Aneurysms In Japan Research Articles

The outcomes and cost analysis of open repair and endovascular aneurysm repair for abdominal aortic aneurysms: a single-center experience in Japan.

Japan has adopted its own reimbursement system, which differs from other countries in terms of its diagnostic procedure combination (DPC) methods. However, there are few reports on the cost analysis of open repair and endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms in Japan. We aimed to evaluate the long-term outcomes and cost-effectiveness of these two procedures. This study included patients who underwent open repair (n = 224) and EVAR (n = 87) between January 2012 and December 2022. After propensity score matching, we compared the two groups. The drug and blood products, procedures, and DPC costs were significantly higher in the open repair group (p < 0.001) than in the EVAR group. The surgical equipment and total costs were significantly higher in the EVAR group than in the open repair group (p < 0.001). There was no significant difference in the 5-year survival rate (88.5% in the open repair group vs. 72.0% in the EVAR group; p = 0.33) and freedom from re-intervention rate at 5years (93.1% in the open repair group vs. 89.9% in the EVAR group; p = 0.15) between the two groups. Open repair is more cost-effective than EVAR. The cost-effectiveness of EVAR may therefore depend on the cost of the endograft.

Declining trend in the estimated annual rupture rate of unruptured cerebral aneurysms in Japan: a nationwide study.

The incidence of subarachnoid hemorrhages (SAHs) in Japan has recently decreased. However, trends in the annual rates of unruptured cerebral aneurysms (UCAs) are unclear because calculations based on follow-up periods are limited to patients with ruptured cerebral aneurysms. We aimed to clarify current trends in the estimated annual rupture rates of UCAs in Japan and to identify the most relevant contributing factors. We analyzed data from the Japanese Ministry of Health, Labour and Welfare and records of the Japan Neurosurgical Society. The estimated annual rupture rates of UCAs between 2003 and 2018 were calculated according to age-adjusted mortality rates of SAH and number of treated ruptured cerebral aneurysms (RCAs). We estimated trends in annual rupture rates using sensitivity analysis and assessed associations between estimated annual rupture rates and the prevalences of hypertension and current smoking. The estimated annual rupture rate of UCAs significantly decreased from 1.44 to 0.87% and from 0.92 to 0.76%, respectively, in terms of age-adjusted mortality rates of SAH and number of treated RCAs (p < 0.001). The range of changes in estimated annual rupture rates of UCAs was - 1.13%‒0.83%, representing a declining UCA trend of 88%. The estimated annual rupture rates of UCAs declined by 0.02-0.10% and 0.01-0.05% with every percent decrease in hypertension and current smoking prevalence, respectively. The estimated annual rupture rate of UCAs has recently decreased in Japan, possibly due to a decrease in the prevalence of hypertension rather than smoking.

It Is Necessary to Pay Attention to Where the Pcom Originate from the Aneurysm to Treat with FD.

Objective With the expansion of indications of flow diverter (FD) for cerebral aneurysms, FD placement for posterior communicating artery (Pcom) aneurysms has been approved. However, it is controversial whether Pcom aneurysms should be treated with FD or not. In this study, we report the outcome of FD treatment for Pcom aneurysms in Japan. Materials and Methods We retrospectively analyzed 36 patients with 38 aneurysms treated with FD placement for Pcom aneurysms between 2015 and 2021 in our hospital. We divided our cases into complete occlusion (CO) and non-CO groups. And we extracted contributing factors to CO using multivariate analysis. We also compared the complications rate among the three types of FDs. Results CO was obtained in 29 cases (79.3%), and complications were observed in 3 cases (7.9%). Multivariate analysis revealed that the type of Pcom branch from the aneurysmal dome was a significant factor contributing to CO (odds ratio: 0.0052, 95% confidence interval 0.000048-0.584, p = 0.029). In terms of complications, complication rate was significantly higher in the Flow-Redirection Endoluminal Device (FRED) group ( p = 0.0491). Conclusion The outcome for Pcom aneurysms treated by FD was acceptable. When treating, we must pay attention to where Pcom originates. Achieving CO with FD is difficult for aneurysms where the Pcom branches from the dome. Furthermore, when treating Pcom aneurysms with FRED, it is necessary to be careful about thromboembolic complications.

Evaluating the Effectiveness and Clinical Outcomes of Endovascular Aneurysm Repair-First Approach for Ruptured Abdominal Aortic Aneurysm in Japan.

To verify the validity of an endovascular aneurysm repair (EVAR)-first strategy for treating patients with ruptured abdominal aortic aneurysm (rAAA) in Japan. This study was conducted on 2 groups of patients with rAAA who underwent surgical treatment at 3 hospitals in the Kanagawa Prefecture, Japan, between January 2007 and September 2016. The open surgical treatment group comprised patients with rAAA who underwent open surgical treatment before January 2012; their data were retrospectively collected from their medical records. The EVAR-first strategy group comprised patients with rAAA who underwent treatment based on the Shonan rAAA protocol (SRAP; the standard protocol-based EVAR-first strategy) in or after February 2012; their data were collected prospectively. The short- and long-term treatment outcomes of both groups were compared. In addition, a risk score-based sensitivity analysis (one-to-one matching) was conducted on both groups using a caliper with 0.2 standard deviations of the score. Of the 163 patients with rAAA, the open surgical and EVAR-first strategy groups comprised 53 and 110 patients, respectively (EVAR: 91.8%, open repair: 8.2%). The 30-day postoperative mortality rate differed significantly, being 42% for the open surgery group and 25% for the EVAR-first strategy group (odds ratio: 0.44, 95% confidence interval: 0.20-0.97). The postoperative survival rates at 6 months, 1 year, and 3 years were 66%, 48%, and 58% for the EVAR-first group, respectively, and 51%, 66%, and 48% for the open surgery group, respectively (p=0.072). In a matched cohort analysis (n=50), the 30-day postoperative mortality rate was 22% for the EVAR-first group and 44% for the open surgery group (odds ratio: 0.35, 95% confidence interval: 0.14-0.90). The postoperative survival rates at 6 months, 1 year, and 3 years were 76%, 76%, and 63% for the EVAR-first group, respectively, and 48%, 45%, and 45% for the open surgery group, respectively (p=0.003). The SRAP-based EVAR-first strategy for rAAA yielded significantly better treatment outcomes than the open surgical strategy. These findings suggest that EVAR should be considered the primary treatment option for rAAA, given its potential to reduce early mortality rates. Multicenter retrospective analysis of prospectively collected registry data was done to compare treatment outcomes of two groups of ruptured abdominal aortic aneurysm patients open surgery and endovascular-aneurysm-repair (EVAR)-first strategy (Shonan ruptured abdominal aortic aneurysm protocol). EVAR-first group showed better outcomes: lower 30-day mortality (25% vs. 42%), higher survival rates at 6 months, 1 year, and 3 years. Take home Message: The study supports the use of the EVAR-first strategy with the Shonan Protocol for treating ruptured abdominal aortic aneurysms in Japan, showing improved outcomes, reduced 30-day postoperative mortality, and better long-term survival rates compared to the conventional approach.

Long-term Follow-up Results after Flow Diverter Therapy Using the Pipeline Embolization Device for Large or Giant Unruptured Internal Carotid Artery Aneurysms: Single-center Retrospective Analysis in the Japanese Population.

Flow diverter (FD) therapy using Pipeline embolization device (PED) has become an important alternative to treat internal carotid artery (ICA) aneurysms. Herein, we report the long-term outcome for 3 years after FD therapy using PED for ICA aneurysms in Japan. The patients who underwent angiographical and/or clinical follow-up for 3 years after the FD therapy using PED of large or giant unruptured ICA aneurysms from December 2012 at our university hospital are the subjects of this study. We retrospectively reviewed the in- and outpatients’ medical charts, and written operative and radiological records. There were 84 patients with 90 aneurysms who could be clinically and/or angiographically followed up for 3 years. Of these, 7 aneurysms were only available for clinical follow-up. Of the remaining 83 aneurysms, 6 aneurysms had vessel occlusion due to stent thrombosis or parent artery occlusion, and 60 of the remaining 77 (77.9%) had complete occlusion. In multivariate analysis, older age (>70 years), wide neck, and non-adjunctive coiling contributed statistically significantly to incomplete occlusion. Of the 84 patients, 2 patients (2.4%) had delayed complications between 6 months and 3 years after the initial FD placement. Three patients (3.6%) had poor outcome due to postoperative major stroke complications, 2 of which were acute complications. The long-term results after FD therapy are good both angiographically and clinically. Endothelialization of the aneurysmal neck and intra-aneurysmal thrombosis contribute to complete occlusion. The primary reason for the somewhat low complete occlusion in Japan may be the patients are generally older.

Use of Contralateral Trans-Anterior Communicating Artery Snare to Rescue Lost Access to a Pipeline Embolization Device Unsheathed in an Aneurysm.

A pipeline embolization device (PED; Medtronic, Minneapolis, MI, USA) is a new vascular reconstruction device used to treat large internal carotid artery (ICA) aneurysms in Japan. We herein present a PED-related complication and describe its rescue strategy. Rescue therapy using a snare via the posterior communicating artery from the contralateral side has already been reported. However, this is the first report of therapy via the anterior communicating artery (AcomA). A 49-year-old woman underwent vascular reconstruction with a PED for a large cavernous ICA aneurysm. During the placement of the PED, the proximal side of the PED slipped into the aneurysm. It was impossible to enter the true lumen of the PED from the proximal side because the orifice of the stent faced the aneurysmal wall. Contralateral trans-AcomA access to the PED was obtained through the distal ICA. The microwire from the distal ICA was connected with Goose Neck snares (Medtronic) from the proximal ICA. Pulling the snares to the proximal side, the PED was straightened and distal access was regained. Another PED was deployed such that it overlapped with the first PED to achieve vascular reconstruction. The patient finally recovered from aphasia, but paralysis of the right upper limb remained after rehabilitation. If the stent slips into the aneurysm, distal access through the true stent lumen may be very difficult. We presented a rescue technique for this complication, through the AcomA from the contralateral side.

Influence of Type 2 Endoleaks on Long-Term Outcomes after Endovascular Repair for Abdominal Aortic Aneurysms: A National Hospital Organization Network Study for Abdominal Aortic Aneurysms in Japan

Although endovascular repair (EVAR) is the first-line treatment for abdominal aortic aneurysm, type 2 endoleak (EL), which is associated with late sac enlargement or rupture, remains a concern. The present study aimed to assess the influence of type 2 EL on long-term outcomes after EVAR. Among 550 patients who underwent EVAR between 2007 and 2013 at 14 Japanese national hospitals, 135 patients had type 2 EL diagnosed on follow-up computed tomography (CT) within 12months after EVAR (EL2[+] group) and 415 patients did not have EL within 12months (EL2[-] group). The cumulative incidences of sac enlargement, late intervention, and aneurysm-related death after EVAR were estimated using the cumulative incidence function method, and prognostic factors were investigated using the Fine-Gray hazard model. The median follow-up period was 5years, and the 5-year cumulative incidence rates of sac enlargement, late intervention, and aneurysm-related death were 30.7%±4.4%, 25.3%±4.1%, and 2.6%±1.4%, respectively, in the EL2(+) group, and 8.7%±1.6%, 7.6%±1.4%, and 0.3%±0.3%, respectively, in the EL2(-) group. The cumulative incidence rates of sac enlargement (P=0.002), late intervention (P<0.001), and aneurysm-related death (P=0.015) were significantly different between the 2 groups. As the first-line treatment for sac enlargement with type 2 EL, transcatheter coil embolization was performed in 30 patients. Information about sac behavior on CT after coil embolization was available in 20 of the 30 patients. Among these patients, no patients experienced sac shrinkage, and the aneurysmal sac dilated after coil embolization in 18 patients. Type 2 EL affects the long-term outcomes after EVAR. It is not recommended to observe large aneurysmal sacs conservatively as they tend to dilate in the presence of type 2 EL.

Effect of actual age on outcome at discharge in patients by surgical clipping and endovascular coiling for ruptured cerebral aneurysm in Japan.

The Japanese population features the highest rate of elderly individuals worldwide. However, the difference of actual age indication for surgical clipping (SC) and endovascular coiling (EC) has never reported. We clarified the effect of actual age on poor outcome at discharge in patients by each treatment for ruptured cerebral aneurysm according to the Japanese Stroke Data Bank. A total of 3593 patients with ruptured saccular cerebral aneurysm were treated by SC and/or EC between 2000 and 2013. The effect of actual age on poor outcome (modified Rankin scale [mRS] score > 2) at discharge was evaluated by the cutoff age using receiver operating characteristic analysis for each treatment. There were 2666 cases in the SC group and 881 cases in the EC group. The cutoff age for poor outcome was 3 to 9years older for EC than for SC. The gap of cutoff age between two treatments was 3years shorter in mild subarachnoid hemorrhage than severe cases. The gap of cutoff age between two treatments was 7years in elderly patients over 65years old. The cutoff age was 78years old for both SC and EC in elderly female patients. In conclusion, the cutoff age for poor mRS score > 2 was 3 to 9years older for EC than for SC. Actual age was one of the indications for elderly patients to achieve the optimum outcome; however, the treatment indication should be carefully considered based on the condition in each country.

Abstract 14: Size Ratio can be a Strong Predictor for Future Rupture of the Unruptured Cerebral Aneurysms

Introduction: Various factors have been nominated for the rupture of unruptured cerebral aneurysms including size, shape and specific locations of aneurysms. Size ratio, which is the quotient of maximum size of the aneurysm divided by the diameter of the adjacent parent artery, has also been nominated as a strong indicator to discriminate ruptured versus unruptured cerebral aneurysms. However, this has never been tested as a risk in the prospective cohort. In this paper, we have assimilated size ratio in cases of UCAS Japan using reported average parent arterial size and evaluated its value. Methods: We used average main intracranial artery diameter reported in anatomical studies as follows: AComA: 1.5mm, MCA: 3.9mm, ICA: 4.3mm, PComA: 1.3mm, BA: 4.1mm and VA: 3.9mm. UCAS Japan cohort, which is a Japanese prospective cohort of unruptured cerebral aneurysms in Japan, were utilized (6,312 aneurysms with 11,011 aneurysm*year follow-up). Result: Rupture risks according to this assimilated size ratio (aSR) were as follows: aSR&lt;1.0: 0.13%/yr, aSR:1∼1.5: 0.24%/yr, aSR 1.5∼2: 1.17%/yr, aSR: 2∼3: 1.03%/yr, aSR 3-; 2.62%/yr. With multivariate logistic regression model, aSR &gt;1.5 was significant factor along with presence of daughter sac, symptomatic presentation and age &gt;=70. Hazard ratio for the aSR&gt;1.5 was 6.01 and the highest among these factors. Aneurysm locations lost its significance as the influencing factor. Conclusions: While our outcome was limited because the parent artery size was not measured in individual cases, our aSR showed clear demarcation of the future rupture risk. Rather than considering specific location as the risk factor, size ratio might be more important rupture predictor in assessing natural course of unruptured cerebral aneurysms.

日本の脳動脈瘤の特徴と脳動脈瘤クリッピング術における脳虚血対策

未破裂脳動脈瘤の保有率は人種差，地域差はなく3～5％とされるが，くも膜下出血の破裂率は日本が世界で最も高い国の一つで，未破裂脳動脈瘤の破裂率が欧米に比較して約3 倍高いためとされる．未破裂脳動脈瘤の破裂危険因子として高血圧，年齢が70 歳以上，動脈瘤のサイズ，部位があげられる．治療は日本ではクリッピングの方が多く，成績もコイル塞栓術に比較して劣らない．脳動脈瘤クリッピング術では親血管一時血行遮断が必要となることがあり，我々は脳虚血対策が重要と考え，術中血圧は収縮期で100 mmHg 以上を保ち，脳保護薬の投与，超軽微低体温麻酔下で手術を行っている．未破裂脳動脈瘤の治療成績は術後永続的神経脱落症状が3.3％で，modified Rankin Scale 低下に関与するものが2.2％であった．脳動脈瘤クリッピング術中一時血行遮断時MEP モニタリングでは，一時血行遮断が原因のMEP 変化を10.3％に認めたが，全例回復した．MEP 陽性のリスクファクターについて多変量解析で解析すると，体温が37 度以上が有意な因子であり，術中は体温の上昇を避けるべきと考えられた．

本邦の脳動脈瘤治療の現状─当院，脳卒中データバンク，（社）日本脳神経外科学会調査より─

本邦の脳動脈瘤治療の現状─当院，脳卒中データバンク，（社）日本脳神経外科学会調査より─

Family history of aortic aneurysm is an independent risk factor for more rapid growth of small abdominal aortic aneurysms in Japan

We aimed to investigate risk factors associated with more rapid growth of abdominal aortic aneurysms (AAA) <50 mm (small AAAs) in Japan. We retrospectively investigated the clinical data of 374 patients with small AAAs (maximum diameter, ≤50 mm) who were referred to The University of Tokyo Hospital, Tokyo Medical University Hospital, or Saitama Medical Center, between 1995 and 2008. A total of 374 patients (321 men and 53 women) were followed up for a median of 66 months. The median diameter on initial examination was 40 mm, and the median growth rate of the AAAs was 2.1 mm/y. The growth rate of AAAs with an initial diameter ≥45 mm was significantly greater than those with an initial diameter <45 mm (3.3 mm/y vs 2.0 mm/y, respectively; P = .007). The growth rate of AAAs was significantly greater in patients with hypertension than in those without (2.3 mm/y vs 1.7 mm/y, respectively; P = .006) and in patients with a family history of aortic aneurysm than in those without (4.2 mm/y vs 2.0 mm/y, respectively; P = .009). Logistic regression analysis revealed that a large initial diameter and family history of aortic aneurysm were independent predictors of accelerated growth rate of small AAAs in Japan. In the present study, a large initial diameter and family history of aortic aneurysm were independent risk factors for more rapid growth of small AAAs. Although few studies have reported similar findings thus far, family history of aortic aneurysm should be carefully considered during follow-up of patients with small AAAs.

Clinical significance of left ventricular apical aneurysms in hypertrophic cardiomyopathy patients: The role of diagnostic electrocardiography

ObjectivesSome patients with hypertrophic cardiomyopathy (HCM) develop left ventricular apical aneurysm, leading to serious cardiovascular complications. The aims of this study were to identify the incidence and clinical course of HCM patients with apical aneurysms in Japan, and to evaluate the role of electrocardiography (ECG) as a screening test to detect apical aneurysms in HCM patients. Methods and resultsIn a retrospective, single center analysis of a population of 247 HCM patients, 21 patients (8.5%) had left ventricular apical aneurysms. Their mean age was 60±14 years (range: 23–77 years) at study entry. Over 4.7±3.3 years of follow-up, 10 patients (47.6%) experienced an adverse clinical event (annual event rate: 10.1%/y), including five implantable cardioverter-defibrillator (ICD) implantations for ventricular tachycardia/ventricular fibrillation (VT/VF), an appropriate discharge of ICD for VT/VF, and four nonfatal thromboembolic strokes. Two patients developed systolic dysfunction (ejection fraction <50%). No sudden cardiac death or progressive heart failure was detected. Fourteen patients showed ST-segment elevation (≥1mm) in V3 through V5 of ECG. In four patients, progression of the ST-segment elevation was recognized. When the ST-segment elevation was used to identify apical aneurysms in HCM patients, the sensitivity was 66.7%, and the specificity was 98.7%. ConclusionApical aneurysms in HCM patients in Japan are not rare, and are associated with serious cardiovascular complications. The early diagnosis of apical aneurysms can be achieved by serial ECG.

The Natural Course of Unruptured Cerebral Aneurysms in a Japanese Cohort

BackgroundThe natural history of unruptured cerebral aneurysms has not been clearly defined.MethodsFrom January 2001 through April 2004, we enrolled patients with newly identified, unruptured cerebral aneurysms in Japan. Information on the rupture of aneurysms, deaths, and the results of periodic follow-up examinations were recorded. We included 5720 patients 20 years of age or older (mean age, 62.5 years; 68% women) who had saccular aneurysms that were 3 mm or more in the largest dimension and who initially presented with no more than a slight disability.ResultsOf the 6697 aneurysms studied, 91% were discovered incidentally. Most aneurysms were in the middle cerebral arteries (36%) and the internal carotid arteries (34%). The mean (±SD) size of the aneurysms was 5.7±3.6 mm. During a follow-up period that included 11,660 aneurysm-years, ruptures were documented in 111 patients, with an annual rate of rupture of 0.95% (95% confidence interval [CI], 0.79 to 1.15). The risk of rupture increased with increasing size of the aneurysm. With aneurysms that were 3 to 4 mm in size as the reference, the hazard ratios for size categories were as follows: 5 to 6 mm, 1.13 (95% CI, 0.58 to 2.22); 7 to 9 mm, 3.35 (95% CI, 1.87 to 6.00); 10 to 24 mm, 9.09 (95% CI, 5.25 to 15.74); and 25 mm or larger, 76.26 (95% CI, 32.76 to 177.54). As compared with aneurysms in the middle cerebral arteries, those in the posterior and anterior communicating arteries were more likely to rupture (hazard ratio, 1.90 [95% CI, 1.12 to 3.21] and 2.02 [95% CI, 1.13 to 3.58], respectively). Aneurysms with a daughter sac (an irregular protrusion of the wall of the aneurysm) were also more likely to rupture (hazard ratio, 1.63; 95% CI, 1.08 to 2.48).ConclusionsThis study showed that the natural course of unruptured cerebral aneurysms varies according to the size, location, and shape of the aneurysm. (Funded by the Ministry of Health, Labor, and Welfare in Japan and others; UCAS Japan UMIN-CTR number, C000000418.)

Current Status of Stent-assisted Coil Embolization for Cerebral Aneurysm in Japan

Current Status of Stent-assisted Coil Embolization for Cerebral Aneurysm in Japan

Practical Decision-Making in the Treatment of Unruptured Cerebral Aneurysm in Japan: The U-CARE Study

Background: Decision-making during the management of unruptured cerebral aneurysms is a delicate process for both neurosurgeons and patients. Guidelines are evidence-based references that can aid in making decisions. However, neurosurgeons do not always follow guidelines in clinical practice. The purpose of this study is to verify the hypothesis that there is substantial dissociation between treatment guidelines and practical decision-making due to a bias in treatment selection for unruptured cerebral aneurysms. This bias is dependent upon clinician-driven factors such as experience and specialty, and patient-driven factors such as patient preference. Methods: This study was performed using internet questionnaires. A total of 282 randomly selected, qualified Japanese neurosurgeons (out of approx. 6,000 registered neurosurgeons), including 45 endovascular specialists, participated in this study. Radiological and demographic data from 88 cases of unruptured cerebral aneurysm were opened on the Web. Participating neurosurgeons decided on the treatment for each case (clipping, coiling or observation). Results: Variations in treatment selection were not significant between neurosurgeons and endovascular specialists, except for aneurysms such as anterior choroidal artery aneurysm. However, contrary to the guidelines, aneurysms larger than 10 mm tended to be treated conservatively because the risk of treatment is high, while aneurysms smaller than 5 mm in diameter were often selected for intervention (clipping or coiling). Conclusions: This study revealed that in real-world clinical practice, physicians are not always faithful to the current guidelines. In making practical treatment decisions for unruptured cerebral aneurysms, the patient’s will and the recognition of unavoidable, treatment-related risks seriously influence neurosurgeons’ decisions.

Retrospective Survey of Endovascular Treatment for Ruptured Intracranial Aneurysm in Japan: Retrospective Endovascular Subarachnoid Aneurysm Treatment (RESAT) Study

Annual retrospective surveys of 20 to 31 medical centers performing endovascular treatment of cerebral aneurysms in Japan from 1997 to 2008 were performed to analyze technical and clinical outcomes of endovascular treatment for ruptured cerebral aneurysm. Patients treated with dome embolization using bare platinum coils within 14 days after onset were retrospectively selected, and clinical features, and technical and clinical outcomes at discharge were studied. Retrospective Endovascular Subarachnoid Aneurysm Treatment (RESAT) 1 covers patients treated from 1997, when the Guglielmi detachable coil was introduced, to 2002, just after International Subarachnoid Aneurysm Trial was reported. RESAT 2 to RESAT 7 were conducted annually between 2003 and 2008. Among 5,624 patients with ruptured aneurysms treated within 14 days after onset, 4,782 patients were treated by dome embolization using platinum detachable coils. The patients in this large retrospective survey included 35.8% aged over 70 years, 36.6% with posterior circulation aneurysms, and 29.3% with poor grades (Hunt and Kosnik grades IV and V). The proportion of patients aged over 70 years tended to increase each year from 33.4% in RESAT 1 to 39.8% in RESAT 7, and the proportion of those with posterior circulation aneurysms decreased from 44.2% in RESAT 1 to 23.8% in RESAT 7 (p<0.001). Overall technical success was obtained in 4,666 patients (97.6%), and favorable clinical outcome (good recovery and moderate disability) at discharge was obtained in 88.0% of grade I-III cases and 73.6% of grade I-V cases. Procedure-related morbidity was 2.9% and mortality was 0.8%. Despite this survey involving high proportions of aged, posterior circulation, and poor-grade patients, the technical success rate and immediate clinical results were relatively favorable. The patient prognosis and aneurysm changes must be investigated over a longer period, together with the effects of the introduction of new endovascular devices for cerebral aneurysms.

破裂脳動脈瘤の治療 破裂脳動脈瘤塞栓術―１０年間の治療成績―

Although endovascular coil embolizations have increased in number, open surgery is still predominant for the treatment of ruptured cerebral aneurysms in Japan, partly because there are not enough follow-up results of endovascular coil embolization to discuss long-term outcomes of the procedure. We retrospectively analyzed radiological and clinical results in patients with ruptured cerebral aneurysms treated with coil embolization. From 1997 to 2006, 100 patients with ruptured intracranial aneurysms were treated with endovascular coil embolization. Clinical records and radiological findings of all these patients were retrospectively checked till the end of 2007. Thirty-one patients were 70 years or over in age, and 39 patients were in WFNS grade IV or V on admission. Although this cohort was older and higher in WFNS grade than in other reports, initial and follow-up results were the same. Mean follow-up periods were 42.1 months. Fifteen patients died during follow-up, and 76 patients showed complete obliterations of the aneurysm by the initial procedure. We experienced 10 major recurrences that needed retreatment, and 1 patient suffered from rebleeding while a retreatment was scheduled. Seven recurrent aneurysms were 10 mm or more in diameter at the initial treatment. The second treatment was successfully performed in 5 patients without complications or recurrences during 38 months of mean follow-up after the second procedure. One patient with a large basilar tip aneurysm suffered from a late regrowth of the aneurysm at 2.5 years after an initial tight packing, for which 4 additional treatments were performed. Endovascular treatment of ruptured cerebral aneurysms with coils seems to have good clinical and radiological results. However, the risk of regrowth, which results in bleeding, may continue until late follow-up periods, particularly in aneurysms more than 10 mm. Retreatment should be considered as soon as possible when major recurrence, which permits additional coils, occurs.

急性期破裂脳動脈瘤の治療選択 急性期破裂脳動脈瘤の治療選択の現状（第一報）―２００５年前向き集計―

To clarify current treatment status of ruptured cerebral aneurysms in Japan, a prospective multicenter observational study on the treatment results for aneurysmal subarachnoid hemorrhage was conducted over calendar year 2005 and final 1-year outcomes were collected. Studied centers were selected from among institutes of committee member of Japanese stroke surgery organization or symposium of vasospasm in Japan. A total of 927 patients were enrolled in this study and treatment policies were left to each institution according to the patients’ background and aneurysmal characteristics. The observational protocol was similar to those of ISAT, especially the categorization of aneurysms, follow-up timing at 2 months and 1 year, patient outcome evaluation and recording of incomplete treatment results. Finally, 770 patients were treated, and clipping was performed on 79% of them. Coil embolization was preferred in aged or vertebro-basilar artery aneurysm patients, and the 2-month outcome was identical in both the clipping and coil-treated groups. The 1-year outcome was better in the clipping group, but the initial patient condition in the clipping group was definitely better. The completeness of treatment was better in clipping, but post-treatment bleeding, hydrocephalus and epilepsy were identical in each group. Evaluation of overall management outcome is mandatory to elucidate the contribution of endovascular treatment on the treatment result for ruptured cerebral aneurysms.

Risk-Adjusted Analyses of the Effects of Hospital and Surgeon Volumes on Postoperative Complications and the Modified Rankin Scale After Clipping of Unruptured Intracranial Aneurysms in Japan

The present study conducted risk-adjusted analyses to investigate the impacts of hospital and surgeon volumes on postoperative complications and the modified Rankin scale (mRS) after intracranial clipping of unruptured aneurysms, and to discuss the efficacy of relevant policy changes. Among 107 Japanese institutions, physician-reported data for 702 unruptured aneurysm patients were registered between December 2006 and April 2007. Postoperative complications and the mRS at the time of discharge were independently regressed against hospital and surgeon volumes, aneurysm size, aneurysm location, and comorbidities. Aneurysm size was a significant predictor of the overall outcomes. After adjusting for prominent confounders, hospital volume did not show any significant associations with postoperative complications (odds ratio [OR] 0.75, 95% confidence interval [CI] 0.34-1.68, p = 0.49) or the mRS (OR 0.60, 95% CI 0.19-1.93, p = 0.39). Higher surgeon volume (>or=100) was associated with lower mRS scores (OR 0.40, 95% CI 0.20-0.83, p = 0.013), but had no significant relationship with postoperative complications (OR 0.72, p = 0.47). Our risk-adjusted analyses showed no significant relationships between hospital volume and comorbidities. Therefore, the justification for hospital volume-based policies remains unclear. Prospective risk-adjusted volume-based studies are required for future evidence-based referral policies.