Ahmet Peker

Preliminary experience with squid: a new liquid embolizing agent for AVM, AV fistulas and tumors.

AIM The aim of the present study was to analyze our experience with a new liquid embolic agent, Squid, for the treatment of cerebral vascular lesions. MATERIAL AND METHODS We present 28 patients who were treated with two formulations of Squid (Squid 18 and Squid 12). The lesions included 16 arteriovenous malformation (AVM)s (Spetzler-Martin grade 2 in 8, 3 in 6 and 4 in 2), 9 arteriovenous (AV) fistulas, 2 tumors (glomus tumor and angiofibroma) and 1 AICA aneurysm. Of the 9 patients presenting with hemorrhage, 6 were AVM, 2 were AVF and 1 was aneurysm. RESULTS The total obliteration rate of the AVMs was 37.5%. Fistulas were closed completely after combined treatment with surgery in 6 out of 9 patients, and one was sent to radiotherapy. There was no mortality. Two reported hemorrhages and thromboembolic complications resulted in permanent deficits in 3 patients. Pathologic examination revealed mild inflammatory reaction with infiltration of polymorphonuclear cells in 5 patients in whom surgery was performed immediately after embolization. Technical problems such as rupture, inability to remove or premature occlusion of the microcatheter related to the embolic agent were not recorded. CONCLUSION Squid is a safe and effective embolic agent for treatment of cerebral AVMs, AV fistulas, tumors and aneurysms with satisfactory obliteration rate.

Silk Device for the Treatment of Intracranial Aneurysms. Part 1: Peri-Procedural Results, Technical Aspects and Learning Curve.

AIM We evaluated the procedural outcomes of intracranial aneurysm treatment with the Silk device and its relation with operator experience. We also detailed some technical points we learned throughout our experience. MATERIAL AND METHODS One hundred and six consecutive patients with intracranial aneurysms treated using Silk (BaltExtrusion, Montmorency, France) stent between October 2010 and November 2013 were included. Patients were evaluated in terms of age, sex, aneurysm size, location, technical success, and adverse events. RESULTS There were 106 patients (71 female) undergoing 116 procedures with a mean age of 49.8 (range: 3-78 years). Mean aneurysm size was 10.7±8.0 (range, 2-40 mm). Technical success of the procedures was 96.5%. Adverse event rate was 11.2%. Among adverse events, there were 4 adverse events without complications, 2 mild complications, 7 severe complications, 4 of which resulted with death. The adverse event rate was significantly higher during the first half of the operators experience. The rate of adverse events seemed to stabilize after around 50 patients. Adverse events, regardless of the presence or absence of a clinical complication, were more frequent in aneurysms larger than 18.5 mm. CONCLUSION Safety of flow-diverter (FD) placement for intracranial aneurysms increases with operator experience. Training programs in endovascular management of cerebrovascular diseases and relevant fellowship curricula must be adapted to include sufficient flow diverter experience. The learning curve needs to be kept in mind when studies comparing different FD devices or those comparing other treatments to FDS are planned.

Silk Device for the Treatment of Intracranial Aneurysms, Part 2: Factors Related to Clinical and Angiographic Outcome.

AIM To report patient and procedure-related factors affecting the angiographic and clinical outcome in patients treated with the Silk device. MATERIAL AND METHODS All patients with intracranial aneurysms in whom treatment was attempted with the Silk flow diverter by our neurovascular team between October 2010 and November 2013 were included consecutively. The data was analyzed by an independent stroke neurologist not involved in the treatment of the patients. RESULTS A total of 96 patients (64 female) with ages range from 3 to 78 were included in this study. We found that 54 of the patients were asymptomatic and 42 of them symptomatic, while 21 had a prior history of subarachnoid hemorrhage (SAH). Mean aneurysm size was 10.2 mm (range 2 to 40 mm). 2 patients died due to consequences of SAH. 3 patients developed visual decline on the follow-up, 2 of these were procedure-related. Symptomatic thromboembolic events were noted in 7 cases. Patients with aneurysms smaller than 13 mm had significantly less complications and higher occlusion rates. The complication rate was significantly high in patients admitted with symptoms. Adjunctive coiling had no impact on outcome. CONCLUSION Safety and efficacy of flow diversion in this series was closely related to aneurysm size and presenting symptoms. A size cut-off for safety and efficacy has not been reported before and will be useful not only for future studies but also for patient counseling in daily practice. The futility of adjunctive coiling in this series calls for reappraisal of the current recommendations for this specific device.

Catch Plus thrombectomy device in acute stroke: initial evaluation

Objective To report our initial experience with the Catch Plus thrombectomy device (CPD) in patients with acute ischemic stroke (AIS). Materials and methods We retrospectively evaluated the procedural variables as well as the clinical and angiographic outcomes of patients with acute occlusion of a major intracranial artery in the anterior circulation who were treated with CPD at our center. Baseline characteristics (gender, age, comorbidities, cardiovascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score, and vessel occlusion sites) of these patients were recorded. Thrombolysis in Cerebral Infarction (TICI) score, incidence of symptomatic and asymptomatic bleeding, and 90 day modified Rankin Scale (mRS) scores were evaluated as indicators of outcome. Results 38 patients with a mean age of 67.5 years were treated with CPD. Mean time from symptom onset to procedure initiation was 226.7 min. Recanalization (TICI 2b–3) was achieved in 27 patients (71.1%). The median NIHSS score on admission was 20. Rates of symptomatic and asymptomatic intracerebral hemorrhage were 7.9% and 13.2%, respectively. The 90 day clinical follow-up data were available for 37 patients. The 90 day mortality rate was 18.9%, and the 90 day clinically acceptable functional outcome (mRS score ≤2) rate was 43.2% (mRS score 0–3, 54.1%). Very distal thrombectomy involving the cortical arteries was performed on four patients without complications. Conclusions Our initial experience suggests that mechanical thrombectomy with the CPD improves 90 day outcomes of patients with AIS by facilitating effective recanalization.

Stent-assisted coiling of cerebral aneurysms with the Neuroform Atlas stent:

Objectives The Neuroform Atlas stent (AS) is the smallest intracranial stent with an open-cell design. This study reports the first clinical experience with AS. Methods All intracranial aneurysms treated by stent-assisted coiling using a single AS in a single institution were retrospectively evaluated. Patient demographics, aneurysm characteristics, angles between the parent artery and stented branch, technical success, and clinical and angiographic follow-up were analyzed. Results Fifty-five consecutive aneurysms treated with AS-assisted coiling were included. Of these, 69.1% were located distal to the circle of Willis. Technical success rate was 100%. The mean diameters of proximal and distal parent arteries were 2.62 mm (range 1.5–4.4) and 1.8 mm (range 0.8–3.5), respectively. Except for a minor stroke in a patient who completely discontinued antiplatelet therapy on postoperative day 4, there were no clinical events with permanent sequelae, and 94.1% of patients had Raymond-Roy score of 1 or 2 aneurysmal occlusion at a mean follow-up duration of 7.9 months. Although the angle between the parent artery and the stented branch increased significantly (p < 0.001) with time, the angular change at follow-up was only 16.45 ± 11.03 degrees and was inversely correlated both with preoperative angle and the diameter of the distal parent artery (r = −0.465 and r = −0.433, respectively, p = 0.004 for both). Conclusion AS-assisted coiling was associated with a favorable early clinical outcome and angiographic results in this series. This stent can be used for distally located aneurysms and results in minimal alteration of the arterial anatomy.

Usefulness of contrast-enhanced and TOF MR angiography for follow-up after low-profile stent-assisted coil embolization of intracranial aneurysms

Background Low-profile, self-expandable stents are used to treat wide-neck aneurysms located on the smaller distal intracranial arteries. This study aimed to assess the usefulness of time-of-flight (TOF) and contrast-enhanced (CE) magnetic resonance angiography (MRA) for follow-up after LEO Baby stent (LBS)-assisted coil embolization. Methods Twenty-four aneurysms treated with LBS-assisted coil embolization were evaluated. Researchers reviewed TOF MRA and CE MRA images in terms of occlusion and stent patency. Aneurysm occlusion was graded according to Raymond–Roy classification as follows: total occlusion (grade 1), residual neck (grade 2), and residual aneurysm (grade 3). Stent patency was scored as follows: occlusion (1), stenosis (2), and normal (3). Interobserver and intermodality agreement values were determined by weighted kappa (κ) statistics. Results Intermodality and interobserver values of TOF MRA and CE MRA with digital subtraction angiography (DSA) were perfect (κ = 1.00, p < 0.001) in terms of aneurysm occlusion. Rate of stent occlusion and stenosis in DSA, TOF, and MRA, respectively, were as follows: 0 and 12.5%, 16.6 and 70.8%, and 0 and 62.5%. Intermodality agreement values of TOF MRA and CE MRA with DSA were insignificant in terms of stent patency (κ = 0.065, p = 0.27; κ = 0.158, p = 0.15, respectively). Interobserver agreement was substantial in both TOF MRA (κ = 0.71, p < 0.001) and CE MRA (κ = 0.64, p = 0.001). Conclusions Both TOF and CE MRA techniques have strong concordance with DSA for the detection of aneurysm occlusion status. CE MRA can be used as a first-line noninvasive imaging modality due to its superiority to TOF MRA with respect to the visualization of in-stent signals.

Hybrid vascular intervention for a giant cervical carotid artery aneurysm in a clopidogrel-hyporesponsive child

Aneurysms of the extracranial internal carotid artery (ICA) in pediatric patients are rare and mostly treated surgically. The authors present the case of a child with a giant extracranial ICA aneurysm presenting with gradual airway compression. A plan was made to explore the aneurysm surgically and straighten the associated carotid artery kinks during the operation to enable further endovascular treatment if primary reconstruction of the carotid artery proved not to be possible. Finally, the aneurysm was successfully treated with staged hybrid intervention, which consisted of surgical correction of parent artery kinks followed by endovascular implantation of stent grafts. The child tolerated the procedure well without adverse events. A craniocervical CT angiogram at 5 months showed patency of the stent construct and relief of airway compression. However, a follow-up CT angiogram at 14 months showed total occlusion of the ipsilateral carotid artery without clinical sequelae and complete cessation of airway compression. The management of this was unique since the patient is the first reported case of clopidogrel hyporesponsiveness in a child undergoing neurovascular intervention with prasugrel monotherapy. Point-of-care testing-based adjustment of prasugrel necessitated education of the patients family regarding the loss of effect of the prasugrel tablets upon crushing and contact with air.

Intermediate catheter placement distal to the cerebral aneurysm during flow diversion embolization with the Surpass device

Purpose We present the preliminary angiographic and clinical results of the combined utilization of an AXS Catalyst 5 (Cat5) distal access catheter and a Surpass flow diverter (SFD) for the endovascular treatment of intracranial aneurysms. Materials and methods Interventional neuroradiology case records were evaluated retrospectively to identify patients treated with an SFD in combination with Cat5. Demographic data, technical success, location of the catheter tip, aneurysm occlusion rate, and procedure-related morbidity and mortality were noted. Results The analysis yielded 24 patients with 25 aneurysms with a mean age of 52.3±19.7 years. The mean aneurysm diameter was 15.7±8.8 mm. Twenty-one were anterior circulation (seven supraclinoid, one middle cerebral, one anterior choroidal and 12 petrocavernous) and four were posterior circulation (three basilar tip, one posterior inferior cerebellar) aneurysms. Only two of these aneurysms were re-treatments for recurrences. For SFD deployment, the distal tip of Cat5 was placed intradurally and at, or distal to, M1 segment in 88% and 48% of patients, respectively. Aneurysms were bypassed with Cat5 in 80% of the procedures. In one patient, flow diversion was abandoned totally due to arterial tortuosity. With the exclusion of this patient, the technical success rate was 91.7%. There was no permanent procedure-related morbidity or mortality. Of the 22 aneurysms treated successfully with the Surpass device, 20 had imaging follow-up at 6.3±3.8 months and 95% were totally occluded. Conclusion The Cat5 catheter, which was manufactured for the navigation of large-bore stent-like devices, is a useful adjunct to the Surpass device and allowed us to deploy the device safely.

The effect of carotid artery stenting on capillary transit time heterogeneity in patients with carotid artery stenosis

Introduction Carotid revascularisation improves haemodynamic compromise in cerebral circulation as an additional benefit to the primary goal of reducing future thromboembolic risk. We determined the effect of carotid artery stenting on cerebral perfusion and oxygenation using a perfusion-weighted MRI algorithm that is based on assessment of capillary transit-time heterogeneity together with other perfusion and metabolism-related metrics. Patients and methods A consecutive series of 33 patients were evaluated by dynamic susceptibility contrast perfusion-weighted MRI prior to and within 24 h of the endovascular procedure. The level of relative change induced by stenting, and relationship of these changes with respect to baseline stenosis degree were analysed. Results Stenting led to significant increase in cerebral blood flow (p < 0.001), and decrease in cerebral blood volume (p = 0.001) and mean transit time (p < 0.001); this was accompanied by reduction in oxygen extraction fraction (p < 0.001) and capillary transit-time heterogeneity (p < 0.001), but an overall increase in relative capillary transit-time heterogeneity (RTH: CTH divided by MTT; p = 0.008). No significant change was observed with respect to cerebral metabolic rate of oxygen. The median volume of tissue with MTT > 2s decreased from 24 ml to 12 ml (p = 0.009), with CTH > 2s from 29 ml to 19 ml (p = 0.041), and with RTH < 0.9 from 61 ml to 39 ml (p = 0.037) following stenting. These changes were correlated with the baseline degree of stenosis. Discussion: Stenting improved the moderate stage of haemodynamic compromise at baseline in our cohort. The decreased relative transit-time heterogeneity, which increases following stenting, is probably a reflection of decreased functional capillary density secondary to chronic hypoperfusion induced by the proximal stenosis. Conclusion: Carotid artery stenting, is not only important for prophylaxis of future vascular events, but also is critical for restoration of microvascular function in the cerebral tissue.

E-087 Pressure-related immediate compromise of side branches in bifurcation aneurysms treated by flow diverters

Purpose Immediate hemodynamic compromise of a side branch jailed by a flow diverter is an infrequently encountered phenomenon in bifurcation aneurysms which is attributed by some authors to the “Coanda effect”. We aimed to check the relevance of this phenomenon with aneurysm occlusion rate on follow-up in bifurcation aneurysms treated by flow diversion. Methods All intracranial aneurysms treated with flow diverters in a single center were retrospectively reviewed. 30 patients treated by flow diverters which jail a major intracranial side branch originating from the aneurysm were identified. 7 patients among these demonstrated hemodynamic compromise of the jailed side branch intraprocedurally, immdeately after FD deployment (Group 1). 23 patients did not demonstrate any immediate side branch stagnation or occlusion (group 2). Patients in group 1 were treated by induced hypertension and augmentation of antiplatelet therapy in the perioperative period. Mann-Whitney U test was used to compare the diameters of the side branch, the parent artery and flow diverter as well as the angle between the parent artery/side branch between these 2 groups. Chi-square analysis was performed to compare the rate of occlusion of aneurysms at 6 months and at final follow-up. Results None of the patients in group 1 developed any permanent neurologic deficits. There were no significant differences between parent artery diameters, side branch diameters, flow diverter diameters and side branch angles between the two groups. Occlusion rate was similar in both groups at 6 months. However at the final follow-up there was a significantly higher rate of aneurysm occlusion in group 1 versus group 2 (p=0.03). Conclusion Intraprocedural, pressure-related compromise of a jailed side branch originating from an intracranial aneurysm treated by flow diversion does not necessarily indicate a bad outcome, on the contrary it may predict occlusion of the aneurysm on long term follow-up. Disclosures: Y. Senturk: None. F. Cay: None. A. Peker: None. O. Ocal: None. A. Arat: None.