Yusuke Nishikawa

Objective: This study aimed to describe telescope-assisted combined thrombectomy for medium vessel occlusion (TACT-MeVO) in patients with M2 occlusion and report our initial experience.Methods: We retrospectively reviewed 52 thrombectomy procedures in 51 patients with M2 occlusion between May 2015 and April 2026: 45 historical-protocol and 7 TACT-MeVO procedures. In TACT-MeVO, a small-bore aspiration catheter and stent retriever are withdrawn together into a large-bore M1 aspiration catheter. Outcomes and between-group P values were exploratory and descriptive; the study was not powered to test superiority.Results: TACT-MeVO was first-line in all 7 procedures. Baseline CT–Alberta Stroke Program Early CT Score was numerically higher in the TACT-MeVO group but did not differ significantly (P = 0.069). Median puncture-to-recanalization/procedure-end time was 59 vs. 71 min (P = 0.014). One-pass completion was achieved in 6/7 (85.7%) vs. 23/45 procedures (51.1%; P = 0.117), and final modified Thrombolysis in Cerebral Infarction ≥2b in 7/7 (100%) vs. 39/45 procedures (86.7%; P = 0.580). Any subarachnoid hemorrhage occurred in 2/7 vs. 8/45 procedures (P = 0.608); both TACT-MeVO events were asymptomatic. Three-month modified Rankin Scale score 0–2 did not differ significantly (5/7 vs. 16/45; P = 0.104). A post hoc comparison with 29 procedures using conventional combined thrombectomy also showed a shorter procedural time (59 vs. 70 min; P = 0.004).Conclusion: TACT-MeVO was technically feasible in this initial 7-procedure experience. Comparative findings are descriptive; superiority or safety cannot be inferred because of the small sample, baseline imbalance, and historical comparator.

Background: Since clazosentan was approved for insurance coverage in Japan, the postoperative management of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) has changed as each facility gains experience. Here, we investigate the prevention, treatment, and management of DCI after SAH throughout Japan in 2023. Methods: In 2024, we conducted an anonymous questionnaire survey—emailed to certified neurosurgeons in hospitals across Japan—regarding management for preventing DCI after aneurysmal SAH. Of them, 78 hospitals responded and were included in this study. These results were compared with the findings of a survey conducted prior to the approval of clazosentan in Japan (2022). Results: The proportion of institutions with a standardized protocol for DCI after aneurysmal SAH at a level of ≥50% was 93.0%. For both craniotomy and endovascular surgery, clazosentan was used most frequently, followed by cilostazol, fasudil, and statins. The most common drug for both direct and endovascular procedures was clazosentan. The predominant reason for discontinuing clazosentan was respiratory complications—such as pulmonary edema—followed by cardiac complications. However, 62.1% of facilities felt that the number of cases wherein clazosentan was discontinued was deceasing. While 77.5% of respondents felt that clazosentan was effective for preventing DCI after aneurysmal SAH, only 49.3% felt that it improved outcomes. Conclusions: Since its approval, clazosentan has been the most common treatment for DCI prevention after aneurysmal SAH. The impression of the effectiveness in preventing DCI and the outcomes of clazosentan have been mixed. As data accumulate, clazosentan use and management protocols will be refined and developed.

Background and purpose: Various prophylactic drugs for cerebral vasospasm and delayed cerebral infarction (DCI) after subarachnoid hemorrhage (SAH) have been used in Japan. To investigate the treatment trends for cerebral vasospasm and frequency of DCI after SAH throughout Japan in 2021.Methods: In 2021 we conducted an anonymous questionnaire survey on management for preventing cerebral vasospasm after aneurysmal SAH, and the frequency of DCI. The questionnaire was emailed to 955 certified neurosurgeons at 553 hospitals in Japan. Of them, 162 hospitals (29% response rate) responded to the questionnaire. Of these, 158 were included in this study, while four hospitals that responded insufficiently were excluded. The efficacy of treatments for reducing DCI were examined through a logistic regression analysis.Results: Among 3,093 patients treated with aneurysmal SAH, 281 patients (9.1%) were diagnosed with DCI related to cerebral vasospasm. Coil embolization had significantly lower DCI frequency (6.9%), compared to microsurgical clipping (11.8%, odds ratio, 0.90; 95% confidential intervals, 0.84–0.96; P, 0.007). In addition, cilostazol administration was associated with significantly lower DCI frequency (0.48; 0.27–0.82; 0.026). The efficacy of cilostazol in reducing DCI remained unchanged after adjustment for covariates. The most effective combination of multiple prophylactic drugs in reducing DCI related to cerebral vasospasm was cilostazol, fasudil, and statin (0.38; 0.22–0.67; 0.005).Conclusions: This study elucidated the trends in prophylactic drugs to prevent cerebral vasospasm and frequency of DCI after aneurysmal SAH in Japan. Coil embolization and cilostazol administration showed effectiveness in reducing DCI related to cerebral vasospasm in 2021.

A 68-year-old man with bladder cancer developed sudden dysarthria and left hemiplegia. MRI revealed occlusion of the right middle cerebral artery (MCA). Cerebral angiography revealed a large carotid free-floating thrombus (CFFT) at the origin of the right internal carotid artery (ICA) and right M1 occlusion. A balloon-guide catheter (BGC) was directly guided distal to the CFFT. Mechanical thrombectomy (MT) was performed on the M1 occlusion while the balloon was inflated to block antegrade blood flow, and good recanalization was achieved. To continue processing the CFFT, the deflated BGC was pulled to the common carotid artery, and the thrombus dispersed into the external carotid artery (ECA). Subsequently, the patient’s symptoms improved. Directly advancing a BGC distally to a CFFT may be a useful treatment strategy for tandem lesions with carotid free-floating thrombi.

Clinical trials have proven the efficacy and beneficial therapeutic outcomes of endovascular therapy in patients with major arterial occlusion. However, its efficacy for very elderly patients, such as nonagenarians or centenarians, is not well established. In this case report, we describe the successful use of mechanical thrombectomy for the management of stroke in a centenarian. The 100-year-old woman with severe right-sided paralysis and total aphasia was admitted to our hospital approximately 30 min from the onset of symptoms. The National Institutes of Health Stroke Scale score was 24 at admission, and three-dimensional computed tomography angiography revealed occlusion in the M1 segment of left middle cerebral artery. She had persistent atrial fibrillation and was diagnosed with colon cancer one month prior to the admission. The modified Rankin Scale score before the stroke was 1, and she was generally independent. The patient successfully underwent mechanical thrombectomy, and recanalization with thrombolysis in cerebral infarction grade 3 was accomplished 129 minutes after the onset. The patient made a remarkable recovery with a National Institutes of Health Stroke Scale score of 4 at 48 h and was discharged home with a modified Rankin Scale score of 2 on day 8. Thus, mechanical thrombectomy can be performed with a good outcome even in centenarians.

Background: Transvenous embolization through the inferior petrosal sinus (IPS) is the most common treatment procedure for cavernous sinus dural arteriovenous fistula (CSDAVF). When the IPS is inaccessible or the CSDAVF cannot be treated with transvenous embolization through the IPS, the superficial temporal vein (STV) is used as an alternative access route. However, the approach through the STV is often challenging because of its tortuous and abruptly angulated course. We report a case of recurrent CSDAVF which was successfully treated using a chronic total occlusion (CTO)-dedicated guidewire and by straightening the STV. Case Description: A 63-year-old woman was diagnosed with CSDAVF on examination for oculomotor and abducens nerve palsy. She was initially treated with transvenous embolization through the IPS. However, CSDAVF recurred, and transvenous embolization was performed through the STV. A microcatheter could not be navigated because of the highly meandering access route through the STV. By inserting a CTO-dedicated guidewire into the microcatheter, the STV was straightened and the microcatheter could be navigated into a shunted pouch of the CS. Finally, complete occlusion of the CSDAVF was achieved. Conclusion: If an access route is highly meandering, the approach can be facilitated by straightening the access route with a CTO-dedicated guidewire.

Background: The precise mechanisms of carotid calcification and its clinical significance have not been established. Methods: We classified ten plaques from carotid endarterectomy patients into high- and low-calcified plaques based on the Agatston calcium scores. We performed whole-exome sequencing for genetic profiles with single nucleotide variations (SNVs), insertions, and deletions. Bioinformatic data mining was then conducted to disclose specific gene variations to either high- or low-calcified carotid plaques. Results: In the carotid plaques, G:C>A:T/C:G>T:A transitions as SNVs, insT after C/insC after A as insertions, and delA after G/delT after C as deletions were most frequently observed, but no significant difference was observed between the high- and low-calcified plaque groups in their proportion of base-pair substitution types. In the bioinformatic analysis, SNVs of ATP binding cassette subfamily C member 6 (ADCC6) were more commonly found in high-calcified plaques and SNVs of KLKB1 were more commonly found in low-calcified plaques compared to the other group. No new genetic variants related to calcification or atherosclerosis among those not registered in dbSNP was detected. Conclusion: Our findings clarified the features of base-pair substitutions in carotid plaques, showing no relation to calcification. However, genetic variants in ADCC6 relating to vascular calcification for high-calcified plaques, and in KLKB1 encoding kallikrein associated with vascular regulation of atherosclerosis for low-calcified plaques were more specifically extracted. These results contribute to a better understanding of the genetic basis of molecular activity and calcium formation in carotid plaques.

The relationship between calcification in primary plaque and recurrent stenosis after carotid artery stenting (CAS) is not established, but an inverse association with restenosis following carotid endarterectomy (CEA) has been suggested. We retrospectively analyzed 75 plaques of 109 consecutive CAS with regard to calcification, using the calcium score and shape, location, and other characteristics of original plaques together with stenting-related factors. CAS was performed in a standard fashion with an embolic protection device. Greater-than-moderate restenosis (≥50%) was assessed by peak systolic velocity (PSV) with duplex ultrasonography (≥130 cm/s, internal/common carotid or distal/proximal PSV ratio ≥2.0). Univariate analysis revealed percentages of dyslipidemia treated with statins (P = 0.03), calcification in distal ICA (P = 0.02), and immediate residual stenosis (P = 0.02) were significantly higher in patients with greater-than-moderate restenosis, whereas calcification in carotid bulb and usage of open-cell stent were rather less frequent (P < 0.001 and P = 0.02, respectively). Multivariate logistic regression analysis showed that rarity of calcification in carotid bulb was a sole independent predictor for greater-than-moderate recurrent carotid stenosis 1 year after CAS (OR = 0.21, CI = 0.06-0.77, P = 0.02). Calcium score was not significantly related to restenosis at 1 year after CAS, as was previously found following CEA, though scarcity of calcification in carotid bulb was suggested as a predictor of in-stent restenosis. Compared to post-CEA restenosis, carotid plaque calcification may be inversely but tenuously associated with recurrent stenosis 1 year post-CAS. No other stenting factors (e.g., stent design, pre-/post-dilation, or protection devices) showed a significant association with recurrent stenosis post-CAS.