Endovascular treatment of posterior cerebral artery aneurysms: a single center's experience of 55 cases

Parent Artery Occlusion for a Dissecting Posterior Cerebral Artery Aneurysm in the P4 Segment Presenting with Ischemic Stroke and Rapid Growth: A Case Report

A dissecting aneurysm in the P4 segment of the posterior cerebral artery (PCA) is extremely rare, and its treatment is sometimes challenging. Endovascular parent artery occlusion (PAO) was performed for an unruptured P4 segment dissecting PCA aneurysm presenting with ischemic stroke and rapid growth. A 70-year-old man was rushed to our emergency department due to a right-sided headache and a visual field defect. Head magnetic resonance imaging showed a right occipital lobe ischemic stroke, with right PCA occlusion and aneurysm formation in the P4 segment. The diagnosis was PCA dissection in the calcarine artery, and oral aspirin was started. Within a week, the dissecting aneurysm had enlarged progressively to 6.2 mm in diameter. Thus, PAO with coils was performed as a preventive measure against aneurysm rupture, assuming that complication risks were low because the tributary area of the dissecting PCA had already infarcted. A 6-Fr guiding sheath was introduced from the right brachial artery to the right vertebral artery, and a microcatheter/microguidewire was placed into the true lumen of the calcarine artery distal to the aneurysm. PAO with coils was performed, and the blood flow to the aneurysm was completely obliterated. After the treatment, the known infarction in the right occipital lobe was enlarged, but no new neurological symptoms developed. The patient was discharged independently on postoperative day 3. Treatment for a distal PCA dissecting aneurysm is challenging. PAO with coils is one of the reasonable choices, especially when a visual field defect has already developed.

Endovascular Treatment for Intracranial Artery Dissections in Posterior Circulation

Intracranial artery dissections (IADs), although uncommon, are an important cause of cerebral infarction and subarachnoid hemorrhage (SAH). Some IADs can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis. Meanwhile, others can progress to stroke that requires treatment. The incidence of IAD in the posterior circulation is higher than that in the anterior circulation. Anterior circulation dissections are more likely to develop into ischemia and posterior circulation lesions into hemorrhage. The mortality rate after IAD among patients with SAH is 19%-83%. Further, the mortality rate of IAD without SAH is 0%-3%. Patients with SAH commonly undergo surgery or receive neuroendovascular treatment (EVT) to prevent rebleeding. However, the treatment of IADs is empirical in the absence of data from randomized controlled trials. Recently, EVT has emerged and is considered for IADs because of its less invasiveness and perceived low rates of procedure-related morbidity with good efficacy. EVT strategies can be classified into deconstructive (involving sacrifice of the parent artery) and reconstructive (preserving blood flow via the parent vessel) techniques. In particular, the number of reports on reconstructive techniques is increasing. However, a reconstructive technique for ruptured IADs has not yet been established. This review aimed to provide an overview of IADs in the posterior circulation managed with EVT by performing a literature search.

Primary coiling of a wide-neck unruptured aneurysm in the trifurcation of the P2 segment of the posterior cerebral artery: A case report

Intracranial aneurysms are now treatable with coils, stents, and flow diverters in recent years. For saccular aneurysms with broad necks and short domes, stent-assisted coiling has become a common technique, but over time, the complications—both intraprocedural and in a delayed fashion—occur more frequently than coiling alone. Nonstent or balloon-assisted coiling results in lower aneurysm recanalization, lower aneurysm rupture or re-rupture, or lower aneurysm retreatment. This paper illustrates a successful coiling of wide-neck unruptured aneurysm in the trifurcation of the left P2 posterior cerebral artery done without the assistance of stents or balloons.

Natural history and management of posterior cerebral artery aneurysms: a systematic review and meta-analysis of individual patient data

We conducted a comprehensive review and meta-analysis to investigate clinical, radiographic characteristics, and treatment outcomes of posterior cerebral artery aneurysms (PCAA). We systematically reviewed English-language articles investigating available treatments (parent artery occlusion (PAO), microsurgery, reconstructive endovascular (rEVT), and conservative treatments) for PCAA and analyzed the based on aneurysm morphology and rupture status. Six-hundred-eighty-five patients with 698 PCAA were identified from 59 studies. Overall, 371 (54.2%) aneurysms were ruptured, 325 (49%) were saccular, and 342 (51%) were non-saccular aneurysms. The mean age of the saccular was lower (40 years) than non-saccular aneurysm group (50 years) (P < .05). In ruptured PCAA, favorable clinical outcomes were comparable between the treatment groups except for patients treated conservatively, which had lower rates of favorable clinical outcomes (35.6%) and higher mortality (55.7%) (P < .0001). Ruptured aneurysms treated with rEVT (22.6%) had the highest recanalization rates compared to PAO (9.2%, P = 0.0001) and microsurgery (3.8%, P = 0.005). In unruptured PCAA, clinical outcomes were similar; higher complication rates were noted in microsurgery (40.4%, P = 0.026) and PAO (21.5%, P = 0.015) compared to rEVT (13.2%), which had higher recanalization rates (15.6%, P < .0001). The rates of subsequent stroke following PAO were 21.8% for unruptured and 32.3% for ruptured PCAA (P = 0.078). Ruptured PCAA portend worse prognosis and typically require an intervention to achieve better outcome whereas the benefit of an intervention in unruptured PCAA is much less clear. rEVT is promising for PCAA management with a good clinical and safety profile but more recurrence compared to PAO and microsurgery.

A Recurrent Large Posterior Cerebral Artery Aneurysm Successfully Treated with Parent Artery Occlusion Using Somatosensory-Evoked Potential: A Case Report

Objective

Treatment of large posterior cerebral artery (PCA) aneurysm involving the P1-P2 segment is difficult by both neurosurgery and endovascular treatment. Balloon occlusion test (BOT) to identify precise peripheral collateral flow is difficult prior to parent artery occlusion (PAO). Besides, PAO at the aneurysm at this location can cause peripheral cortical infarction of the occipital and temporal lobes and/or perforator infarction involving the midbrain and thalamus perfused by the perforating artery arising from the P1-P2 segment. However, detection of the perforator during PAO is difficult.

Case Presentation

The patient was a 49-year-old woman. At the age of 43 years, a right large PCA aneurysm was discovered in the right P1-P2 segment. A simple technique coiling was performed. As recurrence was identified 1 year later, embolization was performed using a same procedure. Since further recurrences were later found, a third round of treatment was planned. Somatosensory-evoked potential (SEP) was recorded as intraoperative electrophysiological monitoring. Tortuosity of the right PCA was observed at the aneurysm neck and the distal right PCA could not be secured. We could neither perform stent-assisted coil embolization nor BOT in the right PCA. Hence, we inflated the balloon in the basilar artery and checked the collateral circulation routes retrograde into the right PCA from the right middle cerebral artery via a leptomeningeal anastomosis. PAO was performed on the right P1-P2 segment at the aneurysm neck. The signal of the SEP was not decreased, and the aneurysm was not visualized. Another coil was added to strengthen the PAO to the right P1 segment, which decreased the SEP amplitude in the extremities by 3 minutes after. As the last coil was thought to be occluding the perforator branching from the right P1 segment, it was removed without detaching. The SEP amplitude began to improve and recovered by 9 minutes after. There was no postoperative deficit. No recurrence of aneurysm was observed on MRA 9 months postoperatively.

Conclusion

During PAO at the P1 segment of large PCA aneurysm involving the P1-P2 segment, SEP may be helpful to prevent perforator infarction, even if perforating artery originating from the proximal portion of the aneurysm was not detected by angiography.

Inverted stent deployment technique for stent assisted coiling of wide-necked posterior communicating artery aneurysm: Technical report

BACKGROUND

Wide-necked aneurysms of the posterior communicating artery associated with a fetal posterior cerebral artery that arises from the neck or dome of the aneurysm is a clinical scenario that poses a challenge to endovascular methods.

CASE DESCRIPTION

A patient presented with spontaneous subarachnoid hemorrhage and was found to have a 4 × 3 × 3 mm posterior communicating artery aneurysm. Of note the aneurysm projected superiorly and a fetal posterior communicating artery aneurysm arose from the neck of the aneurysm. After multidisciplinary discussion a treatment strategy of endovascular stent-assisted coiling was chosen. Given the unique morphology of the aneurysm a novel stent-inversion maneuver was used, in which the stent was deployed from the posterior communicating artery into the distal supra-clinoid internal carotid artery. The patient tolerated the procedure well and complete aneurysm occlusion was achieved.

CONCLUSIONS

This case demonstrates a novel stent inversion technique that can be used for stent-assisted coiling of certain challenging aneurysms.

Braided stents assisted coiling for endovascular management of posterior cerebral artery aneurysms: a preliminary mid-term experience

PURPOSE

Posterior cerebral artery (PCA) aneurysms are rare. This study is to evaluate the preliminary experience of braided stents applied in PCA aneurysms treatment.

METHODS

Angiographic and clinical data of 28 PCA patients treated with braided stents from July 2016 and September 2020 were retrospectively analyzed.

RESULTS

A total of 28 PCA aneurysms were enrolled. 22 (78.6%) aneurysms were dissecting aneurysms, while 6 (21.4%) aneurysms were saccular aneurysms. Thirty-five braided stents were implanted with dual stents implanted in 7 cases. Immediate angiographic results show that Raymond class I was obtained in 13 patients (46.4%), Raymond class II was obtained in 4 patients (14.3%), and Raymond class III was obtained in 11 patients (39.3%). Perioperative hemorrhagic events occurred in 1 patient (3.6%). Twenty-four patients (85.7%) received angiographic follow-up, and the mean follow-up time was 11.2 ± 4.9 months. Two patients (8.3%) were confirmed with IA neck recurrence, and 3 patients (12.5%) were confirmed asymptomatic parent artery occlusion (PAO). The other 19 patients were confirmed promoted occlusion with 18 Raymond class I (75%) and 1 Raymond class II (4.2%). Twenty-seven patients (96.4%) received clinical follow-up, and the mean follow-up time was 32.2 ± 13.5 months. One patient (3.7%) confirmed the death event 2 weeks after discharge. The other 27 patients (96.3%) got favorable clinical outcomes with an mRS score of 0-2.

CONCLUSIONS

Braided stent-assisted coiling with a high occlusion rate and relatively low complication rate provides an alternative strategy in treating PCA aneurysms. Long-term outcomes need further randomized study with larger case numbers.

Diagnostic Impact of Monitoring Visual Evoked Potentials to Prevent Visual Complications During Endovascular Treatment for Intracranial Aneurysm

Introduction

The present study aimed to determine the incidence of intraprocedural visual-evoked potential (VEP) changes and to identify correlations with intraprocedural ischemic complications during endovascular treatment in patients with intracranial aneurysm related to visual function.

Methods

This study analyzed data from 104 consecutive patients who underwent endovascular coil embolization to treat intracranial aneurysms related to visual function under VEP and transcranial motor evoked potential (MEP) monitoring. We analyzed associations between significant changes in MEP and VEP, defined as a >50% decrease in amplitude, and both intraprocedural complications and postoperative neurological deficits. Factors associated with postoperative neurological deficits were also assessed.

Results

Treated aneurysms were predominantly located in the internal carotid artery (95%). Five (5%) were located in the posterior cerebral artery (PCA). Significant decreases in intraprocedural VEP occurred in four patients (4%), although one of those four patients did not show concomitant MEP decreases during procedures. Immediate salvage procedures avoided postoperative visual disturbances. All VEP decreases were transient and not associated with postoperative visual impairment. One of three cases who underwent intraoperative balloon occlusion test showed tolerance to balloon occlusion of the proximal PCA under VEP assessment; parent artery occlusion was performed without postoperative visual disturbance in that case.

Conclusion

Although significant VEP decreases occurred 4% during neuro-endovascular aneurysm treatment related to visual function, intraprocedural VEP monitoring identifies ischemic changes associated with visual pathways and facilitates prompt initiation of salvage procedures.

Radical treatment of ruptured dissecting aneurysm on the P1 segment with monotherapy using multiple LVIS stents

The standard endovascular treatment for ruptured dissecting aneurysm is a parent artery occlusion. However, this treatment is unsuitable when the artery of the lesion gives off perforating vessels that supply blood to critical regions or when the collateral flow cannot be expected due to the sacrifice of the parent artery. Here, we present an infrequent case of ruptured dissecting aneurysm on P1 segment of the posterior cerebral artery. The aneurysm had little sac for coiling and the artery of the lesion had some perforator branches; thus, we selected the monotherapy with three overlapping low-profile visualised intraluminal support stents as radical treatment, which resulted in prompt obliteration of the aneurysm. The patient was fully recovered at 3 months after the procedure. Previous studies have reported the effectiveness of multiple stents alone for dissecting aneurysms, whereas this case showed that overlapping stents may also be effective on the P1 segment.

Stent-Assisted Coil Embolization for Acute Ruptured Dissecting Aneurysm at the P2 Segment of the Posterior Cerebral Artery: A Case Report

Objective

We report a case of ruptured posterior cerebral artery (PCA) dissecting aneurysm treated with stent-assisted coil embolization in the acute phase of ruptured aneurysm.

Case Presentation

A 60-year-old woman presented with sudden onset of severe headache followed by unconsciousness. CT showed severe subarachnoid hemorrhage. Digital subtraction angiography showed a dissecting aneurysm at the P2 segment of the right PCA. Stent-assisted coil embolization was performed for the ruptured dissecting aneurysm. Since thrombus was observed in the stent, ozagrel was administered intravenously, and the thrombus gradually disappeared during the follow-up period. She was discharged without neurological deficit.

Conclusion

Parent artery occlusion is widely performed for acute ruptured PCA dissecting aneurysm, but reconstruction with stent-assisted coiling is considered to be an effective therapeutic strategy.

Endovascular Parent Artery Occlusion for Intracranial Aneurysms is a Viable, Cost-Effective Alternative: An Institutional Experience from Northeast India

Purpose.

Endovascular parent artery occlusion (PAO) may be an alternative approach for complex intracranial aneurysm with potentially life-threatening complications. Moreover, the long-term follow-up of the PAO for an intracranial aneurysm is reported sparingly, limited to the case series. It is therefore important to carry out more research on long-term follow-up of the implication of PAO of intracranial aneurysm. The aim of the study was to analyses our experience of PAO for intracranial aneurysms with emphasis on long-term follow-up.

Materials and Methods.

The data of patients treated with PAO for intracranial aneurysms were reviewed. The outcome was evaluated based on aneurysmal occlusion on immediate angiography, follow-up magnetic resonance angiography (MRA), and complications. The modified Rankin score (mRS) was used to evaluate the functional outcome during the last follow-up. The mean, range, and standard deviation were reported for other variables – the patient’s age, number, and percentage.

Results.

Endovascular treatment was performed in 178 patients including PAO in 18 patients. Of these 18 (eighteen) patients, there were 13 dissecting aneurysms, 4 mycotic aneurysms, and one traumatic aneurysm.

10 (ten) patients underwent PAO for proximal intracranial artery aneurysm and 8 (eight) patients for distal cerebral aneurysms. Complete occlusion of the aneurysm was achieved in 16patients (88.89%) and retrograde filling of the aneurysm was seen in 2 (11.11%) patients. One patient had intraprocedural coil migration resulting in a major infarct with an mRS of 2. Another patient (5.56%) had recanalization of the aneurysm and presented with rupture and intracranial hemorrhage with an mRS score of 4. The mRS of the other 16 patients (88.89%) was zero.

Conclusions.

Endovascular PAO for cerebral aneurysms was highly feasible and achieved complete occlusion. The morbidity and mortality rates were at the long-term follow-up also acceptable with negligible complications.

Intra-Aneurysmal Coil Embolization of a Ruptured Distal Posterior Inferior Temporal Artery Aneurysm: A Case Report

Objective

We report a case of a ruptured aneurysm at the posterior inferior temporal artery (PITA) of the posterior cerebral artery (PCA) treated by intra-aneurysmal coil embolization.

Case Presentation

A 93-year-old man presented with disturbance of consciousness. Angiography revealed a 3-mm aneurysm in the distal PITA of the left PCA. He was diagnosed with subarachnoid hemorrhage and intracerebral hemorrhage due to a ruptured aneurysm. This aneurysm was occluded by intra-aneurysmal coil embolization with preservation of the PITA.

Conclusion

Distal PITA aneurysm of the PCA is rare. Complete occlusion and preservation of the parent artery were achieved by intra-aneurysmal coil embolization, which may be an effective therapeutic option for such aneurysms.

Selection of approach and bypass for fetal-type posterior cerebral artery aneurysm: illustrative cases

BACKGROUND

Unlike in aneurysms of the adult-type posterior cerebral artery (PCA), in aneurysms of the fetal-type PCA, parent artery occlusion (PAO) results in vascular insufficiency and major ischemic strokes. Preservation or reconstruction of fetal-type PCAs is necessary to prevent these complications. Furthermore, it is necessary to select an appropriate bypass method and approach for revascularization of the PCA.

OBSERVATIONS

The authors report 2 cases of aneurysms of fetal-type PCAs that were successfully treated with PAO with revascularization. A 38-year-old man with a large unruptured right PCA aneurysm at the postcommunicating (P2) segment underwent trapping with superficial temporal artery–PCA bypass via the anterior temporal and subtemporal approaches. In addition, a 45-year-old woman with a left PCA aneurysm at the quadrigeminal (P3)–cortical (P4) segments resulting in subarachnoid hemorrhage underwent proximal clipping of the P3 segment via the occipital interhemispheric approach with an occipital artery–PCA bypass. Although she had perforator infarction, major ischemic stroke was prevented, and aneurysm occlusion was accomplished in both cases.

LESSONS

Aneurysms of fetal-type PCAs pose a risk of ischemia due to PAO. The combined use of bypass and revascularization should be considered to prevent major ischemic stroke after occlusion of the fetal-type PCA. However, perforator infarction is a concern.

A case of internal trapping to a thrombosed giant rapidly growing aneurysm at the posterior cerebral artery

We describe a case of internal trapping including the vasa vasorum for a thrombosed giant rapidly growing posterior cerebral artery aneurysm and performing a detailed analysis. A 48-year-old woman was followed up in our hospital for a thrombosed large posterior cerebral artery aneurysm located in the P2 segment. She initially presented after experiencing a sudden headache on two occasions. Head computed tomography and magnetic resonance imaging indicated a larger aneurysm than before. Digital subtraction angiography with balloon occlusion test was assessed, and internal trapping was sequentially conducted. We detected that the vasa vasorum originated from the posterior temporal artery. Therefore, we embolized the posterior temporal artery including the vasa vasorum using N-butyl-2-cyanoacrylate and Lipiodol. Next, the anterior temporal artery was embolized with N-butyl-2-cyanoacrylate and Lipiodol, posterior temporal artery P3 segment and the aneurysm and finally the proximal P2 segment were embolized with coils. Final vertebral and internal carotid angiography showed complete obliteration of the aneurysm. On the day after the procedure her paresis worsened and she developed left upper quadrantanopia, however was finally discharged with no hemiparesis. We reported a case of a rapidly growing thrombosed giant posterior cerebral artery aneurysm treated by parent artery occlusion including the vasa vasorum with detailed image analysis.

Dissecting aneurysms of the posterior cerebral artery - A retrospective review of imaging, angiographic characteristics, endovascular management and outcome

PURPOSE

To review management, clinical and imaging outcomes of dissecting posterior cerebral artery (PCA) aneurysms with emphasis on endovascular management in the form of parent vessel occlusion (PVO) at a tertiary care center.

METHODS

Thirty-six dissecting PCA aneurysms (19 ruptured) encountered at our center between January 2013 and November 2019 were reviewed for aneurysm location/size/presence of fetal PCA/management. Postprocedural imaging of patients who underwent endovascular intervention was reviewed for PCA territory infarcts and clinical records assessed for presence of neuro-deficits and outcome. None of the patients underwent a balloon test occlusion (BTO) prior to PVO.

RESULTS

The location of the aneurysms was as follows-P1 = 8/P1-P2 = 11/P2 = 5/P2-P3 = 10/P3 = 2. The mean size was 11.7x6.8 mm. Endovascular intervention was carried out in 20 patients in the form of PVO with coiling in 16 patients, coiling alone in 3 patients, and reconstruction of the left PCA with flow diverter deployment in one patient. Postprocedural PCA territory infarct was seen in 5 cases of PVO out of which 4 had a good functional recovery. Overall, 15/16 patients (93.7%) who underwent PVO had mRS ≤ 2 on follow-up. The single case with flow diverter also developed an infarct and had adverse outcome on follow up.

CONCLUSION

Among the various management strategies for dissecting PCA aneurysms, PVO is feasible and relatively safe even in absence of BTO in scenarios like critically ill patients with ruptured aneurysms, difficult access and financial constraints. Thromboembolic complications and antiplatelet therapy is a concern in reconstructive strategies.

Safety and Long-term Efficacy of Stent-assisted Coiling for the Treatment of Complex Posterior Cerebral Artery Aneurysms

OBJECTIVE

To evaluate the safety and long-term efficacy of stent-assisted coiling for the treatment of complex posterior cerebral artery (PCA) aneurysms.

METHODS

Angiographic and clinical data of 23 patients harboring 23 complex PCA aneurysms treated with stent-assisted coiling from March 2010 to March 2017 were retrospectively reviewed.

RESULTS

In this study 8 (34.8%) aneurysms were located at the P1 segment, 7 (30.4%) at the junction of P1 and P2 segments (P1-2), and 8 (34.8%) at the P2 segment. The aneurysms were ruptured in 7 cases (30.4%). Thirteen were dissecting in nature, while the other 10 were classical saccular aneurysms. Of the patients, 5 (21.7%) had of history of recent head trauma, immediate angiographic results were Raymond class I in 5 (21.7%) cases, Raymond class II in 8 (34.8%), and Raymond class III in 10 (43.5%). Perioperative complications occurred in one case with occlusion of the PA due to acute in-stent thrombosis without any neurologic deficit at discharge. The last angiographic follow-up (mean 18.7 months) results demonstrated complete aneurysmal occlusion in 20 (87.0%) cases, PA occlusion in 1 (4.3%) and recurrence in 2 (8.7%). Of the two patients with aneurysm recurrence, one was treated by PA occlusion, and the other was treated with two overlapping stents. Clinical follow-up (mean 58.3 months) was available for all 23 patients, 22 (95.7%) patients had good neurologic outcomes (mRS score 0-2), and 1 (4.3%) patient died 7 months after the procedure for unknown reasons.

CONCLUSION

Stent-assisted coiling for the treatment of complex PCA aneurysms is safe and durable with a relatively low rate of complication and a relatively high rate of complete occlusion at long-term follow-up and is a promising alternative strategy for the reconstruction of the PCA.

Ruptured posterior circulation aneurysms: epidemiology, patterns of care, and outcomes from the Swiss SOS national registry

BACKGROUND

The treatment of ruptured posterior circulation aneurysms remains challenging despite progresses in the endovascular and neurosurgical techniques.

OBJECTIVE

To provide epidemiological characterization of subjects presenting with ruptured posterior circulation aneurysms in Switzerland and thereby assessing the treatment patterns and neurological outcomes.

METHODS

This is a retrospective analysis of the Swiss SOS registry for patients with aneurysmal subarachnoid hemorrhage. Patients were divided in 3 groups (upper, lower, and middle third) according to aneurysm location. Clinical, radiological, and treatment-related variables were identified and their impact on the neurological outcome was determined.

RESULTS

From 2009 to 2014, we included 264 patients with ruptured posterior circulation aneurysms. Endovascular occlusion was the most common treatment in all 3 groups (72% in the upper third, 68% in the middle third, and 58.8% in the lower third). Surgical treatment was performed in 11.3%. Favorable outcome (mRS ≤ 3) was found in 56% at discharge and 65.7% at 1 year. No significant difference in the neurological outcome were found among the three groups, in terms of mRS at discharge (p = 0.20) and at 1 year (p = 0.18). High WFNS grade, high Fisher grade at presentation, and rebleeding before aneurysm occlusion (p = 0.001) were all correlated with the risk of unfavorable neurological outcome (or death) at discharge and at 1 year.

CONCLUSIONS

In this study, endovascular occlusion was the principal treatment, with a favorable outcome for two-thirds of patients at discharge and at long term. These results are similar to high volume neurovascular centers worldwide, reflecting the importance of centralized care at specialized neurovascular centers.