Manabu Shirakawa

Experience of Staged Angioplasty to Avoid Hyperperfusion Syndrome for Carotid Artery Stenosis

Hyperperfusion syndrome (HPS) after carotid artery stenting (CAS) may cause hemorrhagic or ischemic events leading to serious sequelae. We previously reported the staged angioplasty (SAP) to prevent HPS. In the present study, we analyzed our treatment results of SAP to know its effectiveness and problems. The study included 43 patients scheduled for SAP in whom preoperative single photon emission computed tomography (SPECT) showed severely impaired cerebral blood flow (CBF). The analyzed subjects were 38 males and 4 females, mean age was 73 ± 8.5 years old. SAP was indicated for the patients whose CBF ratio in the affected/unaffected hemisphere (asymmetry index) was below 0.8, and cerebrovascular reactivity measured by acetazolamide challenge was below 10%. First, percutaneous transluminal angioplasty (PTA) was performed. If PTA was successful, CAS was performed 2 weeks later. If PTA was not successful due to inadequate dilatation or extensive dissection, a stent was placed. SPECT was performed immediately after PTA and CAS to confirm the presence or absence of hyperperfusion phenomenon (HPP) indicating radiologic hyperperfusion. In 39 of 43 patients (91%), SAP was successfully performed and HPP was not observed. On the other hand, in the other four patients (9%), immediate stent placement was added due to inadequate dilatations in three patients and vascular dissection in one. Among 43 candidates for SAP, 41 patients (95.4%) had favorable course, but one hemorrhagic and one ischemic complications were observed after PTA. SAP was a relatively simple procedure, and its clinical results seemed acceptable.

Safety and Effectiveness of Drip, Ship, and Retrieve Paradigm for Acute Ischemic Stroke: a Single Center Experience.

This study analyzed the efficacy and safety of the “drip, ship, and retrieve (DSR)” approach used to improve patient access to thrombectomy for acute stroke. Methods: The study participants were 45 patients who underwent thrombectomy following intravenous tissue plasminogen activator between September 2013 and August 2015. Patients were divided into two groups according to whether they were transferred from another hospital (DSR group; n = 33) or were brought in directly (Direct group; n = 12). The two groups were compared based on their baseline characteristics, time from stroke onset to reperfusion, outcome, and adverse events. Results: There were no significant differences in baseline characteristics. Time from onset until admission to our facility was significantly shorter in the Direct group (56.9 min) than in the DSR group (163.5 min) (P <0.0001). Conversely, time from arrival at the hospital to arterial puncture was significantly shorter in the DSR group (25.0 min) than in the Direct group (109.5 min) (P <0.0001). Time from onset to reperfusion did not differ significantly between the groups. There was no significant difference in patient outcomes, with a modified Rankin scale score of 0–2 (44.8% in DSR group versus 48.7% in Direct group). Moreover, there was no difference in the incidence of adverse events. Discussion: Despite the time required to transfer patients in the DSR group between hospitals, reducing the time from arrival until commencement of endovascular therapy meant that the time from onset to reperfusion was approximately equivalent to that of the Direct group. Conclusion: Time-saving measures need to be taken by both the transferring and receiving hospitals in DSR paradigm.

Effect of Edaravone on Favorable Outcome in Patients with Acute Cerebral Large Vessel Occlusion: Subanalysis of RESCUE-Japan Registry

The data of the nationwide prospective registry of acute cerebral large vessel occlusion (LVO; RESCUE-Japan Registry) were analyzed to know the effect of edaravone, a free radical scavenger, on clinical outcome at 90 days after onset. In this registry, patients with acute cerebral LVO admitted within 24 h after onset were prospectively registered. The effect of various factors including endovascular treatment (EVT), intravenous recombinant tissue plasminogen activator (IV rt-PA), and other medication including edaravone on favorable outcome (modified Rankin scale 0–1) was analyzed. Of the 1,454 registered patients, 1,442 patients (99.2%) had the information of edaravone were analyzed. In total, edaravone group had more patients with favorable outcome compared to non-edaravone group (22.9% vs. 13.8%, p = 0.0006). Edaravone increased favorable outcome in patients treated with IV rt-PA (29.4% vs. 11.1%, p = 0.0107), but not with EVT (21.2% vs. 13.9%, p = 0.309). Logistic regression analysis revealed that higher National Institutes of Health Stroke Scale (NIHSS) score on admission [odds ratio (OR) 0.875, 95% confidence interval (CI) 0.858–0.894] and advanced age (OR 0.963, 95%CI 0.952–0.975) were significantly related to unfavorable outcome. In contrast, IV rt-PA (OR 2.489, 95%CI 1.867–3.319), EVT (OR 1.375, 95%CI 1.013–1.865), and edaravone (OR 1.483, 95%CI 1.027–2.143) were significantly associated with favorable outcome. This analysis indicated that IV rt-PA, EVT, and edaravone were effective to obtain favorable outcome in patients with acute LVO. Combination IV rt-PA with edaravone was more effective.

Endovascular Treatment of Acute Ischemic Stroke: Honolulu Shock and Thereafter

Recently, use of mechanical clot retrievers for acute stroke has gradually spread. However, 3 recent randomized controlled trials failed to show superiority of endovascular treatment compared to intravenous recombinant tissue plasminogen activator (IV rt-PA) alone or standard care. On the other hand, a Japanese nationwide survey demonstrated the efficacy of endovascular treatment in the IV rt-PA failed and ineligible patients, especially with the proximal artery occlusion such as the internal carotid artery. Earlier initiation and higher reperfusion of endovascular treatment seemed to be the main reason for the better result in this survey compared with the reported randomized studies. Because next-generation devices such as stent retrievers have been shown to provide better effects in terms of clinical outcomes compared with the Merci retriever, the efficacy of endovascular treatment is expected to be confirmed again by randomized controlled trials in the near future.

Three-Dimensional Optical Frequency Domain Imaging Evaluation of Novel Dual-Layered Carotid Stent Implantation for Vulnerable Carotid Plaque.

Plaque prolapse through the cell stent has been suggested as one of the major causes of postprocedural distal embolization after carotid artery stenting. A CASPER stent (Terumo, Tokyo, Japan) is the latest-generation stent having the dual layers and expected to reduce the risk of embolization. A 76-year-old male asymptomatic patient with high-grade stenosis in the left internal carotid artery received carotid artery stenting. Preoperative magnetic resonance imaging demonstrated very high intensity signals on T1-weighted images. After a predilatation, a CASPER stent, which has a dual-layer design construction with an inner nitinol micromesh woven onto an external closed-cell stent, was deployed followed by postdilatation. Postprocedural optical frequency domain imaging revealed good apposition of the outer stent to the vascular wall and no significant prolapse of plaque materials between the struts of the inner micromesh. No ischemic lesions were identified on MRI and no abnormal neurological findings were noted after stenting.

Juvenile Cerebral Infarction Caused by Bow Hunter’s Syndrome during Sport: Two Case Reports

We report two cases of juvenile cerebral infarction caused by bow hunter’s syndrome (BHS) during sport. Case 1 was a 17-year-old male who developed a partial visual field defect after playing basketball. BHS was diagnosed because cervical ultrasonography demonstrated occlusion of the vertebral artery when the neck was rotated. After C1–2 posterior fixation was performed, his symptoms resolved. Case 2 was an 18-year-old male with recurrent visual disturbance after playing handball. Cerebral infarction occurred repeatedly despite antiplatelet therapy. After 3 years, vertebral artery dissection was diagnosed and stenting was performed, but his symptoms did not resolve. BHS was diagnosed when he was examined at our department. C1–2 posterior fixation was performed and his symptoms resolved. In these two cases, BHS was caused by sporting activity. For accurate diagnosis and treatment of BHS, neuroimaging with cervical rotation is mandatory.

High-Intensity Signal in Carotid Plaque on Routine 3D-TOF-MRA Is a Risk Factor of Ischemic Stroke

Background: Carotid atherosclerotic disease is recognized as an important risk factor for brain ischemic events. However, high-grade stenosis does not always cause ischemic strokes, whereas moderate-grade stenosis may often cause ischemic strokes. It has been reported that there is an association between carotid intraplaque hemorrhage (IPH) and new cerebral ischemic events. The purpose of this study was to elucidate the relationship between high-intensity signals (HIS) on maximum intensity projection (MIP) images from routine 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and prior ischemic strokes in the patients with moderate carotid stenosis. Materials and Methods: Sixty-one patients with moderate carotid artery stenosis (50-69% stenosis based on North American Symptomatic Carotid Endarterectomy Trial criteria) were included. Carotid IPH was defined as the presence of HIS in carotid plaques on MIP images detected by 3D-TOF-MRA using criteria we previously reported. We analyzed the relationship between the presence of HIS in plaques and prior ischemic strokes defined as ischemic lesions on diffusion-weighted brain images. Results: HIS in carotid plaques were present in 27 (44%) of 61 patients. Prior ipsilateral ischemic strokes occurred more frequently in the HIS-positive group than the HIS-negative group (67 vs. 9%, p < 0.001). Furthermore, there were more smokers in the group with ischemic stroke than without it (62 vs. 25%, p = 0.005). In multivariate logistic regression analysis, HIS in carotid plaque (OR 23.4, 95% CI 4.62-118.3, p < 0.001) and smoking (OR 5.44, 95% CI 1.20-24.6, p = 0.028) were independent determinants of prior ischemic strokes after adjustment for age. Conclusions: HIS in carotid plaques on 3D-TOF-MRA MIP images are independent determinants of prior ischemic strokes in patients with moderate carotid artery stenosis, and they can potentially provide a reliable risk stratification of patients with moderate carotid artery stenosis.

Endovascular Treatment for Acute Ischemic Stroke: Considerations from Recent Randomized Trials.

Background: Despite increasing use of intravenous recombinant tissue plasminogen activator therapy, the large number of patients ineligible for treatment or for whom treatment is ineffective has become problematic. Summary: The number of endovascular treatments for acute ischemic stroke is increasing each year. This treatment provides higher recanalization rates for occluded vessels but may lead to hemorrhagic complications such as subarachnoid hemorrhage. Results were announced for three randomized controlled trials in 2013, with all failing to show the superiority of endovascular treatment. These results have had a major negative impact, but a new randomized controlled trial, the Multicenter Randomized CLinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands (MR CLEAN), showed that acute endovascular treatment was superior to standard medical treatment in terms of clinical outcomes. With this positive result, interim analyses from other randomized trials appear likely to show the effectiveness of endovascular treatment. Key Message: Clinical evidence of acute stroke intervention using mechanical devices might be established in the near future.

Resolving Thrombus in the Left Atrial Appendage by Edoxaban Treatment after Acute Ischemic Stroke: Report of 2 Cases

Here we report first 2 cases of patients with nonvalvular atrial fibrillation with acute cardioembolic stroke in whom thrombi in the left atrial appendage (LAA) were resolved by edoxaban administration. Case 1 reports an 86-year-old woman who suddenly showed right hemiparesis and aphasia due to occlusion of the left middle cerebral artery. She received mechanical thrombectomy and recovered neurologically. Transesophageal echocardiography (TEE) performed on day 1 demonstrated thrombus in the LAA. The thrombus was resolved on day 13 after initiation of edoxaban (30 mg once daily) instead of warfarin, which was administered before stroke onset. Case 2 reports a 49-year-old man who was admitted because of the sudden onset of left hemiparesis and aphasia. TEE demonstrated thrombus in the LAA on day 4, and edoxaban therapy (60 mg once daily) was initiated. The thrombus resolution was observed on day 16, and no embolic stroke occurred.

Acute Embolic Cerebral Infarction and Coronary Artery Embolism in a Patient with Atrial Fibrillation Caused by Similar Thrombi

Although atrial fibrillation (AF) is one of the most frequent causes of ischemic stroke, coronary artery embolism (CE) from AF is rare, and 2.9% of all myocardial infarctions are caused by CE. We present a case of an 87-year-old female patient who suffered ischemic stroke and myocardial infarction at the same time and received intracranial and coronary thrombectomy. Pathological investigation revealed that thrombi were similar and both infarctions were considered as cardioembolism.