Magnetic resonance monitoring of stent deployment: in vitro evaluation of different stent designs and stent delivery systems

RATIONALE AND OBJECTIVES: To evaluate MR imaging features of commercially available stents before, during, and after in vitro deployment as a step toward MR-guided stent deployment. METHODS: Fourteen stents were deployed in a phantom under MR monitoring at 1.5 T by using a gradient-echo sequence. Device visibility was rated on a four-point scale (excellent, fair, poor, not visible). RESULTS: The Memotherm stent and the rolling membrane (RM) Wallstent showed excellent stent visibility and at least fair scores for artifact-induced narrowing of the stent lumen. Three stents (Palmaz, AVE, Easy Wallstent) showed excellent visibility of the stent but no visible lumen. Five stents (Strecker, Accuflex, Hemobahn, Passager, Sinus) displayed fair visibility. The delivery catheters of four stent systems (Smart, Vascucoil, Symphony, ZA) displayed severe black hole artifacts. CONCLUSIONS: The imaging features of several stent systems might be suitable for MR-guided intervention. The Memotherm and the Wallstent RM combine good visibility of the stent and the lumen.     

支架精显技术在冠状动脉支架植入术中的应用

【摘要】 目的 探讨冠状动脉造影定量分析（QCA）、支架精显（StentViz）和血管内超声（IVUS）在经皮冠状动脉介入术（PCI）中评价支架可视性和膨胀性的应用。 方法 收集2016年5月至2018年11月同时接受StentViz和IVUS检查的PCI患者30例。分别在QCA、StentViz和IVUS图像中对植入的33枚支架最小直径、最大直径进行测量,计算支架偏心指数,并进行不同方法间比较分析。对33枚支架共143幅StentViz影像作支架可视性分级评价。 结果 QCA测量的支架最小直径、最大直径均显著大于StentViz、IVUS测量（P＜0.05）,支架偏心指数均显著低于StentViz、IVUS测量（P＜0.05）;StentViz测量的上述指标与IVUS测量比较,差异无统计学意义（P＞0.05）。StentViz与IVUS测量的支架最小直径相关性（r = 0.956）优于QCA与IVUS测量的相关性（r=0.776）。StentViz测量的支架最小直径与QCA测量相比,同IVUS测量具有更好的一致性。143幅StentViz图像中支架可视性评价显示,支架显示优82.1%（评分4分）,良15.3%（2～3分）,差2.6%（0～1分）。 结论 StentViz可显著提高冠状动脉内支架可视性,与QCA相比在测量支架直径方面同IVUS具有更好的相关性和一致性。     

Influence of stent type on hemodynamic depression after carotid artery stent placement

PURPOSE: To assess the effect of stent type on hypotension and bradycardia after carotid artery stent placement. MATERIALS AND METHODS: A retrospective analysis on a prospectively maintained database was conducted in 256 patients (126 men; mean age, 71.8 years +/- 8.6; 194 de novo lesions) undergoing carotid artery stent placement between January 1996 and January 2007 by using self-expanding stents. Braided Elgiloy stents (Wallstents) were used in 44 of the 256 patients (17.2%) and slotted-tube nitinol stents were deployed in 212 (82.8%). Bivariate and multivariable logistic regression models were used to determine the influence of stent design on procedural and 24-hour hypotension and bradycardia. RESULTS: Procedural hemodynamic depression (HD) was encountered in 73 of the 256 patients (28.5%) due to hypotension in 24 (9.4%), bradycardia in 12 (4.7%), or both in 37 (14.5%) patients. Rates of procedural hypotension were 11.3% with nitinol stents and 0% with braided Elgiloy stents (P = .0188). Persistent postprocedural HD occurred in 91 of the 256 patients (35.5%) due to hypotension in 40 patients (15.6%), bradycardia in 23 (9.0%), or both in 28 (10.9%). Within a multivariable analysis adjusted for clinically relevant factors affecting rates of HD, the use of braided Elgiloy stents was associated with a decreased rate of procedural hypotension (odds ratio: 0.165; 95% confidence interval: 0.038, 0.721; P = .017). Procedural hypotension and bradycardia were not correlated to incidence of major adverse events but were associated with an increased duration of hospital stay (P = .0059 and P = .0335, respectively). CONCLUSIONS: Nitinol stents are associated with a higher risk of hypotension as compared to braided Elgiloy stents during carotid artery stent placement.     

药物洗脱支架与金属裸支架治疗颅内动脉狭窄比较北大核心CSCD

目的比较药物洗脱支架(DES)与金属裸支架(BMS)治疗颅内动脉狭窄患者的有效性和安全性。方法回顾性分析2020年3月至2021年11月解放军第九二四医院收治的80例颅内动脉粥样硬化性狭窄(ICAS)患者临床资料。根据所使用支架类型,分为DES组和BMS组,每组40例。比较两组患者治疗效果、术后支架内再狭窄(ISR)发生率及术中和术后并发症。结果DES组术后即刻残余狭窄发生率为5%(2/40,狭窄程度最高25%),与BMS组7.5%(3/40)相比,差异无统计学意义(OR=0.65,95%CI=0.10~4.11,P>0.05);术后6个月ISR发生率7.5%(3/40),显著低于BMS组25%(10/40)(OR=0.24,95%CI=0.06~0.96,P=0.03);术中和术后总体并发症发生率较低于BMS组,但差异无统计学意义(OR=0.78,95%CI=0.19~3.14,P>0.05)。结论DES治疗颅内动脉狭窄具有较高的有效性和安全性,与BMS相比术后ISR发生率更低。     

In vitro comparison of the spiral Z stent and the Gianturco Z stent.

A new spiral Z stent is described, and its characteristics are compared in vitro with those of the modified Gianturco Z stent. The spiral Z stent has a more uniform expansile force throughout its effective length; is more compressible, thus allowing for use of a smaller introductory catheter; and is more stable than the modified Z stent. Flexibility of both stent types is similar. Advantages of the spiral Z stent promise to be beneficial for clinical use.     

支架端改型防治食管支架术后再狭窄的临床应用

目的 观察支架端改型对食管支架术后再狭窄的防治作用及其安全性.方法 10例经病理及影像学确诊的食管癌患者,用支架端增加硅胶膜的改型支架进行治疗.术后每月随访吞咽困难程度Stooler分级评分、胸部X线片、CT和食管钡餐,了解支架的位置及有无梗阻;每2个月行胃镜检查以了解支架有无狭窄,随访有无严重胸痛、出血、肺炎、食管气...     

Inferior vena caval stent filter

New inferior vena caval filters for percutaneous placement were made by attaching filter wires similar to those in the bird's nest inferior vena caval filter onto expandable metallic stents. These stents formed a base on which to anchor the filter to the wall of the inferior vena cava. The stent filter can be introduced through a 12- to 13-French catheter sheath system. The system was successfully tested in 13 dogs.     

Balloon expandable intraluminal vascular stent

The percutaneous, intraluminal placement of an expandable arterial stent is a new method for reducing stenosis in atherosclerotic arteries. This method, used in conjunction with balloon angioplasty, involves the placement of metallic mesh stent at the sight of the stenosis. Use of this technique has resulted in various improvements over angioplasty alone.     

Complications of universal ureteral stent

The universal stent is primarily a ureteral stent that also permits optional nephrostomy drainage. The complications associated with universal stent placement were analyzed with respect to the underlying pathology. The major complications included stent-induced ureteral stricture in 2 patients, and stent migration requiring emergency repositioning in 2 patients. Stent malfunction due to stent migration or occlusion, and bladder irritation were frequent also.     

Massage-induced delayed venous stent migration

Catheter-directed therapies in chronic deep vein thromboses can help improve leg function by mechanically addressing residual obstruction in lower extremity or pelvic veins, although the reported use of stents in leg veins is relatively unusual. The author reports a case of this type with long-term patency and clinical success, culminating in asymptomatic delayed venous migration of a stent to the right atrium after 3 years. Open heart surgery was required to remove the embedded stent fragments. The attributed mechanism was deep tissue massage of the thigh.     

Iliac artery stenting--clinical experience with the Palmaz stent, Wallstent, and Strecker stent.

A total of 82 iliac artery lesions (62 stenoses and 20 occlusions) were treated with 3 different types of endovascular metallic stents (12 lesions with the Palmaz stent, 36 with the Wallstent, and 34 with the Strecker stent). The complication rate was 12%. Occlusion of 2 Wallstents occurred 4 and 12 weeks after stent placement, respectively. Both stents were recanalized by local fibrinolysis. One Strecker stent occluded after 8 months. The observation period was 3 to 26 months (mean 9.7 months). The patency rate with secondary intervention (fibrinolysis) was 100% after 3 and 6 months, and 98% after 9 months. All 3 stent designs turned out to be effective in the treatment of complicated iliac artery occlusive disease.     

Primary stent placement for recanalization of iliac artery occlusions: Using a self-expanding spiral stent

Purpose: To report the clinical results for recanalizations of an occluded iliac artery by a self-expanding spiral stent. Methods: We attempted to recanalize 36 iliac artery occlusions in 34 patients [33 men, 1 woman, aged 51–75 years (average 61.6 years)]. The average lesion length was 6.92 cm (range 1–14 cm). The patients' chief complaints were intermittent claudication and resting pain. Fontaine classification was assigned before and after the procedure. Technical and clinical success were also analyzed. Results: Forty-five stents were successfully deployed in 34 patients. All 36 lesions (13 in the external iliac artery, 12 in the common iliac artery, and 11 in both) were patently recanalized on angiography. The follow-up period ranged from 6 months to 36 months (mean 11.9 months). Fourteen stents (39%) with incomplete expansion were dilated with a balloon catheter. Good technical (100%) and clinical (94%) results were obtained. The only complication was one hematoma at the puncture site. Reocclusions were noted in two lesions (5%) at 1 week and 15 months, respectively. Conclusion: A self-expanding spiral stent is a safe and effective device for recanalization of an iliac artery occlusion as the primary stent without any previous intervention.     

Gastrobronchial fistula: Treatment with a covered tracheobronchial stent and an integrated Y-shaped metallic stent

A 53-year-old man presented with severe cough and pulmonary infection 1 month after receiving a second mushroom-shaped covered metallic stent for occluding a gastrobronchial fistula (GBF). The fistula was caused by an esophageal stent that was placed 4 months after esophagogastrectomy for the treatment of gastroesophageal stenosis. Six months before the patient was admitted to our hospital, he had undergone esophagogastrectomy for esophageal cancer; a thoracic anastomosis was created, and a wide gastric tube was inserted through a left thoracotomy. Multislice computed tomography, gastroscopy, and esophagography with contrast medium revealed a fistulous communication between the right posterior wall of the upper residual stomach and the dorsal segment of the left lower lobe bronchus after the removal of stents. A short covered stent and a partially covered integrated inverted Y-shaped metallic stent were implanted into the bronchi, and subsequently, the fistula was closed completely. The patient was discharged 2 weeks after stent placement; at the time of discharge, he showed full recovery and complete resolution of the symptoms related to GBF.