Endoluminal aortic grafting with renal and superior mesenteric artery incorporation by graft fenestration

Abdominal aortic aneurysm-repair devices

Traditional open aneurysm repair is associated with significant perioperative morbidity. The development of abdominal aneurysm-repair devices has provided a minimally invasive alternative to open repairs. The field of aneurysm-repair devices is burgeoning since the approval of the first device in 1999. A clear perioperative survival advantage and lower perioperative morbidity has been reported by multiple studies. In addition to benefiting the normal risk aortic aneurysm patient, this new technology is making the repair of aneurysms in older patients with high operative risk factors possible. Modifications to devices are introduced rapidly to overcome anatomical limitations and to improve on device-related complications such as endoleaks and migration. Limited long-term outcomes are available for newer devices, and life-long surveillance is still recommended for all patients. Patient selection and preoperative planning are the cornerstones to successful endovascular repair of abdominal aortic aneurysms.

Early experience with fenestrated stent grafts for treatment of juxtarenal aortic aneurysm

BACKGROUND

Fenestrated endovascular abdominal aneurysm repair (FEVAR) using branched arteries devices for visceral arteries is increasingly being used for the repair of juxtarenal aortic aneurysms (JAAs) in Europe, United States, Australia, New Zealand, and Asia. This study aimed to evaluate the technical feasibility and short-term results of FEVAR in treating JAAs in Japanese patients.

METHODS AND RESULTS

FEVAR with Cook fenestrated stent-graft (Cook Medical Inc., Bloomington, Indiana, USA) was performed for 5 patients at high risk for open repair of JAA. Seventeen visceral vessels were successfully accommodated with 12 fenestrations, and five visceral arteries with four scallops with a loss of renal artery. In one case, a type III endoleak occurred at a renal artery fenestration, and this had disappeared in the 1-month postoperative computed tomography (CT). The mean follow-up duration was 8 months. Iliac leg occlusion occurred in 1 case, which was treated with thrombectomy and additional leg device deployment. All patients had survived at the end of the follow-up period and continued their outpatient visits.

CONCLUSIONS

Implantation of a Cook fenestrated stent-graft incorporating the visceral arteries is technically feasible in high-risk Japanese patients with JAA and may be a viable alternative to current methods.

Endovascular treatment of infrarenal abdominal aortic aneurysm with short and angulated neck in high-risk patient

Endovascular treatment of abdominal aortic aneurysms (AAA) is an established alternative to open repair. However lifelong surveillance is still required to monitor endograft function and signal the need for secondary interventions (Hobo and Buth 2006). Aortic morphology, especially related to the proximal neck, often complicates the procedure or increases the risk for late device-related complications (Hobo et al. 2007 and Chisci et al. 2009). The definition of a short and angulated neck is based on length (<15 mm), and angulation (>60°) (Hobo et al. 2007 and Chisci et al. 2009). A challenging neck also offers difficulties during open repairs (OR), necessitating extensive dissection with juxta- or suprarenal aortic cross-clamping. Patients with extensive aneurysmal disease typically have more comorbidities and may not tolerate extensive surgical trauma (Sarac et al. 2002). It is, therefore, unclear whether aneurysms with a challenging proximal neck should be offered EVAR or OR (Cox et al. 2006, Choke et al. 2006, Robbins et al. 2005, Sternbergh III et al. 2002, Dillavou et al. 2003, and Greenberg et al. 2003). In our case the insertion of a thoracic endograft followed by the placement of a bifurcated aortic endograft for the treatment of a very short and severely angulated neck proved to be feasible offering acceptable duration of aneurysm exclusion. This adds up to our armamentarium in the treatment of high-risk patients, and it should be considered in emergency cases when the fenestrated and branched endografts are not available.

Respiration-induced deformations of the superior mesenteric and renal arteries in patients with abdominal aortic aneurysms

PURPOSE

To quantify respiration-induced deformations of the superior mesenteric artery (SMA), left renal artery (LRA), and right renal artery (RRA) in patients with small abdominal aortic aneurysms (AAAs).

MATERIALS AND METHODS

Sixteen men with AAAs (age 73 y ± 7) were imaged with contrast-enhanced magnetic resonance angiography during inspiratory and expiratory breath-holds. Centerline paths of the aorta and visceral arteries were acquired by geometric modeling and segmentation techniques. Vessel translations and changes in branching angle and curvature resulting from respiration were computed from centerline paths.

RESULTS

With expiration, the SMA, LRA, and RRA bifurcation points translated superiorly by 12.4 mm ± 9.5, 14.5 mm ± 8.8, and 12.7 mm ± 6.4 (P < .001), and posteriorly by 2.2 mm ± 2.7, 4.9 mm ± 4.2, and 5.6 mm ± 3.9 (P < .05), respectively, and the SMA translated rightward by 3.9 mm ± 4.9 (P < .01). With expiration, the SMA, LRA, and RRA angled upward by 9.7° ± 6.4, 7.5° ± 7.8, and 4.9° ± 5.3, respectively (P < .005). With expiration, mean curvature increased by 0.02 mm(-1) ± 0.01, 0.01 mm(-1) ± 0.01, and 0.01 mm(-1) ± 0.01 in the SMA, LRA, and RRA, respectively (P < .05). For inspiration and expiration, RRA curvature was greater than in other vessels (P < .025).

CONCLUSIONS

With expiration, the SMA, LRA, and RRA translated superiorly and posteriorly as a result of diaphragmatic motion, inducing upward angling of vessel branches and increased curvature. In addition, the SMA exhibited rightward translation with expiration. The RRA was significantly more tortuous, but deformed less than the other vessels during respiration.

Respiratory-induced 3D deformations of the renal arteries quantified with geometric modeling during inspiration and expiration breath-holds of magnetic resonance angiography

PURPOSE

To quantify renal artery deformation due to respiration using magnetic resonance (MR) image-based geometric analysis.

MATERIALS AND METHODS

Five males were imaged with contrast-enhanced MR angiography during inspiratory and expiratory breath-holds. From 3D models of the abdominal aorta, left and right renal arteries (LRA and RRA), we quantified branching angle, curvature, peak curve angle, axial length, and locations of branch points.

RESULTS

With expiration, maximum curvature changes were 0.054 ± 0.025 mm(-1) (P < 0.01), and curve angle at the most proximal curvature peak increased by 8.0 ± 4.5° (P < 0.05) in the LRA. Changes in maximum curvature and curve angles were not significant in the RRA. The first renal bifurcation point translated superiorly and posteriorly by 9.7 ± 3.6 mm (P < 0.005) and 3.5 ± 2.1 mm (P < 0.05), respectively, in the LRA, and 10.8 ± 6.1 mm (P < 0.05) and 3.6 ± 2.5 mm (P < 0.05), respectively, in the RRA. Changes in branching angle, axial length, and renal ostia locations were not significant.

CONCLUSION

The LRA and RRA deformed and translated significantly. Greater deformation of the LRA as compared to the RRA may be due to asymmetric anatomy and mechanical support by the inferior vena cava. The presented methodology can extend to quantification of deformation of diseased and stented arteries to help renal artery implant development.

Fenestrated endovascular aneurysm repair

Background

Fenestrated endovascular aneurysm repair (FEVAR) is a technically challenging operation. The duration, blood loss, and risk of limb ischaemia, contrast-induced nephropathy and reperfusion injury are likely to be higher than after standard endovascular aneurysm repair (EVAR). Benefits of FEVAR over open repair may be less than those seen with standard infrarenal EVAR. This paper is a meta-analysis of observational studies of all published data for FEVAR, with the aim to highlight current issues around the evidence for the potential benefit of FEVAR.

Methods

A search was performed for studies describing FEVAR for juxtarenal abdominal aortic aneurysms. Small series of fewer than ten procedures and studies describing predominantly branched endografts or FEVAR for aortic dissection were excluded. Authors of included papers were contacted to eliminate patient duplication.

Results

Eleven studies were identified describing a total of 660 procedures. Definitions of aneurysm morphology were variable, and clear inclusion and exclusion criteria were not always documented. Double fenestrations were more common than triple or quadruple fenestrations. Target vessel perfusion rates ranged from 90·5 to 100 per cent. Eleven deaths occurred within 30 days, giving a 30-day proportional mortality rate of 2·0 per cent. Morbidity was poorly reported.

Conclusion

FEVAR for repair of suprarenal and juxtarenal aneurysms is a viable alternative to open repair. However, there is no level 1 evidence for FEVAR, and current evidence is weak with many unanswered questions.

Endovascular treatment of thoracoabdominal aneurysm

OPINION STATEMENT

The use of endovascular modalities for the treatment of simple descending thoracic aneurysms has become standard of care. Expanding endovascular techniques for the treatment of thoracoabdominal aneurysms is now possible with the evolution of branched and fenestrated grafts.

Computed tomography virtual intravascular endoscopy in the evaluation of fenestrated stent graft repair of abdominal aortic aneurysms

BACKGROUND

This study aimed to investigate the diagnostic value of computed tomography virtual intravascular endoscopy (VIE) in the follow-up of patients with abdominal aortic aneurysm (AAA) treated with fenestrated stent grafts.

METHODS

A total of 19 patients (17 males and 2 females; mean age: 75 years) with AAA undergoing fenestrated stent grafts were retrospectively studied. Pre- and post-fenestration computed tomography data were reconstructed for the generation of VIE images of aortic ostia and fenestrated stents and compared with two-dimensional axial and multiplanar reformation (MPR) images. Serum creatinine was measured pre and post fenestration to evaluate the renal function.

RESULTS

The mean intra-aortic length measured by VIE, two-dimensional axial and MPR were 4.7, 4.4 and 4.6 mm, respectively, for the right renal stent; 5.0, 4.9 and 5.0 mm, respectively, for the left renal stent; and 5.9, 6.0 and 6.0 mm, respectively, for the superior mesenteric artery stent. Comparisons of these measurements did not show significant difference (P > 0.05). The mean diameters of renal artery ostia measured on VIE visualization pre and post fenestration were 9.2 x 8.3 and 10 x 8.9 mm for the right renal ostium; 8.3 x 7.1 and 9.9 x 8.9 mm for the left renal ostium, with significant changes observed (P < 0.01). No renal dysfunction was observed in this group.

CONCLUSION

VIE is a valuable visualization tool in the follow-up of fenestrated stent graft repair of AAA by providing intraluminal appearance of fenestrated stents and measuring the length of stent protrusion.

Endovascular stent graft repair of abdominal aortic aneurysms: Current status and future directions

Endovascular stent graft repair of abdominal aortic aneurysm (AAA) has undergone rapid developments since it was introduced in the early 1990s. Two main types of aortic stent grafts have been developed and are currently being used in clinical practice to deal with patients with complicated or unsuitable aneurysm necks, namely, suprarenal and fenestrated stent grafts. Helical computed tomography angiography has been widely recognized as the method of choice for both pre-operative planning and post-operative follow-up of endovascular repair (EVAR). In addition to 2D axial images, a number of 2D and 3D reconstructions are generated to provide additional information about imaging of the stent grafts in relation to the aortic aneurysm diameter and extent, encroachment of stent wires to the renal artery ostium and position of the fenestrated vessel stents. The purpose of this article is to provide an overview of applications of EVAR of AAA and diagnostic applications of 2D and 3D image visualizations in the assessment of treatment outcomes of EVAR. Interference of stent wires with renal blood flow from the hemodynamic point of view will also be discussed, and future directions explored.

Fenestrated stent graft repair of abdominal aortic aneurysm: hemodynamic analysis of the effect of fenestrated stents on the renal arteries

Objective

We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method.

Materials and Methods

Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients' treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles.

Results

Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks.

Conclusion

Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair.

Endovascular treatment of aortic pseudoaneurysm in Behçet disease

OBJECTIVE

This study evaluated the feasibility, efficacy, and outcome of endovascular therapy combined with immunosuppressive therapy for aortic pseudoaneurysms in patients with Behçet disease.

METHODS

Between April 2002 and April 2008, 12 pseudoaneurysms (9 involving the intrarenal abdominal aorta, 1 at the suprarenal level, and 2 in the supraceliac aorta) in nine men and one woman with Behçet disease were evaluated at Peking Union Medical Center (PUMC). Three bifurcated stent grafts and seven tubular stent grafts, including two fenestrated stent grafts, were deployed. All 10 patients received immunosuppressive therapy after the implant procedure.

RESULTS

All patients underwent successful endovascular therapy without major complications during the 30 days immediately after the procedure. One patient with two aneurysms had treatment of only the larger infrarenal symptomatic aneurysm, but the smaller suprarenal pseudoaneurysm was not addressed because of its proximity to mesenteric branches. During a mean follow-up of 25.8 months (range, 6-50 months), nine aneurysms resolved completely in eight patients. The only untreated aneurysm, which coexisted with a treated lesion, remained stable under imaging observation. Three aneurysms recurred in two patients. At 6 months, one patient presented with a new aneurysm at the femoral artery access site for stent graft introduction and another formed at the proximal margin of the stent graft. Despite medical advice, he had stopped immunotherapy. He died from aneurysm rupture 8 months after stent deployment. Another patient with recurrent aneurysmal disease at the distal margin of the primary stent was successfully treated with an additional stent graft. These two were the only patients who did not adhere to taking immunosuppressant medicine after discharge.

CONCLUSION

Endovascular stent graft placement combined with immunosuppressive treatment for aortic pseudoaneurysms in Behçet disease is a feasible and effective management option. Long-term immunosuppressive therapy after endovascular repair is important to limit pseudoaneurysm recurrence.

Multislice CT angiography of fenestrated endovascular stent grafting for treating abdominal aortic aneurysms: a pictorial review of the 2D/3D visualizations

Fenestrated endovascular repair of an abdominal aortic aneurysm has been developed to treat patients with a short or complicated aneurysm neck. Fenestration involves creating an opening in the graft fabric to accommodate the orifice of the vessel that is targeted for preservation. Fixation of the fenestration to the renal arteries and the other visceral arteries can be done by implanting bare or covered stents across the graft-artery ostia interfaces so that a portion of the stent protrudes into the aortic lumen. Accurate alignment of the targeted vessels in a longitudinal aspect is hard to achieve during stent deployment because rotation of the stent graft may take place during delivery from the sheath. Understanding the 3D relationship of the aortic branches and the fenestrated vessel stents following fenestration will aid endovascular specialists to evaluate how the stent graft is situated within the aorta after placement of fenestrations. The aim of this article is to provide the 2D and 3D imaging appearances of the fenestrated endovascular grafts that were implanted in a group of patients with abdominal aortic aneurysms, based on the multislice CT angiography. The potential applications of each visualization technique were explored and compared with the 2D axial images.

Helical CT angiography of fenestrated stent grafting of abdominal aortic aneurysms

Fenestrated stent grafts have been developed to treat patients with abdominal aortic aneurysms (AAA) associated with complicated aneurysm necks, such as short necks, severe angulated or poor quality necks (presence of calcification or thrombus). The technique is performed by creating an opening in the graft material so that the stent graft can be placed above the renal and other visceral branches without compromising blood perfusion to these vessels. In most situations, a supporting stent is inserted into the fenestrated vessel to provide fixation of the fenestrated vessel against stent grafts, as well as to preserve patency of the vessel. Helical CT angiography (CTA) is the preferred imaging modality in both pre-operative planning and post-procedural follow-up of fenestrated repair of AAA. The main concerns of fenestrated stent grafting lie in the following two aspects: patency of the fenestrated vessels and position of the fenestrated stents in relation to the artery branches. In this article, the author presents the clinical applications of 2D and 3D visualizations in the follow-up of patients with AAA treated with fenestrated stent grafts, with the aim of providing useful information to readers and increasing their knowledge of an increasingly used technique, fenestrated stent grafting in the treatment of AAA.

Outcome of renal stenting for renal artery coverage during endovascular aortic aneurysm repair

OBJECTIVE

This study was conducted to determine the outcome of adjunctive renal artery stenting for renal artery coverage at the time of endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

Between August 2000 and August 2008, 29 patients underwent elective EVAR using bifurcated Zenith stent grafts (Cook, Indianapolis, Ind) and simultaneous renal artery stenting. Renal artery stenting during EVAR was performed with endograft "encroachment" on the renal artery ostium (n = 23) or placement of a renal stent parallel to the main body of the endograft ("snorkel," n = 8). Follow-up included routine contrast-enhanced computed tomography (CT), multiview abdominal radiographs, and serum creatinine measurement at 1, 6, and 12 months, and then yearly thereafter.

RESULTS

Thirty-one renal arteries were stented successfully in 29 patients. The 18 patients with planned renal artery stent placement had a proximal neck length <15 mm. Mean proximal neck length was shorter in patients who underwent the "snorkel" technique (6.9 +/- 3.1 mm) compared with those with planned endograft encroachment (9.9 +/- 2.6 mm). None of the patients with unplanned endograft encroachment had neck lengths <15 mm (mean length, 26.3 +/- 10.2 mm). Mean proximal neck angulation was 42.8 degrees +/- 24.0 degrees and did not differ between the groups. One patient had a type I endoleak on completion angiography, and two additional patients had a type I endoleak on the first postoperative CT scan. All type I endoleaks resolved by the 1-month postoperative CT scan. The primary assisted patency of renal artery stents was 100% at a median follow-up of 12.5 months (range, 2 days-77.4 months). In one patient near occlusion of a renal artery stent was noted on follow-up CT scan at 9 months; patency was restored by placement of an additional stent. One patient required dialysis after sustained hypotension from a right external iliac artery injury that resulted in prolonged postoperative bleeding. Mean serum creatinine was 1.1 +/- 0.3 mg/dL at baseline, 1.2 +/- 0.5 mg/dL at 1 month of follow-up, and 1.2 +/- 0.5 mg/dL at 2 years of follow-up. There were no late type I endoleaks (>1 month postoperatively) or stent graft migrations.

CONCLUSIONS

Adjunctive renal artery stenting during endovascular AAA repair using the "encroachment" and "snorkel" techniques is safe and effective. Short- and medium-term primary patency rates are excellent, but careful follow-up is needed to determine the durability of these techniques.

3D stereoscopic visualization of fenestrated stent grafts

The purpose of this study was to present a technique of stereoscopic visualization in the evaluation of patients with abdominal aortic aneurysm treated with fenestrated stent grafts compared with conventional 2D visualizations. Two patients with abdominal aortic aneurysm undergoing fenestrated stent grafting were selected for inclusion in the study. Conventional 2D views including axial, multiplanar reformation, maximum-intensity projection, and volume rendering and 3D stereoscopic visualizations were assessed by two experienced reviewers independently with regard to the treatment outcomes of fenestrated repair. Interobserver agreement was assessed with Kendall's W statistic. Multiplanar reformation and maximum-intensity projection visualizations were scored the highest in the evaluation of parameters related to the fenestrated stent grafting, while 3D stereoscopic visualization was scored as valuable in the evaluation of appearance (any distortions) of the fenestrated stent. Volume rendering was found to play a limited role in the follow-up of fenestrated stent grafting. 3D stereoscopic visualization adds additional information that assists endovascular specialists to identify any distortions of the fenestrated stents when compared with 2D visualizations.

Multislice CT angiography in the follow-up of fenestrated endovascular grafts: effect of slice thickness on 2D and 3D visualization of the fenestration stents

PURPOSE

To investigate the effect of multislice computed tomography (CT) protocols on the visualization of target vessel stents in patients with abdominal aortic aneurysm (AAA) treated with fenestrated endovascular grafts.

METHODS

Twenty-one patients (19 men; mean age 75 years, range 63-86) undergoing fenestrated endovascular repair of AAA were retrospectively studied. Multislice CT angiography was performed with several protocols, and the section thicknesses used in each were compared to identify any relationship between slice thickness and target vessel stents visualized on 2-dimensional (2D) axial, multiplanar reformatted (MPR), and 3-dimensional (3D) virtual intravascular endoscopy (VIE) images. Image quality was assessed based on the degree of artifacts and their effect on the ability to visualize the configuration, intra-aortic location, and intraluminal appearance of the target vessel stents and measure their protrusion into the aortic lumen.

RESULTS

There were 7 different multislice CT scanning protocols employed in the 21 patients (25 datasets, with 2 sets of follow-up images in 4 patients). The slice thicknesses and numbers (n) of studies included were 0.5 (n=3), 0.625 (n=6), 1.0 (n=1), 1.25 (n=9), 2.5 (n=3), 3.0 (n=1), and 5.0 mm (n=2). Of these CT protocols, images (especially 2D/3D reconstructions) acquired at 2.5, 3.0, and 5.0 mm were significantly compromised by interference from artifacts. Images acquired with a slice thickness of 1.0 or 1.25 mm were scored equal to or lower than those acquired with a submillimeter section thickness (0.5 or 0.625 mm), with minor degrees of artifacts resulting in acceptable image quality.

CONCLUSION

Visualization of the target vessel stents depends on the appropriate selection of multislice CT scanning protocols. Our results showed that studies performed with a slice thickness of 1.0 or 1.25 mm produced similar image quality to those with a thickness of 0.5 or 0.625 mm. Submillimeter slices are not recommended in imaging patients treated with fenestrated stent-grafts, as they did not add additional information to the visualization.

EVAR and complex anatomy: an update on fenestrated and branched stent grafts

Endovascular aneurysm repair (EVAR) offers a minimally invasive treatment to patients with improved short-term and similar mid-term results compared to conventional, open repair (OR). EVAR is preferred by patients due to the reduction of surgical trauma. Approximately 20% of patients have aneurysm neck morphology which is inadequate for a standard stent graft and requires the endograft to cross vital aortic side branches to achieve a seal. This chapter describes the evolution of three types of devices, namely the fenestrated and branched stent grafts as well as the chimney grafts. These stent grafts incorporate vital aortic side branches in the repair, thereby increasing the applicability of EVAR which may improve the overall results.

CT virtual intravascular endoscopy in the visualization of fenestrated stent-grafts

PURPOSE

To report the diagnostic value of computed tomographic (CT) virtual intravascular endoscopy (VIE) in the assessment of patients with abdominal aortic aneurysm (AAA) treated with fenestrated endovascular grafts.

METHODS

Eight patients (7 men; mean age 76 years, range 70-82) with AAAs unsuitable for open surgery or conventional endovascular repair had fenestrated endovascular grafts implanted. Both pre- and post-fenestration multislice CT data were used to generate VIE images of the visceral artery ostia and the side branch fenestrated stents. CT VIE images were compared with conventional 2-dimensional (2D) axial CT and multiplanar reformatted (MPR) images for the ability to visualize the intraluminal appearance of stents, as well as to measure the length of stents that protruded into the aortic lumen.

RESULTS

Various fenestrations were deployed in 27 aortic branches. Scalloped and large fenestrations were implanted in 6 side branch ostia, respectively, and small fenestrations in 15 renal artery ostia. Fewer than half of the stents (37%) were found to be circular on VIE images, while the remaining stents were flared to varying extents at the inferior portion. The majority (96%) of stents protruded into the lumen up to 7.0 mm. Although the configuration of the side branch ostia changed to a variable extent, no significant difference was apparent between the diameters of branch ostia before and after fenestration (p>0.05).

CONCLUSION

Our preliminary study shows that VIE proved superior to conventional 2D or MPR images in visualizing the final configuration of the fenestrated vessels and was comparable to the other techniques in measuring stent protrusion into the aortic lumen. VIE could be a valuable technique to identify any suspected abnormalities associated with fenestrated endovascular grafts by demonstrating the final intraluminal configuration of the stents in the fenestrated vessels.

Endovascular Repair of Thoracoabdominal Aneurysms

Background— Morbidity and mortality after conventional repair of thoracoabdominal aneurysms remain high. Alternative techniques have been proposed and are the subject of this report.

Methods and Results— Endovascular grafts that have a means of incorporating the visceral vessels into the aortic repair were divided into devices with fenestrations and those with formal branches. Hybrid procedures whereby an extra-anatomic bypass procedure is used to provide inflow to the renal and mesenteric arteries followed by aortic relining with stent grafts were reviewed and tabulated. A description of the techniques and review of the current results are provided. Only 4 series with >10 cases of hybrid procedures have been published. The experience with such a procedure suggests feasibility, but most reports describe a persistently high risk of mortality (up to 25%). Larger series of fenestrated stent grafts to treat juxtarenal aneurysms have been published, and intermediate-term results confirm the safety and efficacy of the procedure. A larger multicenter trial is under way. Other pure endovascular methods have been used to treat thoracoabdominal aneurysms with both reinforced fenestrations and directional branches. Without counting small series (<10 cases), 2 series exist with ≈100 cases that noted perioperative mortality rates between 3% and 6%, without evidence of late ruptures.

Conclusions— Endovascular repair of thoracoabdominal aneurysms is feasible and is associated with relatively low perioperative mortality. Several methods of visceral vessel incorporation have been described. Because of persistently high mortality, hybrid procedures will likely be relegated to nonsurgical and nonendovascular patients with sizable aneurysms. Endografts with branches continue to evolve and will be assessed in the context of clinical trials.

Endovascular treatment of thoracoabdominal aortic aneurysms

OBJECTIVE

To establish the safety and efficacy of endovascular repair of thoracoabdominal aortic aneurysms.

METHODS

Between May 2004 and February 2006, patients with thoracoabdominal aneurysms considered high risk for conventional surgery were enrolled in a prospective trial to evaluate a novel endovascular grafting system. Devices were custom designed for each patient using high-resolution computed tomography. Patient data included mortality, morbidity, procedural details, and surrogate end points for endovascular repair. These were collected at hospital discharge and at 1, 6, and 12 months.

RESULTS

Seventy-three patients underwent endovascular repair of thoracoabdominal aortic aneurysms for type I, II, or III (n = 28), or for type IV (n = 45) thoracoabdominal aneurysms. Mean aneurysm size was 7.1 cm (range 4.5-11.3 cm). General anesthesia was used in 47% of patients and regional anesthesia in 53%. There were no conversions to open surgery nor ruptures post-treatment. Technical success was achieved in 93% of patients (68/73). Thirty-day mortality was 5.5% (4/73). Major perioperative complications occurred in 11 (14%) patients and included paraplegia (2.7%, 2/73), new onset of dialysis (1.4%, 1/73), prolonged ventilator support (6.8%, 5/73), myocardial infarction (5.5%, 4/73), and minor hemorrhagic stroke (1.4%; 1/72). A majority of patients had no complications. Mean length of stay was 8.6 days. At follow-up, 6 deaths had occurred. There were no instances of stent migration nor aneurysmal growth.

CONCLUSIONS

Endovascular repair of aortic aneurysms involving the visceral segment in nonsurgical candidates is feasible. Known complications of repair are not eliminated, but morbidity and mortality appeared low relative to the high-risk population studied. Further refinement of device design, delivery technique, and patient selection is ongoing. Assessment of durability will require longer follow-up.

Surgery Insight: advances in endovascular repair of abdominal aortic aneurysms

Despite improvements in diagnostic and therapeutic methods and an increased awareness of their clinical significance, abdominal aortic aneurysms (AAAs) continue to be a major source of morbidity and mortality. Endovascular repair of AAAs, initially described in 1990, offers a less-invasive alternative to conventional open repair. The technology and devices used for endovascular repair of AAAs have progressed rapidly and the approach has proven to be safe and effective in short to midterm investigations. Furthermore, several large trials have demonstrated that elective endovascular repair is associated with lower perioperative morbidity and mortality than open repair. The long-term benefits of endovascular repair relative to open repair, however, continue to be studied. In addition to elective repair, the use of endovascular repair for ruptured AAAs has been increasing, and has been shown to be associated with reduced perioperative morbidity and mortality. Advances in endovascular repair of AAAs, including the development of branched and fenestrated grafts and the use of implantable devices to measure aneurysm-sac pressures following stent-graft deployment, have further broadened the application of the technique and have enhanced postoperative monitoring. Despite these advances, endovascular repair of AAAs remains a relatively novel technique, and further long-term data need to be collected.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.