Evaluation of the Straightening Phenomenon of Various Types of Coils.

The straightening phenomenon is known as a cause of catheter kickback in the late phase of coil embolization. The mechanism is supposed to be the relative shortage of the stretch resistance (SR) line, and it occurs when a coil is folded too small. Among many SR coils available, there should be a coil-specific tendency to cause this phenomenon. Here, we conducted an in-vitro experiment to know which coil is the most resistant to the straightening phenomenon. We developed an experimental model to reproduce the straightening phenomenon. Five different coils (Axium Prime, ED Coil, Hypersoft, SMART Coil, and Target 360 nano) of the same size (3 mm × 6 cm) were investigated for five times each. Resistance to the straightening phenomenon, which is represented by the insertion length at the onset of the phenomenon, was compared among coil types. The straightening phenomenon was successfully observed in all insertions. Insertion lengths were significantly different among coil types (p = 0.013). The insertion length of ED was the longest (mean ± SD, 27.0 ± 8.3 mm), which means the most resistant to the phenomenon. Axium was second (21.6 ± 7.0 mm), followed by Target (15.8 ± 6.9 mm), Hypersoft (13.8 ± 5.8 mm), and SMART (12.4 ± 4.7 mm). Difference between ED and Hypersoft (p = 0.037) and difference between ED and Smart (p = 0.018) were significant. ED coil was the one with the most resistance to the straightening phenomenon. Selecting the optimal coil is the key to avoid the phenomenon.

Case-control study of postprocedural arterial puncture site hemorrhage after neuroendovascular treatment.

Puncture site hemorrhage following femoral artery catheterization is a significant cause of morbidity. The aim of this case-control study was to identify predictors of postprocedural arterial hemorrhage at the puncture site. We retrospectively reviewed 255 patients who underwent endovascular treatment at our institution over a 23-month period and classified them into a hemorrhage group and a non-hemorrhage group. Puncture site hemorrhage occurred in 15 patients (5.9%). Clinical factors associated with a significantly increased risk of puncture site bleeding included patients whose postoperative activated clotting time of ≥300 seconds before removal of the sheath (9 patients, 11.8%; P<0.05), those who received triple antiplatelet therapy (n=4, 17.4%; P<0.05) and the group administered heparin postoperatively (7 patients, 13.2%; P<0.05). The effects of low on-treatment platelet reactivity, i.e., P2Y12 reaction units <95%, sheath size, hemostasis method used, and operating time were not clinically significant. Our findings suggest an increased risk of puncture site hemorrhage in patients who either had an activated clotting time ≥300 seconds before the postoperative removal of the sheath, had received triple antiplatelet therapy, or were administered heparin postoperatively.

Factors influencing blood flow resistance from a large internal carotid artery aneurysm revealed by a computational fluid dynamics model.

Hyperperfusion syndrome occurs after treatment of a large or giant cerebral aneurysm. Recently, flow-diverter stent placement has emerged as an effective treatment method for a large cerebral aneurysm, but postoperative ipsilateral delayed intraparenchymal hemorrhage occurs in a minority of cases. The mechanism underlying delayed intraparenchymal hemorrhage is not established, but one possibility is hyperperfusion syndrome. The incidence of delayed intraparenchymal hemorrhage appears to be higher for giant aneurysms; hence, we speculated that large/giant aneurysms may create flow resistance, and mitigation by flow-diverter stent deployment leads to hyperperfusion syndrome and delayed intraparenchymal hemorrhage. The purpose of this study was to identify aneurysm characteristics promoting flow resistance by the analysis of pressure loss in an internal carotid artery paraclinoid aneurysm model using computational fluid dynamics. A virtual U-shaped model of the internal carotid artery siphon portion was created with a spherical aneurysm of various angles, body diameters, and neck diameters. Visualization of streamlines, were calculated of pressure loss between proximal and distal sides of the aneurysm, and vorticity within the aneurysm were calculated. The pressure loss and vorticity demonstrated similar changes according to angle, peaking at 60°. In contrast, aneurysm diameter had little influence on pressure loss. Larger neck width, however, increases pressure loss. Our model predicts that aneurysm location and neck diameter can increase the flow resistance from a large internal carotid artery aneurysm. Patients with large aneurysm angles and neck diameters may be at increased risk of hyperperfusion syndrome and ensuing delayed intraparenchymal hemorrhage following flow-diverter stent treatment.

Cardiac Arrest Induced by Carotid Sinus Reflex Activation During Flow-Diverter Stent Deployment.

BACKGROUND: A 60-year-old female with multiple carotid aneurysms underwent endovascular treatment with a Pipeline Flex embolization device (PED) under local anesthesia via femoral puncture. CASE DESCRIPTION: Cardiac arrest occurred when the delivery systems were pushed to promote adequate opening and apposition of the PED against the vessel wall and was recovered to sinus rhythm in approximately 30 seconds by pulling down the microcatheter. The carotid sinus reflex was suspected as the cause of this temporary asystole. Delivery of the PED was accompanied by application of forward pressure on the delivery system. This resulted in buckling of the delivery systems in the neck and likely excessive pressure on the carotid sinus. The procedure was continued and successfully completed with care not to excessively push the system and with the additional use of atropine. CONCLUSIONS: Although it was a rare complication, the phenomenon and its mechanisms were known in the carotid artery stenting procedure. To the best of our knowledge, this is the first report of cardiac arrest induced by a carotid sinus reflex during PED deployment. It is important for an operator of PED deployment to recognize its possibility. Vital signs should be closely checked during PED deployment, particularly while pushing the catheter.

Phytotoxic effects of trichothecenes on the growth and morphology of Arabidopsis thaliana.

Non-volatile sesquiterpenoids, a trichothecene family of phytotoxins such as deoxynivalenol (DON) and T-2 toxin, contain numerous molecular species and are synthesized by phytopathogenic Fusarium species. Although trichothecene chemotypes might play a role in the virulence of individual Fusarium strains, the phytotoxic action of individual trichothecenes has not been systematically studied. To perform a comparative analysis of the phytotoxic action of representative trichothecenes, the growth and morphology of Arabidopsis thaliana growing on media containing these compounds was investigated. Both DON and diacetoxyscirpenol (DAS) preferentially inhibited root elongation. DON-treated roots were less organized compared with control roots. Moreover, preferential inhibition of root growth by DON was also observed in wheat plants. In addition, T-2 toxin-treated seedlings exhibited dwarfism with aberrant morphological changes (e.g. petiole shortening, curled dark-green leaves, and reduced cell size). These results imply that the phytotoxic action of trichothecenes differed among their molecular species. Cycloheximide (CHX)-treated seedlings displayed neither feature, although it is known that trichothecenes inhibit translation in eukaryotic ribosomes. Microarray analyses suggested that T-2 toxin caused a defence response, the inactivation of brassinosteroid (BR), and the generation of reactive oxygen species in Arabidopsis. This observation is in agreement with our previous reports in which trichothecenes such as T-2 toxin have an elicitor-like activity when infiltrated into the leaves of Arabidopsis. Since it has been reported that BR plays an important role in a broad range of disease resistance in tobacco and rice, inactivation of BR might affect pathogenicity during the infection of host plants by trichothecene-producing fungi.