Tuberothalamic artery infarctions following coil embolization of ruptured posterior communicating artery aneurysms with posterior communicating artery sacrifice

A vertebrobasilar junction aneurysm successfully treated with a combination of surgical clipping and flow diverter placement based on the results of computational fluid dynamics analysis: illustrative case

BACKGROUND

The treatment of vertebrobasilar junction (VBJ) aneurysms is challenging. Although flow diverters (FDs) are a possible treatment option, geometrical conditions hinder intervention. VBJ aneurysms possess dual inflow vessels from the bilateral vertebral arteries (VAs), one of which is ideally occluded prior to FD treatment. However, it remains unclear which VA should be occluded.

OBSERVATIONS

A 75-year-old male with a growing VBJ complex aneurysm exhibiting invagination toward the brainstem and causing perifocal edema required intervention. Preoperative computational fluid dynamics (CFD) analysis demonstrated that left VA occlusion would result in more stagnant flow and less impingement of flow than right VA occlusion. According to the simulated strategy, surgical clipping of the left VA just proximal to the aneurysm was performed, followed by FD placement from the basilar artery trunk to the right VA. The patient demonstrated tolerance of the VA occlusion, and follow-up computed tomography angiography at 18 months after FD treatment confirmed the disappearance of the aneurysm.

LESSONS

Preoperative flow dynamics simulations using CFD analysis can reveal an optimal treatment strategy involving a hybrid surgery that combines FD placement and direct surgical occlusion for a VBJ complex aneurysm.

The Rationale Behind Transcirculation Neuroendovascular Interventions: Literature Review Through a Case-Series Approach

BACKGROUND

With the development of advanced endovascular techniques and materials, neurointerventionalists can perform challenging and complex cases that were previously difficult to perform. Transcirculation approaches could be a useful tool used in complicated cases, providing access to the target vessel, through the contralateral or opposite circulation, when anterograde access is difficult or nonachievable.

OBJECTIVE

To retrospectively review cerebrovascular interventions performed through a transcirculation approach performed by staff at our Institution.

METHODS

English-language studies, published until August 2022, reporting transcirculation interventions in the cerebrovascular circulation were retrospectively collected. Type of intervention, number of cases, rationale, and complications were analyzed. Furthermore, similar cases performed by staff currently at our institution were also reviewed and described.

RESULTS

Including our cases, a total of 273 transcirculation treatment approaches have been reported. Intracranial aneurysm embolization, stroke thrombectomies, intra-arterial ophthalmic chemotherapy, arteriovenous malformationss, arteriovenous fistulas embolizations, and intracranial angioplasty and stenting are common indications. Reason for using a retrograde approach were stent/balloon-assisted coiling of wide neck aneurysm in 116 cases, difficult angulation of branch in 91 cases, occlusion of parent vessel in 55 cases, and bailout/other in 11 cases.

CONCLUSION

Transcirculation approaches can be considered for cases where conventional anterograde treatment options are not feasible or as a bailout strategy in failed or complicated treatment attempts. They represent a strategy to consider when facing challenging cases, and if performed by experienced and dedicated neurointerventionalists, they can represent a safe alternative.

Duplicated fetal posterior cerebral artery in a patient with a ruptured fetal posterior cerebral artery aneurysm: a cerebrovascular variant

BACKGROUND

The most common neurovascular variant is the fetal posterior cerebral artery (FPCA), in which the P1 branch is absent or hypoplastic, and the majority of P2 supply is derived from the anterior circulation. While there are reports of hyperplastic anterior choroidal arteries (AChA) with supply to the temporo-occipital and calcarine regions, no reports of a duplicated FPCA exist.

METHODS

This case report describes a patient with a ruptured right FPCA aneurysm. Digital subtraction angiogram (DSA) revealed an artery with origin distal to the FPCA associated with the aneurysm. This was not consistent with a typical AChA. The FPCA associated with the aneurysm had the typical origin, course, and supply of a FPCA. The distal FPCA had a similar course of a typical FPCA with significant supply to the typical PCA territory. The patient underwent successful clipping of the aneurysm, and the duplicated FPCA was identified during the craniotomy.

RESULTS

The features of this duplicate FPCA, which has not been previously described, are discussed in comparison to another variant, the hyperplastic, anomalous AChA. The artery described in this report does not fit the typical criteria of this AChA variant. Therefore, the authors outline this variant as a duplicated FPCA.

CONCLUSION

Recognition of variant cerebrovascular anatomy is vital to neurosurgeons and interventional neuroradiology specialists. FPCA aneurysms require special management considerations and are often more challenging to treat. This report discusses a duplicated FPCA. To our knowledge, this is the first description of this variant. A duplicated FPCA carries important management considerations in the management of neurovascular pathology.

Transvenous embolization of a ruptured thalamic arteriovenous malformation supplied by the tuberothalamic artery

Background

Basal ganglia and thalamic arteriovenous malformations (AVM) represent 10% of all AVM. They are associated with a high rate of morbidity and mortality due to their high hemorrhagic presentation and eloquence. Radiosurgery has been the first line treatment, whereas surgical removal and endovascular therapy are possible in selected cases. Deep AVM with small niduses and a single draining vein can achieve cure with embolization.

Case Description

A 10-year-old boy with sudden headache and vomiting underwent a brain computed tomography scan that showed a right thalamic hematoma. Cerebral angiography revealed a small ruptured right anteromedial thalamic AVM with a single feeder arising from the tuberothalamic artery and a single drainage to the superior thalamic vein. Transvenous approach using precipitating hydrophobic injectable liquid 25%^® achieved a complete obliteration of the lesion in a single-session. He was discharged home without neurological sequelae and maintained clinically intact at follow-up.

Conclusion

Transvenous embolization of deep-located AVM as a primary treatment is curative in selected cases, with complication rates comparable to other therapeutic strategies.

Cerebral ischemia after treatment of posterior communicating artery aneurysms: clipping versus coiling

Objection

This study aimed to compare the incidence of cerebral ischemia and outcomes between surgical clipping and endovascular coiling in patients with posterior communicating artery (PCoA) aneurysms.

Methods

Clinical and imaging data of patients with at least one PCoA aneurysm who underwent surgical clipping or endovascular coiling in our institution from January 2017 to December 2019 were analyzed.

Results

Three hundred sixty-three aneurysms in 353 patients were included for analysis, 257 in the clipping group, and 106 in the coiling group. The groups did not differ in terms of baseline characteristics. The incidence of postoperative cerebral ischemia (23.35% vs. 11.32%, p = 0.029) was higher in the clipping group. The proportion of patients with a modified Rankin Scale score ≥ 2 was significantly higher in the clipping group at discharge (35.80% vs. 15.09%; p < 0.05) but not six months after discharge (15.56% vs. 8.49%; p > 0.05). In the clipping group, the mean age was significantly higher in patients who developed cerebral ischemia than in those who did not. In the coiling group, modified Fisher grade and incidence of fetal PCoA were significantly higher in patients who developed ischemia.

Conclusion

The incidence of postoperative cerebral ischemia was higher after PCoA aneurysm clipping than after coiling. The causes and characteristics of postoperative cerebral ischemia after PCoA clipping and coiling are different; therefore, treatment should be selected accordingly.

Horizontal stenting via retrograde route for recurrent ruptured posterior communicating artery aneurysm after clipping: A case report and literature review

Treatment of recurrent ruptured aneurysms incorporating a branch vessel arising from the dome is challenging. Here, we attempted horizontal stent-assisted coil embolization via a retrograde route from the contralateral internal carotid artery to treat a small ruptured posterior communicating artery aneurysm incorporating a fetal variant posterior cerebral artery after clipping.

Premammillary artery infarction after microsurgical clipping of unruptured posterior communicating artery aneurysm: risk factors and surgical and anatomical considerations

Posterior communicating artery (PCoA) aneurysm is common and sometimes requires microsurgery; however, as data on premammillary artery (PMA) infarction after clipping is scarce, we retrospectively reviewed cases of post-clipping PMA infarction to analyze incidence, independent risk factors of infarction, and anatomical considerations. Data from 569 consecutive patients who underwent microsurgical clipping for unruptured PCoA aneurysm between January 2008 and December 2020 were included. Patients were categorized into the normal or the PMA infarction group. Statistical analyses and comparisons between the two groups were used to determine the influence of various factors. The normal group included 515 patients while the PMA infarction group had 31. The mean length of hospital stay was significantly longer in the PMA infarction group (10.3 ± 9.1 days) than in the normal group (6.5 ± 6.4 days; p < 0.0001). The distribution of Glasgow Outcome Scale at discharge was significantly different between the two groups (p ≤ 0.0001) but was not so at 6 months after discharge (p = 0.0568). Multivariate logistic regression analysis identified aneurysm size (odds ratio [OR], 1.194; 95% confidence interval [CI], 1.08-1.32; p = 0.0005) and medial direction of aneurysm (OR, 4.615; 95% CI, 1.224-17.406; p = 0.0239) as independent risk factors of post-clipping PMA infarction. Surgeons must beware of PMA infarction after clipping of large aneurysms that are medial in direction. Intraoperative verification of the patency of the PCoA and the PMA from various angles using various intraoperative methods can reduce morbidity due to PMA infarction.

Super-selective balloon test occlusion with electrophysiological monitoring to occlude angiographically invisible posterior communicating artery perforators with unruptured aneurysm

Balloon test occlusion (BTO) can predict the ischemic complication risk associated with arterial occlusion. We present a case of an unruptured, broad-necked internal carotid artery-posterior communicating artery (PcomA) aneurysm that was successfully embolized after super-selective BTO of fetal PcomA with electrophysiological monitoring. The proximal portion of the PcomA was internally occluded without causing major neurological deficits, although we observed a small new infarction in the ipsilateral anterior thalamus postoperatively. We recognized small perforators arising from the proximal PcomA during a previous clipping surgery. Super-selective BTO with electrophysiological monitoring could be useful for functional preservation after infarction from angiographically invisible perforators.

A Case of Coil Embolization with Crossing Y-Configuration Stenting for a Recurrent IC-PC Aneurysm after Clipping

Objective

We report a case in which coil embolization using crossing Y-configuration stenting was effective for an internal carotid-posterior communicating artery (IC-PC) aneurysm with repeated recurrence after clipping.

Case Presentation

The patient was a 57-year-old woman. Nine months after undergoing clipping for a ruptured right IC-PC aneurysm at 55 years of age, she developed a second subarachnoid hemorrhage (SAH) due to recurrence of the aneurysm and underwent clipping at the same site. A third SAH due to rupture of the left IC-PC aneurysm developed 1.5 years after the second clipping. Simultaneously, recurrence of a right IC-PC aneurysm was noted and she was referred to our department. The recurrent right IC-PC aneurysm was considered to have originated from the distal to the initial neck. It was 7 mm in size and had an irregularly shaped wide neck. As it was assumed that there would be marked adhesion due to repeated surgery, we decided to treat the aneurysm by coil embolization instead of direct surgery. Although the aneurysm neck partially involved the posterior communicating artery (Pcom), tight packing with a minimal residual neck was required. Therefore, crossing Y-configuration stenting was deployed on the internal carotid artery and Pcom using two Neuroform Atlas stents, and coil embolization was performed by the jail technique. The recurrent aneurysm was obliterated. There were no deficits or thrombotic complications after surgery. On DSA follow-up, no compaction or recurrence was observed, and the Pcom was well visualized one year later.

Conclusion

Coil embolization by crossing Y-configuration stenting is a viable treatment option for a recurrent IC-PC wide neck aneurysm.

Higher oscillatory shear index is related to aneurysm recanalization after coil embolization in posterior communicating artery aneurysms

BACKGROUND

The recurrence rate of posterior communicating artery (Pcom) aneurysms after endovascular treatment (EVT) is higher than that for aneurysms located in other sites. However, it is still unclear what mechanisms are responsible for the recanalization of cerebral aneurysms. In this investigation, we compared hemodynamic factors related with recanalization of Pcom aneurysms treated by endoluminal coiling using computational fluid dynamics (CFD) with high-resolution three-dimensional digital subtraction angiography images.

METHODS

Twenty patients were enrolled. A double-sinogram acquisition was performed with and without contrast injection after coil embolization to get true blood vessel lumen by relatively complementing the first sinogram with the second. Adaptive Cartesian meshing was performed to produce vascular wall objects for CFD simulation. The boundary condition for inlet (ICA) was set for dynamic velocity according to the cardiac cycle (0.8 s). Hemodynamic parameters were recorded at two specific points (branching point of Pcom and residual sac). The peak pressure, peak WSS, and oscillatory shear index (OSI) were recorded and analyzed.

RESULTS

The median age was 61.0 years, and 18 patients (90%) were female. During a median follow-up of 12 months, seven (35%) treated aneurysms showed recanalization. The median aneurysm volume was significantly higher, and aneurysm height and neck sizes were significantly longer in the recanalization group than those in the stable group. At the branching point of the Pcom, the peak pressure, peak WSS, or OSI did not significantly differ between the two groups. The only statistically significant hemodynamic parameter related with recanalization was the OSI at the aneurysm point. Multivariate logistic regression showed that with an increase of 0.01 OSI at the aneurysm point, the odds ratio for the aneurysm recanalization was 1.19.

CONCLUSIONS

A higher OSI is related with recanalization after coil embolization for a Pcom aneurysm.

Retrograde T-Stent Technique for Large, Wide-Necked Internal Carotid-Posterior Communicating Artery Aneurysm

Objective

We report a case of a wide-necked internal carotid-posterior communicating (IC-Pcom) artery aneurysm treated by the retrograde T-stent technique in which a stent was also placed in the Pcom artery via the posterior circulation.

Case Presentation

A 35-year-old woman was diagnosed with an unruptured right IC-Pcom artery aneurysm (maximum diameter: 11 mm, neck diameter: 8.5 mm) during a detailed examination for vertigo. The Pcom artery (2.1 mm) branched from the aneurysmal dome. A microcatheter was guided in retrograde via the Pcom artery from the posterior circulation. A low-profile visualized intraluminal support (LVIS) Jr. 2.5 mm × 17 mm was deployed from the internal carotid artery (ICA) to the Pcom artery, and then, an LVIS 4.5 mm × 23 mm was deployed while pressing the flare of the LVIS Jr. protruding into the ICA. T configuration stenting was completed, and the coil was inserted as tightly as possible.

Conclusion

The retrograde T-stent technique, which has the advantage of optimal stent positioning, is useful for preserving a Pcom artery branching from the aneurysmal dome.

Endovascular Trapping for Ruptured Blood Blister-Like Aneurysm of the Internal Carotid Artery: A Case Report and Review of the Literature

Objective

Rupture of blood blister-like aneurysm (BBA) of the internal carotid artery (ICA) may result in fatal subarachnoid hemorrhage (SAH). Open surgery including bypass surgery has been performed to treat the aneurysm. Recently, endovascular treatment is developing for the treatment of cerebral aneurysm. Here, we report a case of ruptured BBA of the ICA, treated by endovascular trapping and review the literatures.

Case Presentation

A 37-year-old woman was brought to our hospital to treat SAH. Computed tomography (CT) angiography showed no apparent cause of the hemorrhage except for the minor dilation of the C2 portion of the left ICA. After 3 days, the CT angiography demonstrated progression of the dilation with the formation of a bleb. Evaluating collateral circulation through anterior communicating artery, endovascular trapping of the ICA was performed. Although she suffered minor ischemic stroke postoperatively, the symptoms recovered completely and discharged without neurological deficit.

Review of Literatures

we reviewed the 11 cases of ruptured BBA treated by endovascular trapping. The results of ICA occlusion based on the evaluation of collateral circulation were satisfactory because rebleeding as well as regrowth of the aneurysm were prevented. However, hemodynamic compromise and treatment for vasospasm following SAH are considered.

Conclusion

Rebleeding from BBA of the ICA should be prevented first and ischemic complication is avoided secondary. Endovascular trapping following evaluation of the collateral circulation is definitive treatment of BBA of the ICA.

Aneurysms of the communicating segment of the internal carotid artery with posterior communicating artery agenesis are associated with perforator infarction after embolization

BACKGROUND

While anatomic features associated with the risk of posterior communicating artery (PcoA) occlusion after embolization of aneurysms of the PcoA segment of the internal carotid artery (ICA) are well known, the link between perforator origin and perforator infarction has only been reported following neurosurgical clipping. The aim of this study was to determine the origin of anterior thalamic perforators and correlate it with risk of perforator infarction after embolization of PcoA segment aneurysms.

METHODS

One-hundred-and-ninety consecutive patients treated for PcoA segment aneurysms between 2017 and 2019 were included. PcoA and anterior thalamic perforator origin anatomy was assessed with computed tomography (CT) angiography, digital subtracted angiography, and high-resolution three-dimensional rotational cone-beam CT angiography (CBCT-A) by two independent interventional neuroradiologists. The presence of perforator infarction after embolization was ascertained from the patient's notes and follow-up imaging.

RESULTS

CBCT-A was superior in demonstrating the origin of perforators (P<0.001). The prevalence of perforator origin was estimated at 86% (95% CI 81%-92%) for PcoA, 8% (95% CI 4%-13%) for aneurysm wall, and 5% (95% CI 2%-9%) for ICA. The aneurysm wall origin was exclusively associated with PcoA agenesis, as well as higher risk of perforator infarction after aneurysm coiling compared with other variants (OR=14, 95% CI 2-88, P=0.006).

CONCLUSIONS

Our study suggests that anterior thalamic perforators may arise from aneurysm wall when there is no PcoA. Anatomic association between PcoA agenesis and perforator arising from ICA could underlie such findings, and careful consideration is essential before aneurysm repair to anticipate the risk of thalamic infarction in such cases.

Simultaneous neck coverage and branch preservation using the proximal portion of a self-expandable open-cell stent for embolization of distal internal carotid artery aneurysms: multi-center, long-term results

PURPOSE

We report the long-term results of a modified stent-assisted coil embolization technique using the far proximal part of a self-expanding open-cell stent. The technique was used to cover the neck of the aneurysm while simultaneously preserving the branches of the distal internal carotid artery in patients with aneurysms of the posterior communicating (Pcom) and anterior choroidal arteries (AchA).

METHODS

We performed a retrospective review of the prospectively maintained databases at two tertiary neurosurgical centers to identify all patients who underwent embolization of Pcom or AchA aneurysms using this technique between January 2014 and July 2019. Postoperative and follow-up clinical and radiological results for initial (n = 16) or re-do (n = 4) embolizations were analyzed.

RESULTS

We identified 19 patients with 20 (16 Pcom and 4 AchA) unruptured (n = 19) or ruptured (n = 1) aneurysms. Eighteen among 20 stents (90.0%) were deployed successfully, and complete occlusions were initially attained in 18 aneurysms (90.0%). At follow-up examinations 8 to 56 months later, 6 of 14 aneurysms (42.8%) showed neck remnants. All of the branches were saved and no thromboembolic event, rupture, or sequelae were noted during or after the procedures.

CONCLUSION

These results suggest that this modified stent-assisted technique is a feasible and reasonable alternative to conventional stent deployment for coil embolization of wide-necked sidewall aneurysms in the distal ICA.

Safety and efficacy of anterior communicating artery compromise during endovascular coil embolization of adjoining aneurysms

OBJECTIVE

In the presence of symmetric A1 flow, the safety and efficacy of compromising the anterior communicating artery (ACoA) during coil embolization of ACoA aneurysms has yet to be evaluated. Herein, the authors describe their experience, focusing on procedural safety.

METHODS

Between October 2012 and July 2017, 285 ACoA aneurysms with symmetric A1 flows were treated at the authors' institution by endovascular coil embolization. Clinical and angiographic outcome data were subjected to binary logistic regression analysis.

RESULTS

ACoA compromise was chosen in the treatment of 71 aneurysms (24.9%), which were completely (n = 15) or incompletely (n = 56) compromised. In the remaining 214 lesions, the ACoA was preserved. Although 9 patients (3.2%) experienced procedure-related thromboembolisms (compromised, 4; preserved, 5), all but 1 patient (with ACoA compromise) were asymptomatic. In multivariate analysis, subarachnoid hemorrhage at presentation was the sole independent risk factor for thromboembolism (OR 15.98, p < 0.01), with ACoA compromise being statistically unrelated. In 276 aneurysms (96.8%) with follow-up of > 6 months (mean 20.9 ± 13.1 months, range 6-54 months), recanalization was confirmed in 21 (minor, 15; major, 6). A narrow (≤ 4 mm) saccular neck (p < 0.01) and ACoA compromise (p = 0.04) were independently linked to prevention of recanalization.

CONCLUSIONS

During coil embolization of ACoA aneurysms, the ACoA may be compromised without serious complications if A1 flows are symmetric. This approach may also confer some long-term protection from recanalization, serving as a valid treatment option for such lesions.

Impact of fetal-type posterior cerebral artery on recanalization of posterior communicating artery aneurysms after coil embolization: matched-pair case-control study

BACKGROUND

It is well known that hemodynamic stress may impact the recanalization of coiled aneurysms. One of the most common sites for aneurysms to develop is the posterior communicating artery (PcoA), the variants of which are defined by diameter ratios (PcoA/P1 segment).

OBJECTIVE

This study was undertaken to investigate the impact of a fetal-type posterior cerebral artery (PCA) on recanalization of PcoA aneurysms after coil embolization based on matched-pair (fetal vs non-fetal PCA) analysis.

METHODS

A total of 480 consecutive PcoA aneurysms (PCA: fetal, n=156; non-fetal, n=324) subjected to coil embolization between January 2007 and June 2017 were selected for study. All lesions were followed for ≥6 months via radiologic imaging, grouped by adjacent PCAs as fetal (PcoA/P1 >1) or non-fetal (PcoA/P1 ≤1) type. Paired subjects were matched (1:1) for several relevant variables.

RESULTS

Of the 480 coiled aneurysms, 159 (33.1%) showed recanalization (minor, 76; major, 83) in the course of follow-up (mean 33.8±21.9 months), developing significantly more often in fetal (37.8%) than in non-fetal (26.9%; p=0.020) PCA types. Once matched, however, 6-month and cumulative recanalization rates did not differ significantly by group (p=0.531 and p=0.568, respectively). Complications (hemorrhage, p=0.97; thromboembolism, p=0.94) during endovascular coil embolization also showed similar rates in these groups.

CONCLUSIONS

The chances of recanalization after coil embolization seem to be greater in PcoA aneurysms than in intracranial aneurysms overall, thus calling for careful follow-up monitoring. Surprisingly, PcoA type appeared unrelated in this regard.

Riskier-than-expected occlusive treatment of ruptured posterior communicating artery aneurysms: treatment and outcome of 620 consecutive patients

OBJECTIVE

Occlusive treatment of posterior communicating artery (PCoA) aneurysms has been seen as a fairly uncomplicated procedure. The objective here was to determine the radiological and clinical outcome of patients after PCoA aneurysm rupture and treatment and to evaluate the risk factors for impaired outcome.

METHODS

In a retrospective clinical follow-up study, data were collected from 620 consecutive patients who had been treated for ruptured PCoA aneurysms at a single center between 1980 and 2014. The follow-up was a minimum of 1 year after treatment or until death.

RESULTS

Of the 620 patients, 83% were treated with microsurgical clipping, 8% with endovascular coiling, 2% with the two procedures combined, 1% with indirect surgical methods, and 6% with conservative methods. The most common procedural complications were treatment-related brain infarctions (15%). The occurrence of artery occlusions (10% microsurgical, 8% endovascular) was higher than expected. Most patients made a good recovery at 1 year after aneurysmal subarachnoid hemorrhage (modified Rankin Scale [mRS] score 0-2: 386 patients [62%]). A fairly small proportion of patients were left severely disabled (mRS score 4-5: 27 patients [4%]). Among all patients, 20% died during the 1st year. Independent risk factors for an unfavorable outcome, according to the multivariable analysis, were poor preoperative clinical condition, intracerebral or subdural hematoma due to aneurysm rupture, age over 65 years, artery occlusion on postoperative angiography, occlusive treatment-related ischemia, delayed cerebral vasospasm, and hydrocephalus requiring a shunt.

CONCLUSIONS

Even though most patients made a good recovery after PCoA aneurysm rupture and treatment during the 1st year, the occlusive treatment-related complications were higher than expected and caused morbidity even among initially good-grade patients. Occlusive treatment of ruptured PCoA aneurysms seems to be a high-risk procedure, even in a high-volume neurovascular center.

"Clip Anchor-Assisted Coil Embolization" for Endovascular Parent Artery Occlusion of Intracranial Traumatic Aneurysm

Traumatic cerebral aneurysms are histologically dissecting aneurysms or pseudoaneurysms, thus requiring parent artery occlusion for cure. Combination of endovascular parent artery occlusion and extracranial-intracranial bypass is considered optimal to obtain complete obliteration of the aneurysm and to avoid hemodynamic hypoperfusion. However, endovascular parent artery occlusion of the supraclinoid internal carotid artery (ICA) is at risk of ischemic complications due to distal coil protrusion to adjacent perforating arteries or distal embolism of the thrombi generated in the coil mass. A 20-year-old man presented with progressive left optic neuropathy following motor vehicle accident. Radiological examination revealed left supraclinoid ICA aneurysmal formation with dissecting change. We treated this traumatic supraclinoid ICA aneurysm by combination of endovascular parent artery occlusion and high-flow bypass in the hybrid operating room. An aneurysmal clip was applied on the ICA just distal to the aneurysm prior to coil embolization, and worked as a scaffold for subsequent filling coils and as a blockade for the distal emboli. This "clip anchor-assisted coil embolization" technique resulted in optimal parent artery occlusion for the traumatic aneurysm of the supraclinoid ICA with minimal risks of residual blood flow, intraoperative rupture, and thromboembolic complications.

Feasibility and midterm outcomes of endovascular embolization for true posterior communicating artery aneurysms

PURPOSE

Endovascular treatment (EVT) of true posterior communicating artery (PcomA) aneurysms has been rarely reported. This study reports the outcomes on a single-center cohort with true PcomA aneurysms who underwent EVT.

METHODS

Between June 2011 and June 2017, clinical data from 42 patients with 43 true PcomA aneurysms who underwent EVT were retrieved from a prospectively maintained single-center database. Endovascular techniques, perioperative complications, clinical outcomes, and angiographic results were retrospectively evaluated.

RESULTS

All aneurysms were treated successfully. Treatment modalities included simple coiling in 30 aneurysms, balloon-assisted coiling in two, and stent-assisted coiling in 11 cases. Immediate angiograms showed complete occlusion in 23 aneurysms (53.5%), residual neck in 8 cases (18.6%), and residual sac in 12 (27.9%). No procedure-related complications or mortality were observed. Of the 34 aneurysms that underwent angiographic follow-up at an average duration of 7.1 months post-procedure, complete occlusion was achieved in 22 (64.7%), neck remnant in eight (23.5%), and residual sac in four (11.8%) aneurysms, respectively. Six aneurysms (18.2%) that underwent conventional coiling developed recanalization and required retreatment. Seven cases that received stent-assisted coiling did not develop recurrence. Clinical follow-up (mean, 24.3 months) of all patients demonstrated no neurologic deterioration or (re)bleeding.

CONCLUSION

EVT of the true PcomA aneurysm is a safe and feasible procedure but may be associated with recurrence in midterm follow-up, requiring close surveillance and potential retreatment.

Selective compromise of hypoplastic posterior communicating artery variants with aneurysms treatable by coil embolization: clinical and radiologic outcomes

Background

Posterior communicating artery (PcoA) compromise may serve as adjunctive treatment in patients with hypoplastic variants of PcoA who undergo coil embolization of PcoA aneurysms. However, procedural safety and the propensity for later recanalization are still unclear.

Objective

To evaluate clinical and radiologic outcomes of coil embolization in this setting, focusing on compromise of PcoA.

Methods

As a retrospective review, we examined 250 patients harboring 291 aneurysms of hypoplastic PcoAs, all consecutively treated by coil embolization between January 2004 and June 2016. PcoA compromise was undertaken in conjunction with 81 of the treated aneurysms (27.8%; incomplete 53; complete 28). Medical records and radiologic data were assessed during extended monitoring.

Results

During the mean follow-up of 33.9±24.6 months (median 36 months), a total of 107 (36.8%) coiled aneurysms showed recanalization (minor 50; major 57). Recanalization rates were as follows: PcoA preservation 40.5% (85/210); incomplete PcoA occlusion 34.0% (18/53); complete PcoA occlusion 14.3% (4/28). Aneurysms >7 mm (HR 3.40; P<0.01), retreatment for recanalization (HR 3.23; P<0.01), and compromise of PcoA (P<0.01) emerged from multivariate analysis as significant risk factors for recanalization. Compared with PcoA preservation, complete PcoA compromise conferred more favorable outcomes (HR 0.160), whereas incomplete compromise of PcoA fell short of statistical significance. Thromboembolic infarction related to PcoA compromise did not occur in any patient.

Conclusion

PcoA compromise in conjunction with coil embolization of PcoA aneurysms appears safe in hypoplastic variants of PcoA, helping to prevent recanalization if complete occlusion is achieved.

Endovascular intervention of acute ischemic stroke due to occlusion of fetal posterior cerebral artery

A fetal posterior cerebral artery (FPCA) is an anatomic variant in which the posterior cerebral artery is an embryological derivative of the internal carotid artery. Although most cases of ischemic strokes in patients with FPCAs involve embolic infarcts, emergent large vessel occlusion of a FPCA is extremely rare. We present two cases of successful endovascular intervention for emergent occlusion of a FPCA, one of which is only the second reported case of a mechanical thrombectomy of a FPCA. We review the embryology of FPCA, the controversy regarding its association with cerebral infarcts, and various approaches used in the treatment of such occlusive lesions.

Endovascular embolization of branch-incorporated cerebral aneurysms

Objectives The aim of this study was to examine the feasibility, technique, and clinical and angiographic outcomes of endovascular coiling to treat a cerebral aneurysm with a branch incorporated into the aneurysmal wall. Methods From 2012 to 2016, 25 patients with 26 cerebral aneurysms having a branch incorporated into the aneurysm (9 unruptured, 17 ruptured) were treated to prevent rupture or re-bleeding from the sac while preserving the incorporated branch by using single-catheter ( n = 18), balloon-remodeling ( n = 4), stent-assisted coiling ( n = 3), or double-catheter ( n = 1) techniques. Results Endovascular coiling was conducted in 26 procedures without angiographic occlusion of the incorporated branch. Post-embolization angiography revealed near-complete occlusion ( n = 8; 30.7%), neck remnant ( n = 13; 50%), and incomplete occlusion ( n = 5; 19.3%) aneurysms. Thromboembolisms were observed in four (15.4%) patients during or after the procedure. A procedure-related neurological deficit was observed in one (3.8%) patient. When patients with a preictal modified Rankin Scale (mRS) score of 3 presenting with grade 5 subarachnoid hemorrhage were excluded, all patients had favorable outcomes (mRS 0-2). Six (23.1%) recurrent aneurysms were observed during follow-up, five of which were treated endovascularly at 5-22 months without complication. The location of an aneurysm at the ICA-posterior communicating artery associated with the dominant-type posterior communicating artery was significantly associated with recurrence ( p = 0.041). Conclusions Cerebral aneurysms with an incorporated branch were safely treated using conventional endovascular coiling. However, treatment durability was unsatisfactory, especially for dominant-type ICA-posterior communicating artery aneurysms.

Endovascular Treatment of a Fusiform Aneurysm Involving a Premammillary Artery Originating from the Internal Carotid Artery: A Case Report

The premammillary artery (PMA) is a branch of the posterior communicating artery (PCoA). While the PMA is known to originate from the PCoA as demonstrated by most anatomical studies, it originates directly from the internal carotid artery in approximately 1% of patients. Cerebral aneurysms associated with the PMA have rarely been reported. We report an extremely rare case of a ruptured PMA aneurysm that was managed using endovascular treatment.

Endovascular strategies for treatment of posterior communicating artery aneurysm according to angiographic architecture: Preservation vs. sacrifice of posterior communication artery

We report ischemic complications related to obstruction of the posterior communicating artery (PcomA) and suggest treatment strategies according to the angiographic characteristics of the PcomA and the posterior cerebral artery (PCA). Twenty-one patients with PcomA aneurysm who had initially undergone endovascular treatment and had an identifiable PcomA occlusion on immediate or follow-up angiography were enrolled. We classified PcomA aneurysm according to the characteristics of the PcomA and PCA (P1) on baseline angiography, as follows: type I was defined as PcomA aneurysm with an absent PcomA and a normal-sized P1. Type II was defined as a hypoplastic PcomA and a normal-sized P1. Type III was defined as a normal-sized PcomA and an absent P1. Type IV was defined as a normal-sized PcomA and a hypoplastic P1. Type V was a normal-sized PcomA and a normal-sized P1. Among all cases of PcomA obstruction, 15 (71.4%) were type II PcomA aneurysms, four were type IV, one was type III, and one was type V. Ischemic events related to PcomA obstruction occurred in three cases (type II, III and VI), which included two tuberothalamic infarctions (type III and IV) and one cortical infarction in the territory of the PCA (type II). Follow-up angiographies showed flow change in the PcomA in 14 cases. It is relatively safe to sacrifice type II PcomA if necessary. However, physicians should pay attention to unexpected flow changes, such as recanalization or occlusion of the PcomA, which are possible after treatment.

Pure posterior communicating artery occlusion treated with mechanical thrombectomy

There has been no report of mechanical thrombectomy for a pure posterior communicating artery (PComA) occlusion. Here, we report the case of an 87-year-old woman with a disturbance of consciousness and left hemiparesis diagnosed with a right PComA occlusion. The patient was successfully treated using mechanical thrombectomy in combination with a stent retriever and the Penumbra system. A CT perfusion image showed cerebral blood flow reduction in the ipsilateral occipital lobe and thalamus. A CT angiography supported the diagnosis of an occlusion of fetal type PComA. The PComA could not be detected by internal carotidangiogram, but after deployment of stent retriever, the PComA was recanalised and distal embolus at the right posterior cerebral artery was visualised. The thrombus was then removed using the Penumbra system. Although the treatment for a PComA occlusion requires further investigation, the present case supports a thrombectomy as an effective rescue strategy for PComA occlusions.

Cerebral Blood Flow after Acute Bypass with Parent Artery Trapping in Patients with Ruptured Supraclinoid Internal Carotid Artery Aneurysms

BACKGROUND

Bypass with parent artery trapping is an alternative treatment method for ruptured internal carotid artery (ICA) aneurysms when clipping or coiling is contraindicated. However, the efficacy and safety of this strategy during the acute stage of subarachnoid hemorrhage (SAH) is undetermined.

METHODS

A retrospective review of 955 consecutive patients presenting SAH between 2006 and 2014 identified 17 patients with ruptured ICA aneurysms treated by bypass with parent artery trapping within 72 hours after the bleeding (bypass group). The 26 cases with ruptured posterior communicating artery aneurysms treated with clipping during the same period were defined as a control group (clipping group). Postoperative cerebral blood flow (CBF) was evaluated by single photon emission computed tomography (SPECT). We analyzed the postoperative hemodynamic status, surgical complications, and the clinical outcomes.

RESULTS

Postoperative rebleeding did not occur in any of the cases. CBF in the first postoperative week in the bypass group was lower than that in the clipping group (P = .0165). This CBF decrease improved in the second postoperative week and did not differ from that of the clipping group. The incidence of acute ischemic complications was significantly higher in the bypass group (P = .0284), but the incidence of delayed cerebral ischemia did not differ between the 2 groups. The incidence of favorable outcomes at 6 months was 82.4% in the bypass group and 81% in the clipping group.

CONCLUSIONS

Although the transient CBF decrease with acute ischemic complications should be noted, acute bypass with parent artery trapping is safe and effective for unclippable/uncoilable ruptured ICA aneurysms.

Endovascular treatment of posterior communicating artery aneurysms in the presence of the fetal variant of posterior cerebral artery

Posterior communicating artery (PcomA) aneurysms in the presence of the fetal variant of posterior cerebral artery (PCA) often pose technical challenges for endovascular treatment because of a greater potential for ischemic injury with the fetal PCA compromise. The purpose of this study was to assess the feasibility and results of endovascular treatment for these lesions. We retrospectively reviewed our experience and results of endovascular treatments for a series of nine consecutive patients with PcomA aneurysms occurring at the origin of fetal PCAs at the Department of Neurosurgery of Southwest Hospital, Chongqing, China, between June 2011 and June 2014. Depending on the angiographic findings, location and shape of the aneurysms, various therapeutic strategies were used including coiling by single or double microcatheter, balloon remodeling technique, and single or Y-stenting technique. Overall, fetal PCA was preserved patent in all cases, and complete or near complete occlusion was achieved in 8/9 cases. There was no procedure-related morbidity or mortality. With the exception of one patient who died of pneumonia 6 weeks after treatment, no clinical evidence of neurologic deterioration and hemorrhagic complication was seen during the follow-up period in the remaining 8 patients. Our experience suggests that endovascular treatment is relatively safe and technically feasible in most patients with PcomA aneurysms in the presence of fetal PCA using multiple strategies.

Morphometric Study of the Anterior Thalamoperforating Arteries

Objective

To evaluate the morphometry of the anterior thalamoperforating arteries (ATPA).

Methods

A microanatomical study was performed in 79 specimens from 42 formalin-fixed adult cadaver brains. The origins of the ATPAs were divided into anterior, middle, and posterior segments according to the crowding pattern. The morphometry of the ATPAs, including the premammillary artery (PMA), were examined under a surgical microscope.

Results

The anterior and middle segments of the ATPAs arose at mean intervals of 1.75±1.62 mm and 5.86±2.05 mm from the internal carotid artery (ICA), and the interval between these segments was a mean of 3.17±1.64 mm. The posterior segment arose at a mean interval of 2.43±1.46 mm from the posterior cerebral artery (PCA), and the interval between the middle and posterior segments was a mean of 3.45±1.39 mm. The mean numbers of perforators were 2.66±1.19, 3.03±1.84, and 1.67±0.98 in the anterior, middle, and posterior segments, respectively. The PMA originated from the middle segment in 66% of cases. A perforator-free zone was located >2 mm from the ICA in 30.4% and >2 mm from the PCA in 67.1% of cases.

Conclusion

Most perforators arose from the anterior and middle segments, within the anterior two-thirds of the posterior communicating artery (PCoA). The safest perforator-free zone was located closest to the PCA. These anatomical findings may be helpful to verify safety when treating lesions around the PCoA and in the interpeduncular fossa.

Posterior Communicating Artery Compromise in Coil Embolization of Posterior Communicating Artery Aneurysms

PURPOSE

Whether the posterior communicating artery (PcomA) can be safely compromised during endovascular treatment of a PcomA aneurysm is a matter of debate. Here we present clinical and radiologic outcomes, given this scenario.

METHODS

From data prospectively accrued between January 2004 and December 2012, records of 44 patients harboring 46 PcomA aneurysms were retrieved. All had suffered PcomA compromise in the course of endovascular coil embolization. Patients/aneurysms were stratified into those with complete (Group A) and incomplete (Group B) compromise depending on the degree of PcomA flow limitation documented by postembolization ipsilateral internal carotid artery angiography. Clinical and radiologic outcomes were accordingly assessed.

RESULTS

All affected vessels were hypoplastic PcomA variants (PcomA/P1 ratio, ≤ 1.0), with exception of a single dominant PcomA (PcomA/P1 ratio, 1.1). In Group A (23 patients, 23 aneurysms), no PcomA compromise-related infarction was evident, whereas in Group B (21 patients, 23 aneurysms), two ischemic events occurred. One patient suffered thalamic infarction, although patency of the PcomA was adequate in a follow-up angiogram, and another experienced a transient ischemic attack.

CONCLUSION

Our findings suggest that obstructed flow in hypoplastic PcomA variants during coil embolization of PcomA aneurysms carries no major consequence. However, incomplete compromise of the PcomA may be a source of delayed thromboembolic infarction.

Tuberothalamic artery infarction following coil embolization of a ruptured posterior communicating artery aneurysm belonging to a transitional type posterior cerebral artery. A case report

There are many potential anatomical variations in the connection between the internal carotid artery and the posterior circulation through the posterior communicating artery (PCoA). We describe the endovascular treatment of an aneurysm arising near the origin of the PCoA belonging to a transitional type posterior cerebral artery. Coil embolization subsequently resulted in thrombo-occlusion of the adjacent PCoA causing thalamic infarction even though sufficient retrograde flow had been confirmed pre-operatively by Allcock's test.

Stent-assisted coil embolization of posterior communicating artery aneurysms

BACKGROUND AND PURPOSE

Use of protective stents may not be effective in coil embolization of wide-neck aneurysms involving the posterior communicating artery. Successful implementation depends on the caliber of the vessel, its angle of origin, and the manner in which its orifice is incorporated into the aneurysm. Presented here are the results (clinical and radiographic) of coil embolization in aneurysms of the ICA-posterior communicating artery junction, variably aided by stents. The primary focus is angiographic configurations that impact stent placement.

MATERIALS AND METHODS

From a prospective data repository, we retrieved records of 32 consecutive patients with 33 posterior communicating artery aneurysms, all of which were treated by stent-assisted coil embolization between June 2008 and August 2012. Outcomes were analyzed in terms of aneurysm configuration and clinical status.

RESULTS

Stents were positioned entirely in the ICA (n = 26), from the ICA to the posterior communicating artery (n = 2), in the posterior communicating artery only (n = 3), and retrograde from the posterior communicating artery to the ICA terminus (n = 2). Procedure-related complications occurred in 3 patients (9.1%), but only 1 (3.0%) had mild neurologic sequelae (Glasgow Outcome Score 4). Using coil embolization, we achieved successful occlusion in 24 aneurysms (72.7%), and in 9 others, subtotal occlusion was conferred. During a mean follow-up of 15.7 ± 10.7 months, imaging of 27 aneurysms documented stable occlusion in 19 (70.4%), whereas angiography of 15 aneurysms (39.5%) disclosed 2 instances of in-stent stenosis (13.3%) and a solitary occurrence of stent migration (6.7%).

CONCLUSIONS

In posterior communicating artery aneurysms, stent protection during coil embolization is feasible by adjusting the procedural strategy to accommodate differing configurations of the aneurysm and its vascular source.