Ho Kyun Kim

Inadvertent Detachment of a Retrievable Intracranial Stent: Review of Manufacturer and User Facility Device Experience.

Few systematic surveys have dealt with the potential procedural risks associated with the use of retrievable intracranial stents [Solitaire Flow Restoration (Solitaire FR)], which have become effective tools for recanalizing acutely occluded cerebral arteries. The aim of this study was to present the real-world experiences of Solitaire-FR-related adverse events by reviewing the MAUDE (Manufacturer and User Facility Device Experience) as published on the United States Food and Drug Administration website. In total, 85 adverse events related to the use of the Solitaire FR stent were reported between March 2012 and October 2014. In 80 patients these adverse events were attributable to inadvertent detachment of the device. Thirteen of these 80 patients (16%) died after the procedure. Morbidity data were available in 62 patients, among whom 11 (18%) had suffered a procedure-related injury. Detachment occurred at the first, second, and third pass in nine (21%), 21 (49%), and 13 (30%) of the 43 patients for whom this information was available, respectively. Resistance was perceived by the physician during retrieval of the device in 12 patients, and lesion characteristics were noted in 13. A rescue maneuver was reported in 20 (25%) of the 80 patients in whom the adverse event was attributable to detachment of the device, resulting in flow reestablishment in 13 (65%). The risk of inadvertent detachment during stent retrieval cannot be overemphasized in real-world scenarios, and careful consideration of the “dos and don’ts” is essential for the achievement of a safe procedure.Few systematic surveys have dealt with the potential procedural risks associated with the use of retrievable intracranial stents [Solitaire Flow Restoration (Solitaire FR)], which have become effec...

Locking between a cerebral protection device and a stent-delivering catheter during carotid artery stenting.

The cerebral protection device (CPD) itself may cause complications, including locking between the CPD and other devices, that may result in catastrophic outcomes requiring surgical removal of these locked devices. We describe a case of locking between a CPD and the stent-delivering catheter during carotid artery stenting, which was safely rescued by endovascular retrieval. The mechanism underlying locking with the CPD as well as preventive actions and maneuvers for rescuing the situation are discussed.

Propagation-based phase-contrast X-ray microtomography of a cerebral protection device retrieved after carotid artery stenting

Phase-contrast synchrotron X-ray microtomography (pcSyncX) based on the highly coherent X-ray beam has previously been used to visualize the microstructures of biologic specimens, but it has never been used to evaluate embolic debris adherent on a cerebral protection device (CPD). The purpose of this study was to demonstrate the feasibility of pcSyncX for evaluating embolic debris during carotid artery stenting (CAS). Five patients (four males, age range 67-77 years) with severe carotid artery stenosis underwent CAS. The retrieved CPD was exposed to synchrotron radiation and 1000 pcSyncX projection images were obtained by rotating the CPD through 180°. An X-ray shadow of a CPD was converted into a visual image by the scintillator. After microtomographic reconstruction, the three-dimensionally reconstructed images were further segmented into the embolic debris and CPD. The total volume of emboli was calculated by summing the volume at each scanning level. The number of membrane pores covered by emboli as seen from the outer surface was counted and the percentage of covered area was calculated. Embolic debris was clearly demonstrated not only on the inner surface and within pores but also on the outer surface of the CPD. The mean total volume of embolic debris was 0.538 × 10(-6) mm(3) (range 0.225-0.965 × 10(-6) mm(3)). Most (61.5%) of the debris was located at the apical one-third of the CPD and 20.8% of the pore area was covered by debris.

Quantitative Measurements of Cerebral Circulation in Spontaneously Regressing Traumatic Carotid-Cavernous Sinus Fistula with Velocity-Encoded Magnetic Resonance Imaging.

and quantitative evidence for whether endovascular occlusion would remove the shunts connected to extradural venous drainage alone, or further resolve the disturbance of cerebral venous flow. It is not known how cerebral vessels would change in the long-term as a result of obstructing this shunt flow, or how the clinical symptoms are related to the haemodynamic changes in the rare cases of spontaneous regression. The understanding of the pathophysiology of CCF can be enhanced by correlating the clinical symptoms and MRI findings during a long observational period. Velocity-encoded magnetic resonance imaging (VENCMRI) has shown excellent diagnostic accuracy and reliability for the measurement of the flow volumes (FVs) in cerebral vessels [12]. Furthermore, VENC-MRI does not require contrast medium administration or invasive catheterization, and is considered a safe and appropriate followup imaging technique [13]. However, this tool has never been used for quantifying the shunt volume and cerebral circulation related to CCF. A case in which VENC-MRI was used to measure the shunt volume of and FVs in the cerebral vessels in a direct CCF patient is presented herein. The temporal changes during spontaneous regression are demonstrated, and the relationships between the patient’s clinical symptoms and the measured cerebral haemodynamics are discussed.

Quantification of cerebral circulation and shunt volume in a tentorial dural arteriovenous fistula using two-dimensional phase-contrast magnetic resonance imaging

Venous hypertension is closely related to poor outcome of a dural arteriovenous fistula (DAVF). However, no direct measurements have been made of the shunt flow and impaired venous drainage that are suggestive of venous hypertension. We present a case of a 35-year-old man who presented with cerebral hemorrhage and underwent coil embolization for tentorial DAVF. Two-dimensional (2D) phase-contrast magnetic resonance imaging (MRI) was used to evaluate temporal changes in the flow volumes of the shunt and venous drainage between before and after embolization. The results demonstrated the feasibility of using 2D phase-contrast MRI to measure the shunt volume of a DAVF, which might be useful for assessing the improvement in cerebral circulation after embolization treatment.