Kohsuke Yamashita

Transvenous embolization of dural caroticocavernous fistulae: technical considerations

Sixteen patients with symptomatic dural caroticocavernous fistulae were treated by transvenous embolization, via the jugular vein and inferior petrosal sinus. The fistula was occuladed by thrombogenic coils. Complete resolution of symptoms and signs was achieved in 14 patients, and complete angiographic resolution was also obtained in 14 patients. Failures to achieve angiographic cure were attributed to failure to reach the fistula within the cavernous sinus precisely. Factors which make placement of the catheter at the fistula difficult are trabeculae within the cavernous sinus, a specific configuration of the superior ophthalmic vein and venous thrombosis. To improve the efficacy of tranvenous embolization, every possible venous route to the cavernous sinus therefore should be tried, to facilitate reaching the fistula and the possibility of transvenous embolization should not be thwarted by venous thrombosis.

Embolization of Cerebral Aneurysms with a Liquid Embolus, EVAL Mixture: Report of Three Cases

SummaryEmbolization of three surgically difficult cerebral aneurysms was performed using our newly developed non-adhesive embolic material, EVAL mixture (ethylene vinyl alcohol copolymer). Conventional embolic materials such as detachable balloons or microcoils were not used because of a large or irregular aneurysmal neck. After temporary occlusion of the parent artery with a superselective balloon catheter, the EVAL mixture was slowly injected through a microcatheter placed in the aneurysm or parent artery. The locations of the aneurysms were anterior communicating artery, basilar artery-posterior cerebral artery and basilar artery-anterior inferior cerebellar artery (BA-AICA). One aneurysmal occlusion and 2 parent artery occlusions were performed. Patients had no persistent deficits. The patient with the BA-AICA aneurysm associated with an arteriovenous malformation died of rupture of the residual AVM due to haemodynamic change 2 weeks after embolization. In selected and limited cases, embolization of surgically difficult cerebral aneurysms using EVAL mixture was more effective and safer than embolization using conventional embolic materials such as balloons and microcoils.

Pathogenetic and therapeutic considerations of carotid-cavernous sinus fistulas

SummaryCarotid-cavernous sinus fistula (CCF) is a syndrome in which arteriovenous shunts exist between the carotid artery and the cavernous sinus. These shunts vary widely in pathogenesis, angiogram, haemodynamics and treatment. Several systems of classification in terms of either haemodynamics, aetiology and/or pathogenesis have been reported, but they are not comprehensive. A more comprehensive and simpler nomenclature of classification is now required.Fifty seven cases of CCFs were analyzed and were classified according to their pathogenesis, angiography and treatment modalities. There were 11 traumatic CCFs with direct shunts (T-D group), and 2 traumatic CCFs with indirect shunts (T-I group). Spontaneous CCFs were divided into three groups. There were 37 spontaneous CCFs caused by dural arteriovenous shunts that were naturally classified as being indirect shunts (SD-I group). There were 5 spontaneous CCFs caused by suspected connective tissue disorders, such as fibromuscular dysplasia, Ehlers-Danlos syndrome etc.; these had direct shunts. Care was needed to avoid dissection of the artery or complications due to the fragility of connective tissue (SC-D group). There were 2 spontaneous CCFs caused by the rupture of an inflaclinoid aneurysm without any background of connective tissue disorder; these had direct shunts (SA-D group).By this system of grouping and use of abbreviations, each case of CCF can be clearly delineated in terms of its pathogenesis and selection for appropriate treatment.

Cerebral microbleeds predict first-ever symptomatic cerebrovascular events.

OBJECTIVE Cerebral microbleeds (CMB) on gradient-echo T2*-weighted magnetic resonance image (MRI) are frequently seen in patients with cerebral diseases. In this observational study we assessed whether CMB are a predictive factor for first-ever cerebrovascular events. PATIENTS AND METHODS This study consisted of 698 subjects without a history of symptomatic cerebrovascular events, who received gradient-echo T2*-weighted MRI for 3 months between November 2003 and January 2004 in Kishiwada City Hospital, Osaka, Japan. These subjects were then observed as outpatients for over 3.5 years. RESULTS The prevalence of CMB at baseline was 17.0% (119/698) in this population, and the follow-up rate was 51%. A total of 36 first-ever symptomatic cerebrovascular events were observed during the 3 and a half-year follow-up period. First-ever symptomatic cerebrovascular events occurred significantly more frequently in subjects with CMB (15 cases) than those without CMB (21 cases) (p=0.001). Even after adjusting for age, sex and hypertension, it was revealed that the presence of CMB was an independent predictor for the first-ever symptomatic cerebrovascular event by using the Cox proportional hazards model (hazard ratio, 2.87; 95% CI, 1.27-6.48; p=0.01). CONCLUSION The presence of CMB is an independent predictor of first-ever symptomatic cerebrovascular diseases.

Experimental study and clinical use of poly(vinyl acetate) emulsion as liquid embolisation material

A new material, an emulsion of poly(vinyl acetate) was experimentally developed and clinically used to overcome several disadvantages in currently used liquid embolisation materials. The emulsion microparticles, 0.3–0.7 μm in size, possessed cationic charge on the surface and hence aggregated immediately on contact with fluids containing anions. This inert polymer has the advantage that it does not induce a deleterious reaction in living tissue. Moreover, its medium is water and it is not adhesive, like the cyanoacrylates. Several concentrations of emulsion were injected into the renal arteries of dogs. For the investigation of tissue reactions and the possibility of recanalisation, the emulsion was injected into rats both subcutaneously and into the renal arteries. The renal artery injections in dogs showed adequate radiopacity and consistent complete occlusion. The lower the concentration of the emulsion, the smaller the arteries which could be occluded. Even at very low concentrations, however, venous occlusion did not occur. Histological study of the embolised rat kidney revealed no detectable damage in the vessel wall and no recanalisation for up to 6 months. The subcutaneously injected PVAc emulsion elicited mononuclear cell infiltration and gradual centripetal fibrosis, without any deleterious effect on the surrounding tissue. A cerebral arteriovenous malformation (AVM) was embolised using the material. Histology of the resected nidus showed findings similar to those in the animal experiments.

A cationic polymer, Eudragit-E, as a new liquid embolic material for arteriovenous malformations

We have developed a new liquid material for embolisation of arteriovenous malformations: a mixture of methyl and butyl methacrylate, plus dimethylaminoethyl methacrylate copolymer (Eudragit-E) in a solvent consisting of ethanol and iopamidol. Upon contact with aqueous substances, Eudragit-E precipitates rapidly and forms a soft elastic sponge within 3 s, as the ethanol diffuses. In blood, the positively charged Eudragit-E aggregates the negatively charged blood elements. Transcatheter embolisation of 4 canine and 52 rat renal arteries was feasible. Histological studies revealed no acute inflammatory reaction within 1 week, but mild to moderate reactions in the subacute and chronic stages. No recanalisation was seen. Because of its unique properties and excellent thrombogenicity the Eudragit-E mixture seems a promising embolic material.

A priority treatment of the intraventricular hemorrhage (IVH) should be performed in the patients suffering intracerebral hemorrhage with large IVH

BACKGROUND In patients suffering from intracerebral hemorrhage (ICH) with ventricular hemorrhage (IVH), the IVH severity is thought to be associated with prognosis. Therefore, treating IVH may be a beneficial therapeutic target. In this study, by examining the associations among IVH severity, hydrocephalus, initial level of consciousness and prognosis, we attempted to identify which grade of IVH severity should be considered for surgical treatment. METHODS One hundred twenty-nine patients with spontaneous supratentorial ICH treated in our hospital between 2005 and 2006 were screened in this study. Of these patients, 100 with an ICH volume less than 60 ml were categorized into either the ICH patients without IVH (no-IVH) group (n=65) or the ICH patients with IVH (IVH) group (n=35). The Karnofsky Performance Status (KPS) scale assessed at the time of discharge was employed as an outcome index, and a KPS score of <or=40 was defined as the bedridden state. Age, gender, hemorrhage location, volume of ICH, IVH grade (according to the Graeb score), acute hydrocephalus, surgical ICH removal, and ventricular drainage were selected for univariate analyses with logistic regression. RESULTS Elderly patients, IVH volume, acute hydrocephalus, and poor initial level of consciousness were significantly associated with an unfavorable prognosis in the IVH group. Poor level of consciousness was significantly dependent on acute hydrocephalus, and significantly more occurrences of acute hydrocephalus were found in patients with a high IVH volume (Graeb score >or=6) than in patients with low to moderate IVH volume (Graeb score <or=6). CONCLUSIONS IVH severity influenced the occurrence of acute hydrocephalus and initial level of consciousness, which was significantly associated with prognosis. Our results suggest that priority treatment of the IVH should be given to those ICH patients with IVH admitted with a Graeb score of 6 or more.

Correlation and association of plasma interleukin-6 and plasma platelet-derived microparticles, markers of activated platelets, in healthy individuals

INTRODUCTION The aim of this study was to clarify the correlation and association of plasma IL-6 and PDMPs, both of which are associated with metabolic syndrome, in healthy individuals. MATERIALS AND METHODS We conducted a cross-sectional study of 464 healthy Japanese volunteers (210 men and 254 women, median age 39 and 35years, respectively) who had no signs, symptoms or history of cardiovascular- or cerebrovascular disease and took no medications. We assayed their IL-6 levels with a conventional ELISA kit and their PDMP levels by ELISA and monoclonal antibodies against CD42b and CD42a (glycoprotein Ib and IX). RESULTS By multivariate analysis, the plasma level of PDMP was correlated with diastolic blood pressure (p=0.015), platelet count (p<0.001), high sensitivity C-reactive protein, and the plasma level of IL-6 (p<0.001) in men (R(2)=0.454, p<0.001) and was correlated with platelet count (p<0.001) and the plasma level of IL-6 (p<0.001) in women (R(2)=0.159, p<0.001). Quartile range of plasma level of IL-6 was associated with plasma level of PDMP after adjustment for diastolic blood pressure, platelet count, and high sensitivity C-reactive protein in men (p<0.001) and associated with plasma level of PDMP after adjustment for platelet count in women (p<0.001). CONCLUSIONS These results suggest the plasma IL-6 is correlated and associated with the plasma PDMPs, markers of activated platelets in healthy individuals.

Circulating oxidized LDL, measured with FOH1a/DLH3 antibody, is associated with metabolic syndrome and the coronary heart disease risk score in healthy Japanese

BACKGROUND AND PURPOSE The objective of this study was to clarify the relationship between circulating oxidized LDL (oxLDL) and metabolic syndrome (MS) and the coronary heart disease (CHD) risk score. METHODS We conducted a cross-sectional study of healthy volunteers who had no signs, symptoms or history of cardiovascular or cerebrovascular disease and took no medications. We studied 382 Japanese volunteers, 190 men and 192 women (median age 41 and 38 years, respectively). We used an ELISA kit and a monoclonal oxLDL antibody, FOH1a/DLH3, to measure circulating oxLDL. RESULTS The odds ratio (OR) for elevated oxLDL in individuals with MS compared to those without MS, adjusted for age and sex, was 1.94 (range 1.00-3.78). In individuals with a predicted Framingham 10-year risk for CHD>5% (corresponding with the highest quartile), compared to those with a predicted 10-year risk<5%, the OR, adjusted for age, sex, smoking, and LDL cholesterol, was 2.51 (1.17-5.36). The age-, sex-, smoking- and LDL cholesterol-adjusted OR for a 10-year CHD risk score >5% was 1.03 (1.01-1.04) for LDL cholesterol and 11.7 (4.69-29.0) for smoking. CONCLUSIONS Elevated oxLDL is associated with the presence of MS and the CHD risk score in healthy people.

Embolization of arteriovenous malformations using EVAL mixture (a new liquid embolization material)

For controllable embolization of arteriovenous malformations (AVMs) EVAL mixture, a new liquid material, was developed for use instead of cyanoacrylate derivatives such as isobutyl cyanoacrylate (IBCA) and N-butyl cyanoacrylate (NBCA). When the mixture is injected into blood, EVAL (ethylene vinyl alcohol copolymer) instantly forms sponge and occludes the pedicle and nidus. This new liquid material was used in 38 cerebral AVMs. Twenty cases were cured by embolization and the subsequent surgery. The remaining 18 cases was treated by embolization alone. Total embolization was achieved in 1 case. Between 70% and 90% embolization was achieved in 3 cases; 50–70% embolization was achieved in 10 cases. Less than 50% embolization was achieved in 4 cases. Complications were observed in 11 cases. Nine cases were minor or transient. Two cases were moderate. Rebleeding from the AVM was observed in 3 cases at follow-up examinations.