Flow Diverter Device Research Articles

Basilar Artery Injury During Endonasal Surgery: Stepwise to Control Bleeding.

Intraoperative injury during endoscopic endonasal surgery of the carotid artery has been previously described in the literature. However, the accidental damage of the basilar artery in such scenario is not defined. To define the protocol of action for massive bleeding from an artery in the posterior fossa. The reported patient was diagnosed with a partially calcified clival chordoma featured by a huge intradural component. An endoscopic endonasal transpterygoid transclival approach was selected for the treatment of this tumor. During the surgical procedure, the basilar artery injury was injured, causing intense bleeding. We present and discuss the surgical maneuvers that could save a patient's life after this dramatic complication. Different techniques were performed in order to control the massive bleeding, including injection of hemotastic matrix with thrombin (Floseal©), bipolar coagulation, and vessel reconstruction by means of a vascular clip. Finally, an autologous muscle graft reinforced with an overlying fibrin sealant patch (Tachosil©) was chosen and was an effective technique. Afterwards, the patient was treated with a flow diverter device to occlude an iatrogenic pseudoaneurysm. A monoplegia of the right upper limb was the only remarkable sequel 6 mo after surgery. The muscle graft together with the coordinated action with interventional neuroradiology for the reconstruction of the vessel are possibly the best options to try to preserve the neurological function. In such a scenario, the assumption of potential ischemic events prevails over the intraoperative death of the patient.

Role of the ophthalmic artery in the endovascular treatment for intracranial vascular diseases.

The ophthalmic artery (OA) is a crucial artery. Centered at the OA, there are numerous extracranial-intracranial anastomoses. The OA and its collaterals can be involved in some intracranial vascular diseases. So, it is very important to understand its specific anatomy, variation, and role in different neurovascular diseases. The OA has various anomalies both in the origin and collateral circulation. When performing endovascular treatment (EVT), the OA may suffer unexpected embolization through the numerous dangerous anastomoses. In case of a dural arteriovenous fistula or brain arteriovenous malformation mainly fed by the OA, the OA can be the passage of EVT, during which the central retinal artery could be injured. During interventional recanalization of steno-occlusive diseases of the internal carotid artery, dissection at the cavernous segment could progress to the OA segment and occlude the origin of OA. Under the circumstance of moyamoya disease, the OA can provide collateral flow to the anterior cerebral artery. When performing EVT for OA aneurysm concurrent with moyamoya disease, the parent OA should be preserved. After placement of a flow-diverting device for ophthalmic ICA aneurysm, the covered OA could experience spontaneous occlusion, leading to visual disturbance. Hence, the OA is an extremely important artery in the EVT for intracranial vascular diseases. In this article, we would extensively review the related literature to increase our understanding of the role of OA in intracranial vascular diseases. In addition, some illustrative cases would also be provided.

Long-term clinical and angiographic follow-up results of the dual-layer flow diverter device (FRED) for the treatment of intracranial aneurysms in a multicenter study.

Our aim was to determine the long-term safety and efficacy of the Flow Re-Direction Endoluminal Device (FRED) in this multicenter study with prospective design. This study included 136 consecutive patients with 155 aneurysms treated between March 2013 and June 2016 in 10 centers. Twenty-two (16.2%) patients presented with rupture of the index aneurysm. Large/giant aneurysms comprised 1/3 of the cohort. Adjuvant coil use during the treatment was 15.5%. The effectiveness measure in the study was the percentage of aneurysms with stable occlusion at follow-up. Vascular imaging follow-up was performed at least once in 131/136 (96.3%) patients with 148/155 (95.5%) aneurysms up to 75months (mean: 37.3months; median: 36months according to latest follow-up), and 102/155(65.8%) aneurysms in 90/136 (66.2%) patients had ≥ 24-month control. According to the latest controls, the overall stable occlusion rate was 91.9% (95% CI, 87.5 to 96.3%). Three out of 148 aneurysms with follow-up were retreated (2%, 95% CI 0.0 to 4.3%). Adverse events were noted in 19/136 (14%, 95% CI, 9 to 21%) patients with a morbidity of 1.5% (95% CI, 0.0 to 3.5%). Mortality was 1/136 (0.7%, 95% CI, 0.02 to 2.2%) and was unrelated to aneurysm treatment. In-stent stenosis (ISS) was detected in 10/131 of the patients with follow-up (7.6%, 95% CI; 3.1 to 12.2%), only one being symptomatic. No adverse events have occurred in any of the patients with follow-up after 24months, except the one resulting from ISS. In the treatment of cerebral aneurysms which were candidates for flow diversion technique, this study showed long-term efficacy of FRED with good safety and occlusion rates.

The effects of sevoflurane anesthesia on hemodynamics and cerebral artery diameters in endovascular treatment of intracranial aneurysm: A pilot study.

Cerebral autoregulation is a steady-state of cerebral blood flow despite major changes in arterial blood pressure. Inhalation anesthetics are cerebral vasodilators. In <1 MAC values, the net effect is a moderate decrease in cerebral blood flow and maintenance of responsiveness to carbon dioxide. This study aims to investigate the effects of steady-state sevoflurane anesthesia on hemodynamic and cerebral artery diameter measurements in patients undergoing flow diverter device placement under general anesthesia. Forty-six patients aged 18-70 years who underwent flow diverter devices under general anesthesia were included in this study. Routine monitoring was performed on the patients. Mean arterial pressure (MAP) values were recorded. Internal carotid artery, middle cerebral artery and anterior cerebral artery diameter measurements were made from digital subtraction angiography (DSA) images of patients with anterior aneurysms. Baseline artery, right posterior cerebral artery and left posterior cerebral artery diameter measurements were made from DSA images of patients with posterior aneurysms. These measurements were recorded as preoperative measurements. The same measurements were made from the DSA images performed before the Flow diverter device placement procedure performed under steady-state sevoflurane anesthesia for the same patients. These measurements were recorded as peroperative measurements. The average age of the patients was 56.6±15.1. The MAP of the patients before induction was 76.28±5.13 mmHg, MAP after induction was 64.36±3.23 mmHg, and MAP during sevoflurane anesthesia was 68.26±4.30 mmHg, there was a statistically significant difference. There was a statistically significant difference between the preoperative and perioperative values of anterior cerebral artery diameters. There was a strong relationship between the MAP change percentage and the ICA diameter change percentage (p<0.001, p=-0.785) and a moderate relationship between the MCA diameter change percentage (p=0.033, p=-0.338). In patients undergoing flow diverter devices, <1 MAC sevoflurane has a hemodynamic effect and creates significant vasodilation in the cerebral artery diameters.

Triggering of Carotid Sinus Reflex during Deployment of the Flow-diverter Device.

The carotid sinus reflex (CSR) is a rare complication of the Pipeline Embolization Device (PED) deployment. No study has assessed the potential risk factors in a case series. The purpose of this study was to examine CSR triggering during PED deployment. Thirty-seven consecutive patients who underwent PED deployment were included. All procedures were performed under local anesthesia with mild sedation. We retrospectively analyzed patient characteristics, PED deployment time, and vital signs during the procedure. The vital signs included the pulse rate (PR) and systolic blood pressure (SBP) obtained at three timepoints (pre-deployment, during deployment, post-deployment). We examined the triggering of the CSR during PED deployment by comparing the vital signs at the three timepoints. Moreover, risk factors for CSR were analyzed with univariate analysis. The patients’ average age was 66.3 years. The average size of the aneurysm was 18.0 mm. Six patients (16.2%) showed a decline in the SBP or PR defined as CSR. One patient had a transient cardiac arrest and two had severe transient bradycardia. Deployment into the ophthalmic segment of the internal carotid artery (C2 segment) aneurysm (p = 0.022), prolonged PED deployment time more than 14.5 minutes (p = 0.005), and an acute angle of the anterior genu less than 51.5 degrees (p = 0.005) were risk factors in triggering CSR. CSR may be triggered during PED deployment under local anesthesia with mild sedation. Deployment to the C2 segment aneurysm, prolonged PED deployment time, and an acute angle of the anterior genu were associated with CSR triggering.

Flow diverter device placement for cerebral aneurysm is not effective for the patient with parent artery occlusion for contralateral aneurysm.

There have been many reports on the risks of enlargement and rupture of residual aneurysms and de novo aneurysm formation in the contralateral internal carotid artery after parent artery occlusion (PAO). In the present study, we investigated the efficacy of flow diverter device placement (FDDP) for the treatment of contralateral internal carotid artery aneurysms after PAO. After 11 patients, who had bilateral large or giant internal carotid aneurysms, were treated for either side with PAO or FDDP, they underwent FDDP for residual lesions in our hospital between October 2015 and June 2018. The patients were divided into two groups, depending on the prior procedure: PAO or FDDP. The embolic state after subsequent FDDP was evaluated by angiography. The embolic state was graded using the O'Kelly Marotta scale. Patients' characteristics and the embolic state of intracranial aneurysms after FDDP were compared between the two groups. Comparing patients' characteristics between the PAO group and FDDP group, statistically significant differences were observed in laterality of the lesions and the interval between prior treatment and FDDP for residual aneurysms (p < 0.05). The embolic state at the one-year follow-up revealed that there could be significantly sufficient embolisation in the FDDP group (p < 0.05). When FDDP is performed for the contralateral lesion after PAO treatment, it is difficult to attain sufficient embolisation of intracranial aneurysms because haemodynamic load in this procedure is large compared to that in a regular FDDP.

Is Flow Diversion the Death of Simple Coiling or Stent-assisted Coiling? A Single-center Experience.

Since the introduction of endovascular methods to treat cerebral aneurysms, several technical advances have allowed a greater number of aneurysms to be treated endovascularly as opposed to open surgical clipping. These include flow diverting stents, which do not utilize coils and instead treat aneurysms by acting as an "internal bypass." We sought to investigate whether flow diversion is replacing coiling at our institution. A retrospective chart review on five years of data was conducted to investigate the possible increasing use of flow diversion devices compared to traditional simple or stent-assisted coiling. Over five years, the population revealed a trend toward an increased proportion of female patients, increased frequency of basilar tip and internal carotid artery (ICA) aneurysm location, increased hospital volume, and increased volume of patients treated by dual-trained neurosurgeons over interventional radiologists. Patients were stratified by aneurysm location and statistically significant differences were observed. Flow diversion devices were used with increasing frequency when treating aneurysms arising from the proximal internal carotid artery (Odds ratio (OR)=1.24, 95% CI: 1.02-1.50; p = 0.03), and middle cerebral artery (OR=2.60, 95% CI: 1.38-4.88; p = 0.003). Distal internal carotid artery aneurysm location came close to achieving statistical significance (OR=1.3, 95% CI: 0.99-1.72; p = 0.063). In our single center experience at Houston Methodist Hospital, flow diversion devices are being used more frequently for aneurysms arising from the proximal ICA, MCA, and likely distal ICA (though this third location barely failed to achieve statistical significance.

Editorial: What is the future of the endovascular treatment of intracranial aneurysms?

Intracranial aneurysms rapture is a common cause of mortality or morbidity worldwide. For this reason, in case of rupture, early treatment of the aneurysm is mandatory. The evaluation of unruptured intracranial aneurysms continue to increased due to the improvements in invasive and non-invasive neuroimaging. Securing of this life-threatening condition, considering all demographical and procedural factors is necessary for improving treatment results and patients outcome. The endovascular treatment has become frontline therapy of cerebral aneurysms treatment during the last 20 years, and without a doubt its recent advances shifted this boundary even further. Nowadays endovascular armamentarium continues to grow rapidly. Neuro-interventional procedures have tremendously improved their efficiency and continue to improve device’s safety. However some types of aneurysms are not really easy to treat with ordinary endovascular technique as it can result in devastating consequence, Firstly, it is not always applicable to complex aneurysms or very large neck aneurysms. Secondly, durability of the of the aneurysm occlusion is not guaranteed in all cases even after usage of the remodeling technique or regular stenting. New devices are introduced to decrease these limits. Two new innovative techniques that are increasingly used for endovacular occlusion of the complex aneurysms are flow diversion and intrasaccular flow disruption. The objective of this review is to provide a comprehensive overview of novel paradigms and latest research of flow diversion and intrasaccular flow disruption devices, its current application, limitation and future prospective. The obvious advantages of these new technologies proved progressive expansion of their utilization to the extent that they will ultimately replace standard coiling in an increasing number of cases going forward. The future of the endovascular treatment of intracranial aneurysms is bright. Fast gro-wing improvement in vascular access, treatment modalities and device delivery continue to increase number of patients with intracranial aneurysms treated with endovascular approach versus surgical clipping.

Successful Treatment of Giant Intracranial Aneurysm Using Flow-Diverter Device: First Experience in Nepal.

Giant intracranial aneurysms are defined as aneurysms that measure over 25 mm in the greatest dimension. They are rare vascular lesions that preferentially involve regions with high-velocity blood flow, such as the cavernous and supraclinoid segments of the internal carotid artery, the middle cerebral artery, the vertebrobasilar region, and the basilar apex. The treatment of giant aneurysms is challenging and associated with high rates of morbidity and mortality. Flow-diverter devices have revolutionized their treatment in recent times. We report the successful management of two patients with giant cavernous internal carotid artery aneurysms using flow-diverter devices for the first time in Nepal. Keywords: Endovascular; flow-diverter devices; giant aneurysm.

Tirofiban Protocol Protects Against Delayed Cerebral Ischemia: A Case-Series Study.

There has not been any effective prophylaxis for delayed cerebral ischemia delayed cerebral ischemia (DCI) since the introduction of nimodipine. Platelet inhibition may reduce the risk by preventing the formation of microthrombi. Tirofiban has been used as a single monotherapy bridge given its safety profile and controlled platelet inhibition. To assess the risk of DCI in aneurysmal subarachnoid hemorrhages (aSAH) patients treated with the tirofiban protocol. aSAH patients between December 2010 and March 2019 who were treated with stent assisted coiling or flow-diverting device were started on a continuous tirofiban infusion protocol and were compared with patients who underwent coil embolization without antiplatelet therapy. Safety analysis was performed to assess DCI, hemorrhagic, and ischemic events. A total of 21 patients were included in the tirofiban series and 81 in the control group. There was no statistical difference in age, gender, Hunt-Hess grade, and Fisher scale between the 2 groups except for a higher Fisher grade II in the tirofiban group. Multivariate analysis revealed tirofiban to reduce the risk of vasospasm by 72 percent (OR .28, P=.03), without affecting the risk of hemorrhagic complications (OR=0.50, P=.26). Tirofiban reduced the risk of symptomatic stroke endovascular procedure but it did not reach significance (P=.06). DCI, older age, and postprocedural symptomatic stroke were significant predictors of mortality. Tirofiban reduced the mortality risk, but this association was not statistically significant. The tirofiban protocol in aSAH patients reduces the risk of DCI without conferring additional risks. This supports previous findings were antiplatelet therapy reduced DCI in human and animal models.

Transcirculation Silk Vista Baby-assisted coiling in half-T configuration for the treatment of posterior communicating artery aneurysms associated with a fetal posterior circulation: An alternative flow diversion strategy.

Flow diverter devices have become a routine first-line option for treatment of an increasing population of intracranial aneurysms at many neurovascular centers. Despite the promising results of flow diverter stents on anterior circulation, incomplete occlusion on the presence of fetal posterior circulation has been described on several reports. Here we describe a novel technical alternative to conventional flow diversion approach for this specific subgroup of aneurysms using the low-profile flow diverter, Silk Vista Baby. The device was selectively placed into the fetal type posterior cerebral artery in half-T configuration for the treatment of a posterior communicating aneurysm using a transcirculation approach through the anterior communicating artery. This represents a useful and effective technique and should be considered when encountering the above-described situation.

Endovascular reconstruction of iatrogenic internal carotid artery injury following endonasal surgery: a systematic review.

The objective of this study is to provide an update on endovascular treatments for iatrogenic internal carotid artery (ICA) injuries following endonasal surgery. A systematic review of the literature was performed by using Medline, Cochrane library, and Scopus from 1999 to 2019. We used a combination of the MeSH terms "internal carotid artery," "iatrogenic disease," and "endovascular procedure." Twenty-six articles including 46 patients were identified for in this systematic review. The mean age of the patients was 49years (CI: ± 4.2). The most common site of ICA injury was in cavernous segment (18 patients; 39%). The most common type of iatrogenic ICA injury was a traumatic pseudoaneurysm documented in 28 patients (60%). Endoluminal reconstruction was performed using covered stents in 28 patients, the Pipeline embolization device (PED) in 13 patients, the Surpass flow diverter device in three, the SILK flow diverter in one, and one case was treated using a combined approach of a covered stent and a PED. Flow diversion and covered stents resulted in a good clinical outcome in 94% and 89% of patients, respectively. This difference did not reach statistical significance (p = 1.0). Even though this systematic review was limited due to articles of small sample sizes and considerable heterogeneity, the results indicate that flow diverting devices and covered stents are good therapeutic options for endoluminal reconstruction of iatrogenic ICA injuries following endonasal surgery.

Flow diverter devices in the treatment of posterior communicating artery aneurysms: mid-term clinical and radiological outcomes

BackgroundIn the last decade, flow diverter (FD) devices are one of the widely used endovascular methods in the treatment of intracranial aneurysms. As the frequency of its use is increasing progressively, we thought that studies concerned with the use of FD at specific locations are helpful to clarify the efficacy and safety of FD as a treatment option in cerebral aneurysms. We represent our experiences in the treatment of posterior communicating artery (PCOM) aneurysms by FD devices aiming to assess its angiographic efficacy (complete aneurysm occlusion) and its related complications. This is a retrospective study of 47 patients harboring 47 PCOM aneurysms treated with Pipeline Embolization Device (PED). Acutely ruptured and non-saccular aneurysms were excluded from the study. Short- and mid-term radiological and clinical outcomes were analyzed.ResultsProcedure-related complications were observed in five patients (two ischemic events, two transient ischemic attacks (TIA), and one ipsilateral distal hemorrhage) with no procedure-related mortality. Complete aneurysm occlusion was encountered in 87.2%. In multivariable analysis, large-sized aneurysm and incorporated vessels were an independent predictor of non-occlusion (P = 0.026 and P = 0.035 respectively). A favorable clinical outcome (modified Rankin Scale, 0–2) was observed in 45/47 patients (95.7%); the incidence of postoperative complications was an independent predictor of unfavorable clinical outcomes (P = 0.048).ConclusionPED stent provides a high occlusion rate in the treatment of PCOM aneurysms with good post-treatment clinical outcomes.

Balloon-Mounted Stents for Treatment of Refractory Flow Diverting Device Wall Malapposition.

As indications for flow diversion (FD) have expanded, new challenges in deployment of flow diverting devices (FDDs) have been encountered. We present 4 cases with aneurysms in which deployment of FDDs were complicated by device malapposition and compromised opening in regions of parent vessel stenosis. In all 4 cases, a balloon-mounted stent was ultimately deployed within the FDD. To describe the use of balloon-mounted stents (BMS) within FDDs for correction of flow-limiting stenosis and device malapposition. Patients undergoing FD for treatment of aneurysms complicated by refractory flow-limiting stenosis were identified through multi-center retrospective review. Those cases requiring use of BMS were identified. Further investigation in one of the cases was performed with a simulated pulsatile blood flow model. After attempts to perform balloon angioplasty proved unsuccessful, BMS deployment successfully opened the stenotic parent artery and improved FDD wall apposition in all 4 cases. Simulated pulsatile blood flow modeling confirmed improvements in the distribution of velocity, wall shear stress, oscillatory shear index, and flow pattern structure after stent deployment. One case was complicated by asymptomatic in-stent thrombosis. In cases of FDD deployment complicated by flow-limiting stenosis refractory to conventional techniques, a BMS deployed within the FD can provide radial support to open both the stenotic device and parent artery. Resulting improvements in device wall apposition may portend greater long-term efficacy of FD. In-stent occlusion can occur and may reflect a thrombogenic interaction between the devices.

P64 flow diverter: Results in 108 patients from a single center.

Flow diverters are increasingly used to treat intracranial aneurysms. We report the safety and efficacy of the p64 flow diverter, a resheathable and detachable device for intracranial aneurysms. We retrospectively reviewed 108 patients with 109 aneurysms treated with the p64 between March 2014 and July 2019. There were 87 women and 21 men, mean age 57 years. Of 109 aneurysms, 74 were discovered incidentally, 12 were symptomatic, 18 were previously treated, and five were ruptured dissection aneurysms. A total of 10 aneurysms were located in the posterior circulation. The mean aneurysm or remnant size was 8.1 mm. Hemorrhage by perforation with the distal guidewire occurred in two patients with permanent neurological deficits in one. In one patient, acute in-stent occlusion caused infarction with a permanent deficit. Permanent morbidity was 1.9% (2 of 108, 95%CI 0.1-6.9%); there was no mortality. During follow-up, three in-stent occlusions occurred, all asymptomatic. There were no delayed hemorrhagic complications. At six months, 77 of 96 aneurysms (80.2%) were completely occluded, and at last follow-up, this increased to 93 of 96 aneurysms (96.9%). In-stent stenosis at any degree occurred in 11 patients, progressing to asymptomatic complete occlusion in one. In the other patients, stenosis resolved or improved at further follow-up. The p64 offers an effective and safe treatment option. Aneurysm occlusion rate was 97% at last follow-up, mostly achieved with a single device. There were no delayed hemorrhagic complications. Delayed in-stent stenosis infrequently progresses to occlusion but remains a matter of concern.

Antiplatelet Drugs for Neurointerventions: Part1 Clinical Pharmacology.

The development of endovascular treatment for intracranial aneurysms has established new techniques such as balloon and stent-assistance, flow diversion and endosaccular occlusion devices. Antiplatelet treatment is an important aspect to reduce risk of thrombus formation on microcatheters and implanted devices when utilizing these methods. It is particularly relevant for flow diverting stents to prevent early and late stent thrombosis. Consideration of platelet physiology and appropriate selection of antiplatelet medication is important as platelet dysfunction drives many of the pathological processes and complications of neurointerventional procedures. Part one of this review focuses on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence-based therapeutic regimens.

Radiation dose and fluoroscopy time of modern endovascular treatment techniques in patients with saccular unruptured intracranial aneurysms

ObjectivesModern endovascular treatment of unruptured intracranial aneurysms (UIAs) demands for observance of diagnostic reference levels (DRLs). The national DRL (250 Gy cm2) is only defined for coiling. We provide dosimetric data for the following procedures: coiling, flow diverter (FD), Woven EndoBridge (WEB), combined techniques.MethodsA retrospective single-centre study of saccular UIAs treated between 2015 and 2019. Regarding dosimetric analysis, the parameters dose area product (DAP) and fluoroscopy time were investigated for the following variables: endovascular technique, aneurysm location, DSA protocol, aneurysm size, and patient age.ResultsEighty-seven patients (59 females, mean age 54 years) were included. Total mean and median DAP (Gy cm2) were 119 ± 73 (89–149) and 94 (73; 130) for coiling, 128 ± 53 (106–151) and 134 (80; 176) for FD, 128 ± 56 (102–153) and 118 (90; 176) for WEB, and 165 ± 102 (110–219) and 131 (98; 209) for combined techniques (p > .05). Regarding the aneurysm location, neither DAP nor fluoroscopy time was significantly different (p > .05). The lowest and highest fluoroscopy times were recorded for WEB and combined techniques, respectively (median 26 and 94 min; p < .001). A low-dose protocol yielded a 43% reduction of DAP (p < .001). Significantly positive correlations were found between DAP and both aneurysm size (r = .320, p = .003) and patient age (r = .214, p = .046).ConclusionsThis UIA study establishes novel local DRLs for modern endovascular techniques such as FD and WEB. A low-dose protocol yielded a significant reduction of radiation dose.Key Points• This paper establishes local diagnostic reference levels for modern endovascular treatment techniques of unruptured intracranial aneurysms, including flow diverter stenting and Woven EndoBridge device.• Dose area product was not significantly different between endovascular techniques and aneurysm locations, but associated with aneurysm size and patient age.• A low-dose protocol yielded a significant reduction of dose area product and is particularly useful when applying materials with a high radiopacity (e.g. platinum coils).

Retreatment strategies for recurrent and residual aneurysms after treatment with flow-diverter devices.

The management of residual or persistent intracranial aneurysms after flow-diversion therapy is not well defined in the literature. In this multicentric study, we report clinical and angiographic outcomes of 11 patients that underwent retreatment for 12 aneurysms initially treated with flow-diverter stents. The median patient age was 53years. Aneurysms (median size, 7.3mm) were located at the internal carotid artery in 9 cases, and at the posterior circulation in 3. Treatment strategies, complications, and angiographic outcome were retrospectively assessed. Retreatment was feasible in all cases and performed by overlapping flow-diverter implantation. Overall, 12 side vessels were covered during retreatment, whereof 10 (83.3%) remained patent until mid-term follow-up. There were no further technical or symptomatic complications and no treatment-related morbidity. Angiographic follow-up (median, 17months) showed improved aneurysm occlusion in all patients. Complete or near-complete aneurysm occlusion was achieved in 11 aneurysms (91.7%). Required retreatment after failed flow-diversion therapy can be performed with adequate safety and efficacy by placement of additional flow-diverter stents.

In Reply: The Safety and Efficacy of Continuous Tirofiban as a Monoantiplatelet Therapy in the Management of Ruptured Aneurysms Treated Using Stent-Assisted Coiling or Flow Diversion and Requiring Ventricular Drainage.

Background Hemorrhagic complications are a major concern for aneurysmal subarachnoid hemorrhage patients treated with stenting or stent-assisted coiling and undergoing additional procedures such as shunting, ventriculostomy placement, and craniotomies/craniectomies. Objective To assess the safety and efficacy of using a continuous infusion of tirofiban as a monoantiplatelet therapy in the management of ruptured aneurysms in the setting of either stent-assisted coiling (SAC) or flow diversion devices (FDD) in patients requiring either an external ventricular drain (EVD) or ventriculoperitoneal shunt (VPS). Methods Aneurysmal subarachnoid hemorrhage (aSAH) patients between July 2017 and September 2018 who were treated with SAC or FDD were started on a continuous tirofiban infusion protocol (0.10 μg/kg/min) with no preceding loading dose as a monoantiplatelet therapy. Safety analysis was performed retrospectively to assess the complication rate, hemorrhagic rate, and rate of ischemic events. There were no hemorrhages related to the VPS surgery. Results Nineteen subjects were included in the series. The patients received a total of 25 procedures that included 19 EVDs and 6 VPSs. Two patients (8.3%) developed small asymptomatic track hemorrhages after EVD placement. One patient developed a large retroperitoneal hemorrhage due to renal artery branch injury during procedure, and another patient developed an idiosyncratic transient thrombocytopenia which resolved after stopping the medication. One patient (4%) developed a transient ischemic attack, which resolved after a bolus of tirofiban. Conclusion Our study suggests that long-term use of intravenous tirofiban monotherapy in aSAH subjects for endovascular SAC or FDD is safe in the perioperative setting.

Preliminary study of 3D T1-SPACE combined with 3D-TOF MRA in the follow-up for the intracranial aneurysm treated with Pipeline Flex embolization device

Objective To evaluate the preliminary application of three dimensional T1-weighted sampling perfection with application-optimized contrasts by using different flip angle evolutions (3D T1-SPACE) combined with three dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) in the follow-up for the intracranial aneurysm treated with Pipeline Flex embolization device (FD). Methods A total of 20 patients with 25 intracranial aneurysms were treated with Pipeline Flex embolization at the Department of Cerebrovascular Intervention, People′s Hospital of Zhengzhou University, Henan Provincial People′s Hospital from September 2018 to April 2019 and were prospectively enrolled. All patients were followed up with 3.0T 3D T1-SPACE sequence, 3D-TOF MRA and digital subtraction angiography (DSA) examination. O′kelly-Marotta (OKM) grading scale was used to evaluate the aneurysm residual and the four-point scale was used to evaluate the in-stent lumen visibility. Results The follow-up period for all patients was 6.0±0.8 months (range: 4-7 months). The OKM scale of all aneurysms evaluated by DSA indicated 18 patients with grade D, 2 patients with grade C and 5 patients with grade B. For aneurysms evaluated by 3D-TOF MRA combined with source image, the results showed grade D in 19 patients, C in 2 and B in 4. The overall concordance rate between 3D-TOF MRA and DSA was 88.0% (22/25). Taking DSA as standard(grade 4), the four-point scale of in-stent lumen of all 20 patients treated with 23 Pipeline Flex embolization devices and evaluated by 3D-TOF MRA indicated grade 3 in 16 stents, 2 in 6 and 1 in 1. No one showed the same as DSA results. However, grade 4 was revealed in 21 stents and 3 in 2 based on the evaluation by 3D T1-SPACE. The total concordance rate of 3D T1-SPACE and DSA was 91.3% (21/23). Conclusions Preliminary observations show that compared with DSA, 3D-TOF MRA could better assess the aneurysmal occlusion after FD treatment of intracranial aneurysms. The 3D T1-SPACE sequence shows the in-stent lumen clearly. The combination of the two sequences can be used for follow-up after FD treatment of intracranial aneurysms. Key words: Intracranial aneurysm; Magnetic resonance imaging; Follow-up study; Flow diverter device