1996, 66 patients (63 men; average age 69 years, range 53 to 84) with infrarenal AAAs meeting the inclusion criteria were enrolled. The average diameter of the aneurysm was 4.6 cm (range 4.2 to 7). Three (4.5%) of the 66 AAAs were anastomotic aneurysms.

RESULTS

Sixteen (25%) tubular and 50 (76%) bifurcated endograft procedures were attempted; 4 (6.1%) were converted and 1 terminated owing to technical faults with the bifurcated graft's second limb. One tube graft was too short and failed to exclude an anastomotic aneurysm. Sixty (91%) endograft procedures were completed successfully. Six (9.1%) vascular complications occurred, three in one patient who subsequently died of pulmonary embolism 72 hours postoperatively (1.5% mortality). There were four (6.1%) proximal endoleaks; two sealed spontaneously in < 1 month, and a third was converted (7.6% conversion rate). The fourth is being observed. Clinical success (aneurysm exclusion with no death or endoleak) at 30 days was 86.3% (57/66). In the 23-month follow-up of 57 eligible patients, 2 patients died of unrelated causes and 1 graft limb thrombosed, requiring a crossover femoral bypass. One patient was converted to surgical repair at 5 months postoperatively when increasing aneurysm size signaled an undisclosed endoleak (1.8% late conversion rate). Five other secondary endoleaks were treated with endovascular techniques.

CONCLUSIONS

The Stentor was technically feasible in 10% to 40% of AAA candidates in this study, although deployment of the second limb was problematic in the bifurcated device. Introduction of the second-generation Vanguard endograft brought this study to an end.

Three-year experience with modular stent-graft devices for endovascular AAA treatment

PURPOSE

To evaluate feasibility and present early results of endovascular abdominal aortic aneurysm (AAA) exclusion using modular stent-grafts.

METHODS

In a 3-year period ending July 1997, 201 patients were treated with self-expanding stent-grafts for AAAs with infrarenal necks > or = 10 to 15 mm long and < or = 32 mm wide; subtotal mural thrombus, calcification, and even angulation to some extent were acceptable, as were iliac arteries up to 18 mm wide. The patients were treated with either the Stentor/Vanguard device (178 cases) or the Talent endograft (23 cases). Follow-up on all patients was conducted at 3, 6, 12, 18, and 24 months.

RESULTS

The technical aneurysm exclusion rate was 89% (178/201). There were 18 primary endoleaks (9.0%; 2 proximal, 16 distal), 4 (2.0%) conversions to open surgery, and 1 (0.5%) failure to deploy the graft. Seven (3.5%) patients died in the perioperative period, 5 due to multiorgan failure early in the series and two of hemorrhagic complications. Five (2.5%) renal artery occlusions were encountered; in one case, the graft was removed after 3 weeks. Nineteen late endoleaks were found in follow-up, related primarily to the iliac limb graft extensions of the Stentor device, graft material problems, or unknown causes. To date, 10 primary and 13 secondary endoleaks have been treated endovascularly. Twenty (10.0%) graft-limb thromboses were treated either by thrombolysis, thrombectomy, or a femorofemoral bypass.

CONCLUSIONS

Endovascular grafting is technically feasible and becomes easier with improvements of the introducer systems and the grafts. The seemingly high complication rate in this series is due to the liberal patient selection criteria.