Juxtarenal aortic aneurysm: endoluminal transfemoral repair?

Endoluminal transfermoral repair of an abdominal aortic aneurysm by a stent graft placement requires a segment of the nondilated infrarenal aorta of at least 15 mm long for safe stent graft attachment. The possibility of endoluminal treatment of a juxtarenal abdominal aortic aneurysm with partially covered spiral Z stent was assessed in experiment and in three clinical cases. In the experiment, the noncovered spiral Z stent was placed into the abdominal aorta, across the origins of renal arteries and mesenteric arteries, in six dogs. In the clinical cases, a partially covered stent graft was attached in 3 patients with the juxtarenal abdominal aortic aneurysm (of the group of 12 patients with abdominal aortic aneurysm). The stent grafts were attached with proximal uncovered parts across the origins of the renal arteries. In experiment, the renal artery occlusions or stenoses were not observed 36 months after stent placement, and in clinic 3 patients with the juxtarenal aortic aneurysm were successfully treated by stent graft placement. There were no signs of flow impairment into the renal arteries 14 months after stent graft implantation. This approach can possibly expand the indications for endoluminal grafting in the treatment of juxtarenal aortic aneurysms in patients who are at high risk for surgery.     

Endovascular treatment of thoracic aortic aneurysms: a review

Open surgical repair is considered the traditional treatment for patients with thoracic aortic aneurysms (TAA). In view of the persistent perioperative mobidity and mortality, endovascular stent-graft placement as a minimally invasive and potentially safer treatment for aneurysm of the descending aorta was introduced in 1992. Since then, progress has been made and several institutions have substantiated the safety and effectiveness of stent grafts in the repair of descending TAAs or type-B aortic dissections. Currently, both custom-designed, home-made, and commercially available stent grafts are used. Prior to placement of the endoprosthesis, three major prerequisites must be considered: the localization and morphology of the aneurysm; the distal vascular access of sufficient size; and a limited tortuosity of the abdominal and thoracic aorta. Although short-term results are encouraging, severe complications, including paraplegia, cerebral strokes, and aortic rupture, have been encountered. The long-term durability of currently available stent-graft systems is nonexistent and material fatigue are of major concern to both surgeons and radiologists. Nevertheless, endovascular stent-graft placement could become the procedure of choice in a substantial number of patients with descending TAA.     

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.     

Mycotic aneurysm of the aorta: MRI and MRA features

Mycotic aneurysms of the abdominal aorta are potentially fatal but uncommon. We report the MRI and MRA features of an abdominal aortic mycotic aneurysm in a patient who presented with nonspecific low back pain. By delineating the saccular nature of the aneurysm and identifying the coexistence of vertebral enhancement, MRI was crucial for the final diagnosis. A potential pitfall of contrast-enhanced MRA is also demonstrated.     

Vertebral mass resulting from a chronic-contained rupture of an abdominal aortic aneurysm repair graft.

We describe a case of a 63-year-old man with chronic-contained rupture of an abdominal aortic aneurysm at the site of prior graft repair of the aneurysm. Initially misinterpreted as osteomyelitis on the basis of CT findings, this chronic-contained rupture of the abdominal aorta eroding the vertebrae was preoperatively diagnosed at MR imaging and confirmed at surgery. A conventional angiogram failed to show the pseudoaneurysm. Owing to a major difference in the management of a contained aortic aneurysm rupture versus that for osteomyelitis, MR imaging with CT or MR angiography is recommended before any operative or invasive procedure.     

Determination of accurate stent graft configuration in abdominal aortic aneurysm using computed tomography: a preliminary study

An aortic stent graft is frequently used to cure an abdominal aortic aneurysm (AAA). It is critical to accurately fit the size and shape of the stent graft to the target region on the aorta. Proper sizing and shaping require the measurement of the orthogonal diameter of the target region from medical images. The present study aimed to acquire an accurate three-dimensional (3D) reconstruction of the aorta to determine the shape of the cross-sectional area where the stent graft would be implanted. A conventional geometric-active contour model was enhanced to prevent blurring and to improve edge detection with high noise resistivity. After the segmentation of two-dimensional (2D) images using the model, a 3D-reconstructed configuration of the aorta was achieved using a surface-rendering technique. The model could segment several selected synthetic images more accurately than conventional methods. Also, a 3D-reconstructed configuration of the abdominal aorta could be achieved using boundary coordinates extracted from 2D image segmentation. This preliminary study indicates the utility of the approach in optimizing stent graft configuration for AAA patients, thus enhancing stent graft healing.     

Endovascular Repair of an Actively Hemorrhaging Stab Wound Injury to the Abdominal Aorta

Traumatic injury of the abdominal aorta is rare and potentially lethal (Yeh et al., J Vasc Surg 42(5):1007–1009, 2005; Chicos et al., Chirurgia (Bucur) 102(2):237–240, 2007) as it can result in major retroperitoneal hemorrhage, requiring an urgent open surgery. In case of concomitant bowel injury or other conditions of hostile abdomen, endovascular repair can be an alternative treatment. This case report deals with a 50-year-old man presenting at the emergency ward with three stab wounds: two in the abdomen and one in the chest. During explorative laparotomy, liver laceration and bowel perforation were repaired. One day later, abdominal CT-scan revealed an additional retroperitoneal hematoma associated with an aortic pseudoaneurysm, located anteriorly 3 cm above the aortic bifurcation. Because of the risk of graft infection, an endovascular repair of the aortic injury using a Gore excluder stent-graft was performed. Radiological and clinical follow-up revealed a gradual shrinkage of the pseudo-aneurysm and no sign of graft infection at two years' follow-up.     

腹主动脉复合动脉瘤的腔内隔绝术治疗

目的：讨论复合腹主动脉病变进行腔内隔绝术（EVE）的可行性。方法：1例腹主动脉并存真性、假性和夹层动脉瘤患者，经双侧股动脉切开、肱动脉切开引入贯穿导丝，利用导丝导向技术和牵张技术成功置入模块式支架-人造血管移植物，以隔绝瘤体。结果：腔内隔绝操作技术完全成功，3个瘤体同时被隔绝，未加用任何延伸移植，未出现内漏、移位等并发症，重建血流通畅。结论：本例为EVE扩大适应证提供了经验。     

Treatment of chronic type B aortic dissection with endovascular stent-graft placement

A 74-year-old man with chronic aortic dissection was treated with an endovascular stent graft, fabricated from expanded polytetrafluoroethylene and a Z-stent. It was placed in the true lumen to close an entry tear. Closure was obtained immediately and thrombosis of the false lumen at the descending thoracic aorta was observed on computed tomography (CT) obtained 1 week later. No procedure-related complications developed. The patient is doing well with no adverse events including aortic rupture or aortic branch ischemia.     

Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

Objective

We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm.

Materials and Methods

Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically.

Results

The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall.

Conclusion

Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.     

Dissection of the infrarenal aorta treated by stent graft placement

Aortic dissection is primarily localized in the thoracic aorta. Dissection of the abdominal aorta is exceedingly rare, especially in the absence of a blunt abdominal trauma. Two cases of a primarily infrarenal aortic dissection were diagnosed by US, CT and angiography. The patients were treated by stent graft placement. The stent grafts were introduced via a femoral arteriotomy through the introducer sheath and were placed so that they occluded entry and reentry of aortic dissection. The stent graft placement caused total obliteration of a false channel of the dissection immediately after endoprosthesis deployment. The patients were followed-up by CT and angiography at 16 and 3 months after surgery without complication. Received 3 December 1996; Revision received 14 March 1997; Accepted 10 June 1997     

分体式支架-移植物治疗主动脉病变的初步报告

目的 介绍分体式支架-移植物（separating stent—graft）及其早期应用体会。方法 器械采用12F输送器，先后1次性经皮穿刺置入主动脉分体式支架-移植物的外、内两部分。4例患者为主动脉夹层StanfordB型、胸主动脉瘤与腹主动脉瘤。结果 1例夹层破口被封闭，病灶被隔绝；1例胸主动脉瘤病灶被隔绝，有轻度内瘘；2例腹主动脉瘤，瘤体均被隔绝。结论 分体式支架-移植物治疗主动脉夹层与主动脉瘤是1种有效、方便、更安全、更微创的治疗方法。     

Implantation of Palmaz stent for limb stenosis of Y-graft: a case report

An 81-year-old woman complained of severe right leg claudication in 2000. She had undergone inverted Y-graft placement for infrarenal abdominal aortic aneurysm in 1998. Magnetic resonance angiography (MRA) revealed severe stenosis at the right common iliac graft. Digital subtraction angiography (DSA) demonstrated a rare form of stenosis due to organized thrombus. Stent placement was successfully performed, utilizing a Palmaz stent. The stent has been patent for three years. The patient is asymptomatic and is being followed at our institute.     

国产覆膜支架介入治疗腹主动脉瘤的实验研究

 目的建立10只犬腹主动脉瘤模型,以介入法置入国产覆膜支架,观察其改变.方法10只实验动物建立模型;国产覆膜支架治疗后,CT进行影像学复查;最后取病理检查.结果两只发生并发症,余犬治疗后管腔通畅,但局部管腔有狭窄,病理电镜示覆膜支架内有内皮细胞生长.结论国产覆膜支架介入治疗腹主动脉瘤安全、有效.     

Primary Self-Expandable Nitinol Stent Placement in Focal Lesions of Infrarenal Abdominal Aorta: Long Term Results

Purpose To evaluate the technical and clinical success, safety and long term results of percutaneous transluminal angioplasty/self-expandable nitinol stent placement of infrarenal abdominal aorta focal lesions. Materials and Methods Eighteen patients underwent PTA of focal atherosclerotic occlusive disease of distal abdominal aorta. Two symptomatic occlusions and 16 stenoses in 10 male and 8 female patients (mean age 68.2 years) were treated with primary self-expandable nitinol stent placement. Results Primary self-expandable nitinol stent placement was technically successful in all 18 procedures; clinical success was achieved in 100% of patients. No complications associated with the procedure occurred. During the 49.4 months of mean follow up (range 3–96, 4 months) all treated aortic segments remained patent. Conclusions Endovascular treatment (primary self-expandable nitinol stent placement) of focal atherosclerotic lesions of distal abdominal aorta is a safe method with excellent primary technical and clinical success rates and favourable Long term results.     

应用国产覆膜支架治疗Stanford B型主动脉夹层动脉瘤

目的:评价应用国产覆膜支架治疗B型主动脉夹层动脉瘤的安全性及临床疗效.方法:自2005 - 05～2009 - 12对38例Stanford B型主动脉夹层动脉瘤实施了腔内隔绝术.其中男29例,女9例;年龄(54±12)岁.经CT增强扫描或磁共振成像(MRJ)确诊.切开左或右股动脉置入覆膜支架,封堵胸主动脉破裂口,置入后造影检查证实疗效,随访行CT或MRI检查.结果:支架置入全部成功,术后即刻造影36例无内漏,2例见少量内漏.降主动脉及腹主动脉真腔均明显扩大,远端降主动脉及分支供血均有不同程度改善.住院期间及随访1年内无患者死亡,发生主动脉腔内隔绝术后综合征3例.结论:应用国产覆膜支架腔内隔绝治疗B型主动脉夹层动脉瘤是一种操作简便、安全、成功率高、并发症少,疗效可靠的介入方法.     

多层螺旋CT血管造影在主动脉病变诊断中的应用价值

目的:探讨多层螺旋CT血管造影(MSCTA)诊断主动脉病变的能力。方法:对临床可疑主动脉病变75例患者行MSCTA检查,对比剂使用碘海醇90~100ml,流速3~4ml/s,采用Surestar技术跟踪扫描,阈值140~160HU;采用多种图像后处理技术,包括容积重组(VR)、多平面重组(MPR)、曲面重组(CPR)及最大密度投影(MIP)。结果:主动脉瘤20例(发生在开主动脉3例,主动脉弓部7例,腹主动脉10例);主动脉壁内血肿2例,主动脉硬化性溃疡6例,主动脉缩率1例,其中,主动脉瘤及夹层动脉瘤行介入治疗13例,与选择性血管造影结果一致。结论:从SCTA作为一种无创性血管成像技术应用于主动脉病变的诊断,具有安全、可靠、简便、快捷的优势,为临床诊断与治疗提供可靠依据。     

The value of true-FISP sequence added to conventional gadolinium-enhanced MRA of abdominal aorta and its major branches

To test true-fast imaging with steady-state precession (true-FISP) added to gadolinium-based MR angiography (Gd-MRA) for imaging abdominal aorta and major abdominal vessels, 35 consecutive patients (age 67 ± 11 years) with known or suspected abdominal and/or peripheral vascular disease were studied with sagittal and axial 2D true-FISP during free breathing and coronal 3D fast low-angle shot (FLASH) Gd-MRA (breath-holding, 0.2 mmol/kg of Gd-DOTA at 2 ml/s). We evaluated: suprarenal aorta, celiac trunk, superior mesenteric artery, right renal artery, left renal artery, infrarenal aorta, inferior mesenteric artery, aortic bifurcation/common iliac arteries, lumbar arteries and aortic atheromasia. The possible presence of accessory renal arteries, collateral vasculature and vascular prosthesis/stent was evaluated. A quality four-point score was assigned to each item on both sequences, from 0 (not visible) to 3 (good-to-excellent image quality) and Wilcoxon test was used. Main diagnoses resulted: normal or atheromasic aorta (n = 25); aortic aneurysm (n = 2); patent aorto-iliac surgical prosthesis (n = 2); patent vascular iliac stent (n = 2); aneurysm of iliac artery (n = 1); patent aortic endovascular prosthesis (n = 1); patent aorto-femural bypass (n = 1) and aorto-iliac surgical prosthesis endoleak (n = 1). We also found three patients with accessory renal arteries, two with collateral circulation, and three with surgical aorto-iliac prosthesis. The score of true-FISP (25.9 ± 4.1, median 27) was significantly higher (p = 0.003) than that of Gd-MRA (23.9 ± 3.6, median 24). True-FISP was superior for visualizing inferior mesenteric artery (score 2.5 ± 1.1 vs. 1.0 ± 1.4; p < 0.001) and atheromasic plaques (2.5 ± 1.1 vs. 1.2 ± 1.1; p < 0.001). One collateral vasculature was demonstrated only with Gd-MRA. Summarizing, true-FISP is a power and fast non-breath-hold sequence to be added to Gd-MRA, obtaining an information increase.     

Endovascular Aneurysm Repair and Sealing (EVARS): A Useful Adjunct in Treating Challenging Morphology

An 81-year-old male with previous open abdominal aortic aneurysm repair presented with asymptomatic large pseudoaneurysms at both ends of an open surgical tube graft. Endovascular aneurysm sealing (EVAS) in combination with the iliac limbs of a standard endovascular aneurysm repair (EVAR) successfully excluded both pseudoaneurysms from circulation. We describe the combination of elements of EVAS and EVAR and have termed this endovascular aneurysm repair and sealing (EVARS). EVARS has the advantage of harnessing the benefits of endobag sealing in aortic necks unsuitable for standard EVAR whilst providing the security of accurate stent placement within short common iliac arteries. In conclusion, EVAS may be combined with standard endovascular iliac limbs and is a possible treatment option for pseudoaneurysm following open aneurysm repair.     

Multislice CT virtual intravascular endoscopy for abdominal aortic aneurysm stent grafts

PURPOSE: To investigate the optimal scanning protocols of multislice computed tomographic (CT) angiography in aortic stent graft placement observed on virtual intravascular endoscopy (VIE). MATERIALS AND METHODS: A human aorta phantom was built with a commercial aortic stent graft placed in situ. The phantom was housed in a perspex container and filled with contrast medium with CT attenuation similar to that used in the patient's abdominal scanning. CT was performed with a four-slice multislice CT scanner with section thickness of 1.3 mm, 2 mm, and 3.2 mm, pitch of 0.75, 1, and 1.5, and reconstruction interval of 50% overlap and no overlap. Stair-step artifacts were quantified by measuring the SD of signal intensity on surfaced shaded VIE images in three different locations: superior mesenteric artery (SMA), renal ostium, and aortic aneurysm. RESULTS: Image quality of VIE images was independent of section thickness and pitch values in the level of renal ostium and aortic aneurysm (P >.05), whereas it was determined by the section thickness and pitch in the level of SMA (P <.05). Aortic branch origin became irregular or distorted when section thickness increased to 3.2 mm or pitch reached 1.5. CONCLUSION: A scanning protocol of section thickness of 2 mm, pitch 1, and reconstruction interval of 1 mm is recommended in aortic stent graft placement because it allows fewer stair-step artifacts and better visualization of the aortic stent wires observed on VIE.