Katsuhiro Shinagawa

Carotid artery stenting for vulnerable plaques on MR angiography and ultrasonography: utility of dual protection and blood aspiration method

Background Carotid artery stenting (CAS) for internal carotid artery (ICA) stenosis with vulnerable plaques is controversial. We analyzed the effect of a dual protection and blood aspiration method during CAS in patients with vulnerable plaques. Methods A total of 111 patients with ICA stenosis underwent CAS using the dual protection (simultaneous flow reversal and distal filter) and blood aspiration method. In 103 of 111 patients, preoperative carotid plaque was estimated by both 3 T MRI and ultrasonography (US). ICA plaques with a high intensity signal on time-of-flight-MR angiography (TOF-MRA) and/or mobile component on US were defined as vulnerable plaques. We assessed major adverse events (MAE) (ie, major stroke, myocardial infarction, and death) and hyperintense spots on diffusion-weighted images (DWI) after CAS. We then evaluated the visible debris captured by dual protection and blood aspiration during CAS. Results The preoperative ICA plaque on TOF-MRA and US was judged to be vulnerable in 48.5% (50/103 patients). The success rate of the CAS procedure was 100% with no MAE within 30 days. DWI showed small hyperintense spots in 18% (9/50 patients) and 18.9% (10/53 patients) in the vulnerable and non-vulnerable plaque groups, respectively. Visible debris was captured in 68% (34/50 patients) and 45.3% (24/53 patients) in the vulnerable and non-vulnerable plaque groups, respectively (p=0.0286). Conclusions The combination of dual protection and blood aspiration could provide effective distal embolic protection although vulnerable plaques on TOF-MRA and US had a high incidence of debris during CAS. Thus, CAS using dual protection and blood aspiration is safe in patients with vulnerable plaques.

Single-stage operation for a giant haemangiopericytoma following intracranial feeder embolization

Meningeal haemangiopericytomas (HPC) are malignant intracranial neoplasms that commonly recur and metastasize. Large size at diagnosis, abundant intracranial feeders and the risk of intraoperative bleeding can make them difficult to completely remove in one operation. We report here a rare case of a giant HPC which was treated successfully using a one-stage operation following superselective intracranial feeder occlusion. A 30-year-old man presented with a left middle cranial fossa tumour extending to the left temporal lobe and cerebellar tentorium. Angiography revealed supply from a dilated left posterior temporal artery branching from the posterior cerebral artery. The tumour was totally removed in a single-stage excision after embolization of the intracranial major feeding artery. The present case suggests the usefulness of preoperative embolization for HPC, particularly of intracranial feeders, to achieve total resection safely in a single operation.

Vascular Wall Imaging of Unruptured Cerebral Aneurysms with a Hybrid of Opposite-Contrast MR Angiography

BACKGROUND AND PURPOSE: Inflammation and degeneration of the intracranial saccular aneurysm wall play a major role in aneurysm formation, development and subsequent rupture. The aim of this study was to characterize the walls of unruptured intracranial aneurysms by using a hybrid of opposite-contrast MRA at 3T. MATERIALS AND METHODS: Fourteen consecutive patients with 17 unruptured intracranial aneurysms who initially underwent clipping surgery were prospectively evaluated. All aneurysms were scanned preoperatively by using a hybrid of opposite-contrast MRA in 3T high-resolution MR imaging. We classified intraoperative findings of atherosclerotic plaques in the aneurysms into 3 grades: grade A (major plaques), grade B (minor plaques), and grade C (no plaques). The contrast ratio of the high-intensity area was also measured relative to the background low-intensity area inside the carotid artery. RESULTS: Findings from preoperative plaque imaging of the aneurysm corresponded to the intraoperative findings in 15 of 16 aneurysms (excluding 1 that was impossible to visualize in its entirety due to anatomic reasons). Overall sensitivity and specificity of the hybrid of opposite-contrast MRA were 88.9% and 100%, respectively. During the operation, 4 aneurysms were classified as grade A; 5, as grade B; and 7, as grade C. The means of the contrast ratio for grades A, B, and C were 0.72 ± 0.03, 0.34 ± 0.30, and −0.02 ± 0.09, respectively. CONCLUSIONS: The hybrid of opposite-contrast MRA can detect visible atherosclerotic plaques in the unruptured aneurysm wall, and the contrast ratio in intracranial aneurysms correlated with their presence and extent. A study including a larger series is needed to validate the diagnostic potential of this imaging technique.

The characteristics of human cranial bone marrow mesenchymal stem cells.

Recently, cell-based therapy has attracted attention for treatment of central nervous system (CNS) disorders. Bone marrow-derived mesenchymal stem cells (BMSCs) are considered to have good engraftment potential. Therefore, more efficient and less invasive methods to obtain donor cells are required. Here, we established human BMSCs from cranial bone waste (cBMSCs) obtained following routine neurosurgical procedures. cBMSCs and cells obtained from the iliac crest (iBMSCs, standard BMSCs) showed expression of cell surface markers associated with mesenchymal stem cells and multipotency traits such as differentiation into osteogenic and adipogenic lineages. cBMSCs showed higher expression of the neural crest-associated mRNAs p75, Slug, and Snail than iBMSCs. Neurogenic induced cells from cBMSCs expressed the neural markers nestin, Pax6, neurofilament (NF)-L, and NF-M as seen with RT-PCR, and NF-M protein as seen with western blotting at higher levels than cells from iBMSCs. Immunostaining showed a significantly greater proportion of NF-M-positive cells in the population of induced cBMSCs compared with the population of iBMSCs. Thus, cBMSCs showed a greater tendency to differentiate into neuron-like cells than iBMSCs.

Somatosensory evoked potentials in carotid artery stenting: Effectiveness in ascertaining cerebral ischemic events

Somatosensory evoked potentials (SSEP) have been used in various endovascular procedures and carotid endarterectomy, but to our knowledge no literature deals exclusively with the utility of SSEP in carotid artery stenting (CAS). The purpose of this study was to evaluate the efficacy of SSEP in detecting cerebral ischemic events during CAS. We conducted a prospective study in 35 CAS procedures in 31 patients during an 18month period. Thirty-three patients without near occlusion underwent stenting using dual protection (simultaneous flow reversal and distal filter) combined with blood aspiration, while two patients with near occlusion underwent stenting without dual protection. All 35 patients underwent SSEP monitoring. SSEP were generated by stimulating median and/or tibial nerves and recorded by scalp electrodes. During the aspiration phase post-dilation, seven patients (20%) exhibited SSEP changes with a mean duration of 11.3±8.5minutes (range: 3-25minutes), three of whom later developed minor stroke/transient ischemic attack. Diffusion-weighted imaging showed new lesions in 10 patients (28.6%). Change in SSEP exhibited mean sensitivity of 100% (95% confidence interval, 0.29-1.0) and specificity of 88% (95% confidence interval, 0.71-0.96) in predicting clinical stroke post-CAS. Intra-procedural SSEP change was predictive of post-procedural complications (p=0.005, Fishers exact test). Longer span of SSEP change was positively correlated with complications (p=0.032, Mann-Whitney test). Intra-procedural SSEP changes are highly sensitive in predicting neurological outcome following CAS. Chances of complications are increased with prolongation of such changes. SSEP allows for prompt intra-procedural ischemia prevention measures and stratification to pursue an aggressive peri-procedural protocol for high risk patients to mitigate neurological deficits.

Safety and efficacy of a new outreach distal access catheter, TACTICS, for coil embolization of unruptured intracranial aneurysms:

Background and purpose Current large-bore catheters can be easily and safely placed in the intracranial vessels for the stabilization of microcatheters in several neurointervention scenarios. We considered that a novel 3.4 French catheter (TACTICS, Technorat Corporation, Aichi, Japan) might be useful for intermediate/distal access in a triaxial system. Here, we present our initial experience using the TACTICS catheter for treatment of intracranial aneurysms. Materials and methods A total of 35 endovascular coils were placed to embolize unruptured intracranial aneurysms of the anterior circulation using the TACTICS catheter between December 2016 and November 2017. These procedures were retrospectively reviewed to assess aneurysmal obliteration (Raymond’s classification), the volume embolization ratio (VER) and procedural complications in comparison with 96 conventional coil treatments during the 3-year period up to 2016. Data were matched for aneurysmal morphology (location, maximum diameter and aspect ratio) by the propensity method. Results In all procedures, the TACTICS catheter was atraumatically landed beyond the carotid siphon. There were no hemorrhagic or symptomatic ischemic complications. After propensity matching, 68 procedures were assessed (34 in each group). Achievement of Raymond’s scale 1 (complete occlusion) showed the same frequency in both groups (50% vs. 50%, p = 0.23). The VER was significantly higher with the TACTICS catheter than with the conventional method (34.0% vs. 28.7%, p = 0.003). Conclusion We reviewed our initial experience of the TACTICS catheter. It can be used as an intermediate catheter for safe and effective endovascular coil embolization of anterior circulation aneurysms.

Simple aspiration with balloon catheter technique (simple ABC technique) against proximal internal carotid artery occlusion in cases of cardiogenic cerebral embolism

Background In cases of acute ischemic stroke, manual aspiration of the thrombus is commonly performed with a balloon guiding catheter placed in the cervical segment of the internal carotid artery (ICA). However, most manual aspirations using a balloon guiding catheter are combined with inner catheters, as in the direct aspiration first pass technique (ADAPT). We experienced some cases of acute ischemic stroke with proximal ICA occlusion due to cardiogenic thrombus where we obtained sufficient recanalization by simple manual aspiration from inflated Optimo 9F balloon catheters (Tokai Medical Products, Japan) placed in the origin of the cervical segment of the ICA without any inner catheter or stent retriever. We perform by preference this procedure, named the simple Aspiration with Balloon Catheter (simple ABC) technique. Herein, we report two recent cases and discuss this procedure. Case presentation Case 1: An 80-year-old man with paroxysmal atrial fibrillation developed left ICA occlusion. We performed the simple ABC technique and obtained a large amount of dark red and white thrombus. Puncture-to-reperfusion time was 14 minutes with Thrombolysis in Cerebral Infarction (TICI) grade 3. Case 2: A 69-year-old man with chronic atrial fibrillation developed left internal carotid occlusion. We performed the simple ABC technique and obtained a large amount of dark red thrombus. Puncture-to-reperfusion time was 15 minutes with TICI grade 2b. Conclusion The simple ABC technique is useful to deal with a large amount of thrombus, shortens procedure time, enables less invasive thrombectomy, and can shift immediately to subsequent procedures such as delivering a stent retriever or ADAPT.

Detection of in-stent protrusion (ISP) by intravascular ultrasound during carotid stenting: Usefulness of stent-in-stent placement for ISP

ObjectivesAs in-stent protrusion (ISP) during carotid artery stenting (CAS) may cause postoperative embolism, ISP detection is important. Intravascular ultrasound examination (IVUS) is useful for ISP detection because the blood vessel cross-section can be drawn as a tomogram from the lumen. Our objective was to clarify the occurrence of ISP during CAS using IVUS and relevant factors, and to report the usefulness of stent-in-stent placement when treating ISP.MethodsIn 142 consecutive patients (128 men, average age 71.7 years; 69 symptomatic) who underwent CAS using dual protection and the blood aspiration method, and subsequent IVUS after stent placement were included. The outcome of CAS, and the occurrence rate of ISP and related factors (plaque characteristics, stent design, intraoperative debris capture rate and postoperative diffusion-weighted imaging (DWI) positive rate) were examined.ResultsAll CAS procedures were successful and no major adverse events (MAEs) were observed at 30 days. ISP was found in 12% (17/142), and stent-in-stent placement was performed in all cases. Vulnerable plaques were observed in 12 of 17 ISP cases (71%). A closed stent was used in 13 of 17 ISP cases (71%). The intraoperative debris capture rate was 100%, and no neurological symptoms were observed in any patients. A significant increase in ISP susceptibility was related to vulnerable plaques and the intraoperative debris capture rate.ConclusionsVulnerable plaques and debris capture were significantly correlated with ISP occurrence. In all ISP cases, stent-in-stent placement was performed and good results were obtained.Key Points• ISP detection during CAS using IVUS is important.• ISP-positive patients were correlated with NASCET ≥ 80%, vulnerable plaques and stent length.• Adequate additional treatment of stent in stenting under reliable protection against ISP-positive patients achieved low perioperative complications.

Overlapped Stenting Is Associated with Postoperative Hypotension after Carotid Artery Stenting

BACKGROUND Hypotension (HT) is well recognized to frequently occur during and after carotid artery stenting (CAS), which sometimes causes postoperative complications such as stroke or myocardial infarction. This study aimed to examine the risk factors associated with HT after CAS based on the hypothesis that overlapped stenting may affect postoperative HT. METHODS A total of 106 lesions in 95 patients with carotid artery stenosis who underwent CAS were reviewed. Bradycardia and HT were defined as a heart rate and a systolic blood pressure less than 60 beats/min and 100 mm Hg, respectively. The patients were categorized by the presence (group H) or the absence (group N) of postoperative HT, respectively, and demographic data, risk factors, conditions of carotid artery stenosis, procedures, and pre- and intraoperative hemodynamics were compared between these 2 groups. Multivariate analysis was performed to evaluate independent factors associated with postoperative HT. RESULTS In total, postoperative HT was observed in 30 (28.3%) cases. The incidence of overlapped stenting, the use of an open-cell stent, and intraoperative HT were significantly higher in group H (P = .03, .01 and < .01, respectively). The distance from carotid bifurcation and the maximum stenotic lesion tended to be shorter in group H (P = .09). In the multivariate logistic regression analysis, using all these variables, the overlapped stenting and intraoperative HT were found to be independent predictors for postoperative HT. CONCLUSION The overlapped stenting affected postoperative HT after CAS. Blood pressure should be strictly controlled in cases with overlapped stenting or intraoperative HT after CAS.