Endovascular treatment of complex intracranial aneurysms by pipeline flow-diverter embolization device: a single-center experience

Arterial Bypass in the Treatment of Complex Middle Cerebral Artery Aneurysms: Lessons Learned from Forty Patients

OBJECTIVE

Complex middle cerebral artery (MCA) aneurysms incorporating parent or branching vessels are often not amenable to standard microsurgical clipping or endovascular embolization treatments. We aim to discuss the treatment of such aneurysms via a combination of surgical revascularization and aneurysm exclusion based on our institutional experience.

METHODS

Thirty-four patients with complex MCA aneurysms were treated with bypass and aneurysm occlusion, 5 with surgical clipping or wrapping only, and 1 with aneurysm excision and primary reanastomosis. Bypasses included superficial temporal artery (STA)-MCA, double-barrel STA-MCA, occipital artery-MCA, and external carotid artery-MCA. After bypass, aneurysms were treated by surgical clipping, Hunterian ligation, trapping, or coil embolization.

RESULTS

The average age at diagnosis was 46 years. Of the aneurysms, 67% were large and most involved the MCA bifurcation. Most bypasses performed were STA-MCA bypasses, 12 of which were double-barrel. There were 2 wound-healing complications. All but 2 of the aneurysms treated showed complete occlusion at the last follow-up. There were 3 hemorrhagic complications, 3 graft thromboses, and 4 ischemic insults. The mean follow-up was 73 months. Of patients, 83% reported stable or improved symptoms from presentation and 73% reported a functional status (Glasgow Outcome Scale score 4 or 5) at the latest available follow-up.

CONCLUSIONS

Cerebral revascularization by bypass followed by aneurysm or parent artery occlusion is an effective treatment option for complex MCA aneurysms that cannot be safely treated by standard microsurgical or endovascular techniques. Double-barrel bypass consisting of 2 STA branches to 2 MCA branches yields adequate flow replacement in most cases.

Flow Diversion for the Treatment of Intracranial Aneurysms in a Peruvian Cohort: Experiences from a Limited-Resource Setting and Barriers to Implementation

BACKGROUND

Stenting with flow diverter devices (FDDs) has increasingly emerged as a treatment for intracranial aneurysms. The use of FDDs in the developing world has not been described.

METHODS

A retrospective review was performed of a cohort of patients who underwent flow diversion at 4 tertiary-care centers in Lima, Peru between January 2017 and June 2021. Demographics, clinical features, and aneurysm morphology were evaluated. Clinical outcomes were observed 3 months after discharge and occlusion rates were assessed 12 months after treatment.

RESULTS

Sixty-nine patients (mean age, 46 ±14.5 years; 17% female) were treated with FDDs; 4% (n = 3) of the treated aneurysms were ruptured. Most aneurysms were saccular (n = 65; 94%), <10 mm in maximum size (n = 60; 87%), and located in the anterior circulation (n = 67; 97%). Minor complications, such as groin hematoma, occurred in 7 cases. No serious complications or deaths occurred. Patients' functional status was excellent (modified Rankin Scale score 0-1) in 99% (n = 66) at discharge and 100% (n = 67) at 3 months. Although some patients were lost to follow-up, complete occlusion was seen in 76% (n = 31) of 41 treated patients at 12 months.

CONCLUSIONS

We report the largest multicenter experience of FDDs for cerebral aneurysm treatment in Peru, with reasonable outcomes that are comparable to other settings despite various challenges, suboptimal circumstances, and lack of resources.

Management of Complex Cerebral Aneurysms

BACKGROUND

Complex intracranial aneurysms (CIAs) are challenging pathologies to treat. Characteristics making an aneurysm complex include dimension, history of previous treatment, location, absence of collateral circulation, intraluminal thrombosis, and calcification of the wall. The goal of the therapeutic process is to exclude the malformation from the cerebral circulation and both endovascular and surgical treatments are valid procedures.

METHODS

Between 1990 and 2020, 170 CIAs were treated at our institution (33 ruptured, 137 unruptured). They were 3 prepetrous segment of the internal carotid artery (ICA), 14 purely intracavernous sinus, 27 intracavernous with subarachnoid extension, 60 paraclinoid, 4 ICA bifurcation, 15 anterior communicating artery, 24 middle cerebral artery, and 23 in the posterior circulation. All the patients underwent neuroradiologic examinations and images were evaluated by the neurosurgical and interventional radiologist team. Endovascular treatment was considered as the treatment of choice. Alternative treatment was surgical clipping; revascularization procedures were performed when neither endovascular treatment nor direct clipping were possible.

RESULTS

Of 170 patients, 45 underwent endovascular treatment, 77 surgical clipping, and 55 revascularization procedures. In the unruptured group, 12 patients died, 22 reported major complications, 3 had minor complications, and 101 had an uneventful postoperative course. In the ruptured group, 9 patients died, 10 had minor complications, 1 minor complication, and 13 had a complete recovery.

CONCLUSIONS

Endovascular treatment should represent the treatment of choice for CIAs. Alternative treatments include direct surgical clipping and revascularization. Overall, the correct identification of the therapeutic process guarantees a good clinical outcome.

Complex cerebral aneurysms: intra-luminal reconstruction using Pipeline flow-diverting stent and the obliteration mechanism

OBJECTIVES

Patients with complex cerebral aneurysms can now be treated intravascularly with the help of flow-diverting stents. The primary purpose of this article is to document the clinical and angiographic outcomes in 80 patients who were treated with the Pipeline flow-diverting stent (PFS; Medtronic, Dublin, Ireland) and the obliteration mechanism was discussed.

PATIENTS AND METHODS

Between October 2015 and October 2019, 80 patients with 90 complex (undefined neck, large/giant, blood blister-like, and recurrent side-wall) cerebral aneurysms treated with the PFS were retrospectively reviewed. Forty-five patients were women and 35 were men, with a mean age of 52 years. Large or giant aneurysms were defined as 10 mm or larger and small aneurysms were defined as less than 10 mm at the largest diameter measured on angiogram.

RESULTS

Forty-one aneurysms (45.6%) were large or giant, 41 (45.6%) were small, four (4.4%) were recurrent side-wall aneurysms and four (4.4%) were blood blister-like aneurysms. In total, 87 PFSs were placed in 80 patients with 90 aneurysms. In six patients, coexisting proximal stenosis of parent artery was also covered with PFS without balloon angioplasty. Adjunct coils were placed in 31 aneurysms (34%). One patient died of intracerebral hematoma after thrombolysis. There was one intrastent occlusion at six-month follow-up without any symptoms. The morbidity and the mortality rate is 0% and 1.3% (95% confidence interval (CI), 0%-3.7%). Control angiography was available in 74 (92.5%) patients with 83 aneurysms, and the aneurysm occlusion rate was 98.8% (95% CI, 96.5%-100%) in 6 to 12 months.

CONCLUSION

For wide-necked saccular, large/giant, blood blister-like aneurysms and recurrent side-wall aneurysms, PFS is a valid and safe treatment option.

Usefulness of Silent MR Angiography for Intracranial Aneurysms Treated with a Flow-Diverter Device

BACKGROUND AND PURPOSE

The flow-diverter device has been established as a treatment procedure for large unruptured intracranial aneurysms. The purpose of this study was to compare the usefulness of Silent MR angiography and time-of-flight MRA to assess the parent artery and the embolization state of the aneurysm after a flow-diverter placement.

MATERIALS AND METHODS

Seventy-eight large, unruptured internal carotid aneurysms in 78 patients were the subjects of this study. After 6 months of treatment, they underwent follow-up digital subtraction angiography, Silent MRA, and TOF-MRA, performed simultaneously. All images were independently reviewed by 2 neurosurgeons and 1 radiologist and rated on a 4-point scale from 1 (not visible) to 4 (excellent) to evaluate the parent artery. The aneurysmal embolization status was assessed with 2 ratings: complete or incomplete occlusion.

RESULTS

The mean scores of Silent MRA and TOF-MRA regarding the parent artery were 3.18 ± 0.72 and 2.31 ± 0.86, respectively, showing a significantly better score with Silent MRA (P < .01). In the assessment of the embolization of aneurysms on Silent MRA and TOF-MRA compared with DSA, the percentages of agreement were 91.0% and 80.8%, respectively.

CONCLUSIONS

Silent MRA is superior for visualizing blood flow images inside flow-diverter devices compared with TOF-MRA. Furthermore, Silent MRA enables the assessment of aneurysmal embolization status. Silent MRA is useful for assessing the status of large and giant unruptured internal carotid aneurysms after flow-diverter placement.

Thrombogenicity assessment of Pipeline Flex, Pipeline Shield, and FRED flow diverters in an in vitro human blood physiological flow loop model

Endovascular treatment of intracranial aneurysms with endoluminal flow diverters (single or multiple) has proven to be clinically safe and effective, but is associated with a risk of thromboembolic complications. Recently, a novel biomimetic surface modification with covalently bound phosphorylcholine (Shield Technology™) has shown to reduce the material thrombogenicity of the Pipeline flow diverter. Thrombogenicity of Pipeline Flex, Pipeline Shield, and Flow Redirection Endoluminal Device (FRED) in the presence of human blood under physiological flow conditions—in addition to relative increase in thrombogenicity with multiple devices—remains unknown and was investigated here. Thrombin generation (mean ± SD; μg/mL; thrombin–antithrombin complex or TAT) was measured as FRED (30.3 ± 2.9), Pipeline (13.9 ± 4.4), Pipeline Shield (0.4 ± 0.3), and negative control (no device; 0.1 ± 0.0). Platelet activation (mean ± SD; IU/μL; beta‐thromboglobulin or βTG) was measured as FRED (148 ± 45), Pipeline (92.8 ± 41), Pipeline Shield (16.2 ± 3.5), and negative control (2.70 ± 0.16). FRED was significantly more thrombogenic than Pipeline and Pipeline Shield (p < 0.05) for TAT. Additionally, Pipeline Shield had significantly lower TAT and βTG than the other devices tested (p < 0.05) and these were comparable to the negative control (p > 0.05). TAT and βTG scaled proportionately with multiple Pipeline devices (N = 6) but was unaffected by multiple Pipeline Shield (N = 6) devices—the latter being statistically similar to negative control (p > 0.05). © 2018 The Authors. Journal Of Biomedical Materials Research Part A Published By Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3195–3202, 2018.

Antiplatelet therapy and the risk of ischemic and hemorrhagic complications associated with Pipeline embolization of cerebral aneurysms: a systematic review and pooled analysis

BACKGROUND

Pipeline embolization devices (PEDs) are increasingly used in the treatment of cerebral aneurysms. Yet, major ischemic or hemorrhagic complications after PED treatment associated with antiplatelet regimens are not well-established.

OBJECTIVE

To investigate the risk of ischemic and hemorrhagic complications associated with common antiplatelet regimens following PED treatment, and to examine whether platelet function testing (PFT) is associated with a lower risk of these complications.

METHODS

We searched Medline, Embase, and Cochrane from 2009 to 2017. Twenty-nine studies were included that had reported a uniform antiplatelet regimen protocol and had provided data on major ischemic and hemorrhagic complications following PED treatment. Random-effect meta-analysis was used to pool overall ischemic and hemorrhagic event rates across studies. The rate of these complications with respect to the antithrombotic regimen and PFT was assessed by χ² proportional tests.

RESULTS

Overall, 2002 patients (age 55.9 years, 76% female) were included. A low-dose acetylsalicylic acid (ASA) regimen before and after PED treatment was associated with a higher rate of late ischemic complications than with high-dose ASA therapy (2.62 (95% CI 1.46 to 4.69) and 2.56 (1.41 to 4.64), respectively). Duration of post-procedure clopidogrel therapy <6 months was associated with greater rates of ischemic complications (1.56, 95% CI 1.11 to 2.20) than a clopidogrel regimen of ≥6 months. Performing PFT before PED treatment was not associated with the risk of ischemic complications (1.27, 95% CI 0.77 to 2.10).

CONCLUSION

High-dose ASA therapy and clopidogrel treatment for at least 6 months were associated with a reduced incidence of ischemic events, without affecting the risk of hemorrhagic events.

Intracranial Aneurysms Treated by Flow-Diverting Stents: Long-Term Follow-Up with Contrast-Enhanced Magnetic Resonance Angiography

PURPOSE

Long-term data on aneurysm treatment with flow-diverting stents are still sparse, and follow-up protocols differ widely between institutions. We present long-term results, with a focus on the usefulness of contrast-enhanced MR angiography (ceMRA).

MATERIALS AND METHODS

Interventions and follow-up imaging of patients with aneurysms treated by flow-diverting stents ("Pipeline," "Silk" and "FRED" models) without additional coiling were analyzed. All MRI scans included dedicated two-phase ceMRA. Aneurysm occlusion rates, size of the aneurysmal sac and complications were evaluated on MRI and digital subtraction angiography (DSA), where available. The ability of ceMRA to depict aneurysm occlusion and stent patency was graded on a three-point scale.

RESULTS

Twenty-five patients with 102 MRI scans were included. The median duration of follow-up was 830 days. Aneurysm occlusion rates were 52% at 3 months (10 of 19 patients), 72% at 6 months (18/25) and 84% overall (21/25). Shrinkage of the aneurysmal sac was found in 19 patients (76%) and in 12 cases to <50% of the original size (48%). CeMRA assessability of aneurysmal occlusion was graded as good in all cases. When compared to DSA (18 cases), ceMRA had a sensitivity of 100% and specificity of 91% regarding aneurysm remnant detection. Assessability of the stent lumen varied and was limited in most cases.

CONCLUSIONS

Flow-diverter treatment achieves high occlusion rates and can cause major aneurysm shrinkage. CeMRA is highly valuable regarding imaging of the aneurysmal sac. There are limitations regarding the assessability of the stent lumen on ceMRA.

LEVEL OF EVIDENCE

Level 4, Case Series.

Inadvertent Complication of a Pipeline Embolization Device for Treatment with Vertebral Artery Dissecting Aneurysm : Distal Tip Fracture of Delivery Wire

Use of the Pipeline embolization device (PED) has increased based on studies about its safety and effectiveness, and new reports that describe peri- or postprocedural complications are now emerging. We report a rare periprocedural device-related complication that occurred during endovascular treatment with the pipeline embolization device for a dissecting aneurysm on the vertebral artery. A 55-year old woman was admitted due to left medullary infarction, and angiography showed a fusiform dilatation in the left vertebral artery that was suspicious for dissecting aneurysm. Endovascular treatment with PED was planned. Under general anesthesia, the procedure was performed without significant problems and a PED was deployed in an appropriate position. However, in the final step of the procedure, the distal tip of the PED delivery wire became engaged within a small branch of the posterior cerebral artery and fractured. Fortunately, imaging studies after the procedure revealed neither hemorrhagic nor ischemic stroke, and the patient recovered without neurological morbidities except initial symptoms.