松本 省二

中大脳動脈M2部閉塞に対する機械的血栓回収療法は,M1部閉塞に対する場合と異なりエビデンスがいまだ確立されていない.本研究の目的は,自験例でのM2部閉塞の治療成績を,M1部閉塞のそれと比較検証することである.2014年7月から2021年4月の期間に中大脳動脈M1部とM2部閉塞に対して再開通療法を行った症例を後ろ向きに調査した.それらについて,M1閉塞群とM2閉塞群に分け,患者背景因子,術前重症度(NIHSS),tPAの使用の有無,治療時間経過,TICI 2b以上の有効再開通率,無症候性を含む術後頭蓋内出血の頻度,3ヵ月後のmodified Rankin Scale(mRS)を比較した.また,3ヵ月後のmRS 3-6,すなわち予後不良に寄与する因子をロジスティック回帰分析の手法で検討した.期間中128例(平均年齢75.9歳,男性52.3%)の中大脳動脈閉塞に対して血栓回収を施行していた症例を対象にした.M1部閉塞86例(67.1%)をM1閉塞群,M2部閉塞42例(32.9%)をM2閉塞群とした.両群の比較では,M2閉塞群で年齢が高い(74.5歳vs78:7歳,p=0.03)以外に差異はなく,発症-再開通時間(259.5分vs235.5分,p=0.25),有効再開通(TICI 2b≦;89.5% vs 83.3%,p=0.4),hemorrhagic transformation(34.9% vs 28.6%,p=0.24)も同等であった.多変量解析では,年齢(OR 1.08,95%CI1.03-1.13,p<0.01),術前mRS(OR 3.53,95%CI1.84-6.78,p<0.01),hemorrhagic transformation(OR 7.62,95%CI2.51-23.20,p<0.01)が3ヵ月後の転帰不良(mRS 3-6)に関連し,閉塞部位は関連がなかった.M2部閉塞における血栓回収は,M1部閉塞と同等の再開通率,出血性合併症であり,閉塞部位の違いは,予後不良とは関連を認めなかった.この結果を踏まえて,M2部閉塞に対する機械的血栓回収療法は,有用な治療法と考える.(著者抄録)

It is impossible to predict underlying anomalies in acute large vessel occlusion and it could be a problem when performing mechanical thrombectomy (MT). We report a case of MT for occlusion of the fenestrated middle cerebral artery (MCA) M1 segment. A 49-year-old woman presented to our hospital with dysarthria and left hemiparesis. Acute ischemic stroke due to right occluded MCA was diagnosed. During performing emergent MT, a part of the M1 segment was revealed to be slit-shaped by digital subtraction angiography, suggesting a fenestrated MCA. The aspiration catheter could not be advanced through the narrow limb of the fenestration, and the distal thrombus was retrieved using a stent retriever, additionally. Postoperatively, the patient's symptoms improved without complications. When occlusion of the fenestrated MCA is suspected, it is necessary to consider converting the strategy from an aspiration catheter alone to the combined use of a stent retriever.

PURPOSE: Prasugrel is not approved for patients treated with flow diverters, which have a high metal coverage ratio. However, robust antiplatelet therapy with prasugrel may prevent thromboembolic complications. We administered prasugrel and aspirin to all patients treated with flow diverters and reported the safety of the antiplatelet therapy regimen. METHODS: This retrospective, single-center study evaluated the angiographic and clinical data of consecutive patients treated with flow diverters for cerebral unruptured aneurysms between June 2020 and May 2022. All patients received dual antiplatelet therapy, including prasugrel and aspirin. The administration of prasugrel ended 3 or 6 months after the procedure, whereas aspirin use continued for at least 12 months. Periprocedural complications (< 30 days post-procedure) and delayed complications (> 30 days post-procedure) were recorded. RESULTS: During the study period, 120 unruptured aneurysms were treated with flow diverters in 110 patients. All patients, except one, survived longer than 12 months after the procedure. The rate of thromboembolic complications was 6.4%, and more than half of the patients had transient symptoms; one (0.9%) had a major ischemic stroke. One patient (0.9%) each had an asymptomatic, small subarachnoid hemorrhage and significant hemorrhagic complications with melena. The rate of permanent neurological deficits was 1.8%, and the mortality rate was 0.9%. CONCLUSIONS: Dual antiplatelet therapy comprising routine use of prasugrel and aspirin for flow diverter-implanted patients possibly contributed to a low rate of thromboembolic complications and low risk of hemorrhagic complications.

OBJECTIVE: LEONIS Mova (SB-KAWASUMI LABORATORIES, Kanagawa, Japan, hereinafter called LEONIS Mova) is a steerable microcatheter (MC) that enables angle adjustment of the catheter tip using a hand-operated dial. LEONIS Mova may be useful for flow diverter placement when access to the distal parent artery with a conventional MC and microguidewire (MGW) is considered difficult or impossible. Here, we report three such cases encountered during flow diverter placement in large and giant internal carotid artery aneurysms. CASE PRESENTATION: In Case 1, a strong S-shaped curve was observed in the proximal parent artery of a giant cerebral aneurysm, and the luminal structure of the parent artery was lost within the aneurysm. It was anticipated that the distal side of the parent artery would be difficult to access with conventional MC and MGW. By adjusting the tip of the LEONIS Mova toward the aneurysm outlet beyond the S-shaped curve, it was possible to induce the MGW to secure the distal parent artery easily. In Case 2, the inflow and outflow axes of the parent artery were completely misaligned at the site of the aneurysm, and stenosis was present in the distal parent artery. Firmly bending the catheter tip increased accommodation for the catheter, enabling the induction of an MGW to access the distal parent artery without kicking back. In Case 3, the lesion extended from the cavernous portion to the petrosal portion; however, by adjusting the tip of the LEONIS Mova toward the aneurysm outlet, it was possible to induce the MGW to secure the distal parent artery easily. In each case, the LEONIS Mova enabled more secure and prompt access to the parent artery than anticipated and facilitated flow diverter placement. CONCLUSION: Encountering difficult-to-access lesions is one reason endovascular treatment may be unsuccessful. The LEONIS Mova is an excellent device that can overcome this obstacle, and its utility in certain applications should be recognized.