Phase contrast MR imaging to measure changes in collateral blood flow after stenting of recurrent aortic coarctation: initial experience

PURPOSE: To assess the feasibility of using phase contrast magnetic resonance (PC-MR) imaging to measure the change in collateral blood flow early after stenting of aortic coarctation. MATERIALS AND METHODS: A total of 10 consecutive patients with coarctation of the aorta underwent MR imaging, X-ray angiography, and stent placement. PC-MR at two sites in the descending aorta was performed before and early after stenting in order to estimate collateral inflow to the descending thoracic aorta. The collateral flow and collateral flow percentage before and after stent placement were compared. RESULTS: Before stenting, the mean proximal aortic flow = 43.9 +/- 14.6 mL/second; mean distal flow = 54.2 +/- 10 mL/second; collateral flow = 10.2 +/- 6.8 mL/second; and collateral flow percentage = 30.1 +/- 27.9%. After stenting, the mean proximal aortic flow = 62.1 +/- 17.9 mL/second; mean distal flow = 60 +/- 19 mL/second; collateral flow = -1.9 +/- 3.7 mL/second; and collateral flow percentage = -3.3 +/- 6.8%. CONCLUSION: PC-MR can be used to measure changes in collateral circulation after stent treatment of coarctation of the aorta.     

Interventional cardiovascular procedures guided by real-time MR imaging: an interactive interface using multiple slices, adaptive projection modes and live 3D renderings

PURPOSE: To develop and test a novel interactive real-time MRI environment that facilitates image-guided cardiovascular interventions. MATERIALS AND METHODS: Color highlighting of device-mounted receiver coils, accelerated imaging of multiple slices, adaptive projection modes, live three-dimensional (3D) renderings and other interactive features were utilized to enhance navigation of devices and targeting of tissue. RESULTS: Images are shown from several catheter-based interventional procedures performed in swine that benefit from this custom interventional MRI interface. These include endograft repair of aortic aneurysm, balloon septostomy of the cardiac interatrial septum, angioplasty and stenting, and endomyocardial cell injection, all using active catheters containing MRI receiver coils. CONCLUSION: Interactive features not available on standard clinical scanners enhance real-time MRI for guiding cardiovascular interventional procedures.     

Time-resolved MR angiography for the classification of endoleaks after endovascular aneurysm repair

PURPOSE: To evaluate the utility of time-resolved MR angiography (TR-MRA), compared with digital subtraction angiography (DSA), in the classification of endoleaks in patients who have undergone endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: Thirty-one patients who had undergone EVAR to repair an abdominal aortic aneurysm were evaluated with both TR-MRA and DSA to determine endoleak etiology. The patient population consisted of 26 men and 5 women with a mean age of 78.5 years (range, 55-93 years). The mean time interval between TR-MRA and DSA was 1.5 weeks (range, 1-8 weeks). Endoleaks were classified as type II when enhancement of the external iliac vessels was observed before the appearance of the endoleak; otherwise the endoleak was classified as type I or III. The results of TR-MRA classification were compared with the reference gold standard, DSA. RESULTS: Agreement between TR-MRA and DSA regarding endoleak classification occurred in 30 of 31 cases (97%). Discordant classification occurred in a case in which a Type II endoleak was misclassified as a Type III due to failure to visualize a lumbar vessel. CONCLUSION: TR-MRA is highly effective in classifying endoleaks following EVAR when compared with DSA.     

经皮主动脉腔内修复术初步经验

目的 总结经皮主动脉腔内修复术(PEVAR)中应用ProGlide血管缝合器的经验,探讨PEVAR术适应证及禁忌证,评估该技术可行性、安全性和有效性.方法 回顾性分析2014年4月至2015年5月采用PEVAR术治疗的38例患者临床资料,其中腹主动脉瘤26例,主动脉夹层10例,胸主动脉瘤2例.观察PEVAR术中应用ProGlide血管缝合器治疗手术技术成功率及围手术期并发症发生情况.结果 全部患者经PEVAR术治疗即刻技术成功率为100％ (38/38).术中共缝合64处股动脉入路穿刺点,其中缝合24～25 F血管鞘7例次,20～22 F血管鞘19例次,18 F以下血管鞘38例次.血管缝合器一次成功率为78％ (50/64),二次成功率为100％(14/14).无缝合失败及入路动脉闭塞,无围手术期相关严重并发症,患者均顺利出院.结论 PEVAR术中ProGlide缝合器使用安全有效,增强手术医师经验并严格掌握适应证,有助于降低缝合器缝合失败和手术相关并发症发生率.     

Stanford B型主动脉夹层腔内修复术治疗体会

目的:探讨腔内修复术治疗Stanford B型主动脉夹层的效果。方法:对2005-09~2010-02期间18例Stanford B型主动脉夹层患者实行血管造影和血管腔内带膜支架植入手术治疗,术后3、6、12个月行CTA检查,观察手术疗效以及有无狭窄、移位和扭曲等术后并发症。结果:无中转开胸手术。除1例再发Stanford A型夹层破裂死亡外,其余患者均顺利出院。结论:主动脉夹层腔内修复术治疗Stanford B型主动脉夹层是一种安全有效的方法,早期结果满意,中远期效果还有待观察。     

Standford B型主动脉夹层腔内修复术后主动脉重塑效果

目的 系统性回顾Standford B型主动脉夹层腔内修复术(TEVAR)后主动脉重塑结果.方法 检索已发表的评估TEVAR术后主动脉重塑文献,系统性回顾Standford B型主动脉夹层形态学测量方法及结果.共纳入19篇文献,其中仅3篇文献采用三维重建软件进行测量.各文献测量变量多为夹层真腔、假腔直径或面积,仅有少数文献计算了真假腔体积.结果 各文献测量的主动脉平面、术后随访时间及测量方法不同,无法进行数据整合.但总体趋势为急性B型夹层患者术后主动脉重塑效果(胸主动脉假腔血栓化比率为80％～90％)优于慢性患者(38％～91.3％),且更具有一致性;降主动脉术后假腔完全血栓化比率高于腹主动脉,降主动脉近端的主动脉重塑效果良好,膈肌角平面以下重塑效果较差.结论 尽管TEVAR术后主动脉重塑的描述方式各异,但多数文献显示夹层累及主动脉范围广者术后重塑效果差,与夹层远端裂口旷置有关.覆膜支架长度、治疗时间等因素对术后重塑均有影响.统一的评估标准有利于评估主动脉重塑效果,并为临床决策提供更有力的科学支持.     

主动脉腔内修复术中髂内动脉保留技术

主动脉腔内修复术(EVAR)是腹主动脉瘤的主要治疗手段,腹主动脉瘤伴发髂动脉瘤时保留髂内动脉已成为共识,可避免发生臀肌缺血、乙状结肠缺血及男性性功能障碍等并发症.随着近年腔内器械不断更新,EVAR术中保留髂内动脉成为可能.目前EVAR术髂内动脉重建术包括腔内髂分支支架技术、三明治技术、髂总动脉覆膜支架喇叭口技术、髂外动脉-髂内动脉腔内分流技术(反向“烟囱”技术)以及弹簧圈栓塞技术,该文就此作一总结.     

Vascular interventions guided by ultrafast MR imaging: Evaluation of different materials

The ability of MRI to acquire not only anatomical but also functional information makes MRI guided vascular interventions an interesting goal. Recent developments in ultrafast MR imaging sequences such as fast gradient echo or echo planar (EPI) mean that not only real time MRI but also MRI guided vascular interventions are real possibilities for the not too distant future. However, currently available guide wires and catheters are potentially unusable in MRI because they are either ferromagnetic or MRI invisible. In order to find different materials suitable for real time MRI, various devices were examined with fast gradient echo and interleaved EPI pulse sequences. The measurements were performed using a continuously running, pseudo real time MRI system to investigate the dynamic imaging behavior under guide wire insertion. Suggestions are made as how to construct guide wires and catheters, which can be visualized with ultrafast imaging sequences, while not causing prohibitive artifacts or image distortions.     

急性期Stanford B型主动脉夹层腔内治疗研究进展

随着胸主动脉腔内修复术（TEVAR）的广泛应用及迅速发展,腔内治疗已成为了Stanford B型主动脉夹层的一线治疗方法。腔内治疗主动脉夹层的预后除了依赖于术前个体化方案的制定和术中操作者的经验,更依赖于手术指征及时机的掌握。对于急性期复杂性B型夹层,提倡在药物治疗的基础上早期行TEVAR手术;对于急性期非复杂性B型夹层是否可行TEVAR手术仍存在争议。文章主要就急性期B型主动脉夹层行腔内治疗的研究进展进行综述。     

腔内修复术治疗非复杂性急性B型主动脉夹层及随访结果

目的评价覆膜支架胸主动脉腔内修复术(TEVAR)治疗非复杂性急性Stanford B型主动脉夹层(ATBAD)的近中期效果,并与复杂性ATBAD作比较。方法回顾性分析2003年5月至2012年6月收治的122例ATBAD患者临床资料。根据临床特征,分为非复杂性ATBAD组(A组,n=73)和复杂性ATBAD组(B组,n=49)。TEVAR术后随访5年,对比两组围手术期并发症、30 d死亡率、5年主动脉相关事件、免于主动脉相关事件发生率和中期生存率。结果 A组与B组相比,围手术期并发症发生率(8.2%对42.9%,P<0.01)、30 d死亡率(0%对12.2%,P=0.008)均显著降低;5年中期随访显示,主动脉相关事件发生率(5.5%对7.0%,P=1.000)、中期死亡率(2.7%对7.0%,P=0.352)均相似,免于主动脉相关事件发生率(P=0.661)、中期生存率(P=0.245)差异均无统计学意义。结论 TEAVR治疗非复杂ATBAD可行、有效。与复杂ATBAD相比,非复杂ATBAD经TEVAR治疗获得了更好的近期效果,中期效果相似。     

Branched stent-grafts for endovascular repair of aortic and iliac aneurysms

Endovascular technique, which gains access through indirect transarterial routes and isolates the aneurysm without interrupting flow, has particular advantages in aneurysms of the aortic arch and thoracoabdominal aorta. Yet progress has been slow. The necessary branched stent-grafts face several unique technical challenges. The simplest, most versatile approach involves assembling a modular stent-graft in situ from multiple parts. Techniques vary according to the presence or absence of an overlap zone, or cuff. The first cases of this type, reported over 4 years ago, had axially oriented cuffs. Recent efforts have seen the intercomponent attachment site reduced to a ring of Nitinol around a simple fenestration, with various hybrids of cuffed and fenestrated technique in between. Other advances, such as better sheaths, better covered stents, and commercial manufacture (Cook, Australia), have helped to extend the use of branched stent-grafts to a wider range of users and a wider range of aneurysms. Although their future role remains unclear, all these devices have gone beyond the proof of concept stage, and some, such as the bifurcated component for the endovascular iliac reconstruction, are ready to become standard parts of the endovascular.     

MR imaging during endovascular procedures: An evaluation of the potential for catheter heating

MRI in catheterized patients is considered unsafe due to the potential for focal heating. This concern arises from the continuous metallic braid that is incorporated into catheters to provide their desired physical properties. The potential for catheter heating during MR scanning was assessed in an in vitro model simulating a patient undergoing a neurovascular procedure in which MR scans of the brain will be performed. Heating adjacent to endovascular devices was assessed with fluoroptic temperature probes in a polyacrylamide gel. The effect of variable immersion lengths, lateral and longitudinal offsets, position along the endovascular device, physical MR system, and specific absorption rate (SAR) level were studied to determine their effect on catheter heating. A rapid temperature rise was evident next to endovascular devices during MR scanning and varied moderately with immersed length, position within the bore, measurement point on the device, and MR system used. Peak heating rates were less than 1°C/min with maximal SAR exposure and anatomically realistic geometries. Heating scaled linearly with SAR and SAR values below 0.2 W/kg produced negligible heating near catheters. For the evaluated application, substantial SAR restrictions, coupled with limited imaging durations, are proposed as sufficient to permit MRI without concern for thermal injury. Magn Reson Med 61:45–53, 2009. © 2008 Wiley‐Liss, Inc.     

Clinical evaluation of aortic coarctation with 4D flow MR imaging

Purpose:

To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation.

Materials and Methods:

Time‐resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers.

Results:

Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r = 0.99, limits of agreement = ?20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation.

Conclusion:

4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair. J. Magn. Reson. Imaging 2010;31:711–718. © 2010 Wiley‐Liss, Inc.

     

Stanford B型主动脉夹层腔内修复术后血管重塑分析

目的 探讨Stanford B型主动脉夹层患者经胸主动脉腔内修复术(TEVAR)治疗后血管形态学转归.方法 回顾性分析51例接受TEVAR术治疗的Stanford B型主动脉夹层患者术前及术后临床及影像学资料,分析术后1个月内、1～6个月、6个月后主动脉各段真假腔内径及假腔血栓化情况.结果 TEVAR术后胸主动脉真腔扩大、假腔缩小,与术前比较差异有统计学意义(P＜0.05),腹主动脉管径真腔和假腔变化较术前无统计学差异(P＞0.05),腹部重要分支动脉血供情况较术前有所改善.结论 TEVAR术治疗Stanford B型主动脉夹层患者的近中期效果确切,但仍需要远期随访观察.     

Stanford B型夹层动脉瘤腔内隔绝术治疗30例临床观察

目的探讨腔内隔绝术（EVGE）治疗Stanford B型夹层动脉瘤的经验。方法对2009年2月～2011年7月在我院住院的30例Stanford B型主动脉夹层病患者的治疗经过进行回顾性分析。术前采用320排（640层）动态容积CT对主动脉夹层动脉瘤进行评估,术中在数字减影血管造影监视下,经股动脉将移植物导入胸主动脉封闭夹层裂口。结果 EVGE成功率100%,2例患者完全封闭左锁骨下动脉开口,无左上肢及脑供血不足症状;1例术后有残余内漏,于术后3个月自行封闭;其余患者无明显不适症状,情况良好。结论 EVGE治疗Stanford B型夹层动脉瘤安全、有效、创伤小、恢复快。     

Stanford B型夹层覆膜支架血管腔内修复术后围术期死亡原因分析

目的分析Stanford B型主动脉夹层覆膜支架血管腔内修复术(TEVAR)后围术期患者死亡情况及可能的死亡原因。 方法2004年2月—2012年9月,254例症状性Stanford B型主动脉夹层患者在本中心接受覆膜支架血管腔内修复术(TEVAR)治疗,其中,男性214例,女性40例,平均(51.5±12.5)岁。统计TEVAR术后围术期患者死亡情况,并分析可能的死亡原因。 结果TEVAR术后围术期患者死亡7例(7/254,2.76﹪),其中男性5例,女性2例。可能的死亡原因中,破裂所致死亡3例(3/254,1.18﹪),肠道缺血死亡2例(2/254,0.79﹪),呼吸功能衰竭死亡1例(1/254,0.39﹪),心源性猝死1例(1/254,0.39﹪)。 结论TEVAR术治疗症状性Stanford B型主动脉夹层安全、有效,但TEVAR术后围术期患者死亡情况仍需重视,在引起死亡的各种原因中,破裂和肠道缺血引起的死亡尤其值得关注。     

腔内修复治疗累及左锁骨下动脉的主动脉夹层动脉瘤

目的 探讨累及左锁骨下动脉的主动脉夹层动脉瘤腔内修复治疗的手术方式及疗效.方法 回顾性分析2004年1月至2014年12月采用不同腔内修复术式治疗56例主动脉夹层动脉瘤患者临床资料,其中男42例,女14例.采用“烟囱”技术重建左锁骨下动脉血流26例(A组),分支支架技术重建10例(B组),复合手术重建20例(C组).术中使用国产覆膜支架26例,进口覆膜支架30例;全身麻醉48例,局部麻醉8例.结果 手术全部成功(100％),无手术死亡患者.A组植入裸支架11例,覆膜支架15例;C组4例先植入胸主动脉覆膜支架,直接覆盖左锁骨下动脉,再作腋-腋动脉人工血管旁路移植术;16例先作腋-腋动脉人工血管旁路移植术,再行主动脉腔内修复覆盖左锁骨下动脉.3组患者出院时CTA检查显示支架形态均良好,无明显移位,组间差异无统计学意义(P＞0.05).内漏发生在A组有4例(15.4％),B组1例(11％),C组1例(5％),组间差异均无统计学意义(P＞0.05).52例(92.9％)患者获平均23.5个月随访,死亡5例(9.6％),原因为心肌梗死(2例)、肿瘤(3例).47例CTA随访发现6例仍有部分内漏,24例远端胸腹主动脉仍有夹层但未扩大,未作特殊处理,目前均在随访中.结论 “烟囱”技术、分支支架技术和复合手术修复治疗累及锁骨下动脉的主动脉夹层动脉瘤是安全有效的.