Elective sac perfusion to reduce the risk of neurologic events following endovascular repair of thoracoabdominal aneurysms.

Spinal cord ischemia (SCI) is a catastrophic complication of thoracoabdominal aortic aneurysm (TAAA) repair. This article describes our early experience with a technique for maintaining perfusion of segmental vessels (intercostals and lumbars) in the early postoperative period after endovascular repair of a TAAA, with "sac perfusion branches" added to custom-made stent grafts. These are closed 7 to 10 days after the first procedure to complete exclusion of the aneurysm. We have used this technique in 10 patients with type II TAAAs. One developed monoparesis of the right leg during a period of hypotension secondary to a cardiac event and died within 30 days. Two patients developed lower limb weakness after closure of the perfusion branches, both with full recovery. Controlled perfusion of segmental vessels with perfusion branches is feasible and may be a useful adjunct to prevent SCI, providing protection to spinal cord perfusion during the immediate postoperative period when risk of SCI is greatest.

Placement of a branched stent graft into the false lumen of a chronic type B aortic dissection.

The treatment of chronic type B aortic dissections remains challenging and controversial. Currently most centers advocate open or endovascular intervention for patients with evidence of malperfusion, rupture or impending rupture, continued pain, or aneurysm formation. Regardless of the type of intervention, the incidence of complications or death remains high, even when undertaken in an elective setting. The standard endovascular treatment usually involves placement of a stent graft into the true lumen of the dissection in an effort to exclude the false lumen. This case report describes the placement of a branched stent graft into the false lumen of a patient with chronic type B dissection to encourage exclusion and thrombosis of the true lumen whilst maintaining flow to all visceral vessels.

Early outcome following endovascular repair of pararenal aortic aneurysms: triple- versus double- or single-fenestrated stent-grafts.

PURPOSE: To review the early outcome following endovascular repair of pararenal aortic aneurysm using fenestrated stent-grafts and to determine if the number of fenestrations required is predicative of outcome. METHODS: A retrospective analysis was conducted of 20 consecutive patients (18 men; mean age of 75 ± 7 years) treated with stent-grafts containing either ≤ 2 fenestrations (n = 10, group 1) or 3 fenestrations (n = 10, group 2). Target vessels also included those accommodated by a scallop (renal artery or superior mesenteric artery in group 1 and the celiac artery in group 2). RESULTS: Comorbidities were similar in both groups. Aneurysm size [median 6.9 (IQR 6.7-8.3) versus 6.0 cm (IQR 5.8-6.6), p = 0.03], procedure time (mean 6.6 ± 2.1 versus 4.6 ± 1.7 hours, p = 0.04), and intensive care stay [median 4.5 (IQR 2-14) versus 2 (IQR 1-3) days, p = 0.07] were greater in group 2. There were 2 postoperative deaths, both in group 2. Morbidity was significant and similar in both groups (4 patients in group 1 and 3 patients in group 2), including 1 patient requiring long-term hemodialysis. Target vessel preservation was similar in both groups (96% overall). There were 2 type II endoleaks (one in each group) and no type I or III endoleak. CONCLUSION: Triple-fenestrated stent-grafts allow patients with extensive pararenal aneurysms and significant comorbidity to be treated by endovascular means. Although the number of patients treated was small, which limited the validity of the comparison, longer procedures and greater early morbidity and mortality were seen in the triple-fenestrated group. At present, the procedures are technically more demanding and associated with increased risk compared with double or single fenestrations, but the technology continues to evolve.

Temporary axillobifemoral bypass as an adjunct to endovascular aneurysm repair using fenestrated stent grafts.

Prolonged endovascular procedures requiring a large diameter sheath in each groin can be associated with significant intraoperative lower limb ischemia, particularly in those with pre-existing peripheral vascular disease. We report the case of a patient who suffered severe ischemia-reperfusion injury following endovascular repair of a pararenal aortic aneurysm using a fenestrated stent graft and describe the use of temporary axillobifemoral bypass in a patient with similar comorbidities undergoing the same procedure. We propose this adjunctive technique as a means of maintaining antegrade limb perfusion and avoiding the peripheral and central metabolic consequences of ischemia-reperfusion injury.

Preloaded fenestrated stent-grafts for the treatment of juxtarenal aortic aneurysms.

PURPOSE: To describe a novel technique for target vessel catheterization in patients with juxtarenal abdominal aortic aneurysms requiring treatment with fenestrated stent-grafts (FSG). METHODS: The standard FSG design was modified, substituting a thin-wall tube for the solid central obturator that serves as both an attachment point for the distal end of the graft as well as a top cap retriever. Through this tube, two 0.020-inch wires are run from the hub of the delivery system through the stent-graft, out through each fenestration, and up to the proximal edge of the graft, where they are attached by sutures. The sutures are connected to a trigger wire on the control hub. The preloaded wires facilitate passage of a sheath to the fenestration, providing stability while target vessel catheterization takes place and avoiding the use of a large sheath in the contralateral groin. A third wire attached to the inside of the top cap facilitates its safe retrieval via a 6-mm balloon. The preloaded FSG was used in 5 male patients (mean age 75.6 years) with either juxtarenal aneurysms (n = 2) or aneurysms previously treated with infrarenal stent-grafts that had developed type I endoleak (n = 3). In 3 cases, a double fenestrated stent-graft was required, and in 2 cases a triple fenestrated device was deployed, with scallops for the superior mesenteric or celiac arteries. RESULTS: Sixteen of 17 target vessels were preserved, and all aneurysms were successfully excluded with no endoleak at completion. In 2 patients, tortuosity encountered during device delivery caused twisting of the wires within the preloaded FSG, preventing successful advancement of a sheath over a preloaded wire. An approach from the contralateral groin was necessary to complete the procedure in 1 case, but the target vessel was lost in the other. CONCLUSION: The use of a preloaded FSG is feasible and facilitates the catheterization of fenestrations and of target arteries. This method has the potential to reduce procedure times and lower the risk of intraoperative lower limb ischemia.

In situ fenestration in the aortic arch.

In situ fenestration of aortic stent grafts has the potential to allow for continued perfusion of supra-aortic trunks, without the need for extra-anatomic bypass, and without the need for custom-made devices. Angulation of the target vessel relative to the arch is an obstacle to success with this technique. In this report, we describe a case of successful in situ fenestration of the left subclavian artery (LSA) in a patient with an aortic arch aneurysm, treated with an endovascular stent graft. We outline a novel technique using through and through wire access and a pre-curved semi-rigid sheath, which allows successful access to the lumen of the aortic stent graft, despite an acute angle at the take-off of the LSA.

Endovascular repair of abdominal aortic aneurysms with concomitant common iliac artery aneurysm: outcome analysis of the EUROSTAR Experience.

BACKGROUND: To compare outcomes following endovascular repair in abdominal aortic aneurysm (AAA) patients with and without concomitant iliac artery aneurysm disease. METHODS: Data on patient characteristics and risk factors, aneurysm morphology, interventional details, complications, and mortality were retrieved from the EUROSTAR registry database for the period from October 1996 to November 2006. AAA patients without concomitant iliac aneurysm disease (group I, n = 6286) were compared to 1268 patients with aneurysmal iliac vessels (group II) regarding mortality, device-related complications, and need for secondary interventions. Logistic regression and Cox proportional hazards model were performed to assess independent associations with outcome parameters in the study groups. RESULTS: Group II had more patients classified as ASA III or IV (55.1% versus 50.3% in group I; p = 0.002); they were more frequently unfit for open aortic repair (30.3% versus 23.4%; p<0.0001) and had larger-diameter aneurysms (62.3 versus 60.7 mm; p<0.0001) and infrarenal necks (24.5 versus 24.1 mm; p<0.001). In addition, group II patients had a higher rate of internal iliac artery occlusion (11.4% versus 5.2%; p<0.0001) and more significant angulation of the aortic neck (30.8% versus 24.3%; p<0.0001) and iliac artery (48.3% versus 41.9%; p<0.0001). Group II patients had higher 5-year cumulative incidences of distal type I endoleaks (9.1% versus 4.3%; p<0.0001), iliac limb occlusion (5.9% versus 4.4%; p = 0.040), secondary transfemoral intervention (17.6% versus 8.9%; p = 0.019), and aneurysm rupture (4.5% versus 1.7%; p = 0.042). CONCLUSION: Although aneurysm-related mortality and mortality from other causes were similar in both study groups, concomitant iliac artery aneurysms in AAA patients were associated with an increased incidence of distal type I endoleak, iliac limb occlusion, and aneurysm rupture. Therefore, caution is warranted, and efforts should be made to avoid procedural mishaps.

Neurologic complications associated with endovascular repair of thoracic aortic pathology: Incidence and risk factors. a study from the European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry.

OBJECTIVE: Endovascular treatment of thoracic aortic disease may be associated with severe neurologic complications. The current study used the data of a multicenter registry to assess of the incidence and the risk factors for paraplegia or paraparesis and intracranial stroke. METHODS: The European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) database prospectively enrolled 606 patients. Thoracic pathologies with urgent or elective presentation, which included degenerative aneurysm in 291, aortic dissection in 215, traumatic rupture in 67, anastomotic false aneurysm in 24, and infectious or nonspecified disorders in 9. Study end points included evidence of perioperative spinal cord ischemia (SCI) or stroke. Univariate analysis and multivariate regression models were used to assess the significance of clinical factors that potentially influenced the occurrence of neurological sequelae. RESULTS: Paraplegia or paraparesis developed in 15 patients (2.5%) and stroke in 19 (3.1%); two patients had both complications. At multivariate regression analysis, independent correlation with SCI was observed for four factors: (1) left subclavian artery covering without revascularization (odds ratio [OR], 3.9; P = .027), (2) renal failure (OR, 3.6; P = .02), (3) concomitant open abdominal aorta surgery (OR, 5.5; P = .037) and (4) three or more stent grafts used (OR, 3.5; P = .043). In patients with perioperative stroke, two correlating factors were identified: (1) duration of the intervention (OR, 6.4; P = .0045) and (2) female sex (OR, 3.3; P = .023). A neurologic complication (paraplegia or stroke) developed in 8.4% of the patients in whom left subclavian covering was required compared with 0% of patients with prophylactic revascularization (P = .049). CONCLUSION: Perioperative paraplegia or paraparesis was significantly associated with blockage of the left subclavian artery without revascularization. The clinical significance of this source of collateral perfusion of the spinal cord had not been confirmed previously. Intracranial stroke was associated with lengthy manipulation of wires, catheters, and introducer sheaths within the aortic arch, reflected by a longer duration of the procedure.

Comparison of the fixation strength of standard and fenestrated stent-grafts for endovascular abdominal aortic aneurysm repair.

PURPOSE: To determine whether fenestrated stent-grafts provide better stability to resist migration than standard non-fenestrated stent-grafts. METHODS: Truncated fenestrated stent-grafts with a single fenestration were deployed in bovine aortic segments with a side branch. Balloon-expandable stents were then delivered into the branches. Similarly, standard stent-grafts of the same dimensions were deployed for comparison. The aorta was pressurized to achieve stent-graft oversizing of 5%, 10%, or 20%. The force required to cause distal migration was recorded by a digital force gauge attached to the stent-graft. RESULTS: Displacement of the stent-grafts occurred in 2 distinct phases: an initial yield during which the barbs embedded in the aortic wall and a final displacement leading to significant migration and dislodgement of the device. The displacement force that initiated each phase was dependent upon the degree of oversizing of the stent-graft relative to the aortic diameter. For 5%, 10%, and 20% oversizing, the mean displacement forces in the initial displacement phase were 3.39+/-0.37, 4.32+/-0.63, and 7.69+/-1.18 N, respectively, in non-fenestrated grafts and 10.48+/-1.23, 11.45+/-1.48, 12.12+/-1.42 N in fenestrated grafts. The displacement forces in the final displacement phase were 8.10+/-0.92, 10.76+/-1.74, and 16.82+/-0.92 N for non-fenestrated and 22.56+/-1.60, 28.24+/-1.56, and 33.01+/-1.75 N for fenestrated stent-grafts. The differences in displacement forces between standard and fenestrated stent-grafts were significant for both phases (p<0.001) at all oversizing levels. CONCLUSION: Improvement in fixation strength was noted with increasing stent-graft oversizing of up to 20%. Fenestrated stent-grafts offer higher ultimate fixation compared to standard devices. However, the ultimate fixation strength was not recruited until an initial phase of short migration occurred as the barbs engaged. While this movement is inconsequential with standard stent-grafts, it has the potential to crush the stents placed into aortic side branches with fenestrated endografts.

Secondary interventions after elective endovascular repair of degenerative thoracic aortic aneurysms: results of the European collaborators registry (EUROSTAR).

PURPOSE: The need for secondary interventions is an important indicator of intermediate and long-term success of endovascular repair of degenerative thoracic aortic aneurysm. The purpose of this study was to analyze the occurrence and consequences of secondary procedures. MATERIALS AND METHODS: Data from 213 patients electively subject to operation for degenerative thoracic aortic aneurysm and achieving primary success and who were enrolled in the EUROSTAR registry were analyzed. Secondary procedures were categorized as follows: transfemoral endovascular reintervention, extraanatomic secondary procedures, and transthoracic surgery. RESULTS: Overall, 25 (12%) of the patients with an elective treatment for a degenerative thoracic aneurysm had secondary intervention, occurring at a mean of 8 months after the initial procedure. Seventeen (68%) of the secondary interventions were via a transfemoral approach, six (24%) involved a transthoracic procedure, and two (8%) involved extraanatomic bypass. The cumulative percentage of freedom from intervention at 1 and 2 years was 86% and 83%, respectively. Endoleak (relative risk, 5.21) was the most frequent cause for secondary transfemoral intervention. For the other secondary interventions, no principal indication for reintervention could be identified. Patients who needed secondary interventions more frequently suffered from preoperative back pain (20% vs 44%, P = .008), and their thoracic aneurysms had a longer length (mean, 95.6 mm vs 133.2 mm, P = .006). The 2-year cumulative survival rate of patients without secondary intervention was 85% compared with 58% in the patients who received secondary intervention (P = .0001). CONCLUSIONS: Regular surveillance after endovascular degenerative thoracic aneurysm repair is needed as secondary interventions were required throughout the follow-up period.

Statin use is associated with reduced all-cause mortality after endovascular abdominal aortic aneurysm repair.

It has been shown that preoperative statin therapy reduces all-cause and cardiovascular mortality in patients undergoing major noncardiac vascular surgery. In this report, we investigated the influence of statin use on early and late outcome following endovascular abdominal aortic aneurysm repair (EVAR). The study population, consisting of patients collated in the EUROSTAR registry, was stratified in two groups according to statin use. Baseline characteristics between the two groups were compared by chi-square and Wilcoxon rank sum tests for discrete and continuous variables. The effects of statin use on outcomes after EVAR were analyzed by multivariate regression models. Of the 5,892 patients enrolled in the EUROSTAR registry, 731 (12.4%) patients used statins for hyperlipidemia. Statin users were younger, were more obese, and had a higher prevalence of diabetes, cardiovascular disease, and hypertension. After 5 years of follow-up, the cumulative survival rate was 77% for nonusers of statin versus 81% for statin users (p = .005). After adjustment for age and other risk factors, statin use was still an independent predictor of improved survival (p = .03). Our results revealed that statin prescription was more frequent in younger patients. However, when adjusted for age and medical risk factors, the use of statin in patients who underwent EVAR was still independently associated with reduced overall mortality.

Risk-adjusted outcome analysis of endovascular abdominal aortic aneurysm repair in a large population: how do stent-grafts compare?

PURPOSE: To compare differences in the applicability and incidence of postoperative adverse events among stent-grafts used for repair of infrarenal aortic aneurysms. METHODS: An analysis of 6787 patients from the EUROSTAR Registry database was conducted to compare aneurysm morphological features, patient characteristics, and postoperative events for the AneuRx, EVT/Ancure, Excluder, Stentor, Talent, and Zenith devices versus the Vanguard device (control) and each other. Annual incidence rates of complications were determined, and risks were compared using the Cox proportional hazards analysis. RESULTS: The annual incidence rates were: device-related endoleak (types I and III) 6% (range 4%-10%), type II endoleak 5% (range 0.3%-11%), migration 3% (range 0.5%-5%), kinking 2% (range 1%-5%), occlusion 3% (range 1%-5%), rupture 0.5% (range 0%-1%), and all-cause mortality 7% (range 5%-8%). After adjustment for factors influencing outcome, AneuRx, Excluder, Talent, and Zenith devices were associated with a lower risk of migration, kinking, occlusion, and secondary intervention compared to the Vanguard device. Significant increased risk for conversion (EVT/Ancure) and reduced risk of aneurysm rupture (AneuRx and Zenith) and all-cause mortality (Excluder) were found compared to the Vanguard device. CONCLUSIONS: Significant differences exist between stent-grafts of different labels in terms of applicability and complications during intermediate to long-term follow-up. Since each stent-graft has its drawbacks, no single label can be identified as the best. It is reassuring that developments in stent-grafts indeed result in better performance than the early stent-grafts. However, a single device incorporating all the perceived improvements should still be pursued.

Flow visualization in a model of a bifurcated stent-graft.

PURPOSE: To use an in vitro flow model to investigate the flow patterns in a bifurcated stent-graft for abdominal aortic aneurysm (AAA) repair. METHODS: Experiments were performed in an in vitro test rig incorporating a simplified non-planar model of an AAA. A two-component bifurcated device consisting of a stent structure and transparent polyurethane "graft" was deployed in the AAA model. Using a blood analogue fluid, a pulsatile blood flow waveform simulating resting flow condition was produced by means of a piston pump system. Flow patterns in the lateral and anteroposterior planes of the stent-graft were recorded and analyzed using flow visualization techniques. RESULTS: The flow patterns within the stent-graft were complex and influenced by the geometry of the stent-graft itself, as well as that of the aortic neck and iliac vessels. Regions of flow separation, low velocity and stagnation, and slow oscillatory flow near the walls were seen in the main body of the stent-graft. Constriction at the stump in the contralateral limb resulted in flow disturbances and flow separation. Kinking at the junctions of stent segments and folding of the graft compounded these complex flow structures. CONCLUSIONS: The flow structures within stent-grafts are complex, with features that may predispose to thrombus formation. Arterial geometry, including aortic neck angulation and iliac vessel tortuosity, and the design of the stent-graft are factors that influence hemodynamics and may impact the performance of aortic stent-grafts.

Heterogeneity of tensile strength and matrix metalloproteinase activity in the wall of abdominal aortic aneurysms.

PURPOSE: To measure the tensile strength of the aneurysm wall and the matrix metalloproteinase (MMP) activity in similar samples of aortic tissue. METHODS: Detailed mechanical testing was conducted on 124 standardized specimens of aneurysm wall harvested from 24 patients undergoing elective aneurysm repair. The intrasac pressure required to cause aneurysm rupture was calculated based upon the Law of Laplace. In addition, MMP-2 and 9 were assayed from these specimens. Sixty specimens of nonaneurysmal aorta from 6 cadaveric organ donors served as controls. Intrasubject and intersubject variations were analyzed. RESULTS: In the aneurysm specimens, the Young's modulus was 1.80x10(6) N/m(2), the load at break was 6.36 N, the strain at break was 0.30, the ultimate strength was 0.53x10(6) N/ m(2), and the MMP activity was 312 for MMP-2 and 460 for MMP-9. In the controls, the circumferential measurements were a Young's modulus of 1.82x10(6) N/m(2), a load at break of 5.43 N, strain at break of 0.29, ultimate strength of 0.61x10(6) N/m(2), and MMP activity of 395 for MMP-2 and 2019 for MMP-9. Longitudinal measurements in controls were a Young's modulus of 1.38x10(6) N/m(2), a load at break of 11.39 N, a strain at break of 0.33, and ultimate strength of 1.30x10(6) N/m(2). Intra and intersubject variation of all parameters was very high. Based upon the lowest measured tensile strength for each aneurysm, the intrasac pressure required to cause rupture varied from 142 to 982 mmHg. CONCLUSIONS: Localized "hot spots" of MMP hyperactivity could lead to focal weakening of the aneurysm wall and rupture at relatively low levels of intraluminal pressure. These data suggest that tensile strength of the sac is just as important as intrasac tension in determining the risk of rupture. Moreover, these observations may explain why some small aneurysms rupture and larger aneurysms do not. Assessment of rupture risk based on computation or measurement of wall stress may be subject to error and inaccuracy due to variations in wall tensile strength.

An update on the important findings from the EUROSTAR EVAR registry.

This article summarizes the important findings to emerge from the European Collaborators on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR) Registry since its inception in 1996. The Registry is an open observational study of the outcomes from endovascular aneurysm repair (EVAR). Data have been contributed, on a voluntary basis, by 135 vascular centers from 18 European countries. Patients are registered prospectively, and data analysis is on an intention-to-treat basis. Results from the first generations of endograft were characterized by excellent early results but poor durability of abdominal aortic aneurysm repair. EUROSTAR data have played a vital role in informing the technical evolution of subsequent generations of endograft and their clinical application. The latest data from EUROSTAR show significant improvements in all outcome measures, most importantly, those relating to durability. EUROSTAR has tracked and informed the evolution of EVAR. Improving results confirm that substantial progress has been made since 1996. EUROSTAR continues to contribute to this ongoing process.

In situ stent-graft fenestration to preserve the left subclavian artery.

PURPOSE: To report our first clinical application of a new technique for in situ fenestration of a thoracic stent-graft. CASE REPORT: After completing a series of in vitro and in vivo experiments, in situ stent-graft fenestration was employed during endograft repair of a saccular thoracic aortic aneurysm in a 77-year-old woman. Because the stent-graft would have covered the left subclavian artery ostium, a modified Zenith TX1 thoracic stent-graft was deployed then fenestrated transluminally using a guidewire followed by serial cutting balloons, which created a fenestration over the LSA sufficiently large to accommodate a Jomed covered stent on an 8-mm balloon. Completion angiography showed exclusion of the aneurysm and brisk flow into the LSA. Following the procedure, the arm pressures were nearly equal. The 6-month CT scan showed no endoleak and a patent subclavian artery stent. CONCLUSIONS: In situ graft fenestration to preserve the left subclavian artery after deliberate coverage during endovascular repair of a thoracic aortic aneurysm appears feasible in this initial clinical application. There are uncertainties regarding the long-term stability of the fabric tears that are an inherent part of this technique.

Diameter of abdominal aortic aneurysm and outcome of endovascular aneurysm repair: does size matter? A report from EUROSTAR.

OBJECTIVES: This study was undertaken to determine the effect of the preoperative diameter of abdominal aortic aneurysms on the midterm outcome after endovascular abdominal aneurysm repair (EVAR). METHOD: The data for 4392 patients who had undergone EVAR were analyzed. Patients were enrolled over 6 years to June 2002 in the EUROSTAR database. Outcomes were compared between three groups defined by the preoperative diameter of the aneurysm: group A (n = 1962), 4.0 to 5.4 cm; group B (n = 1528), 5.5 to 6.4 cm; and group C (n = 902), 6.5 cm or larger. Patient characteristics, details of aortoiliac anatomy, operative procedures, old or current device generation, and postoperative complications in the three patient groups were compared. Outcome events included aneurysm-related death, unrelated death, conversion, and post-EVAR rupture of the aneurysm. Life table analysis and log-rank tests were used to compare outcome in the three study groups. Multivariate Cox models were used to determine whether baseline and follow-up variables were independently associated with adverse outcome events. RESULTS: Patients in group C were significantly older than patients in groups A and B (73 years vs 70 and 72 years, respectively; P =.003 - P <.0001 for different group comparisons), and more frequently were at higher operative risk (American Society of Anesthesiologists classification >or=3; 63% vs 48% and 54%; P =.0002-P <.0001). Device-related (type I) endoleaks were more frequently observed at early postoperative arteriography in group C compared with groups A and B (9.9% vs 3.7% and 6.8%; P =.01-P <.0001). Postoperatively systemic complications were more frequently present in group C (17.4% vs 12.0% in group A and 12.6% in group B; P <.0001 and.001). The first-month mortality was approximately twice as high in group C compared with the other groups combined (4.1% vs 2.1%; P <.0001). Late rupture was most frequent in group C. Follow-up results at midterm were less favorable in groups C and B compared with group A (freedom from rupture, 90%, 98%, and 98% at 4 years in groups C, B, and A, respectively; P <.0001 for group C vs groups A and B). Aneurysm-related death was highest in group C (88% freedom at 4 years, compared with 95% in group B and 97% in A; P =.001 and P <.0001, respectively; group B vs A, P =.004). The annual rate of aneurysm-related death in group C was 1% in the first 3 years, but accelerated to 8.0% in the fourth year. Incidence of unrelated death also was higher in groups C and B than in group A (76% and 82% freedom at 4 years vs 87%; P <.0001 for both comparisons). Ratio of aneurysm-related to unrelated death was 23%, 21%, and 50% in groups A, B, and C, respectively. Cox models demonstrated that the correlation between large aneurysms (group C) and all assessed outcome events was independent and highly significant. Older generation devices had an independent association with aneurysm-related and unrelated deaths (P =.02 and P =.04, respectively). However, this correlation was less strong than large aneurysm diameter (P =.0001 and P =.0009, respectively). CONCLUSIONS: The midterm outcome of large aneurysms after EVAR was associated with increased rates of aneurysm-related death, unrelated death, and rupture. Reports of EVAR should stratify their outcomes according to the diameter of the aneurysm. Large aneurysms need a more rigorous post-EVAR surveillance schedule than do smaller aneurysms. In small aneurysms EVAR was associated with excellent outcome. This finding may justify reappraisal of currently accepted management strategies.

Retrograde fenestration of endoluminal grafts from target vessels: feasibility, technique, and potential usage.

PURPOSE: To report initial experiments involving a new method for percutaneous intraprocedural stent-graft fenestration from the target vessel. TECHNIQUE: In bench and canine models, the fabric of an implanted Zenith endograft was punctured easily using the stiff end of a coronary 0.014-inch guidewire delivered through the target vessel (e.g., renal or iliac artery). A 20-G cutting needle was passed over the coronary wire to enlarge the puncture site, followed by a cutting balloon to create a fenestration that was of sufficient size to allow deployment of a stent. CONCLUSIONS: In vivo endograft fenestration of a Zenith endograft is feasible. In addition to providing a percutaneous means of intentionally fenestrating a stent-graft from the artery to be perfused, the technique has potential application as a bailout maneuver after inadvertent side branch occlusion. Although the time to achieve successful fenestration in the experimental model was long, refinement may achieve performance times adequate to maintain viability of the end organ.

Plain radiographic surveillance of abdominal aortic stent-grafts: the Liverpool/Perth protocol.

PURPOSE: To present a protocol for plain radiographic surveillance of abdominal aortic stent-grafts that addresses the main variables in need of standardization: (1) patient position, (2) radiographic centering point, and (3) focus-to-film distance. TECHNIQUE: Our policy is to perform baseline anteroposterior and lateral films following endoluminal grafting and repeat the studies annually. These are the most important films to assess migration and component separation; supplementary right and left posterior oblique radiographs may help identify wireform fractures. It is best to perform radiography before computed tomography if both tests are scheduled for the same day, as excretion of intravenous contrast opacifies the renal collecting systems and interferes with radiographic analysis. CONCLUSIONS: Evaluation of the radiographs depends on the design of the stent-graft, so it is important to understand graft construction and the position of the radiopaque markers to best assess changes on follow-up films.

Frequency, predictive factors, and consequences of stent-graft kink following endovascular AAA repair.

PURPOSE: To determine from the EUROSTAR registry the incidence of stent-graft kink, predictive factors for kinking, and the consequences of this complication on graft patency and aneurysm exclusion. METHODS: From January 1994 to June 2002, 4613 patients who underwent endovascular aneurysm repair were registered in the EUROSTAR registry. Presence of kink was determined according to the information available on the follow-up Case Record Form. The population was divided into those with and without stent-graft kink. Patient characteristics, morphological aneurysm features, team experience, type of device, period of implantation, and outcome were compared between the groups by univariate analysis. Significant factors were subsequently submitted to a multivariate Cox proportional hazard analysis. RESULTS: One hundred seventy (3.7%) patients were reported as having a kink of the stent-graft during a mean follow-up of 21 months (range 1-72). Gender, neck angulation, team experience, period of implantation, ASA classification, and device type were independent predictors of kink. The presence of a kink was significantly associated with type I endoleaks (proximal and distal), type III endoleaks (midgraft), graft stenosis, graft limb thrombosis, graft migration, and conversion to open repair. No relationship was found between a decrease in the aneurysm diameter and the occurrence of stent-graft kink. CONCLUSIONS: Kinks of stent-grafts were infrequent events in the intermediate term. Patients most at risk were women with angulated aortic necks treated by a minimally experienced team. Kinks are potentially damaging events because they may lead to delayed device-related endoleaks, graft stenosis, thrombosis, and conversion to open repair. They appear more closely associated to graft migration than to aneurysm diameter reduction.