Toshihisa Nishizawa

A Stent-Retrieving into an Aspiration Catheter with Proximal Balloon (ASAP) Technique: A Technique of Mechanical Thrombectomy

OBJECTIVE The best technique for the first attempt at mechanical thrombectomy for acute ischemic stroke is a still matter of debate. In this study, we evaluate the efficacy of a stent-retrieving into an aspiration catheter with proximal balloon (ASAP) technique that uses a series of thrombus extraction by withdrawing the stent retriever into the aspiration catheter and continuous aspiration from the aspiration catheter at the first attempt. METHODS We performed a retrospective analysis of 42 consecutive patients with acute ischemic stroke caused by occlusions in the anterior circulation who were treated with the ASAP technique at our institution. Preoperative patient characteristic, including age, thrombus location, Alberta Stroke Program Early CT Score, National Institutions of Health Stroke Scale, and time from onset to puncture; postoperative Thrombolysis in Cerebral Infarction score; modified Rankin Scale score after 3 months; time from puncture to recanalization; the number of passes to achieve recanalization; and procedural complications, including intracranial hemorrhage, embolization to new territory, and distal embolization, were assessed. RESULTS A Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 40/42 patients (95.2%). Average time from puncture to the final recanalization was 21.5 minutes. Recanalization was achieved in a single attempt in 31 patients (77.5%). Embolization to new territory was observed in only 2 patients (4.8%); no patient developed distal embolization or intracranial hemorrhage including asymptomatic subarachnoid hemorrhage. Thirty-two patients (76.2%) achieved modified Rankin Scale scores of 0-2 at 3 months postoperatively. CONCLUSIONS Our ASAP technique showed fast recanalization, minimal complications, and good clinical outcomes in this case series.

Successful Preoperative Endovascular Embolization of an Extreme Hypervascular Glioblastoma Mimicking an Arteriovenous Malformation

BACKGROUND Preoperative endovascular embolization as a treatment for hypervascular glioblastomas has not been established. We report the case of an extreme hypervascular glioblastoma mimicking an arteriovenous malformation that was successfully treated with preoperative embolization and subsequent removal. CASE DESCRIPTION A 66-year-old man presented with progressive right hemiparesis and sensory aphasia. Cranial computed tomography and magnetic resonance imaging revealed a left parietooccipital tumor with ring enhancement. Digital subtraction angiography revealed an extreme high-flow arteriovenous shunt. The patient underwent presurgical endovascular embolization using N-butyl cyanoacrylate in a manner similar to embolization for arteriovenous malformations. Subsequent tumor removal was achieved with minimal blood loss. CONCLUSIONS This is the first reported case of presurgical embolization of a glioblastoma with a high-flow shunt. Embolization of a malignant tumor with a high-flow shunt, in a manner similar to embolization of arteriovenous malformations, is feasible and effective.

Suitability of a 7-F ExoSeal Vascular Closure Device for Femoral Artery Punctures Made by 8-F or 9-F Introducer Sheaths

Purpose: To establish the safety and efficacy of the 7-F ExoSeal device for the closure of femoral puncture sites made by 8-F or 9-F introducer sheaths. Methods: Between January 2013 and December 2016, 332 patients (mean age 68.4±12.1 years; 195 men) underwent neurointerventional procedures via percutaneous puncture of the common femoral artery and an 8-F (n=272, 81.9%) or 9-F (n=60, 18.1%) introducer. The access sites were sealed with a 7-F ExoSeal in all cases. Procedure success and closure-related complication rates were evaluated, and risk factors for complications were analyzed by comparing patient characteristics between those who did and did not experience complications. Results: Procedure success rates were 99.3% in the 8-F group and 100% in the 9-F group. The overall complication rate was 6.3% (n=17; all in the 8-F group), of which 13 (4.8%) were minor sequelae, including access-site hematoma (n=8), oozing (n=3), pseudoaneurysm (n=1), and retroperitoneal bleeding (n=1). Among the 4 (1.5%) major complications were 3 instances of bleeding requiring a blood transfusion and 1 surgical vascular repair. No complications were observed in the 9-F group. Patients who experienced complications had significantly longer activated clotting times (262±46 vs 218±55 seconds; p<0.001) compared with patients without complications. Conclusion: A 7-F ExoSeal vascular closure device is safe and effective for the closure of femoral puncture sites made by 8-F or 9-F introducer sheaths.

Patterns of Recurrence After Resection of Malignant Gliomas With BCNU Wafer Implants: Retrospective Review in a Single Institution

BACKGROUND Bis-chloroethylnitrosourea (BCNU) wafers have been demonstrated to be effective for prolonging survival for patients with malignant glioma and have been approved worldwide. BCNU wafers are implantable and have a unique feature of delivering chemotherapeutic drug at high concentration at tumor margin over time after resection. BCNU wafers presumably, by this mechanistic rationale, have a beneficial effect on local tumor control and thus could change the pattern of recurrence, which is most frequently local. However, no studies have demonstrated such phenomenon after BCNU wafer implants. METHODS To investigate whether the surgeries with BCNU wafers alter the predominant tendency of local recurrence pattern, we retrospectively reviewed 8 malignant glioma patients treated with BCNU wafers (BCNU wafer group), together with 22 glioma patients who did not receive BCNU wafers (no-BCNU wafer group) for comparison. RESULTS Out of 6 patients in BCNU wafer group who exhibited recurrence, 1 showed local, 2 showed diffuse, and 3 showed a distant recurrence pattern, which was away from resection cavity. On the other hand, out of 18 patients in the no-BCNU wafer group who exhibited recurrence, 10 showed a local pattern, 8 showed a diffuse pattern, and no cases showed distant pattern. Distant pattern was observed significantly more frequently in the BCNU wafer group than in the no-BCNU wafer group. CONCLUSIONS These results suggest that BCNU wafers could have a beneficial effect on local tumor control and may provide BCNU wafers with a new profile that could be considered for establishing future chemotherapeutic strategy for glioma patients.

Long-Lasting Symptomatic Cerebral Hyperperfusion Syndrome following Superficial Temporal Artery-Middle Cerebral Artery Bypass in a Patient with Stenosis of Middle Cerebral Artery

Cerebral hyperperfusion syndrome (CHPS) is a complication that can occur after cerebral revascularization surgeries such as superficial temporal artery- (STA-) middle cerebral artery (MCA) anastomosis, and it can lead to neurological deteriorations. CHPS is usually temporary and disappears within two weeks. The authors present a case in which speech disturbance due to CHPS lasted unexpectedly long and three months was taken for full recovery. A 40-year-old woman, with a history of medication of quetiapine, dopamine 2 receptor antagonist as an antipsychotics for depression, underwent STA-MCA anastomosis for symptomatic left MCA stenosis. On the second day after surgery, the patient exhibited mild speech disturbance which deteriorated into complete motor aphasia and persisted for one month. SPECT showed the increase of cerebral blood flow (CBF) in left cerebrum, verifying the diagnosis of CHPS. Although CBF increase disappeared one month after surgery, speech disturbance continued for additionally two months with a slow improvement. This case represents a rare clinical course of CHPS. The presumable mechanisms of the prolongation of CHPS are discussed, and the medication of quetiapine might be one possible cause by its effect on cerebral vessels as dopamine 2 receptor antagonist, posing the caution against antipsychotics in cerebrovascular surgeries.

A Case of Acute Isolated Posterior Cerebral Artery Occlusion Successfully Treated with Endovascular Clot Aspiration

Posterior cerebral artery (PCA) strokes produce various symptoms. Therefore, the diagnosis is often delayed and patients arrive late for thrombolytic therapy. We report a case of acute isolated PCA occlusion that was successfully treated with endovascular clot aspiration. A 63-year-old man presented with right complete homonymous hemianopia. Diffusion-weighted image (DWI) showed a high-intensity area (HIA) in the occipital lobe, and magnetic resonance angiography (MRA) showed PCA occlusion. Emergency endovascular clot aspiration was performed immediately after the diagnosis. Blood flow in PCA completely recovered 210 min after symptom onset. DWI after surgery showed partial disappearance of HIA, and the patient recovered from the symptom of right complete homonymous hemianopia. Endovascular recanalization is useful for acute PCA occlusion. This is the first reported case of acute isolated PCA occlusion successfully treated with endovascular clot aspiration. Prompt reperfusion results in a good clinical course in patients with PCA stroke. In this case, endovascular clot aspiration resulted in prompt recanalization in a patient with acute isolated PCA occlusion.

Aneurysmal neck plasty in broad-necked aneurysms with a unilateral partial stent reconstruction: half-bridge stenting method

● Abstract● Purpose: Here we describe a novel technique named “half-bridge stenting method,” in which the aneurysmal neck was partially covered by a single stent before coiling with a microcatheter through the open side. Case presentation: Two cases of broad-necked terminal-type aneurysm and one broad-necked lateral wall-type aneurysm were treated. The stents were deployed from a unilateral branch or distal parent artery to the aneurysmal neck with a trumpet-like. All aneurysms were satisfactorily embolized with coils. Conclusions: This technique can be used to smoothly insert coils into the aneurysms without restriction of the microcatheter by the stents. Furthermore, additional stenting and coiling can also be performed in case of retreatment.