Inflow Angle and Height-Width Ratio are Predictors of Incomplete Occlusion at One and Two Years After Flow Diverter Treatment for Small- and Medium-Sized Internal Carotid Artery Aneurysms.

OBJECTIVE: We investigated the association between the inflow angle of aneurysms and their occlusion status at 1 and 2 years after flow diverter (FD) treatment. METHODS: We retrospectively analyzed 42 consecutive patients from a single center with 43 untreated, unruptured internal carotid artery (ICA) proximal to communicating segment, saccular aneurysms sized <12 mm. RESULTS: At 1 year posttreatment, the complete occlusion (CO) rate was 58.1%. On univariate analyses, the proportion of inflow angle >90° was significantly lower in the CO group than in the incomplete occlusion group (20.0% VS. 83.3%; P < 0.001). The CO incidence decreased with a height-width (H/W) ratio of <1.2 (P = 0.059). On multivariate analysis, an H/W ratio of <1.2 (odds ratio [OR], 0.076; P = 0.027) and an inflow angle of >90° (OR, 0.020; P = 0.0011) significantly influenced CO at 1 year post FD. At 2 years posttreatment, the CO rate was 76.3% (29/38 cases with available follow-up data). On univariate analyses, in the CO group compared to the incomplete occlusion group, the proportion of H/W ratio <1.2 was significantly lower (P = 0.005) and the proportion of inflow angle >90° was significantly lower (P = 0.021); aneurysm dome size tended to be larger (8.5 mm vs. 7.1 mm; P = 0.080). On multivariate analysis, an H/W ratio <1.2 (OR, 0.042; P = 0.015) and an inflow angle >90° (OR: 0.088; P = 0.031) significantly influenced CO at 2 years post FD. CONCLUSIONS: The inflow angle of >90° and H/W ratio <1.2 may significantly influence the CO rate in small- or medium-sized internal carotid artery aneurysms 1 and 2 years post FD.

Acute Distal Migration and Shortening of the Flow-Redirection Endoluminal Device: A Case Report.

Objective: The flow diverter (FD) is a promising device. Apart from two main complications, hemorrhagic and ischemic ones, stent migration is reportedly an unusual complication. In particular, distal migration of the FD has rarely been reported. We report a case of asymptomatic acute distal migration of the flow-redirection endoluminal device (FRED). Case Presentation: A 50-year-old woman was incidentally diagnosed with an unruptured right internal carotid-ophthalmic artery aneurysm with a maximum diameter of 8.0 mm, and she subsequently underwent endovascular treatment with FRED. Based on the vessel diameter (3.8 mm proximal and 3.6 mm distal to the aneurysm), a 4.0-mm-diameter and 18-mm-long FRED was deployed without postoperative complications. However, on MRA 12 months after treatment, the aneurysm was not occluded; angiography showed distal migration of the FRED. The postoperative MRA and skull X-ray images were retrospectively reviewed to determine the period of the migration. The skull X-ray images and the signal loss area due to the FRED on MRA 1 day after the treatment had already demonstrated the migration of the FRED. In the second treatment, a 4.0-mm-diameter and 23-mm-long FRED was deployed in an overlapping fashion up to the proximal part of the carotid siphon. Prompt identification of distal migration of the FD without neurologic signs could be challenging. Conclusion: It is important to follow up meticulously with MRA and skull X-ray images after FD treatment for detecting stent migrations as early as possible.

Modification by an aspiration catheter for vessel stretching in thrombectomy using a stent retriever in vitro.

OBJECTIVES: Post-thrombectomy subarachnoid hemorrhage, which is caused by vessel stretching when retrieving a stent retriever (SR), is a complication of endovascular mechanical thrombectomy (EVT) using an SR. This in vitro study examined the association between EVT for middle cerebral artery (MCA) occlusion and M2 vessel stretching depending on the positioning of the SR or combined use of SR and aspiration catheter (AC) technique (CBT). MATERIALS AND METHODS: A silicone vascular model was used. The maximum migration distance (MMD) in the anteroposterior view of an X-ray impermeable metal marker located at an M2 trunk 20 mm distal to the M1-2 bifurcation in angiographic images during an SR retrieval was calculated. According to the positioning of SR deployment (distal or proximal) and use of an AC [SR alone without an AC (SR alone) group, stent retrieval into an AC (SA) group, and stent-AC retrieval as a unit into a guiding catheter (SA unit) group], 60 attempts were conducted with each group of 10 attempts. RESULTS: In distal SR deployment, the MMD in the CBT group, consisting of SA and SA unit groups, was significantly smaller than the SR alone group (1.36 ± 0.32 mm VS 2.39 ± 1.10 mm; p = 0.001). In proximal SR deployment, the CBT group showed a tendency to decrease MMD (1.38 ± 0.33 mm VS 1.63 ± 0.28 mm; p = 0.077). CONCLUSIONS: This in vitro study showed that CBT might help modify the stretching of M2 when an SR is distally deployed in MCA occlusion.

Possible Contribution of the Aspiration Catheter in Preventing Post-stent Retriever Thrombectomy Subarachnoid Hemorrhage.

PURPOSE: This study aimed to identify factors related to the incidence of post-thrombectomy subarachnoid hemorrhage (PTSAH). METHODS: This retrospective, observational cohort study enrolled consecutive patients with acute ischemic stroke (AIS) due to the internal carotid artery (IC) top or middle cerebral artery (MCA) M1 or M2 segment occlusion who underwent single-pass stent retriever (SR) treatment between January 2015 and May 2022 at two acute care hospitals. RESULTS: Of the 54 included patients, 10 were in the PTSAH group (18.5%). The occlusion sites were IC top (31.5%), M1 segment (48.1%), and M2 segment (20.4%). Aspiration catheters (ACs) were used in 32 (59.3%) patients; however, the combined technique (AC advancement at least to the most proximal marker of SR) was actually used in 26 (48.1%) patients because a ledge effect at the ophthalmic artery origin from the IC interfered with distal navigation of the ACs. The baseline patient characteristics did not differ between the groups. M2 segment occlusion in the PTSAH and non-PTSAH groups were 40.0% and 15.9%, respectively (p = 0.19). More ACs were used in the non-PTSAH group (65.9% vs. 30.0%, p = 0.07). Significantly fewer combined techniques were performed in the PTSAH group (10.0% vs. 56.8%, p = 0.01). In multivariate analysis adjusted by variables with M2 segment occlusion and the combined technique, the combined technique (odds ratio 0.098; 95% confidence interval, 0.011-0.887; p = 0.039) was identified as a significantly associated factor for PTSAH. There was one PTSAH case (1.9%) with symptom worsening. CONCLUSION: The combined technique significantly influenced PTSAH occurrence as a preventive factor.

Thromboembolic Events Detected by Diffusion-Weighted Magnetic Resonance Imaging after Flow Diverter Treatment: The Impact of Procedure Time.

BACKGROUND: Periprocedural thromboembolism is a serious complication of endovascular treatment for intracranial aneurysms. In addition to symptomatic ischemia, asymptomatic postprocedural diffusion-weighted image-positive lesions (DPLs) are considered important. However, few studies have reported significant risk factors associated with DPLs and symptomatic ischemic stroke after flow diverter (FD) treatment. This study aimed to investigate the frequency and risk factors associated with DPLs after FD treatment. METHODS: Between November 2015 and December 2021, 84 patients harboring 85 untreated, unruptured intracranial aneurysms treated with FD were enrolled. RESULTS: DPLs after FD treatment were confirmed in 74 patients (87.1%), among whom 69 (93.2%) were clinically asymptomatic. In the univariate analyses, age >55 years (P = 0.040), smoking (P = 0.023), preprocedural P2Y12 reaction unit value of >185 (P = 0.030), larger dome size of >9.3 mm (P = 0.013), and prolonged procedure time >80 minutes (P < 0.001) were significantly associated with postprocedural DPLs. In the multiple logistic regression model, only prolonged procedure time >80 minutes (odds ratio, 10.72; 95% confidence interval, 1.346-233.899; P = 0.023) was statistically significant. The mediator effect showed that the association between procedure time and the occurrence of DPLs was not significantly modified by any other factors, although only adjunctive coiling showed a tendency (P-value for interaction = 0.070). CONCLUSIONS: Prolonged procedure time >80 minutes was the only identifiable factor related to postprocedural DPLs. Adjunctive coiling tended to mediate the effects of a prolonged procedure time on the occurrence of DPLs after FD treatment.

Double-Balloon-Assisted Coiling for Wide-Necked Posterior Communicating Artery Aneurysms with a Fetal-Type Variant of the Posterior Cerebral Artery: A Case Series.

Endovascular treatment for wide-necked posterior communicating artery (PcomA) aneurysms with a fetal-type variant of the posterior cerebral artery (PCA) is often challenging. Since the complete occlusion rates achieved with the currently available treatment methods are unsatisfactory, we aimed to study the effectiveness of a double-balloon-assisted technique for these aneurysms. From September 2014 to August 2020, 6 consecutive patients with PcomA aneurysms with fetal-type PCAs and no previous treatment were treated with this technique at our institution (3 ruptured cases and 3 unruptured cases). The indication for this technique is that the neck of the aneurysm should significantly and broadly incorporate both the internal carotid artery and fetal-type PCA, such that a single-balloon remodeling and single stent would be inadequate to protect both the arteries. In all patients, the fetal-type PCAs were preserved without a stent and with adequate occlusion status. This double-balloon technique can be effective in the treatment of these aneurysms.

A case of cribriform plate dural arteriovenous fistulas with a rare complication after endovascular therapy.

Background: Cribriform plate dural arteriovenous fistulas (dAVFs) are rarely encountered. Here, we report a case of cribriform plate dAVF with a rare complication after endovascular therapy. Case Description: A 60-year-old man presented with severe sudden headache. Head computed tomography showed right subdural hematoma, and magnetic resonance angiography showed dilated bilateral frontal cortical vein. Digital subtraction angiography revealed cribriform plate dAVF fed by the anterior and posterior ethmoidal branches of the bilateral ophthalmic arteries. Transarterial embolization with liquid embolic material was performed and the fistula disappeared. Although magnetic resonance imaging showed the disappearance of the cribriform plate dAVF and subdural hematoma, the patient complained of anosmia after the procedure. Conclusion: Endovascular embolization is an effective treatment option for treating cribriform plate dAVFs. However, anosmia is a possible complication, and endovascular surgeons should take care of this complication, especially in cribriform plate dAVFs supplied with blood bilaterally.

Distal migration of the flow-redirection endoluminal device immediately after treatment: A case report and literature review.

Background: A flow diverter (FD) has been a promising endovascular therapeutic modality for challenging intracranial aneurysms. However, stent migration has been an unusual complication. Until recently, among some types of FDs, the migration of the flow-redirection endoluminal device (FRED; MicroVention Inc., Aliso Viejo, CA, USA) has almost never been reported. Herein, we report a case of acute distal migration of a single FRED secondary to in-stent thrombi with symptomatic ischemic stroke and review the literature on the distal migration of FDs. Case Description: A 35-year-old woman was diagnosed with a left unruptured internal carotid-ophthalmic artery aneurysm. A 3.5 mm diameter and 17 mm long FRED was adequately deployed. The patient awoke from general anesthesia without neurological deficits. However, shortly after the procedure, the patient presented with conjugate deviation toward the left side, right severe hemiparesis, and total aphasia. Although the symptoms gradually improved, angiography was performed. Angiography revealed some in-stent thrombi and distal migration of the FRED, and initially, one of the left M2 inferior trunk branches was occluded by an embolic thrombus. However, the thrombus spontaneously migrated distally without any specific treatment. Finally, despite leaving the migrated stent in situ, the flow almost completely improved, and the patient's neurologic deficits disappeared. Magnetic resonance imaging following treatment revealed only a small cerebral infarction in the left temporo-occipital area. Conclusion: Distal migration of an FD in an acute setting, including the FRED, may occur even following appropriate placement. In-stent thrombosis can cause distal stent migration and thromboembolic stroke.

Outflow angle: a risk factor for thromboembolic complications in coil embolisation for treating unruptured middle cerebral artery bifurcation aneurysms.

BACKGROUND: Thromboembolic complications are a relevant risk in coil embolisation of cerebral aneurysms. This retrospective study aimed to assess the treatment outcomes of unruptured middle cerebral artery (MCA) bifurcation aneurysms and the predictors for thromboembolic complications based on the aneurysm morphological characteristics. We examined the following three features: inflow angle, outflow angle (OA), and bifurcation angle, formed by the aneurysm and neighbouring blood vessels. METHODS: A total of 32 MCA bifurcation aneurysms were retrospectively investigated in 32 patients treated consecutively at our institute between April 2008 and March 2019. The predictors for thromboembolic complications were analysed in two groups: patients with and without thromboembolic complications. RESULTS: Perioperative thromboembolic complications were detected in six patients (18.8%), including two and six intra- and post-procedural thromboembolic complications, respectively; all cases were resolved. Regarding the aneurysms' morphological characteristics, the group with thromboembolic complications showed a significantly smaller OA (55.58° ± 14.05° vs. 86.04° ± 28.58°, P = 0.01) than the group without complications. Multivariate analysis revealed that smoking habits and OA < 70° were significant predictors of thromboembolic complications (smoking habits: P = 0.01, odds ratio [OR]: 6.89, 95% confidence interval [CI]: 3.78-12.62; OA < 70°: P = 0.04, OR: 3.19, 95% CI: 1.52-6.56). CONCLUSIONS: Our findings indicate significant pre-procedural predictors of thromboembolic complications to consider for safe treatment; clipping should be preferred to coil embolisation in high-risk patients. The method of choice should be considered in each case to allow the safe treatment of unruptured MCA aneurysms.

Comparison of Pipeline Embolization and Coil Embolization for the Treatment of Large Unruptured Paraclinoid Aneurysms.

The efficacy of flow diversion (FD) in the treatment of paraclinoid aneurysms has been established. The pipeline embolization device (PED) is one of the most commonly used FD devices. Coil embolization is also useful for treating paraclinoid aneurysms. This study aimed to compare the efficacy and safety of PED treatment and coil embolization for large unruptured paraclinoid aneurysms. This was a single-center, retrospective study of large unruptured paraclinoid aneurysms treated endovascularly between 2009 and 2019 (coil embolization between 2009 and 2015, and PED between 2015 and 2019). Cases with a follow-up period of less than 1 year and recurrence after coil embolization were excluded. The treatment outcomes between coil embolization and PED were compared. We investigated 45 patients with 45 large unruptured paraclinoid aneurysms treated by endovascular surgery in our institution. Twenty-four patients were treated with coil embolization and 21 with PED. In the PED group, the device cost was significantly lower (2,770.4 ± 699.5 vs. 1941.2 ± 552.8 [1000 yen], P = 0.03), procedure duration was significantly shorter (155.4 ± 66.7 vs. 95.1 ± 35.4 min, P <0.01), and the numbers of re-treatments were lower than those in the coil embolization group (41.7 vs. 14.3%, P = 0.05). Both PED and coil embolization were effective and safe for large unruptured paraclinoid aneurysms, and their treatment results were similar. The PED is more beneficial because of its lower cost, shorter procedure duration, and fewer retreatments, and is therefore more useful for the treatment of large unruptured paraclinoid aneurysms.

Target Coil Embolization Using the Combined Transarterial and Transvenous Balloon-assisted Technique for Traumatic Direct Carotid Cavernous Fistula.

Herein, we describe a case of traumatic direct carotid cavernous fistula (DCCF) treated with target coil embolization using the combined transarterial and transvenous balloon-assisted technique. The patient was a 59-year-old woman who had been involved in a vehicular accident. She was admitted to the hospital due to chemosis and exophthalmos. Cerebral angiography revealed a shunt from the internal carotid artery (ICA) to the cavernous sinus (CS), which indicated DCCF. Thus, target coil embolization using the combined transarterial and transvenous balloon-assisted technique was performed. Angiography was performed 1 week after surgery to confirm the disappearance of DCCF. No recurrence was observed during the 1-year follow-up after treatment. Thus, target coil embolization using the combined transarterial and transvenous balloon-assisted technique is safe and effective for the treatment of traumatic DCCF.

Transverse-sigmoid Sinus Dural Arteriovenous Fistula Presenting with False Localizing Signs of Cavernous Sinus Dural Arteriovenous Fistula Due to Obstructed Cerebral Venous Outflow into the Bilateral Superior Ophthalmic Veins: A Case Report.

Cavernous sinus (CS) dural arteriovenous fistula (dAVF) presents ocular symptoms and visual disorders due to retrograde drainage from the CS into the superior ophthalmic vein (SOV). Some papers reported non-CS dAVFs with those symptoms. We present a unique case of transverse-sigmoid sinus (TSS) dAVF with localizing signs of CS dAVFs resulting from congested cerebral venous outflow into the CSs and SOVs in an 86-year-old female patient. Right pulsatile tinnitus and chemosis appeared a few years ago. After experiencing progressive bilateral blurred vision and decreased visual acuity with papillary edema for a few months, she was admitted to our hospital. Cerebral angiography demonstrated right sigmoid sinus dAVF with retrograde venous reflux into the superior sagittal sinus (SSS) and contralateral TSS without cortical venous reflux. Under the influence of congestion of the SSS, cerebral venous outflow drained into the CSs subsequently into the SOVs. Trans-arterial embolization using ethylene-vinyl alcohol copolymer was conducted via the right middle meningeal artery. After treatment, right chemosis immediately improved. The 2-month follow-up examination revealed resolution of bilateral visual acuity and improvement of papillary edema. Our case demonstrates that retrograde drainage into the SOVs with not only directly arterialized shunted flow but also congested cerebral venous outflow can cause CS dAVFs-like symptoms.

Stent-assisted coil embolization for an unruptured vertebral artery-posterior inferior cerebellar artery aneurysm with retrograde access via type 1 persistent primitive proatlantal artery: A case report.

Vertebral artery (VA)-posterior inferior cerebellar artery (PICA) aneurysms are rare lesions that are difficult to treat with both endovascular and surgical techniques. Tight angulation of the PICA from VA may make access to the PICA difficult from ipsilateral VA if adjunctive techniques are needed. Recently, the safety and efficacy of retrograde access have been reported. We report a case of endovascular treatment for a VA-PICA aneurysm with a stent-assisted technique using retrograde access via contralateral persistent primitive proatlantal artery (PPA).The patient was a 76-year-old woman with an unruptured VA-PICA aneurysm on the dominant VA side. Coil embolization with a stent-assisted technique using retrograde access seemed appropriate. However, the origin of the left VA was not confirmed. Left common carotid artery angiography demonstrated that the PPA (type 1) branching from external carotid artery joined the VA V4 segment.Retrograde access via the PPA for stenting was performed. A microcatheter for stenting was retrogradely advanced to the right PICA at ease. After deploying the stent, coil insertion was completed from the right VA, and the final angiogram showed adequate occlusion of the aneurysm with preservation of the PICA.Thus, PPA may be an approach route in the treatment of VA-PICA aneurysms with unconfirmed contralateral VA orifice and apparent PPA on angiography, when retrograde access is needed.

[Spontaneous Retroclival Subdural Hematoma Diagnosed Using Magnetic Resonance Imaging in an Adult Patient:A Case Report].

Spontaneous retroclival subdural hematoma is rare among adults. To the best of our knowledge, only six cases have been reported. A 73-year-old man presented with sudden severe headache, diplopia, and dysarthria, with no history of trauma. Head CT revealed a retrociliary hematoma. No obvious causes of bleeding, such as cerebral aneurysms or malformations, were detected. Conservative treatment was provided to the patient. MRI showed an intraventricular hemorrhage and a space between the basilar artery and hematoma three days after onset. The hematoma almost disappeared on day 7. MRI, particularly T2-weighted sagittal MRI, is effective in localizing hematomas and confirming intraventricular hemorrhages.

A Patient with a Ruptured Blood Blister-like Aneurysm of the Internal Carotid Artery in Whom Two LVIS Stents Were Inserted.

Objective: We report a case in which multiple overlapping low-profile visualized intraluminal support (LVIS) stents were used as monotherapy for ruptured blood blister-like aneurysm (BBA) of the internal carotid artery (ICA). Case Presentation: A 48-year-old female presented to the emergency room with acute-onset headache. She was alert without neurological deficit with subarachnoid hemorrhage (SAH) Hunt and Kosnik grade I. Emergency angiography revealed a BBA from the supraclinoid ICA. This aneurysm had a small diameter, which makes coil embolization difficult. Therefore, we planned to use multiple overlapping LVIS stents as monotherapy for the ruptured aneurysm. The postoperative course was uneventful without rebleeding. The patient exhibited no neurological deficits on the clinical follow-up at 1 year. Conclusion: Multiple overlapping LVIS stents as monotherapy is useful for ruptured BBAs of the ICA.

A Patient with an Unruptured Aneurysm in the Internal Carotid Artery-duplicated Middle Cerebral Artery on Whom Coil Embolization with Balloon Remodeling Was Performed.

Objective: Treatment of an unruptured aneurysm at the origin of duplicated middle cerebral artery (DMCA) by coil embolization using balloon remodeling has not been reported. We report a case of coil embolization using balloon remodeling for an unruptured aneurysm at the origin of DMCA. Case Presentation: A 71-year-old female was found to have an unruptured aneurysm at the origin of DMCA during an examination for headache. Coil embolization using balloon remodeling for the wide neck aneurysm to preserve both the internal carotid artery (ICA) and DMCA was successful. The perioperative course was uneventful. Conclusion: This treatment enables complete embolization, and preserves both the ICA and DMCA. Thus, it is useful for aneurysms at the origin of DMCA.

Pipeline embolization for an iatrogenic intracranial internal carotid artery pseudoaneurysm after transsphenoidal pituitary tumor surgery: Case report and review of the literature.

Intracranial pseudoaneurysms are uncommon and among the most difficult lesions to treat with surgery or endovascular means without parent artery sacrifice. Here, we report on a patient who underwent successful treatment using a flow-diverting stent for an iatrogenic intracranial internal carotid artery pseudoaneurysm following a vessel injury after endoscopic pituitary tumor resection via the transsphenoidal approach. A 62-year-old man with a Rathke's cleft cyst presenting with bitemporal hemianopia and progressive decline of left visual acuity underwent endoscopic transsphenoidal pituitary tumor resection. During dura incision, brisk arterial bleeding was encountered from the right internal carotid artery. Immediate packing was performed, and hemostasis was achieved. Three days after the vessel injury, an angiography revealed a pseudoaneurysm (2.9 × 2.1 mm) at the cavernous segment of the right internal carotid artery, which showed enlargement on follow-up magnetic resonance imaging at six days postoperatively. Pipeline embolization was performed nine days after the vessel injury. Angiography performed one month after Pipeline embolization revealed significant stagnation but not complete occlusion of blood flow inside the pseudoaneurysm cavity. Dual antiplatelet therapy was replaced with single antiplatelet therapy. Follow-up angiograms three months after Pipeline embolization confirmed complete obliteration of the pseudoaneurysm and successful endoluminal reconstruction of the damaged vessel. Despite the possibility of short-term bleeding and the need for dual antiplatelet therapy administration for a certain period, the use of flow-diverting stents is a feasible vessel-sparing option in the management of intracranial internal carotid artery pseudoaneurysms resulting from transsphenoidal surgery injuries if intraoperative hemodynamic stability can be achieved with effective packing.