Localization of a misplaced coronary artery stent by magnetic resonance imaging

Coronary artery stents have been developed to overcome arterial abrupt closure and restenosis following balloon angioplasty. Complications of stent insertion include loss of the device from its delivery system into the peripheral circulation. Certain types of stents are almost radiolucent, making localization of the lost devices difficult. Nonferromagnetic metallic biomedical implants induce alteration of the local magnetic field and this leads to loss of signal from the surrounding tissues. We have used this property to localize a misplaced coronary artery stent in a 53-year-old man who underwent unsuccessful stent insertion. A 0.5 Tesla magnetic resonance scanner was used to acquire gradient-echo and spin-echo images. An in vitro experiment was first carried out on a stent similar to that used in our patient to establish that it was nonferromagnetic and to determine the optimum imaging technique. Gradient-echo images with a relatively long echo time (22 ms) gave the largest area of signal loss around the stent, and this sequence was used for localization of the stent found in the patient's left profunda femoris artery. This was subsequently confirmed by digital radiography. We have demonstrated the convenience and practicality of using magnetic resonance imaging for the localization of a misplaced coronary artery stent in a patient. The technique is safe, noninvasive, and uses no ionizing radiation.     

Clinical application of a new palmaz-schatz coronary stent delivery system with a short (8 mm) nonarticulated stent

The standard Palmaz-Schatz coronary stent delivery system (SDS), with a 15 mm articulated stent and a 5F protective sheath, is relatively rigid and high in profile. Its use is contraindicated in vessels where there is severe tortuosity proximal to or in the lesion itself. Recently a new SDS, with a short (8 mm) nonarticulated stent, has become available. We present three patients with complex coronary anatomy solved with this new SDS. The first patient had a distal stenosis in an extremely tortuous and diffusely diseased right coronary artery (RCA). The second patient had a severe proximal RCA stenosis occurring at a bend of more than 90 degrees. The third patient had a very long stenosis of the left anterior descending coronary artery involving the ostium, requiring multiple tandem stenting. The availability of this short stent will greatly expand the clinical application of intracoronary stenting to patients with complex coronary anatomy.     

Initial clinical results with the Wiktor stent: a new balloon-expandable coronary stent

The Wiktor stent, a new coronary balloon-expandable tantalum stent, was implanted in 17 patients for other wise nonmanageable occlusion after balloon angioplasty (n = 11) and for recurrent restenosis (n = 6). Stents of 3.0 to 4.0 mm were implanted (right coronary artery: n = 10, left anterior descending artery: n = 4, left circumflex artery: n = 2, venous graft: n = 1). All patients were fully anticoagulated initially with heparin followed by coumadin for 3 months and were treated with acetylsalicylic acid indefinitely. Due to its good radiopacity, the device could be placed easily without complications. Early occlusion occurred in one patient after 8 h probably due to friable atheromatous material prolapsing between the meshes of the stent. Late occlusion occurred in another patient who was admitted in cardiogenic shock after pre-hospital reanimation and was stented after occlusive disection following balloon angioplasty of an occluded right coronary artery. In this patient with severe hypoxic brain damage, reocclusion and reinfarction to which the patient finally succumbed occurred following cessation of anticoagulation. Histology demonstrated occlusive thrombosis without evidence of a neointimal covering of the stent. Another thrombotic occlusion due to inadvertent omission of anticoagulation occurred in another patient two weeks after stenting. Control angiography after 6 months in 12 patients revealed restenosis in two patients (50% and 80%). The patient with 80% restenosis of the right coronary artery and pathologic results during stress testing underwent surgical revascularization. The other patient with a 50% restenosis of the right coronary artery was managed medically as he was asymptomatic and without evidence of ischemia during stress testing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Embolization of a Wiktor stent within a stent: Successful nonsurgical management

A case of embolization of an unexpanded Wiktor stent while attempting to traverse an expanded Wiktor stent is reported. The embolized stent was subjected to longitudinal axial traction, using a balloon catheter to cause stretching and partial unraveling. This partially unraveled stent was deployed across the dissection to scaffold it. The patient had no postprocedure complications. © 1996 Wiley-Liss, Inc.     

冠状动脉内植入国产支架的临床研究

目的　评价国产冠状动脉支架 (金新支架 )临床应用的有效性和安全性。方法　选择冠心病患者 10例 ,年龄 39～ 70岁 (平均 5 5 2岁 ) ,男 7例 ,女 3例 ,分别在前降支 (2支 ) ,回旋支 (3支 ) ,右冠状动脉 (5支 )植入金新动脉支架 (其中 7例预扩张后植入 ,3例直接植入 )。结果　支架植入前冠脉病变局部狭窄为 80 %～ 10 0 % (平均 85 % ) ,植入后残余狭窄为 0 ,术中无急性血管闭塞和急性血栓形成 ,随诊 6～ 8个月无心脏病事件 (急性心梗、心绞痛、猝死 )发生。结论　金新支架释放和支撑能力好 ,支架扩张程度完全 ,在冠心病介入治疗中应用安全、有效、无急性并发症发生     

Coroflex冠状动脉内支架的临床应用

目的　评估Coroflex冠状动脉内支架的临床应用效果。方法　回顾性分析 81例接受Coroflex冠状动脉内支架置入术患者的即刻疗效和临床随访结果。结果　 81例患者共置入Coroflex冠状动脉内支架 88枚。根据ACC AHA分型 ,A B1 型病变 38处 ,B2 C型病变 5 0处。原发病变 5 2处 ,单纯球囊扩张术疗效不满意病变 2 2处 ,内膜撕裂病变 14处。支架成功置入 82处 (93 2 % )。 3例严重钙化病变需辅以高压 (16～ 18atm)球囊才充分扩张 ,2例支架远端发生内膜撕裂 ,1例弥漫性病变支架置入术后TIMI血流 2级。 75例患者平均随访 (7 5± 3 0 )月 (3～ 13月 ) ,无心源性死亡和心肌梗死 ;17例 (2 2 7% )有心绞痛 (CCS分类Ⅰ级 )发生 ;7例行冠状动脉造影复查 ,2例显示支架内再狭窄 ,予再次血管重建术后缓解。结论　Coroflex冠状动脉内支架可安全有效地应用于冠心病的介入治疗。     

应变率成像评价冠心病支架置入术前后左心室局部收缩功能变化的研究

目的:探讨应变率成像技术(SRI)定量评价冠心病支架置入术后早期左心室局部收缩功能变化的临床价值。方法:50例经冠状动脉造影(CAG)证实存在左前降支(LAD)75%～100%不同程度的狭窄,分别在LAD支架置入术前1～3d,术后7d、3个月测量前壁及前间隔的基底段、中间段和心尖段的收缩期应变率(SRs)及左心室局部收缩功能的变化,测量左心室射血分数(LVEF),并与正常对照组(50例)进行比较。结果:与术前相比,术后7d各节段心肌的应变率均有增加(P<0.05),术后3个月各节段心肌的应变率、LVEF明显增加(P<0.01)。术前平均LVEF为0.468±0.076,术后7d增加为0.517+0.059(P<0.05),术后3个月则增加0.587±0.038(P<0.01)。结论:SRI可以无创定量评价冠心病冠状动脉支架置入术后早期左心室局部收缩功能的变化。     

冠状动脉内置入国产支架的实验研究

目的　评价金新动脉支架置入小型猪正常冠状动脉内的可行性 ,观察支架置入后各时相支架段血管开通情况及血管内膜反应。方法　将 39枚国产冠状动脉内支架置入 2 0头小型猪冠状动脉内 ,每头小型猪的左前降支及左回旋支各被置入支架 1枚 ,观察置入 2 4h、1周、2周、4周、12周及 6个月血液动力学、肝功能、肾功能变化及冠状动脉造影随访结果 ,并对支架置入段血管进行光镜及电镜检查。结果　①该种冠状动脉内支架置入成功率为 97 5 % ,支架置入对血液动力学、肝功能、肾功能无影响。②冠状动脉造影随访示所有支架置入即刻和动物处死前支架段血管开通率10 0 %。支架X光下清晰可见 ,未经特殊抗血栓治疗 ,支架段血管内无血栓形成。未见与置入支架有关的心脏事件发生。③组织病理学形态分析显示新生内膜由不同排列的纤维组织和平滑肌细胞 (SMCs)组成 ,置入支架 1周开始有内膜覆盖支架丝 ,2周时可检测到光滑的新生内膜 ,置入支架后 1周、2周、4周、12周、2 4周支架小梁处新生内膜厚度分别为(5 6 17± 31 15 ) μm、(10 9 72± 4 1 6 1) μm、(348 2 5±5 6 78) μm、(2 5 6 2 5± 5 5 97) μm、(14 8 6 1± 39 82 ) μm。支架小梁间新生内膜厚度分别为 (37 2 1± 2 7 5 0 ) μm、(6 4 5 6±36 5 7) μm、(1     

Driver冠状动脉内支架的临床应用

目的评估Driver冠状动脉内支架的临床应用效果。方法回顾性分析49例接受Driver冠状动脉内支架置入术患者的即刻疗效和临床随访结果。结果49例患者根据ACC/AHA分型,A-B1型病变25处,B2-C型病变29处。全部支架成功置入。1例术后TIMI血流2级。平均随访6～9月,无心源性死亡和心肌梗死,2例行冠状动脉造影复查,未显示支架内再狭窄。结论Driver冠状动脉内支架可安全有效地应用于冠心病的介入治疗。     

门控核素心肌灌注显像判断冠状动脉支架再狭窄的价值

目的:探讨门控核素心肌灌注显像(G-MPI)对冠状动脉(冠脉)支架再狭窄的诊断价值.方法:65例冠脉支架术后3个月以上的患者行两日法负荷/静息99Tcm-甲氧基异丁基异腈(MIBI) G-MPI,所有患者的G-MPI与冠脉造影(CAG)均在同期的1个月内完成,其中先做CAG检查的患者未进行再次血运重建术.以CAG为标准,分析G-MPI诊断冠脉支架再狭窄的价值.结果:65例患者的88支冠脉共置入105枚支架,随访CAG发现38.5%(25/65)的患者出现支架再狭窄,发生再狭窄的支架数为29.5%(31/105);根据典型症状诊断支架再狭窄的敏感性、特异性和准确性分别为64.0%、22.5%、38.5%;心电图运动平板试验(ETT)诊断支架再狭窄的敏感性、特异性、准确性分别为41.2%、71.9%、61.2%;G-MPI诊断支架再狭窄的敏感性、特异性、准确性分别为92.9%、86.7%、88 6%,其准确性明显优于ETT(χ2=14.173,P<0.001)和症状(χ2=42.781,P<0.001).结论:G-MPI诊断冠脉支架术后再狭窄具有良好的价值.     

Protection of side-branches in coronary lesions with a new stent design

Side-branches often complicate stenting of coronary lesions. We investigated a new stent, characterized by four wider cells in its center, which can be expanded up to 3.5 mm and which are meant to be placed over the ostium of a major side-branch. Forty-seven consecutive patients with lesions involving 48 side-branches received one side-branch stent each. Stent deployment was successful in all patients. Twenty-five side-branches needed additional treatment. Nineteen side-branches received a PTCA, and 6 additional side-branches were stented. Postinterventional CK-(creatine kinase) elevation was observed in 3 patients (6%). One additional patient was sent for CABG on the day of the procedure due to loss of a stent intended to be placed into the side-branch. The investigated stent proved to be a safe and effective tool to treat this complex subgroup of stenoses in the presence of favorably preserved flow in the side-branches, with a low incidence of periprocedural complications. Cathet. Cardiovasc. Diagn. 45:456–459, 1998. © 1998 Wiley-Liss, Inc.     

Bifurcation lesion treated with a single stent: a new technique.

Treatment of bifurcation lesions by percutaneous coronary interventions is one of the challenging issues for the interventional cardiologists. The overall complication rate is higher than nonbifurcation lesions. We describe a new stenting technique for the so-called true bifurcation lesions.     

冠状动脉内V—FLEX支架的临床应用

目的　评价球囊释放V FLEX支架在临床应用的疗效。方法　对 92例 (男 84例 ,女 8例 )冠心病患者 (年龄5 4 11岁± 16 11岁 ) ,将 10 3只V FLEX支架置入 97处冠状动脉病变部位。结果　 91例患者均一次成功植入支架 ;无 1例发生急性心脏事件及需要紧急外科冠脉搭桥术 ;6个月复查冠脉造影再狭窄率 17 0 7%。结论　冠状动脉内植入V FLEX支架在临床应用即时效果好 ,远期疗效有待于进一步临床大规模观察及长期随访追踪。     

冠状动脉西罗莫司洗脱支架置入后晚期支架内血栓形成分析

目的分析冠状动脉药物洗脱支架置入后晚期支架内血栓形成的临床相关因素。方法回顾性分析2003年7月至2005年1月我院置入西罗莫司洗脱支架的1304例冠心病患者中发生晚期支架内血栓的8例患者的临床资料、冠状动脉病变特点、支架释放情况以及术后的抗血小板治疗等相关因素。结果8例患者平均年龄（51±10）岁、7例为急性冠状动脉综合征患者且伴有多项心血管病危险因素,仅1例患者伴有左室功能不全,无肾功能不全患者;多支冠状动脉病变患者6例且病变较复杂,包括闭塞、分叉、开口和弥漫长病变;支架释放压力平均（1175.37±167．19）kPa（11．60±1．65atm）,全部患者未用高压球囊进行后扩张;双重抗血小板治疗平均时间为（157．5±41．7）d,1例在停用氯吡格雷第7天、2例在服用阿司匹林和氯吡格雷治疗期间、5例停用氯吡格雷6个月后出现支架内血栓,平均血栓发生时间为术后（450．3±344．7）d,5例表现为急性心肌梗死;1例死亡,5例再次置入西罗莫司洗脱支架,术后随访无症状,1例药物治疗。结论发生晚期支架内血栓的冠心病患者多表现为急性冠状动脉综合征、伴有多项心血管病危险因素;多支、复杂冠状动脉病变;支架低压释放,置入后未行后扩张;双重抗血小板治疗时间短。发生晚期支架内血栓患者预后差,死亡率较高,再次置入西罗莫司洗脱支架是安全、有效的。     

防反流型金属自膨式食管支架的临床应用

目的证实一种新型食管支架具有治疗狭窄并有抗胃食管反流作用。方法１７例（男１６例，女１例）有梗阻症状的食管、贲门恶性肿瘤患者。安装防反流型支架后分别观察症状及体征，并监测２４小时食管ｐＨ（８例）、食管内镜检查（９例）及胃肠Ｘ线检查（３例），以观察狭窄通畅情况及有无胃食管反流迹象。结果置入支架后食管、胃、贲门通畅，无一例有胃食管反流存在。结论此类新型支架有良好的抗胃食管反流作用。