Hyun-Seung Kang

Repeat endovascular treatment in post-embolization recurrent intracranial aneurysms.

OBJECTIVE:The purpose of this study was to describe clinical situations requiring repeat embolization in patients previously treated by endovascular coil embolization for intracranial aneurysms, and to report on our experiences of repeat embolization (RE). METHODS:A total of 466 patients harboring 522 intracranial aneurysms were treated by endovascular coil embolization at our institution during the period between December 1992 and August 2004. We studied 32 patients who underwent repeat coil embolization (RE) owing to recanalization or aneurysm recurrence. Radiological and clinical data were reviewed to determine the reasons, results, and technical problems of RE. RESULTS:Thirty-nine sessions of RE were performed in 32 patients; four patients underwent RE twice and another patient three times. The major reason for RE was asymptomatic aneurysmal recanalization owing to coil compaction and/or loosening. The time interval between RE and the previous embolization was 12 months or less in 27 sessions. Complete or near complete occlusion of the aneurysm was achieved in all cases without procedure-related morbidity or mortality. Radiolucent gaps between the coil masses were observed in 17 cases. CONCLUSION:RE is a safe and effective treatment option in cases of recanalized or recurrent aneurysms. Close follow-up evaluation is essential in patients with intracranial aneurysms after coil embolization.

Plasma Matrix Metalloproteinases, Cytokines, and Angiogenic Factors in Moyamoya Disease

Objective To document the expression patterns of various matrixins, cytokines and angiogenic factors in plasma to assess their involvement in the pathogenesis of moyamoya disease (MMD). Methods This study included plasma samples from 20 MMD patients and nine healthy individuals. The plasma concentration of five matrix metalloproteinases (MMP-1, MMP-2, MMP-3, MMP-9, MMP-12), monocyte chemoattractant protein-1 (MCP-1), resistin, three interleukins (IL-1β, IL-6, IL-8), tumour necrosis factor-α, vascular endothelial growth factor (VEGF), platelet-derived growth factor BB (PDGF-BB) and basic fibroblast growth factor was determined using multianalyte profiling systems. The concentration of the tissue inhibitors of metalloproteinase (TIMP-1 and TIMP-2) was measured using ELISA. Gelatin zymography for MMP-2 and MMP-9 was also performed. Results MMD patients exhibited significantly higher plasma concentrations of MMP-9, MCP-1, IL-1β, VEGF and PDGF-BB, and lower plasma concentrations of MMP-3, TIMP-1 and TIMP-2 compared with healthy controls. Significant correlations were found among MMP-9, MCP-1, VEGF, PDGF-BB and TIMP-2 in MMD patients. Conclusion There were distinctive expression patterns of matrixins, cytokines and angiogenic factors in MMD patients, which seemed to correlate with disease pathogenesis. The balance between MMPs and TIMPs was disrupted in MMD and correlated with disease pathogenesis. Increased plasma levels of MCP-1 and VEGF in MMD patients may play a role in the recruitment of vascular progenitor cells and in the formation of collateral vessels.

Long-Term Outcomes After Combined Revascularization Surgery in Adult Moyamoya Disease

Background and Purpose— The surgical outcomes of adult moyamoya disease are rarely reported. We aimed to evaluate the long-term outcomes of combined revascularization surgery in patients with adult moyamoya disease. Methods— Combined revascularization surgery consisting of superficial temporal artery–middle cerebral artery anastomosis with encephalodurogaleosynangiosis was performed on 77 hemispheres in 60 patients. Clinical, angiographic, and hemodynamic states were evaluated retrospectively using quantitative methods preoperatively and postoperatively in the short-term (≈6 months) and long-term (≈5 years) periods. The mean clinical follow-up duration was 71.0±10.1 months (range, 60–104 months). Results— Clinical status improved until 6 months after surgery and remained stable thereafter, as assessed by the Karnofsky Performance Scale and modified Rankin Scale. The revascularization area relative to supratentorial area significantly increased in the long-term period compared with that in the short-term period (54.8% versus 44.2%; P<0.001). Cerebral blood flow in the territory of the middle cerebral artery improved in the short-term period compared with that in the preoperative period (68.7 versus 59.1; considering blood flow of the pons as 50; P<0.001) and thereafter became stable (65.5 in the long term; P=0.219). The annual risks of symptomatic hemorrhage and infarction were 0.4% and 0.2%, respectively, in the operated hemispheres. Conclusions— Combined revascularization surgery resulted in satisfactory long-term improvement in clinical, angiographic, and hemodynamic states and prevention of recurrent stroke.

Protection filter-related events in extracranial carotid artery stenting: a single-center experience.

Purpose: To report the complications, rescue procedures, and consequences related to the use of an embolus protection filter during carotid artery stenting (CAS). Methods: A retrospective review was undertaken of 72 patients (58 men; mean age 70.0±8.2 years, range 56–87) with extracranial atherosclerotic carotid stenosis who underwent 77 CAS procedures under filter protection. Filter-related events and rescue procedures according to each procedural step were retrospectively evaluated on CAS angiograms. In addition, neurological events and outcomes were also assessed. Results: CAS using a filter was successful in 99% of cases, and the overall rate of minor stroke (n=1), major stroke (0), or mortality (n=1) was 2.6% at 30 days. Filter placement was successful in all cases. However, arterial tortuosity made it difficult for a filter to pass through the stenosis in 1 case; this was overcome with an additional supportive wire (0.018-inch). Filter-related events were flow impairment in 6 (7.8%), filter wedging in the catheter tip in 4 (5.2%), vasospasm >50% narrowing in 7 (9.1%), filling defects within the filter membrane in 5 (6.5%), retrieval failure with the provided retriever in 3 (3.9%), and insecure retrieval without filter collapse in 2 (2.6%). Flow impairment caused drowsy mentality and impaired verbal response in 4, which resolved after prompt filter retrieval. All the cases of filter wedging were resolved with a catheter pulled down into the stented segment to separate the filter element from the catheter tip. Significant vasospasm and filling defects were spontaneously resolved in all cases after filter retrieval. Inability to pass a retriever catheter through a stent was overcome with curved 5-F catheter manipulation in all 3 cases. Conclusion: The use of a filter during CAS may induce various angiographic or technical events at each step. For a severely stenotic and tortuous carotid lesion with difficult access, a filter may become trapped or irretrievable during flow arrest. Physicians should be aware of the preventive and rescue maneuvers to counter filter-related events, perhaps even considering another type of protection mechanism or carotid endarterectomy.

Embolization of intracranial aneurysms with hydrogel-coated coils : Result of a korean multicenter trial. Commentary

OBJECTIVE HydroCoil (MicroVention, Aliso Viejo, CA), a hydrogel-platinum coil hybrid device, is one of various efforts to overcome delayed recanalization of coiled intracranial aneurysms. The purpose of this study was to investigate the outcome of intracranial aneurysms treated with HydroCoils. METHODS This multicenter prospective study included 80 aneurysms in 76 patients treated with HydroCoils. There were 32 (40%) ruptured and 48 (60%) unruptured aneurysms; 22 (28%) were large aneurysms (maximal diameter, ≥10 mm) and 58 (72%) were small. Aneurysm volumes were 100 mm3 or more in 48 (60%) and less than 100 mm3 in 32 (40%); in 13 aneurysms (16%), volumes were 600 mm3 or more. Efficacy and safety were evaluated on the basis of degree of initial occlusion, procedure-related complications, and the follow-up result. RESULTS Initial aneurysmal occlusion was complete in 60 (75%) aneurysms and near-complete in 14 (17.5%). Procedure-related complications included aseptic meningitis-related problems, including delayed hydrocephalus in 13 patients (28% among cases of unruptured aneurysms) and thromboembolism in two patients. Radiological follow-up data obtained 6 months or more after coil embolization were available in 54 aneurysms (68%) and revealed stable occlusion in 48 (89%) aneurysms, minor recanalization in one (2%), and major recanalization in five (9%). All of the recanalized aneurysms were 600 mm3 or more in volume, and aneurysm volume was a single important variable related to delayed recanalization on multiple logistic regression analysis (P = 0.016). CONCLUSION HydroCoil embolization seems to be a feasible treatment option in intracranial aneurysms in terms of initial aneurysmal occlusion rate and durability at the time of the follow-up evaluation; however, caution is required regarding aseptic meningitis and delayed hydrocephalus. Calculated aneurysmal volume of 600 mm3 seems to be critical in determining the anatomic outcome in aneurysms embolized with HydroCoils.

Quantitative angiographic comparison with the OSIRIS program between the direct and indirect revascularization modalities in adult moyamoya disease.

BACKGROUND Up-to-date, quantitative angiographic measurement of revascularization extent after bypass surgery has not been reported. OBJECTIVE To measure the extent of angiographic revascularization quantitatively 6 months postoperatively with the OSIRIS program (University Hospital of Geneva, version 3.1). METHODS A total of 75 bypass procedures were performed in 65 consecutive adult moyamoya disease patients, and 71 bypass surgeries in 61 adult moyamoya disease patients were studied 6 months postoperatively with angiography. We performed 5 different types of bypass surgeries: encephaloduroarteriosynangiosis (EDAS), superficial temporal artery-middle cerebral artery anastomosis (SMA), SMA with encephalomyosynangiosis (EMS), SMA with EDAS, and SMA with encephaloduroarteriomyosynangiosis (EDAMS). We also investigated single-photon emission computed tomography (SPECT) results after 6 months postoperatively and compared the angiographic revascularization extent with the SPECT results. RESULTS The mean values for the extent of revascularization among 5 different bypass surgeries were as follows: 32.4% for EDAS only, 57.4% for SMA only, 58.4% for SMA with EMS, 66.1% for SMA with EDAS, and 70.8% for SMA with EDAMS. There was a statistically significant difference in the extent of revascularization among the 5 surgical modalities (P = .000) and between the EDAS-only group and various SMA groups (P = .000). Statistical analysis between angiographic revascularization extent and SPECT results demonstrated significant statistical correlation (P = .000). CONCLUSION The extent of angiographic revascularization in adult moyamoya disease patients was highest in the SMA with EDAMS group and lowest in the EDAS-only group. In addition, angiographic revascularization extent was well correlated with the change in SPECT.

Nonoverlapping Y-configuration stenting technique with dual closed-cell stents in wide-neck basilar tip aneurysms.

BACKGROUND: Stent-assisted coiling is increasingly used to treat wide-neck intracranial aneurysms to protect the lumen of the parent artery from coil protrusion. This technique is insufficient for treating some aneurysms, depending on their configurations. OBJECTIVE: To describe a variant of the Y-configuration stent-assisted coiling technique for the treatment of basilar tip aneurysms with wide necks. METHODS: This technique, called the nonoverlapping Y stenting technique, consists of the deployment of a closed-cell self-expandable stent from the basilar trunk to a posterior cerebral artery and then placement of a second stent from the basilar bifurcation to the other posterior cerebral artery without overlapping the first stent. The proximal flared portion of the second stent was located at the neck of the aneurysm. Coil embolization was performed under dual-stent protection. RESULTS: We successfully filled wide-neck aneurysms with coils under stent protection by forming a bridge across the aneurysmal neck without overlapping 2 closed-cell stents. Six basilar tip aneurysms were successfully treated with this technique. CONCLUSION: The nonoverlapping Y stenting technique is a good alternative to traditional stent-assisted coiling. This technique is particularly suitable for the treatment of broad-neck bifurcation aneurysms. ABBREVIATION: PCA, posterior cerebral artery

ENDOVASCULAR TREATMENT OF RUPTURED ANEURYSMS OR PSEUDOANEURYSMS ON THE COLLATERAL VESSELS IN PATIENTS WITH MOYAMOYA DISEASE

OBJECTIVERuptured aneurysms or pseudoaneurysms on the collateral vessels in patients with moyamoya disease have been known to be difficult to treat surgically because of their deep location and combined ischemic condition of the brain. For several years, we have treated these aneurysms by endovascular means. In this article, we describe the detailed techniques and outcomes. METHODSEight patients with moyamoya disease who presented with intracerebral or intraventricular hemorrhage were treated by endovascular embolization. All had small aneurysmal lesions on distal collateral arteries (the distal part of the anterior and lateral posterior choroidal artery as periventricular collaterals in 7 patients and a small collateral branch from anterior communicating artery in 1 patient) that were located at corresponding area to the hemorrhage demonstrated on angiography. After superselecting the arteries as distally as possible, the aneurysms were occluded by n-butyl-cyanoacrylate injection. RESULTSSeven of 8 aneurysms were successfully and completely occluded without complication. One failed due to a small artery. Neither additional neurological deficit nor newly developed infarction was observed during the follow-up period. Clinically, 6 of the 8 patients demonstrated complete recovery. No further bleeding occurred during the follow-up period (mean, 24 months; range, 11–60 months). CONCLUSIONAlthough further investigation is required to determine many aspects of this treatment, including indication, safety, and efficacy, the endovascular occlusion of aneurysms on the collateral vessels in moyamoya disease with glue could be an effective treatment option.

Is clopidogrel premedication useful to reduce thromboembolic events during coil embolization for unruptured intracranial aneurysms

BACKGROUND:Thromboembolism is a common complication related to coil embolization of intracranial aneurysms. OBJECTIVE:To identify factors related to thromboembolic events during coil embolization for unruptured intracranial aneurysms and to evaluate the role of clopidogrel premedication to prevent thromboembolisms. METHODS:Since March 2006, clopidogrel has been administered to patients with unruptured aneurysms before coil embolization (the clopidogrel group) in our institution. The clopidogrel group (416 patients with 485 aneurysms) and the historical control group (140 patients with 159 aneurysms who received no antiplatelet premedication) were compared to find the efficacy of clopidogrel premedication. Various factors, including age, sex, body weight, and medical history of hypertension, diabetes mellitus, hyperlipidemia, smoking, previous stroke, and heart disease, as well as clopidogrel premedication, were analyzed in relationship to the development of a procedure-related thromboembolism. RESULTS:Procedure-related thromboembolic events tended to occur less frequently in the clopidogrel group compared with the control group (7.4% vs 12.6%; P = .05), and clopidogrel premedication could modify the risk in female patients from 11.1% to 5.2% (P = .04). The use of multiple logistic regression analysis identified clopidogrel premedication (P = .03), smoking (P = .002), and hyperlipidemia (P = .02) as significant factors related to the formation of thromboembolism. CONCLUSION:Clopidogrel premedication seems to have a beneficial effect in reducing the number of procedure-related thromboembolisms during coil embolization for unruptured intracranial aneurysms, especially in female patients. Smoking and hyperlipidemia were independent risk factors related to thromboembolism.

Decreased level and defective function of circulating endothelial progenitor cells in children with moyamoya disease

Circulating endothelial progenitor cells (EPCs) play an important role in physiological and pathological neovascularization and may be involved in attenuating ischemic diseases. This study aimed to characterize circulating EPCs in moyamoya disease (MMD), one of the most common pediatric cerebrovascular diseases. Twenty‐eight children with MMD prior to any surgical treatment and 12 healthy volunteers were recruited. Peripheral blood mononuclear cells (PBMNCs) were isolated and cultured in endothelial cell growth medium. Temporal change of phenotype of cells was analyzed on days 0 and 7. The formation of EPC clusters was evaluated on day 7. The CD34+, CD133+, and KDR+ cells, and the number of EPC clusters was significantly reduced in children with MMD. In controls, CD34+ cells were significantly decreased on day 7 compared with day 0, but in MMD they were only slightly decreased. The change in KDR+ cells on day 7 compared with day 0 was the reverse of that for CD34+ cells. Functional assay of EPC demonstrated less tube formation and increased senescent‐like phenotype in children with MMD. Analysis of the circulating EPCs of MMD children reveals decreased level and defective function. This study suggests that circulating EPCs may be associated with MMD pathogenesis.