Factors related to vessel displacement due to stent retriever retraction: An in vitro study

BACKGROUND

Thrombectomy with a stent retriever (SR) may lead to intracranial hemorrhage due to vessel displacement. We aimed to explore factors related to vessel displacement using an in vitro vessel model.

METHODS

A vessel model mimicking two-dimensional left internal carotid angiography findings was used in this study. Six SR types (Solitaire 3 × 40, 4 × 40, and 6 × 40; Embotrap 5 × 37; Trevo 4 × 41; and Tron 4 × 40) were fully deployed in the M2 ascending, M2 bend, or M1 horizontal portion. Subsequently, the SR was retracted, and the vessel displacement, maximum SR retraction force, and angle of the M2 bend portion were measured. A total of 180 SR retraction experiments were conducted using 6 SR types at 3 deployment positions with 10 repetitions each.

RESULTS

The mean maximum distance of vessel displacement for Embotrap Ⅲ 5 × 37 (6.4 ± 3.5 mm, n = 30) was significantly longer than that for the other five SR types (p = 0.029 for Solitaire 6 × 40 and p < 0.001 for the others, respectively). Vessel displacement was significantly longer in the M2 ascending portion group (5.4 ± 3.0 mm, n = 60) than in the M2 bend portion group (3.3 ± 1.6 mm, n = 60) (p < 0.001) and it was significantly longer in the M2 bend portion group than in the M1 horizontal portion group (1.1 ± 0.7 mm, n = 60) (p < 0.001). A positive correlation existed between the mean maximum SR retraction force or mean angle of the M2 bend portion due to SR retraction (i.e., vessel straightening) and the mean maximum distance of vessel displacement (r = 0.90, p < 0.001; r = 0.90, p < 0.001, respectively).

CONCLUSIONS

Vessel displacement varied with the SR type, size, and deployment position. Moreover, vessel displacement correlated with the SR retraction force or vessel straightening of the M2 bend portion.

Aortogenic calcified cerebral embolism diagnosed with an embolus retrieved by thrombectomy: illustrative case

BACKGROUND

Calcified cerebral embolism has been reported as a cause of acute cerebral infarction, but an aortogenic origin has rarely been identified as the embolic source. The authors describe a case of aortogenic calcified cerebral embolism in a patient with other embolic sources.

OBSERVATIONS

In a patient with cerebral infarction and atrial fibrillation, a white hard embolus was retrieved by mechanical thrombectomy. Pathological analysis of the embolus revealed that it was mostly calcified, with some foam cells and giant cells. The macroscopic and pathological findings allowed the authors to finally diagnose an aortogenic calcified cerebral embolism.

LESSONS

Even in patients with cardiogenic embolic sources, it is possible to identify a complex aortic atheroma with calcification as the embolic source, based on the macroscopic and pathological findings of the embolus retrieved by mechanical thrombectomy.

Factors for failure of ultrasound-guided compression repair for femoral pseudoaneurysms after neuroendovascular therapy

OBJECTIVE

Pseudoaneurysms are a serious complication of neuroendovascular therapy with femoral artery puncture, for which ultrasound-guided compression repair (UGCR) is often the first choice of radical therapy. We sought to retrospectively investigate the factors for failure of UGCR for pseudoaneurysm at the femoral artery puncture site.

METHODS

Among patients undergoing neuroendovascular therapy with femoral artery puncture at our hospital between January 2018 and April 2021, those who received a diagnosis of pseudoaneurysm and underwent UGCR were enrolled. They were classified into two groups according to whether UGCR was successful (UGCR group) or was converted to surgical repair (SR group). Patient and procedural characteristics were compared between the two groups.

RESULTS

During the study period, 577 patients underwent neuroendovascular therapy with femoral artery puncture, 10 of whom (1.7%) received a diagnosis of pseudoaneurysm and underwent UGCR. There were seven patients in the UGCR group and three patients in the SR group. The sheath diameter tended to be larger in the SR group than in the UGCR group (p = 0.16). The modified Rankin scale score when a diagnosis of pseudoaneurysm was made was significantly lower in the SR group than in the UGCR group (1 [0-2] vs. 3 [2-5], p = 0.037).

CONCLUSIONS

Physical activity may be associated with failure of UGCR. In patients with high physical activity, the use of sedatives and analgesics to keep them at rest during puncture site compression after UGCR may lead to successful UGCR.

Anterior condylar arteriovenous fistula mainly fed by peripheral branches of the bilateral internal maxillary arteries: illustrative case

BACKGROUND

The main feeding artery of an anterior condylar arteriovenous fistula (AC-AVF) is the ascending pharyngeal artery and rarely the internal maxillary artery.

OBSERVATIONS

A 58-year-old male with a history of sinusitis since adolescence presented with a 5-year history of bilateral pulsatile tinnitus and a 2-month history of right ocular symptoms. Angiography showed that the peripheral branches of the bilateral internal maxillary arteries were the main feeding arteries of the AC-AVF and that they gathered in the clivus with a relatively large shunted pouch in the left jugular tubercle. Shunt flow drained to the right external jugular vein via the right superior ophthalmic vein. A sheath was placed in the right external jugular vein, and a small distal access catheter was guided to the right superior ophthalmic vein to allow the microcatheter to reach the shunted pouch. Selective angiography of the contralateral sphenopalatine artery allowed us to confirm the gathering site of the feeding arteries and the shunted pouch and archive the complete occlusion.

LESSONS

Selective angiography of the contralateral sphenopalatine artery may be useful to confirm the gathering site of the peripheral branches of the bilateral internal maxillary arteries in an AC-AVF.

White Embolus-induced Basilar Artery Occlusion Due to Pulmonary Vein Invasion of a Metastasis of a Malignant Melanoma

An 80-year-old woman presented with impaired consciousness after malignant melanoma resection. Magnetic resonance angiography showed basilar artery occlusion, which was subjected to mechanical thrombectomy for recanalization. A pathological analysis of the retrieved embolus revealed that it was derived from a metastasis of malignant melanoma. Contrast-enhanced chest computed tomography showed multiple pulmonary metastases, one of which was in the right upper lobe and invaded the pulmonary vein. To our knowledge, this is the first case of white embolus-induced cerebral embolism due to pulmonary vein invasion of a metastasis of a pathologically diagnosed malignant melanoma.

Parent artery occlusion for cerebral infarction after spontaneous recanalization in traumatic vertebral artery: A case report

Background

There is no established treatment strategy for traumatic vertebral artery occlusion that does not require cervical spine repair surgery.

Case Description

A 49-year-old man was brought to our hospital with traffic trauma. Fractures were observed in the left lateral mass and transverse process of Atlas and the left vertebral artery was occluded at the level of the foramen transversum of Atlas. No acute cerebral infarction was observed. Because the cervical spinal cord was not compressed by the fracture, no repair surgery was performed. Continuous intravenous heparin and oral aspirin were started for traumatic vertebral artery occlusion. Thereafter, the left vertebral artery spontaneously recanalized, but no cerebral infarction was observed. The patient was discharged home on day 16 of injury. Four days later, however, he was brought to our hospital with nausea and lightheadedness. Acute cerebral infarction was observed in the left posterior inferior cerebellar artery territory and a thrombus in the left vertebral artery V4 segment. Parent artery occlusion was performed to prevent further cerebral infarction due to distal embolization of the thrombus. No further cerebral infarction occurred after the operation and the patient was discharged home with a modified Rankin scale score of 1.

Conclusion

In cases of traumatic vertebral artery occlusion without an occlusive mechanism, parent artery occlusion may be considered in terms of recanalization risk, regardless of the need for repair surgery.

Factors related to white thrombi in acute ischemic stroke in cancer patients

OBJECTIVES

Thrombi in cerebral large vessel occlusion associated with active cancer are often fibrin and platelet-rich white thrombi. However, evaluating the thrombus composition in a short time before thrombectomy is often ineffective. We sought to determine factors related to white thrombi in acute ischemic stroke due to large vessel occlusion in cancer patients.

METHODS

Consecutive cancer patients undergoing thrombectomy for acute ischemic stroke due to large vessel occlusion between January 2018 and May 2022 were retrospectively reviewed. The patients were classified into white thrombus and red thrombus groups on the basis of the pathological findings of retrieved thrombi. Patient characteristics and laboratory findings were compared between the two groups.

RESULTS

There were 12 patients in the white thrombus group and 11 patients in the red thrombus group. Active cancer was significantly more in the white thrombus group than in the red thrombus group (91.7% vs. 36.3%, p = 0.0094). Internal carotid artery occlusion was significantly less in the white thrombus group than in the red thrombus group (0% vs. 36.4%, p = 0.037). Among laboratory findings, D-dimer levels were an independent factor associated with white thrombi (odds ratio 8.97 [95% confidence interval 1.71-368.99], p < 0.0001). The cutoff value of D-dimer levels for predicting white thrombi was 3.5 μg/mL (83.3% sensitivity and 100% specificity).

CONCLUSIONS

In acute ischemic stroke in cancer patients, active cancer, no internal carotid artery occlusion, and higher D-dimer levels (≥3.5 μg/mL) may be associated with occlusion with fibrin and platelet-rich white thrombi.

Disconnection of a stent retriever's pushwire caught by an accordion-like deformed aspiration catheter during mechanical thrombectomy: illustrative case

BACKGROUND

In mechanical thrombectomy for acute large vessel occlusion, a combined technique of using both a stent retriever and an aspiration catheter has been widely used. The authors report a case in which a stent retriever's pushwire and a microcatheter were caught and disconnected by an accordion-like deformed aspiration catheter.

OBSERVATIONS

A 74-year-old man underwent mechanical thrombectomy for a left M1 occlusion. A stent retriever was deployed from the left M2 to the left distal M1, and an aspiration catheter was advanced to the left distal M1. When the stent retriever and microcatheter were pulled into the aspiration catheter at the distal M1 without releasing the deflection, traction resistance of the stent retriever occurred, and the aspiration catheter contracted and deformed like an accordion distal to the tip of the guiding catheter. The stent retriever's pushwire and the microcatheter were caught and disconnected.

LESSONS

When a stent retriever is pulled into a flexible aspiration catheter in a case with vascular tortuosity, it may be caught by an accordion-like deformed aspiration catheter and disconnected. It is necessary to release the deflection of the aspiration catheter once traction resistance of the stent retriever and deflection of the aspiration catheter occur.

Cavernous sinus dural arteriovenous fistula embolized through an occluded superior petrosal sinus: illustrative case

BACKGROUND

Transvenous embolization for cavernous sinus (CS) dural arteriovenous fistulas (CS-DAVFs) with limitations of the major access routes to the CS is challenging.

OBSERVATIONS

A 74-year-old woman presented with left-sided conjunctival injection and exophthalmos. Cerebral angiography showed a left CS-DAVF draining into the left uncal vein and superior ophthalmic vein, with the fistulous point located in the posterosuperior compartment of the left CS. The left inferior petrosal sinus and internal jugular vein were occluded, and no drainage route from the left superior ophthalmic vein was seen. The anterior segment of the left superior petrosal sinus (SPS) was occluded, but the posterior segment was not. Microangiography from the posterior segment of the left SPS showed a beak-like orifice in the anterior segment of the left SPS toward the left CS. A micro-guidewire was guided through the beak-like orifice, and the microcatheter was advanced into the left CS. The left CS was packed and the DAVF was occluded.

LESSONS

Transvenous embolization through an occluded SPS may be an option in the endovascular treatment of CS-DAVFs. Penetration along the beak-like orifice of the occluded SPS visualized by venography at the blind end of the SPS may be useful in reaching the CS via the SPS.

De novo expansion formation in the outer curvature of the internal carotid artery after flow diverter deployment for an infectious cavernous carotid aneurysm: illustrative case

BACKGROUND

Infectious aneurysms very rarely occur in the cavernous carotid artery. Recently, treatment by flow diverter implantation with preservation of the parent artery has been the treatment of choice.

OBSERVATIONS

A 64-year-old woman presented with stenosis at the C5 segment of the left internal carotid artery (ICA), followed by ocular symptoms within 2 weeks, with a de novo aneurysm in the left cavernous carotid artery and wall irregularity with stenosis from the C2 to C5 segments of the left ICA. Antimicrobial therapy was given for 6 weeks, and a Pipeline Flex Shield was implanted. Angiography 6 months after treatment showed complete obliteration of the infectious aneurysm and improvement of the stenosis. However, de novo expansions were formed in the outer curvature of C3 and C4 segments of the ICA where the Pipeline device had been deployed.

LESSONS

Aneurysms that develop rapidly and show shape changes over time, accompanied by fever and inflammation, may be associated with an infection. Because of the fragility in the irregular wall of the parent vessel associated with infectious aneurysms, de novo expansion may form in the outer curvature of the parent vessel after flow diverter placement; thus, careful follow-up is necessary.

Microcatheter movement in the aneurysm due to low-profile visualized intraluminal support deployment: An in vitro study

BACKGROUND

When a microcatheter is in the aneurysm, it may move due to low-profile visualized intraluminal support (LVIS) deployment. This study was designed to determine this mechanism.

METHODS

Six silicon aneurysm models were created by combining the aneurysm location (side wall or bifurcation) and the parent vessel configuration (straight, ipsilateral bending, or contralateral bending). After adjusting the microcatheter tip position in the aneurysm by pushing or pulling, an LVIS stent was deployed to cover the aneurysm neck, and the changes in the microcatheter tip position was measured. Pushing and pulling were performed 15 times each for each model, for a total of 180 experiments.

RESULTS

In all experiments, the microcatheter tip moved with LVIS deployment. The total movement distance was 3.00±1.59 mm, which was significantly different between the push and pull groups (p = 0.049), between the three side-wall aneurysm models (p<0.0001), and between the three bifurcation aneurysm models (p<0.0001). Backward movement in the aneurysm occurred in 21% (37/180). The frequency of backward movement was significantly different between the side-wall and bifurcation aneurysm models (p = 0.0265) and between the push and pull groups (p<0.0001). The forward movement distance was significantly different between the side-wall (n = 78) and bifurcation (n = 65) aneurysm models (p<0.0001).

CONCLUSIONS

The aneurysm location, the parent vessel configuration, and adjustment of the microcatheter tip position by pushing or pulling may affect the total movement distance and forward/backward movement of the microcatheter tip due to LVIS deployment.

Dilation of proximal internal carotid artery collapse due to severe distal stenosis after angioplasty for distal stenosis: A case report

Background

We report a case of proximal internal carotid artery (ICA) collapse due to severe distal stenosis that dilated after angioplasty for distal stenosis.

Case Description

A 69-year-old woman underwent thrombectomy for the left ICA occlusion due to stenosis of C3 portion and was discharged home with a modified Rankin Scale score of 0. One year later, she developed cerebral infarction due to progressive stenosis of the C3 portion of the left ICA with proximal ICA collapse and underwent emergency percutaneous transluminal angioplasty (PTA) for distal stenosis. Device guidance to the stenosis was difficult due to proximal ICA collapse. After PTA, blood flow in the left ICA increased, and proximal ICA collapse dilated over time. Due to severe residual stenosis, she underwent more aggressive PTA followed by Wingspan stenting. Device guidance to the residual stenosis was facilitated because proximal ICA collapse had already dilated. Six months later, proximal ICA collapse further dilated.

Conclusion

PTA for severe distal stenosis with proximal ICA collapse may result in dilation of proximal ICA collapse over time.

Short-term aneurysm formation and rupture due to septic embolism diagnosed with a thrombus retrieved from another occluded artery

Background:

In rare cases, septic embolism is diagnosed on the basis of pathological findings of retrieved thrombi. Infected aneurysms can rapidly form and rupture after septic embolism, leading to a poor prognosis. We report a case of subcortical hemorrhage due to an infected aneurysm forming shortly after septic embolism in the left anterior cerebral artery.

Case Description:

In this case, the diagnosis of septic embolism was made on the basis of pathological findings of a thrombus retrieved from the simultaneously occluded left middle cerebral artery, and endovascular embolization of the infected aneurysm was performed.

Conclusion:

The pathological findings of a retrieved thrombus were useful for making a diagnosis of septic embolism. The possibility of short-term formation and rupture of an infected aneurysm after septic embolism should be noted. Endovascular embolization of occluded vessels due to septic embolism may prevent aneurysm formation and subsequent bleeding.

Clinical features and long-term outcomes of symptomatic low-grade carotid stenosis

OBJECTIVE

In symptomatic low-grade stenosis, most of the reports did not clarify the long-term outcome. This study aims to clarify the clinical features and long-term outcomes of symptomatic low-grade stenosis cases.

MATERIALS AND METHODS

We included 123 symptomatic patients with low-grade (<50%) carotid stenosis. The relative plaque signal intensity (rSI) and expansive remodeling rate (ERR) were measured using carotid magnetic resonance imaging (MRI). Antiplatelet therapy and treatment for atherosclerosis risk factors were administered in all cases. Carotid endarterectomy (CEA) was performed when ischemic symptoms appeared, or the percent stenosis progressed despite medical treatment.

RESULTS

The mean percent stenosis, rSI, and ERR on admission were 22.3, 1.70, and 2.01, respectively. The mean volume of the hyperintense plaque on carotid MRI was 641.4± 540 mm3. Sixty percent of cases involved intraplaque hemorrhage and expansive remodeling. During a mean follow-up of 52 months, recurrence of ischemic events was confirmed in 45 cases (36.6%). Of the 67 cases performed follow-up MRI, 34 cases (50%) had an increased volume of T1-hyperintense plaque. CEA or carotid artery stenting was performed in 49 cases. During a mean follow-up of 57.8 months after CEA, two cases of death (fatal intracerebral hemorrhage and asphyxia) and one case of brain stem lacunar infarction were observed, but ipsilateral ischemic events were not.

CONCLUSION

Most of the symptomatic patients with low-grade stenosis had both intraplaque hemorrhage and expansive remodeling and presented a high risk of recurrence and stenosis progression. CEA may have preventive effects against ischemic events in low-grade stenosis.

Inferior Epigastric Artery Injury due to Femoral Venipuncture for Neuroendovascular Intervention: Two Cases Requiring Transcatheter Arterial Embolization

Objective

Injury to the inferior epigastric artery (IEA) caused by femoral puncture may lead to retroperitoneal hematoma. We report on two cases of IEA injury due to femoral venipuncture for neuroendovascular intervention that resulted in hemorrhagic shock and required transcatheter arterial embolization.

Case Presentations

A 67-year-old woman and a 71-year-old man receiving dual antiplatelet therapy sustained injury to a branch of the IEA in the process of right femoral venipuncture for neuroendovascular intervention. In both cases, stent placement in the intracranial artery was accomplished as intended with systemic heparinization throughout the procedure; however, the patients became hypotensive during the procedure, and contrast-enhanced CT scans taken after the stenting revealed extravasation of contrast from the IEA and retroperitoneal hematoma. Transcatheter arterial embolization of the bleeding branch of the IEA was performed with the left femoral approach, and subsequent angiography confirmed the disappearance of the extravasation of contrast.

Conclusion

Femoral venipuncture for neuroendovascular intervention in patients receiving antithrombotic agents may cause IEA injury requiring transcatheter arterial embolization. The risk of IEA injury may be reduced by using the femoral head as a reference, performing ultrasound-guided puncture, and confirming the course of the IEA by femoral angiography before venipuncture.

Hemodynamic Change due to Vessel Straightening Immediately after LVIS Jr. Deployment for an Anterior Communicating Artery Aneurysm

Objective

Stent-assisted coil embolization for cerebral aneurysms may lead to straightening of the parent vessel. However, detailed reports documenting the hemodynamic change in bifurcation type aneurysms due to straightening of the parent vessel immediately after stent deployment are scarce.

Case Presentation

A 48-year-old woman with a history of polycystic kidney disease underwent aneurysm neck clipping with left frontotemporal craniotomy for a ruptured bifurcation-type anterior communicating artery (AComA) aneurysm. Angiography 18 days after clipping showed a recurrent AComA aneurysm, for which stent-assisted coil embolization was performed. Straightening of the parent vessel immediately after deployment of a low-profile visualized intraluminal support junior (LVIS Jr.) stent from the AComA to the A1 segment of the right anterior cerebral artery was confirmed by working projection angiography. The aneurysm was easily embolized with coils with the support of the stent covering the aneurysm neck. The embolization was finished with a slight dome filling of the aneurysm. The parent vessel angle in 3D angiography changed from 90° before stent deployment to 160° immediately after stent deployment. Angiography 2 months after embolization showed the aneurysm with a complete occlusion and the parent vessel angle of 170° in a 3D image.

Conclusion

The hemodynamic change in a bifurcation-type AComA aneurysm due to straightening of the parent vessel immediately after the LVIS Jr. stent deployment led to the covering of the aneurysm neck, resulting in good coil embolization, to which the vessel mobility and the stenting method may have contributed.

Low-profile visualized intraluminal support Blue stenting within a Neuroform Atlas stent for a large wide-necked aneurysm: A case report and a bench-top experiment

Low-profile visualized intraluminal support deployment in an Enterprise has been reported; however, that in an Atlas has yet to be in detail. Enterprise has a closed-cell design, while Atlas has an open-cell design. We detail here a case of a large wide-necked aneurysm treated by coil embolization with low-profile visualized intraluminal support Blue deployment within a Neuroform Atlas and a bench-top experiment using a silicon tube to test low-profile visualized intraluminal support, Atlas, Enterprise, and their combinations. A better low-profile visualized intraluminal support expansion was achieved by simultaneously pushing the wire and the system within the Atlas placed at the aneurysm neck, which resulted in an increased metal coverage of the aneurysm neck and a shorter transition zone with low metal coverage at both ends of the aneurysm neck. This technique may enable a high metal coverage by low-profile visualized intraluminal support expansion without restriction by the Atlas and contribute to aneurysm occlusion by increasing the flow-diverting effect.

Gradual dilatation of an occluded transverse sinus associated with dural arteriovenous fistula after balloon angioplasty with sinus packing: A case report

BACKGROUND

There is no consensus as to whether balloon angioplasty alone or stent placement is effective for sinus occlusion associated with dural arteriovenous fistula (DAVF). Herein, we first report a case of transverse sinus occlusion associated with DAVF in which gradual sinus dilatation was observed after balloon angioplasty with embolization of the affected sinus with shunt flow.

CASE PRESENTATION

A 69-year-old man presented with executive dysfunction. Magnetic resonance imaging revealed left transverse sinus-sigmoid sinus DAVF with occlusion of the left jugular vein and right transverse sinus. Before endovascular treatment, the patient had symptomatic epilepsy and subarachnoid hemorrhage. Retrograde leptomeningeal venous drainage disappeared with packing of the left transverse sinus-sigmoid sinus. Subsequently, balloon angioplasty of the right occluded transverse sinus was performed to maintain the normal venous drainage and remaining shunt outflow. Dilatation of the right transverse sinus was poor immediately after surgery. However, angiography after 10 days and 6 months revealed gradual dilatation of the right transverse sinus.

CONCLUSION

Sinus occlusion, which is thought to be caused by sinus hypertension associated with DAVF rather than chronic organized thrombosis or thrombophilia, may dilate over time after balloon angioplasty and shunt flow reduction if occluded sinus is necessary for facilitating normal venous drainage.

Factors related to microcatheter passage through the trans-cell approach using a low-profile visualized intraluminal support device: an in-vitro study

BACKGROUND AND PURPOSE

The trans-cell approach using a low-profile visualized intraluminal support (LVIS) device is sometimes used for aneurysm coil embolization. However, factors related to microcatheter passage remain uninvestigated. We aimed to examine in-vitro factors related to microcatheter passage using the trans-cell approach with an LVIS.

METHODS

Silicone vessel models (inner diameter, 4 mm) were created with different bend segments and a 4-mm hole assuming an aneurysm neck on the side of the greater curvature. The LVIS Blue (4.5 × 32 mm) was deployed at the bend segment, and passability on the trans-cell surface was evaluated by passing the microcatheter along the micro guidewire. A total of 800 passage experiments were performed using two types of microcatheter, ten types of silicone vessel, four cell widths, five cells with the same LVIS device, and two micro guidewire directions in the aneurysm.

RESULTS

The Headway Duo microcatheter (35.5%, 142/400) tended to have better passability compared with the Headway 17 microcatheter (29.3%, 117/400) (p = 0.070). As the cell width and angle between the trans-cell surface and microcatheter direction increased, passability significantly increased (p = 0.027 and p < 0.001, respectively). There was no significant difference in passability when the micro guidewire was directed to the proximal side versus the distal side (p = 0.45).

CONCLUSIONS

A large cell width and an obtuse angle between the trans-cell surface and microcatheter direction facilitated good passability. Although statistically marginal, microcatheters with small ledges and small tips had relatively good passability.

Endoscope-assisted microsurgical repair in trigeminal meningocele: case report

Trigeminal meningocele is a rare disease that results in rhinorrhea. Treatments with endoscopic approaches and open craniotomies have high recurrence rates, and controversy regarding the most effective surgical strategy for trigeminal meningocele is ongoing. The authors report a case of a 13-year-old female patient with a diagnosis of trigeminal meningocele determined after she presented with a history of intermittent headaches, suspected rhinorrhea, and recurrent meningitis. In addition to the conventional method of covering the efflux point of CSF and filling the inside of the meningocele with fascial tissues, the authors selectively closed the influx point of CSF from the prepontine cistern to the meningocele using an anterior transpetrosal approach. On the basis of the preoperative images, the authors hypothesized that the influx point of CSF could not be observed under the microscopic direct view and instead used a flexible endoscope. A check valve-like structure with one-way communication of CSF from the prepontine cistern into the cystic cavity was identified and was closed. At the time of this report, 36 months postoperatively, the patient had no indications of recurrence. Although cases of trigeminal meningoceles are infrequently encountered and require a tailored approach, the results in this case thus far indicate that the use of an endoscope and open craniotomy is an effective strategy for surgical treatment.

A Simple Surgical Technique for Pediatric Sinus Pericranii: Intraoperative Manual Compression of a Major Shunting Point

INTRODUCTION

Sinus pericranii is a vascular anomaly with extra- and intracranial venous connections. Sinus pericranii is categorized into 2 groups according to its contribution to the normal venous circulation. The accessory type sinus pericranii, which does not contribute to the normal major venous circulation, can be managed. Despite several proposed operative maneuvers, a standardized technique is yet to be established to control intraoperative bleeding.

CASE PRESENTATION

A 2-week-old neonate underwent examination of a subcutaneous mass in the parieto-occipital region. The subcutaneous mass had a major venous connection to the superior sagittal sinus on ultrasonography. The subcutaneous mass was partially thrombolized on magnetic resonance imaging and was minimally enhanced on computed tomography venography. The subcutaneous mass seemed not to contribute to the normal venous circulation. Surgical removal of the subcutaneous mass was performed due to its increased size at the age of 1 year and 3 months. While subcutaneous mass was detached from the scalp, the major venous connection was manually compressed, and minor venous connections were easily detected. The intraoperative bleeding was controllable. The pathological diagnosis was sinus pericranii. The patient is now followed up in the outpatient clinic. No recurrence was seen 18 months after the surgery.

DISCUSSION/CONCLUSION

Intraoperative hemostasis is essential while sinus pericranii is detached from the cranium. Hemostatic agents such as bone wax or absorbable gelatin and heat coagulation seem to be useful. However, complicative hemorrhage concerning to the preceded technique has been also reported. As seen in our case, to detect minor shunting points between the sinus pericranii and the intracranial veins, the major venous connection was manually compressed. Intraoperative manual compression of a major venous connection of sinus pericranii can be an option to manage intraoperative bleeding.

Prediction of Stroke Risk by Detection of Hemorrhage in Carotid Plaques: Meta-Analysis of Individual Patient Data

OBJECTIVES

The goal of this study was to compare the risk of stroke between patients with carotid artery disease with and without the presence of intraplaque hemorrhage (IPH) on magnetic resonance imaging.

BACKGROUND

IPH in carotid stenosis increases the risk of cerebrovascular events. Uncertainty remains whether risk of stroke alone is increased and whether stroke is predicted independently of known risk factors.

METHODS

Data were pooled from 7 cohort studies including 560 patients with symptomatic carotid stenosis and 136 patients with asymptomatic carotid stenosis. Hazards of ipsilateral ischemic stroke (primary outcome) were compared between patients with and without IPH, adjusted for clinical risk factors.

RESULTS

IPH was present in 51.6% of patients with symptomatic carotid stenosis and 29.4% of patients with asymptomatic carotid stenosis. During 1,121 observed person-years, 66 ipsilateral strokes occurred. Presence of IPH at baseline increased the risk of ipsilateral stroke both in symptomatic (hazard ratio [HR]: 10.2; 95% confidence interval [CI]: 4.6 to 22.5) and asymptomatic (HR: 7.9; 95% CI: 1.3 to 47.6) patients. Among patients with symptomatic carotid stenosis, annualized event rates of ipsilateral stroke in those with IPH versus those without IPH were 9.0% versus 0.7% (<50% stenosis), 18.1% versus 2.1% (50% to 69% stenosis), and 29.3% versus 1.5% (70% to 99% stenosis). Annualized event rates among patients with asymptomatic carotid stenosis were 5.4% in those with IPH versus 0.8% in those without IPH. Multivariate analysis identified IPH (HR: 11.0; 95% CI: 4.8 to 25.1) and severe degree of stenosis (HR: 3.3; 95% CI: 1.4 to 7.8) as independent predictors of ipsilateral stroke.

CONCLUSIONS

IPH is common in patients with symptomatic and asymptomatic carotid stenosis and is a stronger predictor of stroke than any known clinical risk factors. Magnetic resonance imaging might help identify patients with carotid disease who would benefit from revascularization.

Abstract TP78: Classification of Ischemic Core Distribution Pattern Using Computed Tomography Perfusion in Anterior Circulation Acute Large Vessel Occlusion

Introduction: The evaluation of ischemic core is important in acute cerebral infarction with large vessel occlusion. The ischemic core is thought to approximate the region that is difficult to receive collateral circulation. We classified the ischemic core distribution pattern into four types on the basis of the tendency of cerebral blood volume (CBV) decrease in the ischemic core, and examined the prognostic ability.

Methods: We included M1 or ICA occlusion which completely recanalized (TICI3) by thrombectomy in our institute from January 2015 to May 2019. The ischemic core was defined as a region where CBV were reduced less than 1.9 ml/100cc. Ischemic core distribution pattern was classified into the following 4 types. Type A: absent of ischemic core. Type B: ischemic core is confined to the basal ganglia and white matter. Type C1: ischemic core is present in the cortex but less than half of MCA region. Type C2: ischemic core is present in the cortex, and more than half of MCA region. The patient characteristics, temporal parameters, ASPECTS and ischemic core distribution pattern were analyzed with mRS0-2 at discharge as a good outcome group.

Results: A total of 47 cases (14 ICA, 33 M1) were included. Ischemic core distribution pattern correlated well with mRS at discharge (p<0.004). Factors that showed a significance in univariate analysis between the good outcome group (n=19) and the poor outcome group (n=28) were age (76 vs 80.5, p=0.037), ASPECTS (10 vs 9, p=0.027), ischemic core distribution type (B vs C1, p=0.002), last known well to recanalization time (191 vs 272.5, p=0.027). Among these factors, multivariate analysis correlated significantly with age (OR, 1.18; 95CI,1.01-1.36), ischemic core distribution pattern (OR, 5.01; 95CI, 1.8-13.9), and recanalization time (OR, 1.46; 95CI, 1.01-2.12).

Conclusions: The distribution pattern of ischemic core defined by reduced CBV have good correlation with outcome. There is a possibility that it can be used as a simple tool to predict prognosis using CT perfusion in anterior circulation acute large vessel occlusion.

Expansive carotid artery remodeling: possible marker of vulnerable plaque

OBJECTIVE

Accumulated findings in the pathophysiology of atherosclerosis have demonstrated that not only luminal narrowing but also plaque characteristics influence the risk of future ischemic events. The morphology of the carotid artery (CA) changes in response to atherosclerotic development by expansive remodeling (ER), the clinical significance of which remains unclear. This study aimed to define associations between ER and local risk factors, including CA geometry and traditional systemic risk factors for ischemic events, to determine whether ER could serve as a clinical marker of carotid vulnerable plaque.

METHODS

The authors retrospectively analyzed 66 patients with CA stenosis who were scheduled to undergo carotid endarterectomy or CA stenting. They calculated ER ratios in the internal CA (ICA) from long-axis MR images and as the maximal distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA/the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis. Relative overall signal intensity (roSI) was calculated to assess intraplaque hemorrhage and defined as the signal intensity of plaque on an axial T1-weighted image with maximal stenosis relative to that of the adjacent sternocleidomastoid muscle. The authors evaluated CA geometry by calculating the angles between the common CA (CCA) and ICA, and between the CCA and external CA (ECA) using digital subtraction angiography. The ER ratios, age, sex, percentage of stenosis, roSI, hypertension, hyperlipidemia, low-density lipoprotein, statin medication, diabetes, smoking habit, and ischemic heart disease were compared between 33 symptomatic and 33 asymptomatic patients. The authors also compared symptomatic status, age, sex, percentage of stenosis, ICA angle, ECA angle, roSI, and other traditional atherosclerotic risk factors between groups with extensive and slight ER.

RESULTS

The ER ratio was significantly greater in symptomatic than in asymptomatic patients (1.91 ± 0.46 vs 1.68 ± 0.40, p < 0.05). The ICA angle was significantly larger in the group with extensive ER than in those with slight ER (33.9° ± 20.2° vs 21.7° ± 13.8°, p < 0.01). The roSI, ECA angle, percentage stenosis, or any other traditional vascular risk factors were not associated with ER.

CONCLUSIONS

Carotid ER might be an independent indicator of carotid vulnerable plaque, which should be validated in a longitudinal study of patients with carotid atherosclerosis, including those with nonstenotic to moderate stenosis.

Abstract WP175: The Significance of Perfusion Computed Tomography in the Prediction of Hyperperfusion After Carotid Endarterectomy

Purpose: Cerebral hyperperfusion syndrome (CHS) is a rare devastating complication associated with hyperperfusion after carotid endarterectomy. Single photon emission computed tomography (SPECT) is usually used with acetazolamide challenge to measure the cerebrovascular reserve (CVR), and a decreased CVR is indicative of a high risk of post CEA hyperperfusion. However, acetazolamide administration can rarely cause serious adverse effects, and thus, alternative methods may be required. Perfusion computed tomography (PCT) is a rapid, more accessible modality, which can be acquired with CT angiography. PCT seems to be useful as a screening tool in identifying groups at high-risk of hyperperfusion, but its usefulness has not sufficiently investigated. Our purpose was to clarify the relationship between hyperperfusion and the preoperative PCT parameters of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT).

Method: We included patients who underwent carotid endarterectomy in our hospital from 2014 December to 2018 April. PCT was obtained preoperatively and on postoperative day 1. Hyperperfusion is defined as a postoperative CBF of the middle cerebral artery area which has increased twice that of the preoperative value. CHS was defined as any symptom and imaging findings related with hyperperfusion, which include headache, seizure, neurological dysfunction, and any intracranial hemorrhage in the related area. Preoperative CBF, CBV, MTT and other patient characteristics are statistically analyzed between a hyperperfusion group and non-hyperperfusion group.

Result: There are 73 patients who underwent CEA during the study period, and hyperperfusion was observed in 5 cases, from which 2 were considered as CHS. In the hyperperfusion group, the preoperative CBF was significantly lower (p=0.0008), and the CBV and MTT significantly higher (p=0.0196, p=0.0002). ROC analysis showed that the PCT parameters with the maximal area under the receiver-operating characteristic curve for hyperperfusion was preoperative MTT with an optimal threshold at 8.0 seconds (sensitivity 100%, specificity 100%).

Conclusion: Patient with prolonged preoperative MTT tend to develop hyperperfusion, which is related to CHS.

A Rare Case of Giant Solid Hemangioblastoma Accompanied with Hemophilia Type A

The surgical removal of giant solid hemangioblastoma involves a high risk of perioperative bleeding and requires attentive hemostasis. Here, we present a case of a giant solid hemangioblastoma accompanied with hemophilia which was previously undiagnosed. A 35-year-old man without any past medical history was admitted with diplopia and ocular motility disorder. computed tomography (CT) and magnetic resonance imaging (MRI) revealed obstructive hydrocephalus and a solid giant tumor of more than 4.0 cm in diameter in the right cerebellopontine angle (CPA). Hemangioblastoma was suspected on cerebral angiography. After ventriculoperitoneal shunt for obstructive hydrocephalus, oozing from the skin incision continued for several days. Hemophilia type A was diagnosed based on the result of laboratory blood coagulability examination. Supplemental administration of factor VIII and coil embolization of the feeding arteries of the lesion on the CPA were performed, and the tumor was subtotally resected without hemorrhagic complications. The histopathological diagnosis was hemangioblastoma. We report this case to emphasize the importance not to overlook previously undiagnosed coagulopathy before surgical excision of hemangioblastoma. And, with appropriate perioperative management for coagulopathy, surgical treatment involving a high risk of perioperative bleeding can be safely undertaken.

Pituitary Apoplexy in Long-Term Cabergoline User During Thrombocytopenia Due to Chemotherapy for Chronic Myelocytic Leukemia

BACKGROUND

Pituitary apoplexy (PA) is a life-threatening syndrome. The usage of a dopamine agonist, such as bromocriptine or cabergoline, is considered a predisposing factor for PA, which commonly occurs 1.5 years within commencement.

CASE DESCRIPTION

A 64-year-old female with a >15-year history of cabergoline therapy for pituitary prolactinoma was referred to our department of neurosurgery after complaining of headache, blurred vision, diplopia, and ptosis for 3 days during hospital admission for chemotherapy of chronic myelocytic leukemia. Computed tomography and magnetic resonance imaging revealed findings indicative of PA. As the patient was experiencing thrombocytopenia related to chemotherapy, blood transfusion was preceded, and after a platelet count of 15.0 × 104/μL was confirmed, transnasal neuroendoscopic surgery was performed 5 days from the onset of symptoms. The majority of the prolactinoma was removed, and the prolactinoma in the cavernous sinus was intentionally left. The postoperative course was generally good. The ptosis and diplopia improved, and the blurred vision resolved.

CONCLUSIONS

PA related to dopamine agonist therapy can occur in cases of elevated bleeding tendency, even in long-term users, suggesting that attention should be paid in the administration of a dopamine agonist in the patient experiencing thrombocytopenia. Surgical intervention should be performed after the preoperative platelet number and adequate response to transfusion are confirmed, and the aggressive removal of prolactinoma in the cavernous sinus should be avoided to reduce the risk of hemorrhagic complications.

Effect of intrathecal milrinone injection via lumbar catheter on delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) is an important complication after aneurysmal subarachnoid hemorrhage (aSAH). Although intrathecal milrinone injection via lumbar catheter to prevent DCI has been previously reported to be safe and feasible, its effectiveness remains unknown. The goal of this study was to evaluate whether intrathecal milrinone injection treatment after aSAH significantly reduced the incidence of DCI.

METHODS

The prospectively maintained aSAH database was used to identify patients treated between January 2010 and December 2015. The cohort included 274 patients, with group assignment based on treatment with intrathecal milrinone injection or not. A propensity score model was generated for each patient group, incorporating relevant patient variables.

RESULTS

After propensity score matching, 99 patients treated with intrathecal milrinone injection and 99 without treatment were matched on the basis of similarities in their demographic and clinical characteristics. There were significantly fewer DCI events (4% vs 14%, p = 0.024) in patients treated with intrathecal milrinone injection compared with those treated without it. However, there were no significant differences between the 2 groups with respect to their 90-day functional outcomes (46% vs 36%, p = 0.31). The likelihood of chronic secondary hydrocephalus, meningitis, and congestive heart failure as complications of intrathecal milrinone injection therapy was also similar between the groups.

CONCLUSIONS

In propensity score–matched groups, the intrathecal administration of milrinone via lumbar catheter showed significant reduction of DCI following aSAH, without an associated increase in complications.

Flexible endoscopically assisted evacuation of acute and subacute subdural hematoma through a small craniotomy: preliminary results

BACKGROUND

The first choice to treat acute subdural hematoma (SDH) is a large craniotomy under general anesthesia. However, increasing age or comorbid burden of the patients may render invasive treatment strategy inappropriate. These medically frail patients with SDH may benefit from a combination of small craniotomy and endoscopic hematoma removal, which is less invasive and even available under local anesthesia. Although hematoma evacuation with a rigid endoscope for acute or subacute SDHs has been reported in the literature, use of a flexible endoscope may have distinct advantages. In this article, we attempted to clarify the utility of small craniotomy evacuation with a flexible endoscope for acute and subacute SDH in the elderly patients.

METHOD

Between November 2013 and September 2016, a total of 17 patients with acute SDH (15 patients), subacute SDH (1 patient), or acute aggravation of chronic SDH (1 patient) underwent hematoma evacuation with a flexible endoscope at our hospital and were enrolled in this retrospective study. Either under local or general anesthesia, the SDH was removed with a flexible suction tube with the aid of the flexible endoscope through the small craniotomy (3 × 4 cm). Hematoma evacuation rate, improvement of clinical symptoms, and procedure-related complications were evaluated.

RESULTS

Hematoma evacuation rate was satisfactory, and statistically significant clinical improvement was observed in postoperative Glasgow Coma Scale in all cases compared to the preoperative assessment. No procedure-related hemorrhagic complications were observed.

CONCLUSIONS

The results reported here suggest that small craniotomy evacuation with a flexible endoscope is a safe, effective, and minimally invasive treatment for acute and subacute SDH in selected cases.

Abstract TP138: The Clinical Features and the Long-Term Outcomes of Carotid Symptomatic Low-Grade Stenosis

Background: Ischemic events caused by carotid artery stenosis are affected not only by stenosis but also by the instability of plaque. In symptomatic low-grade stenosis cases medical treatment is generally performed, but there are cases with repeated recurrence. The purpose of this study is to clarify the clinical features and long-term outcomes in cases of symptomatic low-grade stenosis.

Methods: We included seventy-one symptomatic patients with carotid low-grade stenosis (<NASCET 50%) who were admitted to our hospital from 2005 to 2016. The relative plaque signal intensity (rSI) with reference to muscle and expansive remodeling rate (ERR) were measured using carotid MRI. Antiplatelet therapy and treatment for atherosclerosis risk factors were administered in all cases. Carotid endarterectomy (CEA) was performed when ischemic symptoms appeared or the stenosis rate progressed despite medical treatment.

Results: The mean stenosis rate, rSI and ERR on admission were 20.4, 1.75 and 1.96, respectively. Seventy percent of cases involved intraplaque hemorrhage and positive remodeling. During a mean of 52-months follow-up, a recurrence of ischemic events was confirmed in 33 cases (46%), from which the duration until recurrence was within 7 days (33%), 3 months (18%), 1 year (18%), 2 years (21%), and over 2 years (15%). Nine cases had impending stroke, 3 of which were associated with major artery occlusion. CEA was performed in 28 cases (39%) for impending stroke (25%), recurrence of ischemic events (46%), asymptomatic infarction (7%), and stenosis rate progression (11%). During a mean of 47-months follow-up after CEA, 2 cases of death (fetal intracerebral hemorrhage, asphyxia) and one case of brain stem lacunar infarction were observed, but an ipsilateral ischemic event was not observed.

Conclusion: Most of the symptomatic patients with low-grade stenosis had both intraplaque hemorrhage and positive remodeling. The risk of recurrence and stenosis progression was high. CEA might have had a preventive effect against ischemic events in low-grade stenosis.

Asymptomatic Carotid T1-High-Intense Plaque as a Risk Factor for a Subsequent Cerebrovascular Ischemic Event

Background: Intraplaque hemorrhage, detected as a high-signal intensity on carotid MRI, is also strongly associated with ischemic events in symptomatic patients. However, in asymptomatic patients, the relationship of the T1-high intense plaque and the subsequent stroke is not clear. The aim of this study is to test the hypothesis that asymptomatic carotid T1-high intense plaque is a risk factor for a subsequent cerebrovascular ischemic event. Methods: Of the 1,353 consecutive patients, who underwent head and carotid MRI as part of their annual medical check-up, the imaging quality of 13 was poor and 150 did not present for follow-up examination, thus leaving 1,190 subjects for evaluation. Of the 1,190 patients, 96 patients had findings of high-signal intensity on carotid MRI and 1,094 patients did not. Cerebrovascular events were retrospectively evaluated. Results: During a mean follow-up period of 53 months, 4 patients with high-signal intensities on carotid MRI (4%) and 3 with no findings (0.3%) had a cerebrovascular ischemic event, with the occurrences significantly higher in the high-signal-intensity group. (p < 0.01) Cox regression analysis indicated that the presence of the high-intense plaque on carotid MRI (hazard ratio [HR] 4.2; 95% CI 1.0-17.1; p = 0.04), age (HR 1.1; 95% CI 1.0-1.2; p = 0.003), and diabetes mellitus (HR 7.2; 95% CI 1.8-27.4; p = 0.004) were associated with the occurrence of subsequent ischemic cerebrovascular events. Conclusions: Asymptomatic carotid T1-high-intense plaque might be a potential high-risk factor for a subsequent cerebrovascular ischemic event.

Short-Term Results of Carotid Endarterectomy and Stenting After the Introduction of Carotid Magnetic Resonance Imaging: A Single-Institution Retrospective Study

OBJECTIVE

Although carotid artery stenting (CAS) has been gaining popularity as an alternative to carotid endarterectomy (CEA), perioperative stroke rate following contemporary CAS remains significantly higher than stroke rate after CEA. The purpose of this study was to assess perioperative (within 30 days) therapeutic results in patients with carotid stenosis (CS) after introduction of preoperative carotid magnetic resonance imaging plaque evaluation in a single center performing both CEA and CAS.

METHODS

Based on prospectively collected data for patients with CS who were scheduled for carotid revascularization, retrospective analysis was conducted of 295 consecutive patients with CS. An intervention was selected after consideration of periprocedural risks for both CEA and CAS. Concerning risk factors for CAS, results of magnetic resonance imaging plaque evaluation were emphasized with a view toward reducing embolic complications.

RESULTS

CAS was performed in 114 patients, and CEA was performed in 181 patients. Comparing baseline characteristics of the 295 patients, age, T1 signal intensity of plaque, symptomatic CS, urgent intervention, and diabetes mellitus differed significantly between CAS and CEA groups. Among patients who underwent CAS, new hyperintense lesions on diffusion-weighted imaging were confirmed in 47 patients. New hyperintense lesions on diffusion-weighted imaging were recognized in 21.4% of patients who underwent CEA (n = 39), significantly less frequent than in patients who underwent CAS.

CONCLUSIONS

The overall short-term outcome of CEA and CAS is acceptable. Preoperative carotid magnetic resonance imaging evaluation of plaque might contribute to low rates of ischemic complications in CAS.

Abstract TP417: Plasma D-dimer Elevation Predicts Poor Functional Outcomes Through Systemic Complications After Aneurysmal Subarachnoid Hemorrhage

Introduction: Plasma D-dimer levels elevate during acute stage of aneurysmal subarachnoid hemorrhage (SAH) and are associated with poor functional outcomes. However, the mechanism in which D-dimer elevation on admission affects functional outcomes remains unknown.

Hypothesis: We hypothesize that D-dimer levels on admission are correlated with systemic complications rather than neurological complications, and therefore have an additive predictive value on conventional risk factors for poor functional outcomes.

Methods: A total of 187 patients with aneurymal SAH were retrospectively analyzed from a single center, observational cohort database. Correlations of plasma D-dimer levels on admission with patients’ characteristics, initial presentation, neurological complications, and systemic complications were identified. We also evaluated additive value of D-dimer elevation on admission for poor functional outcomes by comparing predictive models with and without D-dimer.

Result and Conclusions: D-dimer elevation on admission was associated with increasing age, women, and severity of SAH. Patients with higher D-dimer levels had increased likelihood of nosocomial infections (OR 1.22 [95% CI 1.07-1.39], p = 0.004), serum sodium disorders (OR 1.11 [95% CI 1.01-1.23], p = 0.033), and cardiopulmonary complications (OR 1.20 [95% CI 1.04-1.37], p = 0.01) by multivariable analysis. D-dimer elevation was an independent risk factor of poor functional outcomes (modified Rankin scale 3-6, OR 1.50 [95% CI 1.15-1.95], p = 0.003). A novel prediction model with D-dimer had significantly better discrimination ability for poor outcomes than conventional models without D-dimer, evaluated by C statistics, net reclassification improvement, and integrated discrimination improvement methods. These results suggest that elevated D-dimer levels on admission were independently correlated with systemic complications, and had an additive value for outcome prediction on conventional risk factors after aneurysmal SAH.

The role of alternative anastomosis sites in occipital artery–posterior inferior cerebellar artery bypass in the absence of the caudal loop using the far-lateral approach

OBJECTIVE

Occipital artery–posterior inferior cerebellar artery (OA-PICA) bypass is a technically challenging procedure for posterior fossa revascularization. The caudal loop of the PICA is considered the optimal site for OA-PICA anastomosis, however its absence can increase the technical difficulty associated with this procedure. The use of the far-lateral approach for accessing alternative anastomosis sites in OA-PICA bypass in patients with absent or unavailable caudal loops of PICA is evaluated.

METHODS

A morphometric analysis of OA-PICA bypass with anastomosis on each segment of the PICA was performed on 5 cadaveric specimens through the conventional midline foramen magnum and far-lateral approaches. The difficulty level associated with anastomoses at each segment was qualitatively assessed in each approach for exposure and maneuverability by multiple surgeons. A series of 8 patients who underwent OA-PICA bypass for hemodynamic ischemia or ruptured dissecting posterior fossa aneurysms are additionally reviewed and described, and the clinical significance of the caudal loop of PICA is discussed.

RESULTS

Anastomosis on the caudal loop could be performed more superficially than on any other segment (p < 0.001). A far-lateral approach up to the medial border of the posterior condylar canal provided a 13.5 ± 2.2–mm wider corridor than the conventional midline foramen magnum approach, facilitating access to alternative anastomosis sites. The far-lateral approach was successfully used for OA-PICA bypass in 3 clinical cases whose caudal loops were absent, whereas the midline foramen magnum approach provided sufficient exposure for caudal loop bypass in the remaining 5 cases.

CONCLUSIONS

The absence of the caudal loop of the PICA is a major contributing factor to the technical difficulty of OA-PICA bypass. The far-lateral approach is a useful surgical option for OA-PICA bypass when the caudal loop of the PICA is unavailable.

Focal Fatty Masses of the Pancreas

Five patients with solitary fatty mass of the pancreas examined with CT and ultrasound (US) were evaluated. The areas of fat replacement were located in the pancreatic neck, body or tail. The size ranged from 4 to 30 mm in the longest diameter. The shape varied from roundish, to ovoid to semicircular, and the contour was universally well defined. The internal structure was homogeneous in 3 patients, but in one case there were thin septa and, in another, a slightly hyperdense part in the peripheral portion. All the masses except the smallest one were in part contact with pancreatic fat. CT showed fat with the same density as the peripancreatic fat and low HU units. The mass was hypoechoic in 2 cases and hyperechoic in one. The masses in the tail of the pancreas were not detected by US.

Acute Compressive Myelopathy Caused by Spinal Subarachnoid Hemorrhage: A Combined Effect of Asymptomatic Cervical Spondylosis

BACKGROUND

Patients with subarachnoid hemorrhage (SAH) by hemorrhagic arteriovenous fistulas (AVFs) usually presents with meningeal signs, including headache and nausea, and focal neurologic deficit is found in rare cases. In this article, we report a case of acute compressive cervical myelopathy caused by hemorrhagic AVF at the craniocervical junction.

CASE DESCRIPTION

A 73-year-old woman was transferred to our hospital for sudden headache and subsequent left hemiparesis. Head computed tomography scan showed SAH exclusively in the posterior fossa, and catheter angiography revealed a perimedullary arteriovenous fistula at the craniocervical junction as a source of the SAH. Detailed neurologic examination showed the sensory disturbance of bilateral upper extremities and bladder and rectal disturbance, suggesting concurrent cervical myelopathy. Magnetic resonance imaging of the cervical spine showed disk herniation at the C4-5 level, spinal SAH deposition above the C4-5 level, and accompanying myelomalacia. No intramedullary hemorrhage was found.

CONCLUSIONS

Spinal SAH alone rarely causes focal neurologic deficit. However, this case suggests spinal SAH can cause acute compressive myelopathy when complicated with preexisting spinal canal stenosis.

Plasma D-dimer may predict poor functional outcomes through systemic complications after aneurysmal subarachnoid hemorrhage

OBJECTIVE Plasma D-dimer levels elevate during acute stages of aneurysmal subarachnoid hemorrhage (SAH) and are associated with poor functional outcomes. However, the mechanism in which D-dimer elevation on admission affects functional outcomes remains unknown. The aim of this study is to clarify whether D-dimer levels on admission are correlated with systemic complications after aneurysmal SAH, and to investigate their additive predictive value on conventional risk factors for poor functional outcomes. METHODS A total of 187 patients with aneurysmal SAH were retrospectively analyzed from a single-center, observational cohort database. Correlations of plasma D-dimer levels on admission with patient characteristics, initial presentation, neurological complications, and systemic complications were identified. The authors also evaluated the additive value of D-dimer elevation on admission for poor functional outcomes by comparing predictive models with and without D-dimer. RESULTS D-dimer elevation on admission was associated with increasing age, female sex, and severity of SAH. Patients with higher D-dimer levels had increased likelihood of nosocomial infections (OR 1.22 [95% CI 1.07-1.39], p = 0.004), serum sodium disorders (OR 1.11 [95% CI 1.01-1.23], p = 0.033), and cardiopulmonary complications (OR 1.20 [95% CI 1.04-1.37], p = 0.01) on multivariable analysis. D-dimer elevation was an independent risk factor of poor functional outcome (modified Rankin Scale Score 3-6, OR 1.50 [95% CI 1.15-1.95], p = 0.003). A novel prediction model with D-dimer had significantly better discrimination ability for poor outcomes than conventional models without D-dimer. CONCLUSIONS Elevated D-dimer levels on admission were independently correlated with systemic complication, and had an additive value for outcome prediction on conventional risk factors after aneurysmal SAH.

Carotid artery plaque assessment using quantitative expansive remodeling evaluation and MRI plaque signal intensity

OBJECT

Plaque characteristics and morphology are important indicators of plaque vulnerability. MRI-detected intraplaque hemorrhage has a great effect on plaque vulnerability. Expansive remodeling, which has been considered compensatory enlargement of the arterial wall in the progression of atherosclerosis, is one of the criteria of vulnerable plaque in the coronary circulation. The purpose of this study was risk stratification of carotid artery plaque through the evaluation of quantitative expansive remodeling and MRI plaque signal intensity.

METHODS

Both preoperative carotid artery T1-weighted axial and long-axis MR images of 70 patients who underwent carotid endarterectomy (CEA) or carotid artery stenting (CAS) were studied. The expansive remodeling ratio (ERR) was calculated from the ratio of the linear diameter of the artery at the thickest segment of the plaque to the diameter of the artery on the long-axis image. Relative plaque signal intensity (rSI) was also calculated from the axial image, and the patients were grouped as follows: Group A = rSI ≥ 1.40 and ERR ≥ 1.66; Group B = rSI< 1.40 and ERR ≥ 1.66; Group C = rSI ≥ 1.40 and ERR < 1.66; and Group D = rSI < 1.40 and ERR < 1.66. Ischemic events within 6 months were retrospectively evaluated in each group.

RESULTS

Of the 70 patients, 17 (74%) in Group A, 6 (43%) in Group B, 7 (44%) in Group C, and 6 (35%) in Group D had ischemic events. Ischemic events were significantly more common in Group A than in Group D (p = 0.01).

CONCLUSIONS

In the present series of patients with carotid artery stenosis scheduled for CEA or CAS, patients with plaque with a high degree of expansion of the vessel and T1 high signal intensity were at higher risk of ischemic events. The combined assessment of plaque characterization with MRI and morphological evaluation using ERR might be useful in risk stratification for carotid lesions, which should be validated by a prospective, randomized study of asymptomatic patients.

Abstract TP232: Symptomatic Plaque with Low-grade Stenosis Which Retains Hyperintensity After an Ischemic Event may Indicate a High Risk of a Subsequent Ipsilateral Ischemic Event

Introduction: Intraplaque hemorrhage (IPH) has been reported to be a characteristic feature of a vulnerable plaque, indicated by an area of high signal intensity on carotid MRI. It has been reported that symptomatic low-grade stenosis with IPH is strongly associated with ischemic events, but there are limited data regarding the dynamics of the carotid plaque signal. The aim of this study was to assess the time-dependent change of carotid plaque in the symptomatic patient with low-grade stenosis.

Methods: Thirty-eight symptomatic patients with carotid low-grade stenosis (0.31 between time points was considered significant. We then investigated changes in rSI and subsequent ipsilateral ischemic events.

Result: Of the 38 patients, there were strong-positive and positive plaque at baseline in 22 and 12 patients, respectively. During a mean follow-up period of 42.5 months, 26 positive plaques (74%) at baseline kept an rSI of >1.25, and all of 4 negative plaques at baseline changed positive. Strong-positive plaques at baseline showed a lower tendency to be negative than positive plaque (p=0.08). Twenty-one of the 38 patients (55%) experienced a total of 26 recurrent ischemic events. In patients who experienced recurrent ischemic events, 19 plaques (73%) were strong-positive and 5 plaques (19%) were positive. Compared to the most recent carotid MRI, rSI at the event was stable in 18 patients (69%) and increased in 8 patients (31%).

Conclusions: Most symptomatic plaque with low-grade stenosis retained its hyperintensity after ischemic events and had a high rate of subsequent ipsilateral ischemic events. A sustaining high signal intensity might be associated with an increased risk of subsequent ischemic events. Follow-up observation by carotid MRI has the potential to increase the accuracy of stroke risk stratification in the management of carotid low-grade stenosis.

Impact of Aneurysm Projection on Intraoperative Complications During Surgical Clipping of Ruptured Posterior Communicating Artery Aneurysms

BACKGROUND:

Surgical clipping of ruptured posterior communicating artery (PCoA) aneurysms is a well-established procedure to date. However, preoperative factors associated with procedure-related risk require further elucidation.

OBJECTIVE:

To investigate the impact of the direction of aneurysm projection on the incidence of procedure-related complications during surgical clipping of ruptured PCoA aneurysms.

METHODS:

A total of 65 patients with ruptured PCoA aneurysms who underwent surgical clipping were retrospectively analyzed from a single-center, prospective, observational cohort database in this study. The aneurysms were categorized into lateral and posterior projection groups, depending on direction of the dome. Characteristics and operative findings of each projection group were identified. We also evaluated any correlation of aneurysm projection with the incidence of procedure-related complications.

RESULTS:

Patients with ruptured PCoA aneurysms with posterior projection more likely presented with good-admission-grade subarachnoid hemorrhage (P = .01, χ2 test) and were less to also have intracerebral hematoma (P = .01). These aneurysms were found to be associated with higher incidence of intraoperative rupture (P = .02), complex clipping with fenestrated clips (P = .02), and dense adherence to PCoA or its perforators (P = .04) by univariate analysis. Aneurysms with posterior projection were also correlated with procedure-related complications, including postoperative cerebral infarction or hematoma formation (odds ratio, 5.87; 95% confidence interval, 1.11-31.1; P = .04) by multivariable analysis.

CONCLUSION:

Ruptured PCoA aneurysms with posterior projection carried a higher risk of procedure-related complications of surgical clipping than those with lateral projection.

Reflux of Anterior Spinal Artery Predicts Recurrent Posterior Circulation Stroke in Bilateral Vertebral Artery Disease

BACKGROUNDS AND PURPOSE

Predictive value of reflux of anterior spinal artery for recurrent posterior circulation ischemia in bilateral vertebral arteries steno-occlusive disease was evaluated.

METHODS

We retrospectively reviewed 55 patients with symptomatic posterior circulation stroke caused by bilateral stenotic (>70%) lesions of the vertebral artery. We investigated any correlation of clinical and angiographic characteristics including collateral flow patterns, with recurrent stroke. Risk factors for poor 3-month functional outcome were also evaluated.

RESULTS

Recurrent posterior circulation stroke was observed in 15 (27.3%) patients. Multivariable analysis using Cox proportional hazards model showed anterior spinal artery reflux as a significant risk factor for stroke recurrence (adjusted hazard ratio, 19.3 [95% confidence interval, 5.35-69.9]; P<0.001). Anterior spinal artery reflux was also correlated with poor functional outcome (modified Rankin Scale score, 3-6; adjusted odds ratio, 7.41 [95% confidence interval, 1.24-44.4]; P=0.028).

CONCLUSIONS

In patients with symptomatic bilateral vertebral artery occlusive disease, anterior spinal artery reflux predicted recurrent posterior circulation stroke and poor functional outcome.

The association between expansive arterial remodeling detected by high-resolution MRI in carotid artery stenosis and clinical presentation

OBJECT

The purpose of the present study was to investigate the association between carotid artery (CA) expansive remodeling (ER) and symptoms of cerebral ischemia.

METHODS

One hundred twenty-two consecutive CAs scheduled for CA endarterectomy (CEA) or CA stent placement (CAS) were retrospectively studied. After excluding 22 CAs (2 were contraindicated for MRI, 8 had near-occlusion, 6 had poor image quality, and 6 had restenosis after CEA or CAS), there were 100 CAs (100 patients) included in the final analysis. The study included 50 symptomatic patients (mean age 73.6 ± 8.9 years, 6 women, mean stenosis 68.5% ± 21.3%) and 50 asymptomatic patients (mean age 72.0 ± 5.9 years, 5 women, mean stenosis 79.4% ± 8.85%). Expansive remodeling was defined as enlargement of the internal carotid artery (ICA) with outward plaque growth. The ER ratio was calculated by dividing the maximum distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA by the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis using long-axis, high-resolution MRI.

RESULTS

The ER ratio of the atherosclerotic CA was significantly greater than that of normal physiological expansion (carotid bulb; p < 0.01). The ER ratio of symptomatic CA stenosis (median 1.94, interquartile range [IQR] 1.58–2.23) was significantly greater than that of asymptomatic CA stenosis (median 1.52, IQR 1.34–1.81; p = 0.0001). When the cutoff value of the ER ratio was set to 1.88, the sensitivity and specificity to detect symptoms were 0.6 and 0.78, respectively. The ER ratio of symptomatic patients was consistently high regardless of the degree of stenosis.

CONCLUSIONS

There was a significant correlation between ER ratio and ischemic symptoms. The ER ratio might be a potential indicator of vulnerable plaque, which requires further validation by prospective observational study of asymptomatic patients.

Reduced cerebrovascular reserve is associated with an increased risk of postoperative ischemic lesions during carotid artery stenting

Background

Reduced cerebrovascular reserve (CVR) is associated with increased risk of ischemic events in carotid steno-occlusive diseases.

Objective

To determine whether pretreatment CVR can predict postoperative ischemic lesions after carotid artery stenting (CAS) by retrospective analysis.

Methods

We retrospectively reviewed the medical records of 46 patients (42 men; mean age 74.2±8.3 years) who underwent CAS and preprocedural cerebral blood flow measurement by quantitative single-photon emission CT. Ischemic lesions were evaluated by diffusion-weighted image (DWI) within 72 h after the intervention. We also evaluated plaque characteristics using black-blood MR plaque imaging.

Results

New ipsilateral DWI-positive lesions were found in 11 cases (23.9%). Patients were classified into two groups based on the presence or absence of new DWI-positive lesions, and no significant differences in characteristics were found between the DWI-positive and DWI-negative groups, except for age and CVR of the ipsilateral middle cerebral artery (MCA) territory. The DWI-positive group was significantly older than the DWI-negative group (79.7±4.1 vs 72.5±8.6 years; p=0.0085) and had lower average regional CVR (1.4±18.2% vs 22.4±25.8%; p=0.016). MR plaque imaging showed no significant difference in relative overall plaque MR signal intensity between the two groups (1.53±0.37 vs 1.34±0.26; p=0.113). In multivariate logistic regression analysis, lower CVR of the ipsilateral MCA territory (<11%) was the only independent risk factor for new ischemic lesions following CAS (OR=6.99; 95% CI 1.17 to 41.80; p=0.033).

Conclusions

Impaired pretreatment CVR was associated with increased incidence of new infarction after CAS.

Surgical dissection of the internal carotid artery under flow control by proximal vessel clamping reduces embolic infarcts during carotid endarterectomy

OBJECTIVE

To evaluate the efficacy of flow control of the internal carotid artery (ICA) by the clamping of the common carotid artery, external carotid artery, and superior thyroid artery during surgical ICA dissection to reduce ischemic complications after carotid endarterectomy (CEA).

METHODS

Sixty-seven patients (59 men; age, 70.5 ± 6.2 years) who underwent CEA by the same surgeon were retrospectively studied. Both conventional CEA (n = 29) and flow-control CEA (n = 38) were performed with the patient under general anesthesia and with the use of somatosensory-evoked potential and near-infrared spectroscopy monitoring as a guide for selective shunting. The number of new postoperative infarcts was assessed with preoperative and postoperative diffusion-weighted images (DWIs) obtained within 3 days of surgery. In addition to surgical technique, the effects of the following factors on new infarcts also were examined: age, side of ICA stenosis, high-grade stenosis, symptoms, and application of shunting.

RESULTS

New postoperative DWI lesions were observed in 7 of 67 patients (10.4%), and none of them was symptomatic. With respect to operative technique, the incidence rate of DWI spots was significantly lower in the flow-control group (2.6%) than in the conventional group (20.7%), odds ratio: 0.069; 95% confidence interval: 0.006-0.779; P = 0.031). On multiple logistic regression analysis, age, side of ICA stenosis, high-grade stenosis, symptoms, and the use of internal shunting did not have significant effects on new postoperative DWI lesions, whereas technique did have an effect.

CONCLUSION

The proximal flow-control technique for CEA helps avoid embolic complications during surgical ICA dissection.

Abstract WP218: Assessment of Carotid Plaque Vulnerability Using Quantitative Expansive Remodeling Evaluation and MRI Plaque Signal Intensity

Background: Assessment of plaque vulnerability is important in evaluating the future risk of stroke. Plaque characteristics and plaque volume are important components of plaque vulnerability. Expansive remodeling (ER) is one of the criteria for vulnerable plaque in the coronary arteries, and influences the plaque volume. The aim of this study is risk stratification of carotid plaque through the evaluation of quantitative ER and MRI plaque signal intensity.

Methods: We studied and obtained both pre-operation carotid MRI T1-weighted axial and long axis images of 72 patients who underwent carotid endarterectomy or carotid aretery stenting. ER ratio (ERR) was calculated from the ratio of the linear diameter of the artery at the thickest segment of the plaque to the diameter of the artery beyond any poststenotic dilatation on the long axis image on carotid MRI. We also calculated relative plaque signal intensity (rSI) from the axial image and grouped the patients as follows: Group A, rSI≥1.4 and ERR≥1.8; Group B, rSI<1.4 and ERR≥1.8; Group C, rSI≥1.4 and ERR<1.8; Group D, rSI<1.4 and ERR<1.8. Ischemic events within 6 months were retrospectively evaluated in each group.

Results: Of the 72 patientis, the number of patients in each group was as follows: Group A, 20 patients; B, 12 patients; C, 19 patients; D, 21 patients. Fifteen patients (75%) in Group A, 6 patients (50%) in Group B, 8 patients (42%) in Group C and 7 patients (33%) in Group D had ischemic events within 6 months. Ischemic events in Group A was significantly higher than in Group C and D (p<0.05, p<0.001).

Conclusion: The combined assessment of plaque characterization with MRI and morphological evaluation using ERR are useful in risk stratification for carotid lesions.