Shoichi Tani

X-ray Angiography Perfusion Analysis for the Balloon Occlusion Test of the Internal Carotid Artery

BACKGROUND A perfusion study should be performed during the balloon occlusion test (BOT) to prevent ischemic events after therapeutic carotid occlusion. We evaluated the efficacy of X-ray angiography perfusion analysis during the BOT. METHODS Twenty-one consecutive patients who underwent the BOT of the internal carotid artery were included. Patients who had a venous phase delay of less than .5 seconds and a mean stump pressure of more than 50 mm Hg without any neurologic symptoms were considered tolerant, and other patients were considered intolerant. A time-density curve was constructed for each hemisphere using X-ray angiography perfusion software (2D-Perfusion). The mean transit time and area under the curve, which correspond to cerebral blood volume, were calculated from the curve. Differences in these parameters between the occluded and nonoccluded hemispheres and the perfusion index were compared between the tolerant and intolerant groups. RESULTS In the intolerant group, the mean transit time was significantly longer (1.31 ± .72 seconds versus .44 ± .21 seconds, P = .001) and the perfusion index was significantly lower (.72 ± .16 versus .94 ± .08, P = .001) compared with those in the tolerant group. The area under the curve was not different between the groups. CONCLUSIONS Parameters obtained by X-ray angiography perfusion analysis were significantly different between the tolerant and intolerant groups. The X-ray angiography perfusion analysis could be a safe and effective method for assessing ischemic tolerance before therapeutic carotid occlusion.

Bilateral Chronic Subdural Hematoma is Associated with Rapid Progression and Poor Clinical Outcome

Chronic subdural hematoma (CSDH) has been recognized as a benign disease, but its clinical outcome is not well documented. This study aims to expand the knowledge base regarding the outcome of CSDH. We retrospectively reviewed clinical characteristics of CSDH operated in the Kobe City Medical Center General Hospital between June 2005 and June 2012. Variants included age at onset, sex, laterality, presence of headache, consciousness level, and risk factors for hemorrhage such as malignancy or intake of anticoagulants. A total of 368 cases were analyzed. Six patients (1.4%) had a poor outcome, defined as any morbidity or mortality at 7 days postoperatively. Bilateral hematoma was significantly associated with a poor outcome (p = 0.041). Warfarin use and malignancy, albeit statistically not significant, were more frequently observed in patients with a poor outcome. Bilateral CSDH was observed in 53 patients (14.4%). Age at onset, sex, history of malignancy, anticoagulant use, and antiplatelet use did not differ between bilateral and unilateral CSDH. Recurrence rate was not different between bilateral and unilateral CSDH (14.2% vs. 11.3%), but poor outcome as a result of brain herniation was significantly higher in bilateral than in unilateral hematomas (5.7% vs. 0.3%, p = 0.01). Bilateral CSDH was associated with rapid progression and showed worse outcome as a result of brain herniation in comparison with unilateral CSDH. Urgent trephination surgery for decompression of hematoma pressure may be recommended for bilateral CSDH.

Effect of coil packing proximal to the dilated segment on postoperative medullary infarction and prognosis following internal trapping for ruptured vertebral artery dissection.

Introduction Medullary infarction is an important complication of internal trapping for vertebral artery dissection. This study investigated risk factors for medullary infarction following internal trapping of ruptured vertebral artery dissection. Methods We retrospectively studied 26 patients with ruptured vertebral artery dissection who underwent endovascular treatment and postoperative magnetic resonance imaging between April 2001 and March 2013. Clinical and radiological findings were analyzed to identify factors associated with postoperative medullary infarction. Results Ten of the 26 patients (38%) showed postoperative lateral medullary infarction on magnetic resonance imaging. Multivariate logistic regression analysis revealed that medullary infarction was independently associated with poor clinical outcome (odds ratio (OR) 17.01; 95% confidence interval (CI) 1.68–436.81; p = 0.032). Univariate analysis identified vertebral artery dissection on the right side and longer length of the entire trapped area as risk factors for postoperative medullary infarction. When the trapped area was divided into three segments (dilated, distal, and proximal segments), proximal segment length, but not dilated segment length, was significantly associated with medullary infarction (OR 1.55 for a 1-mm increase in proximal segment length; 95% CI 1.15–2.63; p = 0.027). Receiver operating characteristic analysis showed that proximal segment length offered a good predictor of the risk of postoperative medullary infarction, with a cut-off value of 5.8 mm (sensitivity 100%; specificity 82.3%). Conclusions Longer length of the trapped area, specifically the segment proximal to the dilated portion, is associated with a higher incidence of medullary infarction following internal trapping, indicating that this complication may be avoidable.

Risk factors for and outcomes of intraprocedural rupture during endovascular treatment of unruptured intracranial aneurysms

Background and purpose The risk factors for intraprocedural rupture (IPR) of unruptured intracranial aneurysms (UIAs) and the outcomes of IPR itself are unclear. This study was performed to identify the independent risk factors for and outcomes of IPR. Materials and methods We retrospectively evaluated the medical records and radiologic data of 1375 patients (1406 UIAs) who underwent coil embolization from January 2001 to October 2016. Results IPR occurred in 20 aneurysms of 20 patients (1.4%). Univariate analyses showed that the rate of IPR was significantly higher in the treatment of aneurysms with a small dome size, aneurysms in the anterior communicating artery (AcomA) (6.6%), and patients with a medical history of dyslipidemia. Multivariate analyses showed that a small dome size and aneurysms in the AcomA were independently associated with IPR (p=0.0096 and p=0.0001, respectively). IPR induced by a microcatheter was associated with a higher risk of severe subarachnoid hemorrhage than other causes of IPR (57% vs 0%, respectively). Thromboembolic complications occurred in seven (35%) patients with IPR. Six (30%) patients required external ventricular drainage placement after developing symptoms of acute hydrocephalus. The overall morbidity and mortality rates from IPR were 0.22% and 0.15%, respectively. Conclusions Aneurysms in the AcomA and with a small dome size are likely to be risk factors for IPR. IPR induced by microcatheters can result in poor outcomes. The rate of IPR-associated thromboembolic complications is high, and IPR itself is associated with acute hydrocephalus. If managed appropriately, however, most patients with IPR can survive without neurological deterioration.

Endovascular parent-artery occlusion of large or giant unruptured internal carotid artery aneurysms. A long-term single-center experience ☆

The development of stent-like devices has increased treatment options for complex internal carotid artery (ICA) aneurysms, but the optimal treatment remains unclear. The purpose of this study was to evaluate the safety and efficacy of endovascular parent-artery occlusion (PAO) for ICA aneurysms. We retrospectively reviewed 28 patients with unruptured ICA aneurysms ⩾10mm treated with PAO between April 2002 and March 2015 at our institution. Patients who developed neurologic symptoms or with venous-phase delay >2s during balloon test occlusion were not treated by PAO. Patients with venous-phase delays of 1-2s underwent superficial temporal artery to middle cerebral artery (STA-MCA) bypass prior to PAO. The median patient age was 65 (range, 26-84)years. Nineteen aneurysms (68%) were located in the cavernous segment. The median aneurysm size was 25 (range 11-40)mm. Venous-phase delay of 1-2s was observed in five patients. Perioperative ischemic complications (N=9, 32%), which occurred within 30days after treatment, were significantly associated with venous-phase delays of 1-2s (p<0.01) and history of hypertension (p<0.01). Six-month morbidity was observed in one (3.6%) patient. Complete occlusion at final follow-up and delayed (i.e. ⩾31days after treatment) ischemic events were observed in 100% and 0% of patients, respectively, over a median period of 63 (range, 6-147) months. Despite the high frequency of perioperative ischemic episodes, endovascular PAO with selective use of STA-MCA bypass showed excellent long-term outcomes in patients with unruptured ICA aneurysms ⩾10mm.

Postoperative Subdural Air Collection Is a Risk Factor for Chronic Subdural Hematoma after Surgical Clipping of Cerebral Aneurysms

The precise mechanism of the development of chronic subdural hematoma (CSDH) as a postoperative complication after aneurysmal clipping remains unclear. The purpose of this study was to identify the independent risk factors for CSDH after craniotomy for aneurysmal clipping and to elucidate the relationship between CSDH and subdural air (SDA) collection immediately after surgery. The medical records and radiologic data of 344 patients who underwent surgical clipping of unruptured aneurysms from July 2010 to July 2016 were retrospectively evaluated. Patient characteristics, aneurysm characteristics, and operation data were statistically analyzed to reveal their relationships with CSDH development. Among the 344 patients, 46 (13.4%) developed CSDH and 13 (3.8%) required subsequent burr-hole surgery for evacuation and irrigation. Multivariate analyses showed that advanced age (P < 0.0001), male sex (P = 0.035), and surgical clipping of multiple aneurysms (P = 0.037) were independent preoperative predictors of CSDH development. Advanced age (P = 0.0005) and postoperative SDA after clipping surgery (P < 0.0001) were independent postoperative predictors of CSDH development. Postoperative SDA and CSDH were not associated with the individual surgeon or operation time. Postoperative severe SDA was significantly associated with the ipsilateral development of CSDH, irrespective of the side of craniotomy. Postoperative SDA is an independent risk factor for CSDH after surgical clipping of unruptured aneurysms and is as important as advanced age, male sex, and surgical clipping of multiple aneurysms in predicting CSDH.

First-in-man experience of the Versi Retriever in acute ischemic stroke.

Objective To describe our initial experience with the Versi Retriever for mechanical thrombectomy in patients with acute ischemic stroke. Methods This study is a single-center, single-arm, first-in-man registry under institutional review board control to evaluate the efficacy and safety of the new stent retriever, the Versi Retriever. Patients with acute ischemic stroke were consecutively enrolled between September and November 2017. The clinical and procedural data were retrospectively analyzed. The angiographic result after the procedure was self-graded based on the Thrombolysis in Cerebral Infarction (TICI) scale by each operator. Results Eleven patients with a mean age of 69.4 years were treated with the Versi Retriever. Median National Institutes of Health Stroke Scale score on admission was 16 (IQR 10–34). The occluded vessel was located in the anterior circulation in 81.8%. Revascularization rates of TICI 2b–3 and TICI 3 at final angiogram were achieved in 100% and 63.6%, respectively. A favorable functional outcome (modified Rankin Scale 0–2) at 90 days was obtained in 72.7%. No symptomatic intracranial hemorrhage occurred and no procedure-related complication was observed. Conclusions Our initial experience suggests that the Versi Retriever is a safe and effective stent retriever for mechanical thrombectomy in patients with acute ischemic stroke. Clinical trial registration NCT03366818

Improvement in venous-phase delay after superficial temporal artery to middle cerebral artery bypass

The utility of superficial temporal artery to middle cerebral artery (STA-MCA) bypass before therapeutic internal carotid artery (ICA) occlusion is unclear. A 65-year-old woman with a symptomatic giant left paraclinoid ICA aneurysm underwent endovascular ICA occlusion following STA-MCA double bypass. Preoperative balloon test occlusion (BTO) demonstrated a venous-phase delay of 1.5 s. Only focal improvement in the venous-phase delay was observed immediately after treatment, but three-week postoperative angiography showed remarkable improvement of 0.5 s. To our knowledge, this is the first known case that demonstrates the effect of STA-MCA bypass on postoperative improvement in venous-phase delay.

Delayed ischemic stroke due to stent marker band occlusion after stent-assisted coiling

A middle-aged patient with an internal carotid-posterior communicating artery aneurysm and basilar artery tip aneurysm was treated by stent-assisted coiling. One ischemic infarction and two transient ischemic attacks occurred with the same symptoms (inability to walk unassisted and tendency to fall to the left) during the first 2 years post-treatment. The ischemic infarction was found in the right side of the pons, consistent with the vascular territory of the stent-containing vessel. The cause of the delayed ischemic stroke was investigated on DSA and cone beam CT, which revealed that the proximal end of the stent, one marker band, was just covering a small perforating artery of the basilar artery trunk. The present case suggests that marker band occlusion can induce delayed ischemic stroke. To prevent this complication, it is important to evaluate the perforating vessels preoperatively and carefully deploy a stent for the marker band to avoid occlusion of large perforating vessels. Post-treatment evaluation is also important because dual antiplatelet therapy will be required for a longer period if an artery is occluded by a marker band.

Onyx extravasation during embolization of a brain arteriovenous malformation

During Onyx embolization to treat brain arteriovenous malformation (AVM), carefully observing the penetration of Onyx to the nidus is important in order to avoid complications such as hemorrhage, ischemia, and difficulty with microcatheter removal. We encountered a case of Onyx extravasation during embolization of a cerebellar AVM confirmed by surgical resection and pathological analysis. The patient was a 44-year-old man with Spetzler-Martin grade I cerebellar AVM who underwent Onyx embolization prior to resection of the brain AVM. While injecting Onyx into the nidus using the “plug-and-push” technique, Onyx extravasation was observed. Onyx injection was paused and subsequently restarted, thereby allowing continuation of embolization. An oblate Onyx cast that was entirely covered in cerebellar tissue was removed during total resection of the AVM, performed the same day. The surgically removed oblate Onyx cast did not contain brain tissue or vessel wall, and immunohistochemical staining against glial fibrillary acidic protein (GFAP) showed Onyx penetration into GFAP-positive cerebellar tissue. Onyx extravasation was confirmed based on intraoperative findings during resection as well as pathological findings. The patient has been followed for four years postoperatively, and adverse events caused by Onyx extravasation have not been observed. Unexpected cast of Onyx, remote from the vascular architecture of the AVM, may represent an intra-parenchymal extravasation.