Accumetrics-based clopidogrel dosing in endovascular neurosurgery

Abstract

Introduction:

The role of the VerifyNow test to guide clopidogrel therapy in neurosurgical patients is still unclear. This study compared outcomes in patients undergoing neurointerventional procedures on either standard clopidogrel or tailored clopidogrel regimens.

Methods:

Adult patients undergoing neurointerventional procedures from 1 May 2002 to 31 December 2012 at the University of Illinois Hospital and Health Sciences System were included if they were receiving dual antiplatelet therapy (DAPT) for their procedure. Patients were categorised based on the use of VerifyNow to guide therapy. The primary endpoint was the incidence of thromboembolic complications within 6?months post procedure. Secondary endpoints included the incidence of haemorrhagic complications and death. P2Y₁₂ reaction units (PRU) were recorded when available and categorised based on relation to procedures and/or events.

Results:

A total of 228 patients were screened with 130 meeting inclusion criteria. Ninety patients were grouped into the standard therapy arm and 30 patients into the tailored therapy arm. There were no differences in the incidence of ischaemic complications (1.1 vs 2.5%, P?=?0.522), haemorrhagic complications (17.8 vs 15.0%, P?=?0.455) or death (3.0 vs 0%, P?=?0.552). Seventeen of 32 patients (53.1%) with PRUs were clopidogrel resistant defined as a PRU >180.

Discussion:

Use of the VerifyNow test to guide clopidogrel therapy in patients undergoing neurointerventional procedures did not result in a decrease in the incidence of thromboembolic complications compared to standard therapy. There was no difference in the incidence of haemorrhagic complications or death. Further studies are needed to evaluate the impact of tailored therapy using VerifyNow.     

Uncertainty assessment of imaging techniques for the 3D reconstruction of stent geometry

This paper presents a quantitative assessment of uncertainty for the 3D reconstruction of stents. This study investigates a CP stent (Numed, USA) used in congenital heart disease applications with a focus on the variance in measurements of stent geometry. The stent was mounted on a model of patient implantation site geometry, reconstructed from magnetic resonance images, and imaged using micro-computed tomography (CT), conventional CT, biplane fluoroscopy and optical stereo-photogrammetry. Image data were post-processed to retrieve the 3D stent geometry. Stent strut length, separation angle and cell asymmetry were derived and repeatability was assessed for each technique along with variation in relation to μCT data, assumed to represent the gold standard. The results demonstrate the performance of biplanar reconstruction methods is comparable with volumetric CT scans in evaluating 3D stent geometry. Uncertainty on the evaluation of strut length, separation angle and cell asymmetry using biplanar fluoroscopy is of the order ±0.2 mm, 3° and 0.03, respectively. These results support the use of biplanar fluoroscopy for in vivo measurement of 3D stent geometry and provide quantitative assessment of uncertainty in the measurement of geometric parameters.     

Flow-induced corrosion behavior of absorbable magnesium-based stents

The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15 Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056 Pa was nearly twice that (17%) at 0 Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed.     

后循环缺血的名称演变及治疗进展

【摘要】 后循环缺血（posterior circulation ischemia,PCI）的概念逐渐被临床医师接受,其治疗亦越来越受到重视,但目前仍缺乏专门针对后循环缺血的大样本随机对照研究,除常规的药物治疗外,溶栓治疗与介入治疗可使后循环缺血患者明显受益,但手术治疗方面未见有更多研究报道。我们结合国内外文献,概述了后循环缺血名称的演变,总结了后循环缺血治疗的最新研究成果并做一简要综述。     

Various Techniques of Stent-Assisted Coil Embolization of Wide-Necked or Fusiform Middle Cerebral Artery Aneurysms : Initial and Mid-Term Results

Objective

To evaluate the feasibility and clinical and angiographic outcomes of stent-assisted embolization for complex middle cerebral artery (MCA) aneurysms.

Methods

The records of 23 consecutive patients with 24 MCA aneurysms, who underwent stent-assisted embolization of the aneurysm, were retrospectively evaluated.

Results

Fifteen aneurysms were treated with one stent and 8 were treated using more than two stents (5 a stent-within-a-stent, 1 triple stents, and two Y-stent). Angiographically, complete or near complete occlusion was achieved in 15 aneurysms (65.2%), residual neck in five (21.7%), and residual aneurysm in three (13.1%). Five aneurysms demonstrated thrombosis within the stent during the procedure and hospitalization, and were resolved by intraarterial and intravenous Tirofiban injection. Symptomatic thromboembolic complications were developed in five patients and permanent deficits demonstrated in two patients with modified Rankin Scale 1 and 2, respectively. Treatment-related permanent morbidity and mortality rates were 8.3% and 0% with relatively high complication rate. Angiographic follow-up was available in 17 aneurysms at 6-31 months (mean, 13.2 months) and showed stable or improved in 15 (88.2%) and major and minor recurrence in one, respectively.

Conclusion

Complex MCA aneurysms could be treated by stent-assisted coiling and showed lower recanalization rate during mid-term follow-up by effective flow diversion due to various stent-assisted techniques. Our results warrant further study with a longer follow-up period in a larger sample.     

Inadvertent Self-Detachment of Solitaire AB Stent during the Mechanical Thrombectomy for Recanalization of Acute Ischemic Stroke: Lessons Learned from the Removal of Stent via Surgical Embolectomy

We recently experienced self-detachment of the Solitaire stent during mechanical thrombectomy of acute ischemic stroke. Then, we tried to remove the detached stent and to recanalize the occlusion, but failed with endovascular means. The following diffusion weighted image MRI revealed no significant increase in infarction size, therefore, we performed surgical removal of the stent to rescue the patient and to elucidate the reason why the self-detachment occurred. Based upon the operative findings, the stent grabbed the main thrombi but inadvertently detached at a severely tortuous, acutely angled, and circumferentially calcified segment of the internal carotid artery. Postoperative angiography demonstrated complete recanalization of the internal carotid artery. The patient''s neurological deficits gradually improved, and the modified Rankin scale score was 2 at three months after surgery. In the retrospective case review, bone window images of the baseline computed tomography (CT) scan corresponded to the operative findings. According to this finding, we hypothesized that bone window images of a baseline CT scan can play a role in terms of anticipating difficult stent retrieval before the procedure.     

介入栓塞治疗颅内动脉瘤46例临床分析

目的观察颅内不同部位和类型动脉瘤介入治疗疗效,总结个体化治疗经验。方法回顾性分析46例不同部位和类型共51个动脉瘤栓塞治疗的临床资料。结果 51个动脉瘤完全闭塞43个,闭塞95%以上5个,闭塞90%以上3个,术中动脉瘤破裂2例,死亡1例,成功随访30例。3¹2个月无复发。结论对不同部位和类型颅内动脉瘤采用可脱性弹簧圈栓塞及支架辅助弹簧圈栓塞疗效可靠。     

Longitudinal deformation – Price we pay for better deliverability of coronary stent platforms

Coronary stents, especially drug eluting stents (DES), have revolutionized the practice of interventional cardiology. Newer stents are manufactured by altering basic design characteristics to tackle complex coronary morphologies more effectively. Alteration in one particular attribute might affect other attributes adversely. Even though, reduction in the number and alteration of the orientation of the connectors improves the stent flexibility and deliverability, it adversely decreases the axial strength of the stent with resulting longitudinal stent deformation. A 67 year old female underwent percutaneous coronary intervention for a mid left anterior descending artery stenosis with a 2.75 × 16 mm Promus Element stent (Boston Scientific, Natick, Massachusetts). The stent got longitudinally distorted during post-stent balloon dilatation which was effectively managed with further dilatation with non-compliant balloon.     

Tours experience of endovascular treatment in superior vena cava syndrome

Superior vena cava syndrome is a clinical entity including symptoms arising from an obstruction of return flow in the superior vena cava. It can be life threatening. In the context of lung cancer, by far the most prominent etiology (nine of ten cases in our series), the condition is particularly serious, with only 20% survival at one year. Medical treatment may be insufficient, requiring surgical salvage. Palliative procedures are rapidly effective and well tolerated. We perform a first intention transluminal angioplasty under local anesthesia via the right femoral vein. This ultrasound-guided procedure enables insertion of a non-coated nitinol stent. The success rate in our hands has been 90%. Clinical improvement is constant and immediate with long-term efficacy. The early and late post-operative period is uneventful.     

覆膜支架腔内修复处理降主动脉破裂的临床体会

目的总结运用胸主动脉覆膜支架腔内修复急诊救治降主动脉破裂的经验和体会。方法回顾分析2013年5月~2017年3月我科收治降主动脉破裂患者16例,其中胸主动脉夹层动脉瘤破裂14例,感染性假性动脉瘤致降主动脉破裂1列,不明原因的食管降主动脉瘘1例。16例患者术前均通过胸腹主动脉计算机断层血管造影(Computed tomography angiography,CTA)明确诊断,均在急诊全麻下经股动脉入路行胸主动脉覆膜支架腔内修复术(Thoracic Endovascular Aortic Repair,TEVAR)。结果 16例患者均顺利完成手术。其中1例患者术后因血流动力学不稳定死亡,1例患者术后急性肾功能衰竭死亡,余14例患者均痊愈出院,未发生截瘫、逆撕、肢体缺血等相关并发症。无术中中转开胸手术。结论胸主动脉覆膜支架腔内修复是急诊救治降主动脉破裂的有效方法,尽早进行急诊手术是抢救的关键。