Perioperative Low-Dose Aspirin Management for Planned Clipping Surgery: When, How Long, and With What Precautions?

BACKGROUND AND OBJECTIVE: Perioperative low-dose aspirin (ASA) management for open craniotomy surgery lacked information. We analyze to establish the perioperative ASA strategy to minimize both hemorrhagic and thromboembolic complications. METHODS: The investigators designed a multicenter retrospective study, which included patients scheduled to have clipping surgery for unruptured intracranial aneurysm. The incidence and risk factors were analyzed for postoperative hemorrhagic complications and major cardio- and cerebrovascular events (MACCEs) within 1 month postoperation. RESULTS: This study included 503 long-term ASA users of 3654 patients at three tertiary centers. The incidence of hemorrhagic complications and MACCEs was 7.4% (37/503) and 8.8% (44/503), respectively. Older age (>70 years, odds ratio [OR]: 2.928, 95% CI [1.337-6.416]), multiple aneurysms operation (OR: 2.201, 95% CI [1.017-4.765]), large aneurysm (>10 mm, OR: 4.483, 95% CI [1.485-13.533]), and ASA continuation (OR: 2.604, 95% CI [1.222-5.545]) were independent risk factors for postoperative hemorrhagic complications. Intracranial hemorrhage was the only type of hemorrhagic complication that increased in the ASA continuation group (10.6% vs 2.9%, P = .001). Between the ASA continuation and discontinuation groups, the overall incidence of MACCEs was not significantly different (log-rank P = .8). In the subgroup analysis, ASA discontinuation significantly increased the risk of MACCEs in the secondary prevention group (adjusted hazard ratio: 2.580, 95% CI [1.015-6.580]). CONCLUSION: ASA continuation increased the risk of postoperative intracranial hemorrhage. Simultaneously, ASA discontinuation was the major risk factor for postoperative MACCEs in the high-risk group. Without evidence of intracranial hemorrhage, early ASA resumption was indicated (a total cessation duration <7-10 days) in the secondary prevention group.

Stereotactic radiosurgery for noncavernous sinus dural arteriovenous fistulas: treatment outcomes and their predictors.

OBJECTIVE: Stereotactic radiosurgery (SRS) has emerged as a safe and effective treatment modality for dural arteriovenous fistulas (dAVFs), particularly cavernous sinus (CS) dAVFs. However, the long-term outcomes of non-CS dAVFs are not well known. This study aimed to evaluate the efficacy and safety of SRS for non-CS dAVFs and to investigate the risk factors for incomplete obliteration. METHODS: Between 2007 and 2020, 65 non-CS dAVFs in 63 patients were treated using SRS at a single institution. Demographic characteristics, initial clinical presentations, clinical outcomes, and radiological findings were retrospectively reviewed. The procedure-related complications were assessed. Radiological outcomes were evaluated as complete obliteration, incomplete obliteration, and angiographic worsening, whereas clinical outcomes were evaluated for symptom recovery. RESULTS: At a median follow-up of 17 months, the overall complete obliteration rate was 63.1%, and the cumulative obliteration rates were 24.6%, 60.0%, 70.0%, and 74.3% at 12, 24, 36, and 48 months, respectively. Six patients underwent retreatment due to angiographic worsening; in 5 of these patients, recruitment of arterial feeders was newly observed in the adjacent sinus, which was not treated in the initial SRS. In the multivariate analysis, high-flow shunt and venous ectasia were associated with incomplete obliteration. No adverse events occurred after SRS. CONCLUSIONS: SRS for non-CS dAVFs is safe, and its efficacy is highly variable according to location. High-flow shunts may indicate greater radioresistance. In the retreated cases, new fistulas tended to be accompanied by sinus steno-occlusion and formed in the adjacent sinus segments.

Subdural hygroma and hemorrhagic conversion after microsurgical clipping for unruptured intracranial aneurysm.

BACKGROUND: Chronic subdural hematoma (cSDH) is a unique hemorrhagic complication associated with microsurgical clipping. We aimed to investigate the risk factors of subdural hygroma (SDG) formation and its hemorrhagic conversion to cSDH. METHODS: We reviewed the medical records of 229 patients who underwent microsurgical clipping for unruptured intracranial aneurysms (UIA) from 2016 to 2019. Risk factors for SDG and cSDH formation were analyzed. RESULTS: Male sex, age ≥ 60 years, higher degree of arachnoid dissection, severe brain atrophy, and a large volume of subdural fluid collection (SFC) before discharge were independent risk factors for SDG formation. The risk factors for hemorrhagic conversion from SDG were continuous use or early resumption of antiplatelet drugs (odds ratio (OR): 15.367, 95% CI: 1.172-201.402) and a larger volume of SFC before discharge (OR: 0.932, 95% CI: 0.886-0.980). In the early resumption group, antiplatelet drug was resumed at a mean duration of 7.48 days postoperatively, and hemorrhagic conversion was detected earlier than that in the late resumption or no-use groups (4.09 vs. 7.18 weeks, P = 0.046). Following the receiver operating characteristic analysis, the SFC cutoff volume for hemorrhagic conversion was determined to be 23.55 mL. CONCLUSION: These findings can assist clinicians in identifying patients at a high risk of SDG and cSDH formation. Antiplatelet resumption and its timing should be determined with consideration of the risk of cSDH formation as well as individual medical conditions.

Tailored antiplatelet therapy in stent assisted coiling for unruptured aneurysms: a nationwide registry study.

BACKGROUND: Antiplatelet therapy, where regimens are tailored based on platelet function testing, has been introduced into neurointerventional surgery. This nationwide registry study evaluated the effect and safety of tailored antiplatelet therapy in stent assisted coiling for unruptured aneurysms compared with conventional therapy using a standard regimen. METHODS: This study enrolled 1686 patients in 44 participating centers who received stent assisted coiling for unruptured aneurysms between January 1, 2019 and December 31, 2019. The standard regimen (aspirin and clopidogrel) was used for all patients in the conventional group (924, 19 centers). The regimen was selected based on platelet function testing (standard regimen for clopidogrel responders; adding cilostazol or replacing clopidogrel with other thienopyridines (ticlopidine, prasugrel, or ticagrelor) for clopidogrel non-responders) in the tailored group (762, 25 centers). The primary outcome was thromboembolic events. Secondary outcomes were bleeding and poor outcomes (increase in modified Rankin Scale score). Outcomes within 30 days after coiling were compared using logistic regression analysis. RESULTS: The thromboembolic event rate was lower in the tailored group than in the conventional group (30/762 (3.9%) vs 63/924 (6.8%), adjusted OR 0.560, 95% CI 0.359 to 0.875, P=0.001). The bleeding event rate was not different between the study groups (62/762 (8.1%) vs 73/924 (7.9%), adjusted OR 0.790, 95% CI 0.469 to 1.331, P=0.376). Poor outcomes were less frequent in the tailored group (12/762 (1.6%) vs 34 (3.7%), adjusted OR 0.252, 95% CI 0.112 to 0.568, P=0.001). CONCLUSION: Tailored antiplatelet therapy in stent assisted coiling for unruptured aneurysms reduced thromboembolic events and poor outcomes without increasing bleeding.

Incidence rate and predictors of recurrent aneurysms after clipping: long-term follow-up study of survivors of subarachnoid hemorrhage.

Recurrent aneurysms are a major cause of re-aneurysmal subarachnoid hemorrhage (aSAH), but information on long-term clip durability and predictors is insufficient. This study aimed to present the incidence rate of > 10 years and investigate predictors of a recurrent aneurysm in aSAH survivors. We included 1601 patients admitted with aSAH and treated by microsurgical clipping between January 1993 and May 2010. Of these patients, 435 aSAH survivors were included in this study (27.2%). The total follow-up time was 5680.9 patient-years, and the overall incidence rate was 0.77% per patient-year. The cumulative probability of recurrence without residua and regrowth of the neck remnant was 0.7% and 13.9% at 10 years, respectively. Neck remnant (hazard ratio [HR], 10.311; 95% confidence interval [CI], 5.233-20.313) and alcohol consumption over the moderate amount (HR, 3.166; 95% CI, 1.313-7.637) were independent risk factors of recurrent aneurysm. Current smoking and multiplicity at initial aSAH presentation were significant factors in a univariate analysis. Furthermore, de novo intracranial aneurysms (DNIAs) were more common in the recurrent group than in the non-recurrent group (40.9% vs. 11.5%, P < 0.001). In the present study, we noted the long-term clip durability and predictor of recurrence after microsurgical clipping. These findings can assist clinicians in identifying patients at a high risk of recurrent aneurysm and recommending selective long-term surveillance after microsurgical clipping.

The effect of hematoma evacuation with decompressive craniectomy on clinical outcomes in patients with parenchymal hematoma type 2 of hemorrhagic transformation after middle cerebral artery infarction.

OBJECTIVES: The purpose of this study was to investigate the feasibility of hematoma evacuation (HE) with decompressive craniectomy (DC) and to evaluate whether HE with DC is associated with improvement of clinical outcomes in patients with parenchymal hematoma type 2 (PH2) after middle cerebral artery (MCA) infarction. METHODS: Between March 2007 and August 2020, 73 patients with PH2 after MCA infarction underwent DC. The HE group (n = 28) consisted of subjects who underwent HE with DC and the non-HE group (n = 45) consisted of subjects who underwent only DC without HE. The clinical outcomes were analyzed and compared between groups. RESULTS: Significant differences in clinical outcomes were not observed between the groups at discharge (P = 0.648) and 12-month follow-up (P = 0.346). Mortality rate within 12 months was not significantly different between the groups (log-rank, P = 0.685). There were 12 reoperations in the HE group (42.9%) and three reoperations in the non-HE group (6.7%; P = 0.037). Logistic regression analysis showed the initial National Institutes of Health Stroke Scale score (OR, 2.320; 95% CI, 1.128-5.965; P = 0.046) and the infarction volume (OR, 1.876; 95% CI, 1.935-11.892; P = 0.041) were independently associated with mortality (modified Rankin Scale, 6) within the 12 months. CONCLUSIONS: In patients with PH2 of hemorrhagic transformation after MCA infarction, HE with DC does not change the clinical outcomes or mortality but might increase the reoperation risk.

Basilar artery trunk aneurysm: clinical and angiographic outcomes of endovascular treatment.

BACKGROUND: Basilar artery (BA) trunk aneurysms are rare, and the clinical characteristics and outcomes of endovascular treatment (EVT) remain unclear. The purpose of this study was to report clinical and angiographic outcomes of BA trunk aneurysm treated with EVT and to analyze risk factors for unfavorable outcomes. METHODS: From October 2004 to December 2020, a total of 40 patients with BA trunk aneurysms underwent EVT. Clinical characteristics and outcomes were evaluated retrospectively from a prospectively collected database. Of the 40 enrolled patients, nine were treated by coiling without stents, 17 were treated by stent-assisted coiling, six by stent only, five by flow diverters, and three by vertebral artery occlusion. RESULTS: In total, 27 (67.5%) patients had subarachnoid hemorrhage as an initial presentation, and 20 (50.0%) had large/giant aneurysms. Procedure-related complications occurred in five patients (12.5%); favorable clinical outcome was achieved in 27 patients (67.5%); and six patients (15.0%) died. Favorable angiographic outcome was achieved in 26 (83.9%) of 31 patients who underwent follow-up angiography. Poor initial Hunt-and-Hess grade (OR 7.67, 95% CI 1.55 to 37.80; p=0.018) was the only independent risk factor for unfavorable clinical outcome. Large/giant aneurysm (OR 8.14, 95% CI 1.88 to 27.46; p=0.047) and long lesion (OR 14.25, 95% CI 1.48 to 69.80; p=0.013) were independent risk factors for unfavorable angiographic outcomes during follow-up. CONCLUSIONS: EVT might be a feasible option for this rare disease entity. Unfavorable angiographic outcome might be expected in a large/giant aneurysm or a long lesion. It can be difficult to treat BA trunk aneurysms by EVT, needing multiple procedures or various techniques due to diverse clinical and angiographic features.

The Impact of Smoking and Multiple Health Behaviors on All-Cause Mortality.

Four common health risk behaviors have the greatest impact on all-cause mortality risk, but studies are needed with larger samples and the appropriate age range for cigarette smokers. We examined the impact of smoking in the context of multiple health behaviors on all-cause mortality using a nationally representative sample of adults aged 30 and older in the United States. National Health Interview Survey data from 1997 to 2005 were linked to the National Death Index with a follow-up to December 2015. The primary dependent variable was all-cause mortality, and the primary predictors were smoking, heavy drinking, physical inactivity, and unhealthy weight (underweight or obesity). The sample contained 189,087 individuals (≥ age 30; population estimate = 140.7 million). Our primary statistical analysis tool involved fitting Cox proportional hazards models. Our findings demonstrated that smoking led to the highest mortality risk among the four risk behaviors examined, but more than half of smokers engaged in at least one additional health risk behavior. Smokers who engaged in multiple health behaviors experienced higher increased mortality risks: smoking combined with one other health risk behavior increased mortality risk by 32% and by 82% when combined with two behaviors. Engaging in all four risk behaviors more than doubled the mortality risk of smokers. Smoking cessation interventions that address multiple risk behaviors-physical inactivity, heavy drinking, and unhealthy weight-will likely prevent premature death better than interventions that address only smoking.

Recurrent epistaxis from inflamed granulated tissue and an associated pseudoaneurysm of the internal carotid artery: case report.

BACKGROUND: Chronic inflamed tissue in nasal cavity is a rare complication of transsphenoidal approach (TSA). Inflamed tissue is rich in blood vessels, which can lead to frequent nosebleeds. In addition, chronic inflammation can cause pseudoaneurysm, whose rupture results in massive epistaxis. There have been few reported cases of pseudoaneurysm of ICA occurring more than 10 years after TSA surgery. CASE PRESENTATION: We report a case of a patient who had recurrent epistaxis for over a decade after TSA surgery, and analyzed the causes of the nosebleeds. The aspect of occurrence of the nosebleeds and the result of biopsy and imaging tests suggest that the nosebleeds were due to chronic inflamed tissue and an associated pseudoaneurysm. The rupture of pseudoaneurysm recurred after treatment with stent placement, and brain abscess was developed. After removing the inflamed tissue by endoscopic resection, the patient no longer had recurrence of ruptured pseudoaneurysm or nosebleeds. CONCLUSIONS: In patients with recurrent nosebleeds, the possibility of intranasal inflammation and subsequent pseudoaneurysm should be considered. Therefore, people who consistently have epistaxis after TSA, even if the bleeding is not in large amount, should be actively screened and treated for nasal chronic inflammation.

Microsurgical clipping of ruptured anterior choroidal artery aneurysms: Incidence of and risk factors for ischemic complications.

OBJECTIVE: Temporary clipping of the internal carotid artery can be required during microsurgery of a ruptured anterior choroidal artery (AchoA) aneurysm. Although it is suspected that such temporary clipping might be related to ischemic complications following surgery, no detailed analysis has been reported yet. PATIENTS AND METHODS: Eighty-nine patients with ruptured AchoA aneurysms treated by microsurgical clipping were recruited between January 1996 and December 2017. Patient medical records, radiographic data, and intraoperative video findings were retrospectively reviewed. Multivariate logistic regression analysis was conducted to investigate the risk factors for treatment-related ischemic complications. RESULTS: Treatment-related ischemic complications occurred in eight (9.0 %) patients, all of whom underwent temporary clipping during microsurgery. Patients who did not undergo temporary clipping (n = 20) did not experience treatment-related ischemic complications. Among patients who underwent temporary clipping (n = 69), multivariate logistic regression analyses indicated that the total duration, number of attempts, and longest time per attempt were not risk factors for poor clinical outcome at discharge. However, the longest time per attempt was identified as the only independent risk factor for treatment-related ischemic complications (odds ratio, 2.883; 95 % confidence interval, 1.725-6.525; P = 0.042). CONCLUSION: The longest time per attempt might be associated with a higher risk of treatment-related ischemic complications during microsurgery for ruptured AchoA aneurysms. Treatment-related ischemic complications may be minimized by intermittent application of temporary clipping during surgery.

Usefulness of high-resolution three-dimensional proton density-weighted turbo spin-echo MRI in distinguishing a junctional dilatation from an intracranial aneurysm of the posterior communicating artery: a pilot study.

BACKGROUND: Discriminating a junctional dilatation from a true saccular aneurysm is clinically important. PURPOSE: To evaluate the usefulness of high-resolution three-dimensional proton density-weighted turbo spin-echo magnetic resonance imaging (PD MRI) in distinguishing a junctional dilatation from an aneurysm of the posterior communicating artery (PcomA). METHODS: Eighty-two consecutive patients with 83 PcomA lesions, which were evaluated by time-of-flight (TOF) MR angiography (MRA), PD MRI, and digital subtraction angiography (DSA), were enrolled. These radiologic data were retrospectively and independently reviewed by two neurosurgeons, and each diagnosis based on TOF MRA, PD MRI, and DSA was compared. The diagnostic efficacy (interobserver agreement, intermodality agreement, and diagnostic performance) of PD MRI was compared with that of TOF MRA. RESULTS: PD MRI showed higher AC1 (Gwet's agreement coefficient, PD MRI: 0.8942, 95% CI 0.8204 to 0.968; TOF MRA: 0.7185, 95% CI 0.5753 to 0.8617) and prevalence-adjusted bias-adjusted kappa coefficient (PABAK) (PD MRI: 0.8554, TOF MRA: 0.5904) than TOF MRA for interobserver agreement. For intermodality agreement, PD MRI also showed higher AC1 (PD MRI: 0.9069, 95% CI 0.8374 to 0.9764; TOF MRA: 0.7983, 95% CI 0.6969 to 0.8996) and PABAK (PD MRI: 0.8735, TOF MRA: 0.7289) than TOF MRA. The diagnostic performance of PD MRI was statistically superior to that of TOF MRA in sensitivity, specificity, positive predictive value, and negative predictive value. CONCLUSIONS: PD MRI could provide excellent diagnostic accuracy and better information in distinguishing a junctional dilatation from a true saccular aneurysm of the PcomA compared with TOF MRA.

Coil-Protected Technique for Liquid Embolization in Neurovascular Malformations.

OBJECTIVE: To evaluate the safety and efficacy of the coil-protected technique for liquid embolization in neurovascular malformations. MATERIALS AND METHODS: Twenty-two patients who underwent coil-protected liquid embolization for symptomatic cranial (n = 13) and spinal (n = 9) arteriovenous fistula (AVF) or arteriovenous malformations (AVMs) were identified. A total of 36 target feeder vessels were embolized with N-butyl cyanoacrylate and/or Onyx (Medtronic). This technique was used to promote delivery of a sufficient amount of liquid embolic agent into the target shunt or nidus in cases where tortuous feeding arteries preclude a microcatheter wedging techniqu and/or to prevent reflux of the liquid embolic agent in cases with a short safety margin. The procedure was considered technically successful if the target lesion was sufficiently filled with liquid embolic agent without unintentional reflux. Angiographic and clinical outcomes were retrospectively evaluated. RESULTS: Technical success was achieved for all 36 target feeders. Post-embolization angiographies revealed complete occlusion in 16 patients and near-complete and partial occlusion in three patients each. There were no treatment-related complications. Of the six patients who showed near-complete or partial occlusion, five received additional treatments: two received stereotactic radiosurgery for cerebral AVM, two underwent surgical removal of cerebral AVM, and one underwent additional embolization by direct puncture for a mandibular AVM. Finally, all patients showed complete (n = 19) or near-complete (n = 3) occlusion of the target AVF or AVM on follow-up angiographies. The presenting neurological symptoms improved completely in 15 patients (68.2%) and partially in seven patients (31.8%). CONCLUSION: The coil-protected technique is a safe and effective method for liquid embolization, especially in patients with various neurovascular shunts or malformations who could not be successfully treated with conventional techniques.

In vitro and in vivo experiments of a novel intra-arterial neurovascular decompressor for treating neurovascular compression syndromes: a brief report.

Objectives: Neurovascular compression syndromes (NVCS) could be cured with an intravascular device that releases compression of the root entry zone of cranial nerves by changing the course of offending vessels. The purpose of this study was to report our results of in vitro and in vivo experiments with a novel intra-arterial neurovascular decompressor (IA-NVD) for NVCS. Methods: A nitinol-based IA-NVD was developed to release pressure applied to the root entry zone of cranial nerves by changing the course or angle of an offending vessel, which can possibly cure NVCS. We performed in vitro tests for safety and feasibility and preliminary in vivo tests up to 4 weeks for safety. Results: The bending stiffness of the device was similar to but slightly stronger than that of current, closed-cell intracranial stents. Hemocompatibility tests showed no significant thrombogenesis in whole blood. After the 4-week follow-up, all animals (20-month-old female Gottingen mini-pigs weighing 15-18 kg, n = 4) had a normal upright position and gait. Scanning electron microscopy images and H&E staining of arteries containing the devices showed good neointima formation on the devices. Intima hyperplasia occurred over wires and connecting tubes, but it did not interrupt the patency of the arterial lumen. Discussion: An IA-NVD was created and tested to demonstrate its functionality and biocompatibility in the present experiments. The device may be safely applied to intracranial arteries, providing us a chance to test the efficacy of an upgrade version of the device on changing the course of an artery that compresses a cranial nerve. Abbreviations: CN = cranial nerve; EVT = endovascular treatment; H&E = hematoxylin and eosin; HFS = hemifacial spasm; IA-NVD = intra-arterial neurovascular decompressor; MVD = microvascular decompression; NVCS = neurovascular compression syndrome; REZ = root entry zone; SEM = scanning electron microscopy; TN = trigeminal neuralgia.

Preliminary outcomes of single antiplatelet therapy for surface-modified flow diverters in an animal model: analysis of neointimal development and thrombus formation using OCT.

OBJECTIVE: To evaluate the rate of neointimal development and thrombus formation of surface-modified flow diverters in single antiplatelet therapy (SAPT) using optical coherence tomography (OCT) in a porcine model. METHODS: We divided 10 experimental pigs into two groups. One group (n=6) received dual antiplatelet therapy (DAPT) and the other group (n=4) received SAPT. Four stents (two per carotid artery) were implanted in both groups. The stents used were the Pipeline Flex embolization device (PED Flex), Pipeline Flex with Shield technology (PED Shield), and the Solitaire AB stent. All animals underwent weekly angiography and OCT. The OCT data were analyzed using the following measurements: neointimal ratio ((stent - lumen area)/stent area), stent-coverage ratio (number of stent struts covered by neointima/total stent struts), and the presence or absence of thrombus formation per 1 mm cross-section. RESULTS: PED Flex and Shield in the SAPT group had higher neointimal ratios than in the DAPT group (P<0.001, respectively). In the DAPT group, the speed of endothelial growth on day 7 in the PED Shield group was higher than that in the PED Flex group (P<0.001). In the SAPT group, PED Flex demonstrated significantly more thrombus formation on day 7 than PED Shield (P<0.001). CONCLUSIONS: The PED Shield stent showed faster endothelial growth than the other devices and comparable neointimal volume. There was significantly less thrombus formation on PED Shield than PED Flex when using SAPT in a porcine model.

Y-configuration stenting for coiling of wide-neck bifurcation aneurysms using Low-profile Visualized Intraluminal Support Junior.

BACKGROUND: Little has been reported about the feasibility and durability of a Low-profile Visualized Intraluminal Support Junior (LVIS Jr) Y-stenting device for wide-neck bifurcation aneurysms. PURPOSE: To evaluate the feasibility and durability of LVIS Jr Y-stenting for coiling of unruptured wide-neck bifurcation aneurysms. METHODS: We identified patients in whom LVIS Jr Y-stenting was attempted for unruptured wide-neck bifurcation aneurysms from a prospectively maintained registry of a referral hospital. Procedural success rate, treatment-related morbidity, and clinical and angiographic outcomes were retrospectively assessed. RESULTS: LVIS Jr Y-stenting was attempted for a total of 21 aneurysms in 21 patients (mean age 60±8.9 years; M:F=6:15): nine basilar artery, six anterior communicating artery, four middle cerebral artery, one internal carotid artery, and one vertebrobasilar fenestration aneurysms. The mean dome and neck size were 7.9±2.7 mm and 5.7±1.8 mm, respectively. All attempts were successful. Treatment-related morbidity occurred in one individual with a modified Rankin Scale (mRS) score of 2. Immediate postprocedural angiograms showed complete occlusion in 15 (71.4%) and neck remnant in 6 (28.6%) patients. All 21 patients had good outcomes (mRS score 0-2) for a mean of 12 months' follow-up (range 6-27 months); mRS score 0 in 20 patients and mRS score 2 in one patient, respectively. Follow-up imaging over a mean of 11 months (range 6-18 months) was available in 18 patients (85.7%). All aneurysms showed complete occlusion at follow-up. CONCLUSIONS: LVIS Jr Y-stenting and coiling for wide-neck bifurcation aneurysms seems to be feasible with acceptable safety and to provide durable aneurysm occlusion for wide-neck bifurcation aneurysms.

Therapeutic strategies for residual or recurrent intracranial aneurysms after microsurgical clipping.

OBJECTIVES: Therapeutic strategies for residual or recurrent aneurysm (RRA) after microsurgical clipping have not been well established. The purpose of this study was to report our retreatment experiences with previously clipped aneurysms and to demonstrate retreatment strategies for these RRAs. PATIENTS AND METHODS: From 1996-2016, we treated 68 RRAs after previous clipping. Among them, 34 patients underwent microsurgical retreatment, and the other 34 underwent endovascular retreatment. Radiographic images and clinical data were reviewed retrospectively to determine the treatment efficacy, clinical outcomes, and important factors for selecting the proper treatment modality. RESULTS: The most common aneurysm location was the middle cerebral artery (50%) in the microsurgery group and the internal carotid artery (47.1%) in the endovascular surgery group (p = 0.001). In the microsurgery group, 16 (47.1%) patients had additional clipping without removal of previous clips, 17 (50.0%) had clipping with removal of previous clips, and 1 (2.9%) had bypass surgery with trapping. In the endovascular surgery group, 28 (82.4%) patients had simple coiling, 5 (14.7%) had stent-assisted coiling, and 1 (2.9%) had a flow diverter. Procedure-related complications during retreatment occurred in 4 (5.9%) patients. Complete obliteration was achieved in 51 (75.0%) patients (microsurgery group, 82.4% and endovascular surgery group, 67.6%; p = 0.002). CONCLUSIONS: In properly selected cases, treatment of RRAs could be safely performed either by microsurgery or endovascular surgery and result in a good clinical outcome with acceptable morbidity. The decision to choose the treatment modality for RRAs after clipping is not easy but should be considered to lower the risk of retreatment.

Subdural Fluid Collection After the Clipping of Unruptured Intracranial Aneurysms: Its Clinical Course and Significance.

OBJECTIVE: We evaluated the clinical course and significance of postoperative subdural fluid collection (SFC) and identified the patients who were at risk of developing postoperative chronic subdural hematoma (CSDH) after the clipping of unruptured intracranial aneurysms (UIAs). METHODS: Between January 2012 and June 2014, we retrospectively reviewed 298 patients with UIAs treated by microsurgical clipping. Among them, 257 patients were enrolled in the present study. Subdural lesions (SDLs) were defined as SFC at 1-month follow-up computed tomography (CT) and a CSDH at any time within 1 month after the clipping of UIAs. We examined the volume changes, Hounsfield unit (HU) values, and the end results of SFC in serial CT scans. RESULTS: The incidence of postoperative CSDH that needed burr hole surgery was 2.5%. Changes in SFC volume that occurred within 1 week of surgery were a risk factor for the occurrence of SDL at the 1-month follow-up CT (odds ratio 34.039; P < 0.001). The corrected average HU value of SCF (cut-off value: 11.9, with a sensitivity of 83.3% and specificity of 73.7%) on postoperative day 7 was an independent risk factor for development of a CSDH at the 1-month follow-up CT (odds ratio 19.261; P = 0.003). CONCLUSIONS: SDLs seen during 1-month follow-up may be associated with the occurrence of increased SFC volume within a week after the clipping of UIAs. The corrected average HU value of the SFC on postoperative day 7 was the only risk factor for the development of CSDHs at 1-month follow-up CT.

A comparison between the new Low-profile Visualized Intraluminal Support (LVIS Blue) stent and the Flow Redirection Endoluminal Device (FRED) in bench-top and cadaver studies.

OBJECT: The aim of this study is to demonstrate the differences between the new Low-profile Visualized Intraluminal Support (LVIS Blue) stenting device and the Flow Redirection Endoluminal Device (FRED) using a series of bench-top evaluations and optical coherence tomography (OCT) images in a cadaveric preparation of the basilar artery. METHODS: The first part of the evaluation was bench-top microscopic documentation of metal coverage for LVIS Blue and FRED stents. OCT images of the cerebral vessels and deployed stents were acquired using OCT intravascular imaging. The stents were deployed from the left posterior cerebral artery to the basilar artery in a fresh frozen cadaver. Wall apposition and the relationship to jailed perforators were evaluated. RESULTS: The metal coverage along the inner curves of the LVIS Blue stent was similar to that along the outer curves of the FRED stent. The LVIS Blue stent cell size was compatible for crossing with the tested microcatheters after deployment of the stent. The LVIS Blue stent showed better wall apposition and less coverage of the perforator than the FRED stent in the cadaver experiment. CONCLUSIONS: LVIS Blue has a good crossing profile for microcatheters, better wall apposition, and less perforator coverage than FRED. These are desirable features in territories with high densities of perforators such as the posterior circulation.

Assessment of human placenta as an ex-vivo vascular model for testing of liquid embolic agent injections with adjunctive techniques.

PURPOSE: This project sought to test the utility of post-delivery human placenta (HP) as a vascular model for liquid embolic agent (LEA) simulation, along with adjunctive techniques. MATERIALS AND METHODS: Twelve LEA injections were performed under fluoroscopy in HP with two reflux control methods: dual lumen 'mini' balloon-catheter (n=9); and injection after proximal nBCA plug formation through a second microcatheter ('pressure cooker') (n=3). Measured outcomes included liquid embolic agent (LEA) advancement and reflux. Reflux was categorized into three grades: grade 0=no reflux; grade 1=occlusion of side branches without reflux beyond the balloon or plug; and grade 2=reflux beyond the balloon or plug. RESULTS: Simulation success was greater when a balloon was used rather than with a nBCA plug (89% vs 33%, P=0.054). In eight successful balloon-assisted injections, the reflux grades were: 50% grade 0; 12.5% grade 1; and 37.5% grade 2. The one successful nBCA plug injection had grade 2 reflux. All grade 2 balloon injections occurred when the balloon was positioned across a vessel bifurcation. CONCLUSIONS: HP provides excellent simulation for liquid embolic agents with a dual lumen balloon catheter.

Analysis of neointima development in flow diverters using optical coherence tomography imaging.

BACKGROUND: Flow diverters are used for the treatment of intracranial aneurysms. Surface modification may decrease the thrombogenicity of flow diverters but the details are unknown. Optical coherence tomography (OCT) is an intravascular imaging test with high resolution which identifies neointimal growth over stents. We compared the development of neointima in a flow diverter and stents with and without surface modification in a swine model. METHODS: In this study we implanted four devices (two in each carotid artery) in four pigs. The devices used were the Pipeline Flex embolization device (PED Flex, n=6), PED with Shield technology (PED Shield, n=6), and Solitaire AB (n=4). Serial carotid angiographic and OCT images were obtained on days 0, 7, 14, and 21. The data analyzed included: neointimal area (lumen area - stent area), neointimal ratio ([lumen area - stent area]/stent area), and the neointimal thickness ratio (minimum neointimal thickness/maximum neointimal thickness). RESULTS: There was no significant difference in where neointima formation was initiated in relation to the implanted device (distal vs middle vs proximal). The PED Shield had a trend towards earlier endothelial formation at day 7. By day 21 the neointimal ratio was significantly higher for the PED Flex and PED Shield devices than for Solitaire (p<0.05 and p<0.01, respectively). The neointimal thickness ratio was significantly higher with PED Shield than with PED Flex and Solitaire (p<0.05 and p<0.01, respectively). CONCLUSIONS: OCT enabled us to follow and compare in vivo the development of neointima over implants. PED Shield showed a similar neointimal volume to PED Flex and more concentric neointima.