The very first experiences in the early 1990s with endovascular aortic stent-grafts were associated with significant numbers of complications including an inability to deploy the stent-graft, conversion to open surgery, and aneurysm rupture. By the mid-1990s, improved home-made and commercially available stent-grafts started to appear. These devices could be successfully deployed in the aorta, achieving aneurysm exclusion with low morbidity and mortality. However, follow-up results raised concerns about the longer-term durability. Gradually, too, these problems have been addressed such that, in the recent UK multi-centre randomized controlled trial of endovascular versus open aneurysm repair, aneurysm-related mortality was 3 per cent less in the endovascular group four years following surgery. Currently the indications for aortic stent-grafts are being expanded. It is now possible to maintain perfusion successfully in aortic side branches and to treat aneurysms that would have once been thought untreatable. This review paper reviews the main developments in endovascular stent-grafting and the major role played by medical engineering and technology.

Purpose: To investigate the theoretical forces involved in and the nature of fixation between the modular components of a variety of aortic stent-grafts.Methods: An in vitro study of 6 aortic stent-grafts was performed using a tensometer. The modular stent-graft components were distracted until the iliac limb was completely separated from the main body. Tests were repeated at least 6 times for each stent-graft.Results: The maximum pullout force was 36.0 N using the Fortron stent-graft, which resulted in stent-graft disintegration. The maximum median forces of the other stent-grafts were 23.7 N (19.9-31.2) for the Aorfix, 7.3 IN (6.9-7.6) for the AneuRx, 7.0 N (6.8-7.1) for the Zenith BiFab, 5.4 N (5.0-6.5) for the Talent, and 2.4 N (2.2-2.4) for the Vanguard II.Conclusion:The results of this in vitro study suggest that current forms of iliac limb fixation in modular aortic stent-grafts are adequate provided the components are deployed with sufficient overlap. However, for many of the stent-grafts tested, the safety margin was small.

Aim. The aim of this paper was to report the results of a multicenter study on endovascular repair of abdominal aortic aneurysms (AAA) in patients with important angulation of proximal neck using a flexible stent-graft (Aorfix).Methods. Endovascular repair of AAA using a flexible stent-graft was performed at 16 centers in 29 patients with angulation of proximal neck greater than 45 degrees. Twenty-three patients (79%) had angulation greater than 60 degrees and were therefore contraindicated for repair with other contemporary devices.Results. Technical success was achieved in all but one case (96%). There was one postoperative death due to multiorgan failure following revision of groin wound for hemorrhage. No patients were converted to open repair. One patient had persisting proximal endoleak despite placement of proximal extension. One patient in whom wireform fractures had been detected died from ruptured aneurysm at nearly 4 year follow-up.Conclusion. Endovascular repair using a flexible stent-graft is feasible in patients with highly angulated necks. This flexible stent-graft allows the possibiity of a repair for patients unsutable for the currently available commercial grafts. Mid-term results are acceptable and need to be confirmed by longer follow-up and larger series.

Neck angulation (NA) is an important risk factor for type 1 proximal endoleaks following stenting of abdominal aortic aneurysms. The Aorfix (Lombard Medical, Oxon, UK) is a new flexible stent graft designed to overcome this issue. The aim of this study was to compare the endoleak flow rate (EFR) in relation to NA between the Aorfix and other manufactured stent grafts. A flow model with silicone proximal and distal necks was used. EFRs corresponding to 10 neck angles between 0 and 70° were measured. Eight stent grafts were tested: Aorfix, Ancure (Guidant, Indianapolis, IN), Powerlink (Endologix, Irvine, CA), AneuRx (Medtronic, Sunnyvale, CA), Excluder (W.L. Gore & Associates, Flagstaff, AZ), Zenith and Zenith-Flex (Cook Inc., Bloomington, IN), and Lifepath (Edwards Lifesciences, Irvine, CA). For all stent grafts except the Aorfix, the EFR was greater than at baseline for NA ≥ 30° (p < .01). The EFR at NA ≥ 30° was lower with the Aorfix compared with the other stent grafts (p < .01). NA had no influence on the EFR with the Aorfix. The Aorfix may decrease the incidence of proximal type 1 endoleak in patients with a severely angulated aortic neck.

AIM:First generation stent-grafts were associated with low applicability, high conversion rates due to technical failure and low durability. Second generation stent-grafts need to address these problems in order to secure endovascular aneurysm repair (EVAR) as a viable option to open repair in patients with abdominal aortic aneurysms (AAA). The early results of a second-generation stent-graft (Aorfix) for the treatment of AAA are reported.METHODS:A European multi-centre study of the Aorfix bifurcated endovascular stent-graft was performed. The Aorfix stent-grafts were inserted according to a predefined clinical protocol in 4 centres experienced in EVAR and all data was collected prospectively on a central database.RESULTS:A total of 24 patients underwent attempted aneurysm repair with the Aorfix stent-graft. There were no conversions to open repair. One technical failure resulted in insertion of another stent-graft. At 30-day follow-up there had been no secondary endovascular or open interventions. There were only 2 endoleaks, both of which were type II.CONCLUSIONS:Aorfix currently offers early results, which are at least as good as other second-generation stent-grafts. It has given satisfactory results with highly angulated proximal necks and may improve the treatment outlook for these patients. Whether the unique design features increase durability and reduce long-term complications remains to be seen.

Endovascular aneurysm repair (EVAR) is a controversial technique, which remains the subject of a number of prospective randomised trials. Although questions remain regarding its long-term durability objective evidence exists which demonstrates its reduced physiological impact compared with conventional open repair. If this technique could be used in patients with ruptured abdominal aortic aneurysm (AAA) it may reduce the high peri-operative mortality. A review of the literature identified a limited experience with EVAR of ruptured AAA. Only a small number of case series with selected patients exist. The majority of patients were haemodynamically stable. However, the selective use of aortic occlusion balloons allowed successful endovascular management in a small number of unstable cases. All investigators had access to an "off the shelf" endovascular stent-graft (EVG). Per-operative mortality ranged from 9 to 45% and may reflect increasing experience and patient selection. A number of patients who underwent successful EVAR were turned down for open repair. A number of important lessons have been learned from these studies but questions remain regarding patient suitability and staffing issues. If these difficulties can be surmounted then the technique may offer an alternative to open repair.

INTRODUCTION:abdominal aortic dilatation can occur above the graft following repair of infra-renal abdominal aortic aneurysm (AAA). This study aimed to determine the incidence and possible aetiological associations of recurrent juxta-anastomotic aneurysms following open repair of AAA.METHODS:the diameter of the infra-renal aorta above the graft of 135 patients who had previously undergone open AAA repair was determined using ultrasound. In those where the diameter was greater than 40 mm a CT scan was undertaken. Co-morbid and operative details were determined from the patients and their clinical notes.RESULTS:seven patients had true juxta-anastomotic aneurysms (>40 mm) in the residual infra-renal abdominal aorta, the occurrence of which was associated with tobacco smoking and hypertension. There was no association with other co-morbid factors, surgical operative details or the development of iliac aneurysms (which occurred in 3% of patients).CONCLUSIONS:true juxta-anastomotic aneurysms develop in the residual infra-renal neck of patients following open repair of abdominal aortic aneurysm. Tobacco smoking and hypertension are significant factors associated with the development of these aneurysms. This group of patients may warrant surveillance to prevent aneurysm rupture.

The standard surgical management of bypass graft occlusion has been thromboembolectomy with additional procedures performed as necessary to treat any underlying occlusive lesion. This approach yields rather disappointing results. Alternatively some authors advocate graft removal and replacement in an attempt to improve the outcome. The surgical management of bypass graft occlusion is associated with significant morbidity and mortality. Many patients are simply too frail to undergo further major arterial bypass surgery. With an aggressive surgical approach only 12% of patients will be alive at five years (1). Thrombolysis was popularised in the 1970s by Dotter as an endovascular method of restoring patency in native artery occlusions. The minimally invasive nature of thrombolysis, its potential to reveal occlusive lesions amenable to endovascular therapy and restore flow in thrombosed distal vessels became established. Later, reports emerged regarding its use in the management of bypass graft occlusion.

OBJECTIVE:Endovascular repair (EVR) of abdominal aortic aneurysm (AAA) is being performed with increasing frequency worldwide. No studies have a complete follow-up of more than 4 years. Our study objective was to assess the long-term results and the durability of a first-generation stent graft with complete 7-year follow-up.METHODS:Between March 1994 and May 1995, 23 consecutive patients underwent treatment with the Chuter stent graft at a single center. All patients underwent computed tomographic scan before discharge, at 3 and 6 months, and annually thereafter. The data were prospectively collected on all patients. The median follow-up period was 72.5 months (range, 0.2 to 91 months). None of the patients were lost to follow-up.RESULTS:Among these 21 men and two women with a median age of 69 years (range, 52 to 85 years), 11 (47.8%) were at high risk. The 30-day technical success rate was 87%. Acute (30-day) complications were one graft deployment failure (4.3%) that necessitated an immediate conversion, 20 intraoperative graft limb kinks (87%), all of which needed additional Wallstent (Schneider, Minneapolis, Minn) placement, four renal failures (17.4%), one type Ia endoleak complicated with AAA rupture (4.3%), and three perioperative deaths (13%). Late complications were eight type I or II endoleaks (34.8%) after a mean delay of 23.9 months (range, 3 to 69 months), 13 proximal stent migrations (56.5%) after a mean delay of 29.6 months (range, 7 to 58 months), six graft limb thromboses (26.1%) after a mean delay of 38.7 months (range, 3 to 71 months), one AAA rupture (4.3%), and 11 deaths (47.8%), with five AAA-related deaths (21.7%). The 3-year, 5-year, and 7-year cumulative endoleak rates were 34%, 41%, and 49%, respectively; the cumulative migration rates were 66%, 75%, and 75%, respectively; and the cumulative open surgery rates were 30%, 50%, and 50%, respectively. At the same intervals, the cumulative survival rates for any death were 69%, 56%, and 49%, respectively; the cumulative survival rates for AAA-related deaths were 82%, 82%, and 73%, respectively; and the cumulative secondary success rates were 54%, 28%, and 28%, respectively.CONCLUSION:This studies emphasizes the need for close lifelong surveillance of AAAs treated with EVR. Despite the small population of this series, a long-term follow-up highlights that the first-generation homemade stent graft evaluated in this study failed to adequately protect the patient from AAA-related death and that most of the serious complications were related to a late failure of the aortic neck attachment. Better proximal fixation of the aortic stent graft is essential to improve the durability of EVR.

Purpose: To assess the anatomical suitability of ruptured abdominal aortic aneurysms (AAA) for emergency endovascular repair. Methods: All cases (46 patients [35 men; mean age 74 years, range 54–85]) in which computed tomographic angiography (CTA) confirmed AAA rupture over a 5-year period at our university hospital were reviewed for anatomical suitability for endovascular repair. Measurements were made by a radiologist experienced in anatomical assessment of CT criteria for elective endovascular aneurysm repair (EVAR). Results: The mean aneurysm neck length was 18 mm (range 0–59); 17 were conical, 13 straight, 4 barrel, and 6 reverse conical. Six cases had no proximal neck. Overall, 37 (80%) patients were unsuitable for EVAR according to our criteria. Nearly half the patients (22, 48%) had ≥2 adverse features. Unsuitable neck morphology (35, 76%) was the primary reason for exclusion, but CIA aneurysm (10, 22%) and EIA tortuosity (7, 15%) were secondary adverse features. Conclusions: With current stent-graft design, the majority of ruptured abdominal aortic aneurysms are anatomically unsuitable for endovascular repair.

Introduction: Endovascular aneurysm repair (EVAR) with aortouniiliac prostheses extends the morphologic range of aneurysms that can be treated and is potentially a more rapid and simple operation than bifurcated endovascular repair. It may, however, be limited by durability of the femorofemoral extra-anatomic bypass graft required to revascularize the contralateral lower limb. Previous studies of femorofemoral bypass grafts were performed almost exclusively in patients with occlusive disease. An 8-year single center experience with use of the femorofemoral bypass graft in aneurysmal disease is reported.Methods. All patients undergoing EVAR with an aortouniiliac endovascular stent graft over eight years (1994-2002) at a single institution were included in a retrospective study. Patient data were collected from a prospectively maintained local endovascular database. All patients gave informed consent and were part of an endovascular program approved by the local ethics committee.Results. Over the 8 years, 231 patients underwent EVAR with an aortouniiliac endovascular stent-graft. Median follow-up was 22 months. Localized wound complications were observed in 25 patients (11%). Cumulative 3-year patency rate for the femorofemoral bypass graft was 91%. At the end of 5-years 83% of grafts remained patent.Conclusions. The femorofemoral bypass graft used during EVAR with aortouniliac stent grafts offers encouraging medium and long-term patency. When graft occlusion occurs, it is usually directly attributable to inadequate inflow from the endovascular stent graft itself or to endoluminal damage of the external iliac artery. Awareness and early detection of stent-graft distortion or complications in the external iliac artery may result in improved patency rates.

Introduction: Endovascular aneurysm repair (EVAR) has been suggested as a technique to improve outcome of ruptured abdominal aortic aneurysm (AAA). Whether this technique becomes an established treatment will depend, in part, on the anatomy of ruptured AAA.Methods: The anatomy of intact and ruptured AAA seen in a university department of vascular surgery over 5 years was reviewed. Aneurysm anatomy was assessed with spiral computed tomographic angiography. Suitability for EVAR was assessed from the dimensions of the proximal neck and common iliac arteries. Neck length less than 15 mm, neck width greater than 30 mm, and common iliac artery diameter greater than 22 mm were declared unsuitable for EVAR.Results: Three hundred sixty-three patients with intact AAA and 46 with ruptured AAA were identified. Larger intact aneurysms were significantly associated with longer renal artery-bifurcation distance and more complex proximal neck architecture. In this sample, patients with ruptured AAA were more likely to have larger aneurysms with shorter and narrower proximal necks. Significantly more intact aneurysms were morphologically suitable for endovascular repair compared with ruptured AAA (78% vs 43%; P < .001).Conclusions: Ruptured AAA are less likely to be suitable for endovascular repair than are intact AAA, most probably because of larger diameter at presentation. Open repair will likely remain the treatment of choice in most patients with ruptured AAA, because of current morphologic constraints of endovascular repair.

Purpose: To report the successful repair of a ruptured pseudoaneurysm of the infrarenal abdominal aorta secondary to pancreatitis Case Report: A 47-year-old man was admitted with abdominal pain due to an acute exacerbation of chronic alcoholic pancreatitis. He was found to have an infrarenal abdominal aortic aneurysm, which was confirmed by spiral computed tomography (CT), but there had been no evidence of aneurysm formation on a scan performed 1 year previously. Persistent symptoms prompted a further CT scan 48 hours later; this revealed evidence of a ruptured infrarenal abdominal aortic pseudoaneurysm. The pseudoaneurysm was excluded using a Zenith aortomonoiliac endovascular graft. Recovery was uneventful, and the patient underwent pancreatic resection 6 months later. A duplex scan 10 months after endograft placement could not identify an aneurysm sac. Conclusions: In selected cases, endovascular repair provides a useful method of excluding ruptured aortic pseudoaneurysms due to pancreatitis. It allows hemorrhage control in a potentially infected operative field and permits elective pancreatic resection. Prolonged follow-up is mandatory to ensure there is no evidence of graft sepsis and that aneurysm exclusion is maintained.

We read with interest the article written by Baum et al (J Vasc Surg 2001;33;32-41) and congratulate them on presenting some valuable data. Type 2 endoleaks are becoming a difficult management problem. We are now realizing that they might not be as benign as originally thought, being capable of transmitting systemic and pulsatile pressure, therefore risking sac rupture. In Nottingham we have been performing intrasac injections of contrast (aneurysmograms or “sacograms”) to detect type 2 endoleaks for 3 years.1Walker SR Macierewicz J Hopkinson BR Endovascular AAA repair: prevention of side branch endoleaks with thrombogenic sponge.J Endovasc Surg. 1999; 6: 350-353Crossref PubMed Scopus (50) Google Scholar The method we use is an endovascular one in which we gain access to the aneurysm sac intraoperatively via the contralateral common iliac artery. We have found the sacogram to be a useful predictor of subsequent type 2 endoleak.2Lehmann JM Macierewicz JA Davidson IR Whitaker SC Wenham PW Hopkinson BR Prevention of side branch endoleaks with thrombogenic sponge: one year follow-up.J Endovasc Ther. 2000; 7: 431-433Crossref PubMed Google Scholar If the sacogram shows patent side branch vessels, we go on to fill the aneurysm sac with polyvinyl alcohol sponge, thus obviating the need for further intervention. Using this method of intraoperative sacogram and aneurysm packing, we have reduced our type 2 endoleak rate from 9% to 1.3% (at completion of 2-year follow-up in 149 patients using our original, absorbable thrombogenic agent, Spongostan).3Hinchliffe RJ, Hopkinson BR. Experimental and clinical benefits by packing aneurysms after endografting. Proceedings of the 6th International Symposium on Critical Issues in Endovascular Surgery; 2001 Feb 23; Leiden, the Netherlands.Google Scholar The results in Dr Baum's article have ignited further interest in intrasac embolization and aneurysm packing; however, we agree that the material of choice should be carefully chosen. Our method of packing the aneurysm sac was originally only applicable to uniiliac devices. It was feared that with bifurcated devices a large sheath would be required to be advanced between an iliac limb and the common iliac artery. More recently, we have devised a method of packing an aneurysm sac after bifurcated endovascular repair. Using smaller “bullets” of polyvinyl alcohol sponge, we have decreased the diameter of the introducer sheath to 11F and thus reduced the likelihood of injury to the iliac artery or disruption of the endograft limb.

PURPOSE:To classify and analyze the volumetric changes seen on spiral computed tomographic angiography (CTA) following endovascular abdominal aortic aneurysm (AAA) repair.METHODS:Fifty patients (46 men; mean age 71 years, range 51-83) with >1 year of imaging follow-up were retrospectively selected. The volume of the aneurysm sac was calculated on standard CT workstations to obtain plots of volume changes over time. For the purpose of this study, a 10% change in sac volume was considered significant.RESULTS:Over a mean 32-month follow-up, 256 CTA scans were performed; initial mean sac volume was 259 mL and initial mean AAA diameter was 6.5 cm. Six distinct patterns of volume change were recognized: group Ia (28 patients, 56%): progressive reduction in aneurysm sac volume; group Ib (3 patients, 6%): transient initial increase then same as Ia; group II (4 patients, 8%): no significant change; group IIIa (5 patients, 10%): late increase in volume; group IIIb (8 patients, 16%): progressive increase in volume; and group IV (2 patients, 4%): late reduction in volume after secondary intervention. Group III changes were associated with endoleak types I and III (p<0.0001).CONCLUSIONS:This classification system of spiral CTA volumetric changes features 6 patterns with recognized clinical significance and predictive value for endoleaks. Group I is the ideal outcome when the aneurysm sac shrinks and often completely disappears, while group III is associated with types I and type III endoleak and should prompt further investigation. Long-term volumetric analysis of all patients is advised.

INTRODUCTION Endovascular aneurysm surgery (EVAR) was introduced a decade ago. Early results are promising, however, there remain concerns regarding the longer-term durability of this technique. Consequently, the national multi-centre EVAR trial has been commenced to define the role of endovascular surgery in the management of abdominal aortic aneurysm. DISCUSSION Successful EVAR requires accurate pre-operative assessment of aneurysm morphology. Current stent-grafts allow 60% of all infra-renal AAA to be treated. Reduced physiological stress and low peri-operative morbidity and mortality rates have been demonstrated with this technique when compared to open repair. Endoleak is an Achilles heel of EVAR, although in itself does not accurately predict outcome. First and second generation devices are estimated to have a 1% per year risk of rupture. CONCLUSIONS Increased understanding of the issues surrounding aneurysm morphology and successful stent-grafting have allowed a major reduction of early type I endoleak. Late endoleak and graft migration remain problematic. Type I and III endoleaks are risk factors for subsequent rupture although the significance of type II endoleak remains uncertain. More robust indicators of outcome success/failure are required so that follow-up may be rationalised.