Creation of aortic dissection model in swine

The use of mongrel dogs for experimental purposes was recently restricted and this report presents the experience of creating an aortic dissection model in swine. All the swine in group 1 were anesthetized without pentobarbital and the descending aorta was side-clamped during the creation of the aortic dissection. The false lumen of the completed dissection was patent in the long term despite not having the anchoring suture that the previous canine model required to stabilize the opening of the entry tear. All the swine anesthetized with pentobarbital (ie, group 2) died of heart failure either during cross-clamping of the descending aorta or postoperative aortography. In conclusion, creation of a thoracic aortic dissection is possible in swine, but cross-clamping of the thoracic descending aorta and pentobarbital anesthesia should be avoided.     

Transesophageal Doppler echocardiography in the diagnosis of dissecting aortic aneurysm

Transesophageal Doppler echocardiography (TEDE) was performed in three patients with proven or suspected DeBakey type I and type III aortic dissection. Case 1: A 66-year-old woman, with DeBakey type I aortic dissection. Clear images of a widened dissected aorta and an intimal flap were obtained in both the ascending and descending aorta, including the aortic arch. The site of an entry into the false lumen was identified by the defect of the intimal flap and the pulsatile entry flow through it. The reentry into the true lumen was also identified near the orifice of the celiac trunk. In this case, the observation was performed using this technique during the operation; i.e., replacement of the ascending aorta with an artificial graft. Case 2: A 77-year-old man, DeBakey type III aortic dissection. The study was performed after surgery which consisted of replacement of the descending aorta with an artificial graft. TEDE provided clear images of the artificial graft, the aorta, and their boundaries. The remaining intimal flap was clearly confirmed. Case 3: An 80-year-old man, DeBakey type III aortic dissection. In this case, though abdominal echography suggested aortic dissection, angiography and X-ray CT failed to facilitate the diagnosis. Only TEDE confirmed the diagnosis. The abnormal flow via the entry directing toward the false lumen was clearly demonstrated on the color Doppler images. We therefore conclude that TEDE is a useful and reliable means of diagnosing dissecting aortic aneurysm.     

Transcatheter, Endovascular Repair of Abdominal Aortic Aneurysm: Feasibility, Noninvasive Diagnosis, Problems, and Follow-Up

Until recently, the repair of an abdominal aortic aneurysm (AAA) required major surgery. Recently, the transcatheter technique has allowed minimally invasive endovascular stenting of infrarenal AAAs. This procedure is less traumatic and is associated with a shorter hospital stay than conservative surgery. With the stent placement, the effective aortic lumen diameter decreases and the aneurysmal space is excluded from the circulation. Ultrasonographic studies have allowed imaging of the abdominal aorta, its main branches, and the endovascular stent. The aortic blood flow after the repair is ideally limited to the stent lumen. Follow-up studies have permitted reevaluation of the aorta and the stent, with special emphasis on the aortic expansion and blood flow within the excluded space. These studies have correlated well with other imaging techniques such as intravascular ultrasound, computed tomography scanning, and aortography.     

Expanding false lumen in the abdominal aorta 5 years after endovascular repair of a type B aortic dissection: successful exclusion of 3 distal re-entry sites.

PURPOSE: To report endovascular treatment of an expanding aneurysmal false lumen several years after successful stent-graft deployment in the descending thoracic aorta for type B aortic dissection. CASE REPORT: A 54-year-old woman who had a stent-graft placed at the entry site of a type B aortic dissection 5 years prior presented with abdominal discomfort and palpable abdominal mass. Successful remodeling of the thoracic aorta was demonstrated by computed tomography; however, a false lumen aneurysm in the abdominal aorta had expanded from 4.8 to 6.5 cm and caused symptoms. She was successfully treated with 3 additional stent-grafts at 3 re-entry sites. Six months after the procedure, the false lumen aneurysm was completely excluded. CONCLUSIONS: Endovascular repair of the re-entry sites can prevent further expansion of false lumen aneurysm, which occurs in some patients with type B dissection treated with stent-grafts.     

Endovascular thoracic aortic aneurysm repair: evaluating the utility of intravascular ultrasound measurements.

PURPOSE: To compare intravascular ultrasound (IVUS) and computed tomography (CT) measurements of aortic diameter for the determination of stent-graft sizes used in thoracic endovascular aneurysm repair (TEVAR). METHODS: A retrospective review was conducted of 71 IVUS measurements performed in 33 patients (17 men; mean age 69 years) undergoing endovascular repair for thoracic aortic aneurysm (TAA). For comparison, an inanimate model of the aortic arch and the great vessels was created; 5 independent operators took multiple blinded IVUS measurements. Measurement accuracy is presented as the mean and coefficient of variance in percent. RESULTS: In 47 (66%) of the 71 clinical measurements, IVUS yielded a value that was larger than the CT scan measurement; in 8 (11%), the difference was at least 5 mm. In the model, CT centerline measurements were accurate within a mean 0.3 mm (0.6%) of the actual diameter; IVUS measurements were accurate within a mean 1.4 mm (2.8%). Centerline IVUS measurements increased the accuracy to within 0.8 mm (1.8%) of the actual diameter. CONCLUSION: IVUS measurements of the thoracic aorta were larger than CT measurements 66% of the time. However, there are 2 concerns with IVUS: off-center measurements distort the image and tangential measurements on a curve do not reflect a true centerline diameter. Thus, off-center IVUS measurements or those taken in the tortuous portion of the aorta may not be as accurate as centerline CT measurements.     

Endovascular stent-graft repair of aortic dissection

Between October 2000 and January 2002, 9 consecutive male patients with subacute or chronic aortic dissection underwent stent-graft placement. The indication for surgery was continuous pain or aneurysm development. One patient had a type A dissecting aortic aneurysm with a primary tear in the ascending thoracic aorta; the other 8 had type B dissection. Placement of an endovascular stent-graft was technically successful in 8 patients, and one underwent an open procedure for abdominal aortic fenestration. The entry site was sealed and the false lumen disappeared in 8 cases, and thrombosis of the false lumen was obtained. Rupture of an iliac artery dissecting aneurysm occurred in one patient 2 days after stent-graft placement; abdominal aortic fenestration with prosthetic replacement of the distal abdominal aorta was performed. One patient died of myocardial infarction 3 days after the stent-graft procedure. During a mean follow-up period of 7 months (1-16 months), one patient died of acute myocardial infarction at 11 months. It was concluded on the basis of these short-term results that endovascular repair of aortic dissection is a promising treatment, and abdominal aortic fenestration is a useful adjuvant procedure.     

Postoperative evaluation of ascending aortic prosthetic conduits by magnetic resonance imaging

Operative repair of ascending thoracic aortic dissection and aneurysm often involves the placement of prosthetic aortic conduits and stents with wrapping of the native aorta around the prosthetic device. Postoperative assessment has been clinical because of the absence of an adequate noninvasive imaging modality and a reluctance to perform invasive contrast aortography. Magnetic resonance imaging was performed on ten patients after operative placement of a prosthetic ascending aortic graft. The MR images were reviewed and a grading system was devised based on appearance of the operative site. An increase in MR signal was noted in some patients between the graft and wrapped native vessel. In 20 percent of patients vascular lumen compromise was noted. Magnetic resonance imaging offers a noninvasive technique to assess postoperative complications and offers a viable alternative to invasive contrast aortography.     

Aortic dissection after open repair of an infrarenal aortic aneurysm

INTRODUCTION:

A case of thoracic-abdominal dissection after open surgical exclusion of an infrarenal aortic aneurysm is presented.

CASE PRESENTATION:

A 62-year-old woman was diagnosed with an infrarenal abdominal aortic aneurysm with a rapid increase in maximal diameter. She underwent surgery for aneurysm exclusion by an end-to-end aortoaortic bypass with Dacron collagen (Intervascular; WL Gore & Associates Inc, USA). After 15 days, she was admitted to the emergency department with intense epigastric and lumbar pain. Computed tomography angiography with contrast revealed an aortic dissection with origin in the proximal bypass anastomosis and cranial extension to the thoracic aorta. The true lumen at the level of the eighth thoracic vertebra was practically collapsed by the false lumen. The celiac trunk, and the mesenteric and renal arteries were perfused by the true lumen. After the acute phase of the aortic dissection, surgical repair was planned. Two paths of false lumen were found – one at the thoracic aorta and the second in the proximal bypass anastomosis. Surgical repair comprised two approaches. First, a Valiant Thoracic stent graft (Medtronic Inc, UK) was implanted distal from the left subclavian artery, expanding the collapsed true lumen and covering the false and dissected lumen. Second, an infrarenal Endurant abdominal stent graft (Medtronic Inc) was implanted. This second device was complemented with an aortic infrarenal extension using a Talent abdominal stent graft (Medtronic Inc) in the infrarenal aortic neck to achieve a hermetic seal. The postoperative clinical course was uneventful, and her symptoms were completely resolved in six months.

CONCLUSION:

Arteritis must be taken into account in young patients with high inflammatory markers. Covered stents and endoprosthetic devices seem to be effective methods to seal the dissected lumen.     

Right pulmonary artery occlusion secondary to a dissecting aortic aneurysm

This report describes a case of right pulmonary artery obstruction caused by a dissecting aneurysm of the thoracic aorta. Initial ventilation-perfusion (V/Q) scan revealed no perfusion to the right lung. Lack of right lung perfusion plus other clinical abnormalities led to an initial diagnosis of massive embolism in the right lung. Bilateral pulmonary arteriography of the thoracic and abdominal aorta revealed extrinsic compression of the right pulmonary artery near its origin and the suggestion of an ascending aortic dissection. Subsequent ascending aortography and computed tomography (CT) confirmed a dissection of the ascending aorta. Aortography in the true lumen of the aorta revealed trivial aortic insufficiency. These diagnostic procedures confirmed the presence of an acute dissecting aneurysm of the ascending aorta that caused compression of the right pulmonary artery. The finding of a massive unilateral segmental defect with normal ventilation upon lung scanning does not always ensure a diagnosis of acute pulmonary embolus. Patient presentation with massive unilateral perfusion defect merits further evaluation with pulmonary arteriography.     

DeBakeyⅢ型主动脉夹层21例的临床诊治

目的 探讨主动脉腔内隔绝术（endovascular aortic repair,EVAR）治疗DeBakeyⅢ型主动脉夹层的技术方法及疗效.方法 对近3年江西省人民医收治的21例DeBakeyⅢ型主动脉夹层患者的临床资料进行回顾性分析.19例患者均行左锁骨下动脉穿刺,行升主动脉造影,了解主动脉真假腔、夹层裂口及其与重要血管分支的位置关系.切开右侧股动脉置入覆膜血管内支架,封堵原发破口,置入支架后重复造影检查以观察真假腔血流变化、主动脉分支供血的情况.结果 19例患者支架置入定位准确,术后即刻造影显示真腔血流恢复正常.手术成功率100％,无截瘫及瘤体破裂等严重并发症,无围术期死亡.所有患者术后3～6个月复查增强计算机断层扫描,假腔不再显影,支架通畅,无扭曲、移位.结论 EVAR治疗DeBakeyⅢ型主动脉夹层是安全有效的,但远期效果有待进一步观察.     

腔内隔绝术治疗主动脉瘤23例疗效观察

目的：探讨腔内隔绝术治疗主动脉瘤的疗效。方法回顾性分析23例经腔内隔绝术治疗主动脉瘤患者的一般临床资料、手术情况、手术结果和术后随访情况。结果23例患者均手术成功,术后造影见主动脉瘤体（或夹层假腔）消失,支架无移位,无发生截瘫;1例术后18h突发脑血管意外抢救无效死亡,总治愈率为95．7％（22／23）。术后并发症主要为内漏,其中Ⅰ型内漏3例,Ⅱ型内漏2例,发生率为21．7％（5／23）,急性肾功能不全4例（17．4％）;脑卒中1例,发生率为4．3％（1／23）。随访4个月-60个月,2例失访。随访期间死亡2例,死亡原因1例为恶性肿瘤转移,另1例为复发性降主动脉夹层破裂大出血：随访期经复查,5例早期并发内漏者内漏消失,假腔血栓形成。结论腔内隔绝术治疗主动脉瘤安全而且有效。     

Midterm results of aortic diameter outcomes after thoracic stent-graft implantation for aortic dissection: a multicenter study.

PURPOSE: To evaluate aortic diameter outcomes after stent-graft implantation for aortic dissection in the descending thoracic aorta. METHODS: Fifty patients with type A dissection after ascending aortic surgery (n = 10), type B dissection (n = 34), or intramural hematoma (n = 6) underwent stent-graft repair in 3 centers. Thrombosis and aortic diameter were analyzed by computed tomographic angiography at different levels of the aorta before stent-graft implantation, at discharge, and at follow-up. Measurements were standardized. RESULTS: In all, 67 stent-grafts were implanted for acute (n = 18) and chronic (n = 32) dissection. Stent-graft placement was successfully performed with high technical success (100%) despite 4 major complications (iliac thrombosis in 2 cases, aortic rupture, and a type A dissection) in 3 (6%) patients. Complete thrombosis of the thoracic false lumen was observed in 42% and 63% of cases at discharge and at follow-up (mean 15 months), respectively. At follow-up, the diameters of the entire aorta (mean 5 mm, p < 0.05) and the false lumen (mean 11 mm, p < 0.0001) decreased. Diameters of the abdominal aorta remained stable in association with persistent false lumen perfusion at this level. Aortic diameter results were better in the subgroup of patients with intramural hematoma compared to patients with Marfan syndrome. Three early deaths unrelated to the stent-graft procedure occurred; 2 patients with partial thrombosis of the false lumen died in follow-up secondary to aortic diameter growth. CONCLUSION: Complete thrombosis of the false lumen by stent-graft coverage of the entry tear results in decreased diameter of the entire aorta. In patients with partial thrombosis of the false lumen, the aneurysm continues to enlarge.     

Rapid progression of discrete type A intramural hematoma: prevention of a "procedure-related" complication by intraoperative transesophageal echocardiography.

PURPOSE: To report a case illustrating the utility of transesophageal echocardiography (TEE) before planned stent-graft placement for chronic type B aortic dissection. CASE REPORT: A 64-year-old man with acute aortic syndrome and an 8-year-old interposition graft in the distal aortic arch for acute type B dissection was referred for dissection of the descending thoracic aorta down to the aortic bifurcation; the false lumen was dilated to 65 mm and was partially thrombosed. The ascending aorta showed discrete, eccentric, 4-mm wall thickening that was not considered clinically significant. Stent-graft closure of the entry tear in the proximal descending thoracic aorta was elected. However, as the endovascular procedure was about to commence, TEE showed striking eccentric thickening of the aortic wall of up to 18 mm. The endovascular procedure was stopped, as it was decided to urgently replace the ascending aorta. The next day, the patient underwent successful ascending aortic replacement and simultaneous antegrade stent-graft implantation over the descending thoracic aortic entry tear via the open aortic arch. The postoperative course was uncomplicated, and the patient was discharged 19 days after surgery. He remains well at 6 months after the procedure. CONCLUSIONS: Our case demonstrates that dissection of the ascending aorta may occur not only due to endograft-induced intimal injury, but may also occur due to underlying but undiagnosed or underestimated disease of the ascending aorta or arch. Besides procedural guidance, intraoperative TEE is a useful tool to detect such disease to avoid subsequent "procedure-related" complications.     

Distal Aortic Malperfusion Exacerbated by Antegrade Stent-Graft Placement During Hybrid Repair of Acute DeBakey Type I Aortic Dissection

We present the case of an acute DeBakey type I aortic dissection with malperfusion. The patient underwent valve resuspension, ascending aortic and partial arch replacement, debranching of the innominate artery, and placement of a small-diameter stent within the left common carotid artery, after which antegrade deployment of a stent-graft into the proximal descending thoracic aorta was performed to expand the true lumen. Distal malperfusion was exacerbated by the stent-graft''s traversal into the false lumen, necessitating further endovascular repair to reestablish flow to the distal aorta. Mitigation before stent-graft placement (for example, inserting a wire within the true lumen under fluoroscopic guidance to ensure stent-graft placement in the true lumen) and prompt corrective procedures are paramount, given the grim consequences of prolonged distal ischemia.     

血管腔内覆膜支架治疗胸降主动脉瘤

目的探讨覆膜支架治疗急、慢性胸降主动脉瘤的方法及效果。方法对36例胸降主动脉瘤的临床资料作回顾性分析。结果使用覆膜支架36枚,完全封堵动脉内膜破口,真腔血流恢复正常,近期疗效满意。结论使用覆膜支架腔内隔离术治疗胸降主动脉瘤,符合其病理解剖特点,能很好地封闭内膜破口．具有创伤小、适应证宽、治疗效果确切、康复迅速等优点。     

Provisional extension to induce complete attachment after stent-graft placement in type B aortic dissection: the PETTICOAT concept.

PURPOSE: To report the use of a technique (PETTICOAT: provisional extension to induce complete attachment) to obliterate sustained abdominal false lumen flow and pressurization despite successful stent-graft sealing of the thoracic entry tear in patients with complicated type B aortic dissection. METHODS: Of 100 initial patients subjected to stent-graft repair for complex type B aortic dissection with thoracoabdominal extension, 12 patients (10 men; mean age 58.7 years, range 44-76) demonstrated distal true lumen collapse and a perfused abdominal false lumen despite successful sealing of the proximal tears. As an adjunctive or staged procedure, a scaffolding stent was placed for distal extension of the previously implanted stent-graft. In each case, a Sinus aortic stent, Fortress stent, or a Z-stent system was customized with maximum 2-mm oversizing versus the original stent-graft diameter. Magnetic resonance or computed tomographic angiography was performed at discharge, at 3 months, and then annually to determine false channel thrombosis, true and false lumen dimensions, and re-entry flow. RESULTS: Delivery was successful in all cases (100%). The compressed distal true lumen (mean 4+/-3 mm) was reconstructed to a mean width of 21+/-3 mm, and malperfusion was abolished without any obstruction of the abdominal side branches. At up to 1-year follow-up, there were no signs of expansion or distal progression of the scaffolded dissected aorta. All patients with complete thoracic thrombosis showed evidence of improved aortic remodeling; 1 patient with no false lumen thrombosis died at 11 months from thoracoabdominal aortic rupture. CONCLUSION: The PETTICOAT technique may offer a safe and promising adjunctive endovascular maneuver for patients with distal malapposition of the dissecting membrane and false lumen flow. The technique can both abolish distal true lumen collapse and enhance the remodeling process of the entire dissected aorta.     

Endoluminal stent-graft repair in a patient with coarctation of the aorta and previous iatrogenic type B aortic dissection and expanding pseudoaneurysm

Purpose: To report endoluminal repair of aortic coarctation in a patient with a chronic type B aortic dissection presenting with an expanding pseudoaneurysm after failure of surgical repair. Case Report: This 30-year-old man with a congenital coarctation of the aorta suffered an iatrogenic type B aortic dissection during angiography at the age of 6. Emergent surgery at that time included a left subclavian artery-to-distal thoracic aorta surgical conduit; the coarctation itself was not repaired. The patient presented 24 years after the surgery with a chronic distal extension of the dissection and a pseudoaneurysm severely compressing the aortic true lumen; the disrupted surgical conduit drained into the false lumen. In a novel approach, the true aortic lumen was intentionally occluded, and the surgical conduit was secured with stent-grafts to successfully exclude the pseudoaneurysm from the circulation. Conclusion: Type B dissection and coarctation of the aorta, in the setting of complex aortic pathology and comorbidities, can be treated with an endovascular approach.     

A Spontaneous Dissecting Abdominal Aneurysm Originating from the Iliac Artery

Aortic dissection often involves the thoracic and abdominal aorta, whereas isolated abdominal aortic dissection is rare. Few cases of abdominal aortic dissection caused by iliac arterial dissection have been reported. Herein, we report a case of spontaneous isolated abdominal dissection in which both the entry and exit sites were in the iliac arteries. The patient was treated successfully using the endovascular aneurysm repair procedure.     

血管内超声介导下主动脉夹层腔内修复术——无造影剂介入治疗1例报道

目的探讨血管内超声代替基于造影剂的血管显影指引主动脉腔内修复术的可行性和价值。方法我们对1例StandfordB型主动脉夹层合并肾功能不全患者行主动脉腔内修复术,术中使用血管内超声指引寻腔、定位、支架释放和进行解剖学检查,全程避免使用造影剂。结果手术使用造影剂0mL,手术时间125min,寻腔、定位及支架释放过程顺利。支架到位准确,扩张及贴壁良好。术后无内漏或新发夹层,无其他并发症。术后1周患者血清肌酐浓度无增高。结论在本例患者中,血管内超声代替基于造影剂的血管显影指引主动脉腔内修复术可行,该技术可能避免肾功能不全患者肾功能恶化。     

Value of transesophageal echocardiography combined with computed tomography for assessing repaired type A aortic dissection.

Thirty-two patients with repaired type A aortic dissection were examined by transthoracic echocardiography (TTE) (n = 32), transesophageal echocardiography (TEE) (n = 30), computed tomography (CT) (n = 29), or a combination of all 3, to assess course and complications as a function of the surgical procedure. The mean follow-up period was 55.7 months (range 3 to 132). Surgery consisted of a replacement of the ascending aorta in 25 patients (group 1) with extension to the transverse aorta in 7 (group 2). The transverse diameter of the aorta, the persistence of the false lumen, thrombus formation and flow dynamics in the false lumen were evaluated by TEE. Ten patients (31%) had a dilation in the initial ascending aorta (sinus of Valsalva aneurysm in 6 patients, and a false aneurysm in the other 4). Three of 4 patients with a proximal pseudoaneurysm underwent operation after TEE and CT evaluation. In the descending thoracic aorta, there was good agreement between TEE and CT scan determinations of transverse vessel diameter. Persistence of flow within the false lumen was significantly more frequent in patients with a dilated aorta (p < 0.05), whereas thrombosis was seen more often and false lumen less often in patients with nondilated aorta. No significant differences in vessel status or outcome were observed between the 2 groups, although this may have been due to the small size of group 2. TEE is thus a well-tolerated method for postoperative follow-up of type A aortic dissection whatever the type of surgery. For the upper ascending aorta, CT provided sufficient data.