Vascular Endothelial Repair and the Influence of Circulating Antiplatelet Drugs in a Carotid Coil Model

Background: Clinicians may choose to administer antiplatelet medications to patients with cerebral aneurysms following endovascular coiling to prevent thrombus formation and vascular occlusion, if they fear a thrombus will form on the platinum wire where it diverges into the vessel from the aneurysm sac. However, the mechanism by which vascular endothelial cells repair a vessel in the living body in the event of a coil deviation and the effects of antiplatelet drugs on these cells have not been fully elucidated. We aimed to investigate the association between endothelial progenitor cells (EPCs) and endothelium formation at the surface of the platinum coils deployed in the carotid artery of rats, and to determine the effects of different antiplatelet drugs on this process. Subjects and Methods: We established an experimental model using normal and diabetic rats at 12 months of age. The diabetic rats were assigned to 4 different diet groups, distinguished by whether they were fed plain rat feed, or the same feed supplemented by 1 of 3 antiplatelet drugs (cilostazol, aspirin, or clopidogrel: all 0.1%) for 2 weeks, and the carotid artery was perforated by an embolization coil (“carotid coil model”). We monitored the process by which vascular endothelial cells formed the new endothelium on the surface of the coil by sampling and evaluating the region at 1, 2, and 4 weeks after placement. This repair process was also compared among 3 groups treated with different antiplatelet drugs (i.e. aspirin, clopidogrel, and cilostazol). One-way analysis of variance tests were performed to evaluate the differences in vascular thickness between groups, and P < .05 was considered statistically significant. Results: The diabetic rats showed delayed neoendothelialization and marked intimal hyperplasia. Cilostazol and clopidogrel effectively counteracted this delayed endothelial repair process. Flk1 immunostaining revealed greater expression in the diabetic rats administered cilostazol, second only to normal rats, suggesting that this agent acted to recruit EPCs. Conclusion: Neoendothelialization is delayed when vascular endothelial cells fail to function normally, which consequently leads to the formation of hyperplastic tissue. Cilostazol may remedy this dysfunction by recruiting EPCs to the site of injury.

Balloon-Assisted Enteroscopy for Retrieval of Small Intestinal Foreign Bodies: A KASID Multicenter Study

Background and Aims. Balloon-assisted enteroscopy (BAE) can be used to retrieve small intestinal foreign bodies (FBs). Here, we aimed at exploring the clinical usefulness of BAE for the retrieval of small intestinal FBs. Methods. We retrospectively reviewed the medical records of 34 patients who underwent BAE to retrieve small intestinal FBs at 3 tertiary referral centers between April 2005 and June 2017. Results. The retained materials included capsule endoscopes (CEs; n=18 [52.9%]), self-expandable metal stents (SEMSs; n=5 [14.7%]), biliary drainage catheters (n=4 [11.8%]), gallstones (n=3 [8.8%]), an embolization coil (2.9%), a needle, an intragastric bariatric balloon, and a razor blade. FBs were located or stuck in the ileum (n=17 [50%]), jejunum (n=16 [47.1%]), and an undetermined small intestinal segment (n=1). Seventeen cases of FBs (50%; 7 CEs, 3 biliary drainage catheters, 3 SEMSs, 2 gallstones, 1 intragastric balloon, and 1 needle) were successfully retrieved enteroscopically. FBs of 4 asymptomatic patients (3 CEs and 1 razor blade) passed spontaneously. The remaining 13 patients underwent surgery for persistent or symptomatic FBs: 12 were successfully removed and 1 CE removal procedure failed due to severe peritoneal adhesions. The presence of symptoms was the only independent predictor of successful retrieval using BAE (odds ratio 13.40, 95% confidence interval 1.10–162.56, P=0.042). BAE-related complications such as bowel perforation and acute pancreatitis occurred in 2 patients (5.9%). Conclusions. BAE can be the first option for FB removal in the small intestine. The presence of symptoms was associated with successful enteroscopic retrieval.

Evaluation of the quality of CT images acquired with smart metal artifact reduction software

ObjectiveTo evaluate the practical effectiveness of smart metal artifact reduction (SMAR) in reducing artifacts caused by metallic implants.MethodsPatients with metal implants underwent computed tomography (CT) examinations on high definition CT scanner, and the data were reconstructed with adaptive statistical iterative reconstruction (ASiR) with value weighted to 40% and smart metal artifact reduction (SMAR) technology. The comparison was assessed by both subjective and objective assessment between the two groups of images. In terms of subjective assessment, three radiologists evaluated image quality and assigned a score for visualization of anatomic structures in the critical areas of interest. Objectively, the absolute CT value of the difference (ΔCT) and artifacts index (AI) were adopted in this study for the quantitative assessment of metal artifacts.ResultsIn subjective image quality assessment, three radiologists scored SMAR images higher than 40% ASiR images (P<0.01) and the result suggested that visualization of critical anatomic structures around the region of the metal object was significantly improved by using SMAR compared with 40% ASiR. The ΔCT and AI for quantitative assessment of metal artifacts showed that SMAR appeared to be superior for reducing metal artifacts (P<0.05) and indicated that this technical approach was more effective in improving the quality of CT images.ConclusionA variety of hardware (dental filling, embolization coil, instrumented spine, hip implant, knee implant) are processed with the SMAR algorithm to demonstrate good recovery of soft tissue around the metal. This artifact reduction allows for the clearer visualization of structures hidden underneath.

Republished: Delayed extrusion of embolic coils into the airway after embolization of an external carotid artery pseudoaneurysm

Carotid blowout syndrome (CBS) is a known devastating complication of head and neck surgery. The risk of developing CBS increases in the setting of radiation therapy, wound breakdown, or tumor recurrence. Traditionally, the treatment of choice for CBS is surgical ligation of the bleeding artery; however, recently, endovascular occlusion has become a more common option. If a pseudoaneurysm is present, treatment consists of trapping with endovascular coils or occlusion with a liquid embolic agent. Delayed migration of embolization coils into the airway causing acute respiratory distress is a rare occurrence. This report presents a case of a 57-year-old woman who presented to her otolaryngologist after experiencing an episode of acute respiratory distress which resolved when she expectorated embolization coil material from her tracheostomy tube. Three months prior to the episode she underwent coil embolization of an external carotid artery pseudoaneurysm for life-threatening hemorrhage.

Radiation exposure, and procedure and fluoroscopy times in endovascular treatment of intracranial aneurysms: a methodological comparison

BackgroundLimited data are available for radiation exposure, and procedure and fluoroscopy times in neuroendovascular treatment (NET) strategies.ObjectiveThis study establishes and compares related parameters between coil embolization (COIL), balloon assisted coil embolization (BAC), stent assisted coil embolization (SAC), and flow diverting technology (FDT) in NET of intracranial aneurysms.Materials and methodsBetween 2010 and 2017, 249 consecutive intracranial aneurysms underwent NET at a single center, all performed by the same operator. Dose area products (DAP), and procedure and fluoroscopy times were recorded and compared between COIL, BAC, SAC, and FDT techniques. Differences in parameters between cohorts were analyzed for significance using the Mann–Whitney U test, unpaired t test and χ2test. Additional subgroup analysis was performed for emergency and elective cases.Results83 aneurysms were treated with COIL (33%), 72 with BAC (29%), 61 with SAC (25%), and 33 with FDT (13%). Baseline characteristics were largely similar within these groups (P>0.05). Among COIL, BAC, and FDT cohorts, no significant difference was found for mean DAP, or procedure and fluoroscopy times (P>0.05). However, compared with all other cohorts, SAC was associated with a significantly higher DAP and longer procedure and fluoroscopy times (P<0.005). No significant difference was recorded for emergency and elective case subgroups.ConclusionCompared with other NET strategies, SAC was associated with a significantly higher DAP, and longer procedure and fluoroscopy times. This study provides an initial dataset regarding radiation exposure, and procedure and fluoroscopy times for common NET, and may assist ALARA (As Low As Reasonably Achievable) principles to reduce radiation risks.

Hemodynamics and coil distribution with changing coil stiffness and length in intracranial aneurysms

PurposeThe purpose of this study was to investigate hemodynamics and coil distribution with changing coil stiffness and length using the finite element method (FEM) and computational fluid dynamics (CFD) analysis.MethodsBasic side-wall and bifurcation type aneurysm models were used. Six types of coil models were generated by changing the coil stiffness and length, based on commercially available embolic coils. Coil embolization was simulated using FEM. CFD was performed to characterize the hemodynamics in the aneurysms after embolization. Coil distribution and velocity reduction in the aneurysms were evaluated.ResultsThe median value of radial coil distribution was shifted from the center to the outer side of the aneurysmal dome by changing coil stiffness: harder coils entered the outer side of the aneurysmal dome more easily. Short coils were more distributed at the neck region, since their small size made it easy for them to enter the tighter area. CFD results also indicated that velocity in the aneurysm was effectively reduced when the coils were more distributed at the neck region and the outer side of the aneurysmal dome because of the disturbance in blood inflow.ConclusionsIt is easier for coils to enter the outer side of the aneurysmal sphere when they are harder. If coils are short, they can enter tighter areas more easily. In addition, high coil density at the outer side of the aneurysmal dome and at the neck region is important to achieve effective velocity reduction.