Endovascular Surgery using Stents for Vertebral Artery Dissecting Aneurysms and a Review of the Literature

Flow-Diverting Devices in the Treatment of Vertebral Artery Aneurysms: Insights into Efficacy and Safety from a Systematic Review and Meta-analysis

The objective of this study is to conduct a systematic review and meta-analysis aimed at evaluating the efficacy and safety of flow-diverting devices (FDs) treatment for intracranial vertebral artery (VA) aneurysms. We searched PubMed, Web of Science, OVID, and Embase for English-language studies up to February 2024 and included clinical studies on FD treatment of intracranial VA aneurysms. Sensitivity analysis evaluated outcome stability. Of 2273 articles, 29 studies involving 541 aneurysms treated with FDs were included. Based on the Methodological Index for Non-Randomized Studies (MINORS), six were high-quality and 23 moderate quality. FD treatment showed a 95% rate of favorable clinical outcomes (95% CI, 89-99%), 81% (95% CI, 74-88%) complete aneurysmal occlusion, 4% (95% CI, 2-7%) ischemic complication incidence, 1% (95% CI, 0-3%) hemorrhagic complication incidence, 95% (95% CI, 87-100%) posterior inferior cerebellar artery (PICA) preservation, and 6% (95% CI, 3-10%) in-stent stenosis or occlusion across clinical and angiographic follow-up periods of 13.62 months (95% CI, 10.72-16.52) and 11.85 months (95% CI, 9.36-14.33), respectively. Subgroup analyses, based on a 12-month angiographic follow-up threshold, indicated no statistically significant differences in rates of complete aneurysm occlusion, PICA preservation, or in-stent stenosis or occlusion incidence (p > 0.05) between subgroups. Moreover, significant differences were observed in clinical and angiographic outcomes between ruptured and unruptured aneurysms, particularly in hemorrhagic complications (p < 0.05), without significant disparity in ischemic complications (p > 0.05). The results' stability was confirmed via sensitivity analysis. FDs treatment for VA aneurysms is efficacious and safe, offering high rates of positive clinical and angiographic outcomes with minimal complications, underscoring FDs' viability as a treatment option for VA aneurysms. The study was registered with PROSPERO (registration number: CRD42024499894).

Endovascular treatments of intracranial vertebral and internal carotid arteries dissections: An interactive systematic review and meta-analysis

INTRODUCTION

Management of intracranial artery dissection (IAD) remains elusive in medical practice. Intracranially, vertebral artery dissection (VAD) is more commonly encountered than internal carotid artery dissection (ICAD). Deconstructive (EVT-d) and reconstructive (EVT-r) endovascular techniques have been utilized to treat VAD and ICAD. This meta-analysis investigates the safety and efficacy of EVT-r and EVT-d in the management of VAD and ICAD.

METHODS

The literature was searched for all studies with consecutive patient series evaluating EVT-d or EVT-r for VAD or ICAD management. Baseline characteristics and outcomes were compared between EVT-r and EVT-d groups using the random-effect model and meta-regression approaches.

RESULTS

Overall, 1095 cases pooled from 56 studies were included. There was no statistically significant difference in baseline characteristics between VAD and ICAD. EVT-r was applied in 647 cases (59.1%) and EVT-d in the rest There was no statistical difference in the rate of procedural complications between EVT-r and EVT-d. Although EVT-d was significantly associated with higher rates of complete aneurysm occlusion (86.4%), lower rates of good clinical outcomes (72.1%) and higher mortality (15.1%) were achieved compared to EVT-r (70.2%, 83.3%, and 9.5%; respectively). The mortality rate was higher, and good clinical outcomes were less common in ruptured aneurysms. Ischemic presentation was statistically associated with poor outcomes (mRS 3-5) but low mortality. ICAD often tended to grow following treatment and resulted in poor neurological outcomes.

CONCLUSIONS

IAD has favorable outcomes when treated appropriately. Novel reconstructive endovascular techniques are promising and should be integrated well in endovascular practice. Further studies are warranted.

Stent-Assisted Coil Embolization Versus Flow-Diverting Stent in Unruptured Vertebral Artery Dissecting Aneurysms: Efficacy and Safety Comparison

BACKGROUND

Reconstructive strategies for unruptured vertebral artery dissecting aneurysms (VADAs) have increasingly relied on newly developed endovascular devices. However, their clinical performance metrics are seldom reported.

OBJECTIVE

To compare stent-assisted coil embolization (SACE) and flow-diverting stent (FDS) deployment as treatments for unruptured VADAs, focusing on efficacy and safety.

METHODS

A total of 72 VADAs were submitted to SACE (n = 48) or FDS (n = 24) between April 2009 and September 2021. We reviewed medical records and radiological data to assess efficacy and safety outcomes by method, building an inverse probability of treatment-weighted (IPTW) logistic regression model and conducting survival analyses.

RESULTS

Ultimately, 24 aneurysms (33.3%) showed signs of recanalization (major, 14; minor, 10) at 6-month follow-up. Initially determined 6-month rates of overall (SACE, 31.2%; FDS, 41.7%) and major (SACE, 20.8%; FDS, 16.7%) recanalization did not differ significantly by modality; but in the IPTW logistic regression model, adjusted for aneurysm morphology, major recanalization at 6 months was lower for the FDS (vs SACE) subset (odds ratio = 0.196; P = .027). Likewise, the cumulative rate of major recanalization was more favorable for the FDS (vs SACE) subset (hazard ratio = 0.291; P = .048) in IPTW Cox proportional hazards model adjusted for aneurysm morphology. Modality-based assessments of procedural and delayed complications were similar.

CONCLUSION

Both reconstructive VADA interventions are safe and effective by adjusting treatment modality depending on the angioanatomic configuration. However, follow-up data after treatment proved more favorable for FDS deployment than for SACE in limiting major recanalization. Case-controlled studies of more sizeable cohorts are needed for corroboration.

The Use of Flow Diverter in Ruptured, Dissecting Intracranial Aneurysms of the Posterior Circulation

OBJECTIVE

Acute dissecting aneurysms of the posterior circulation are a rare cause of subarachnoid hemorrhage. Established endovascular treatment options include parent artery occlusion and stent-assisted coiling, but appear to be associated with an increased risk of ischemic stroke. Vessel reconstruction with flow diverters is an alternative treatment option; however, its safety and efficacy in the acute stage remains unclear.

METHODS

This is a multicentric retrospective analysis of 15 consecutive acutely ruptured dissecting posterior circulation aneurysms treated with flow diverters. The primary end point was favorable aneurysm occlusion, defined as OKM C1-3 and D (O'Kelly Marotta scale). Secondary end points were procedure-related complications and clinical outcome.

RESULTS

Nine of 15 aneurysms (60%) arose from the intradural portion of the vertebral artery, 3 were located on the posterior inferior cerebellar artery and 1 each on the anterior inferior cerebellar artery, posterior cerebral artery, and basilar artery. Flow diverter placement was technically successful in 14 of 15 cases (93%). After endovascular treatment, none of the ruptured aneurysms rebled. Median clinical follow-up was 217 days and median angiographic follow-up was 203 days. Favorable occlusion was observed in 7 of 14 aneurysms (50%) directly after flow diverter placement; of those, 5 were completely occluded (36%). Seven patients (47%) with poor-grade subarachnoid hemorrhage died in the acute phase. Favorable clinical outcome (modified Rankin scale ≤2) was observed in 4 of 15 patients (27%) and a moderate outcome (modified Rankin scale 3/4) was observed in 5 of 15 patients (33%). All aneurysms showed complete occlusion at follow-up.

CONCLUSIONS

Flow diverters might be a feasible, alternative treatment option for acutely ruptured dissecting posterior circulation aneurysms and may effectively prevent rebleeding. Larger cohort studies are required to validate these results.

Predictive factors of medullary infarction after endovascular internal trapping using coils for vertebral artery dissecting aneurysms

OBJECTIVE The first choice of treatment in cases of vertebral artery dissecting aneurysms (VADAs) is endovascular internal trapping (EIT) of the dissecting segment using coils. However, this procedure carries the risk of medullary infarction, and the risk factors for this complication are not well understood. This study investigated the risk factors causing medullary infarction. METHODS One hundred patients who underwent EIT for VADAs were included in this study. Ninety-three patients presented with subarachnoid hemorrhage. In cases involving the posterior inferior cerebellar artery (PICA), partial internal trapping targeting the ruptured site was performed to preserve the PICA. The VADAs were classified into the distal VA stump group, proximal VA stump group, and entire VA stump group, according to the location of VA segments without adequate flow-out vessels (such as the PICA [VA stump]) at risk of delayed thrombosis. The occurrence of medullary infarction was examined in each group using diffusion-weighted MRI and/or clinical symptoms. Various measurements were performed on digital subtraction angiography, and the risk factors for medullary infarction were analyzed. RESULTS Medullary infarction occurred in 30 patients, affecting the posterolateral medulla in 27 patients and the anteromedial medulla in 3 patients. Medullary infarction occurred in 3 of 47 patients (6%) in the distal VA stump group, 10 of 19 patients (53%) in the proximal VA stump group, and 17 of 34 patients (50%) in the entire VA stump group. The length of trapping was significantly longer in the infarction group than in the noninfarction group but did not differ among the 3 groups. Total length (length of trapping plus VA stump) was a risk factor for medullary infarction in the proximal VA stumps. CONCLUSIONS The primary risk factor for medullary infarction after EIT is not the length of trapping; rather, it is the anatomical location of the VADAs. The risk of medullary infarction is low in cases with distal VA stumps, but the symptoms are severe. Preservation of the origin of the anterior spinal artery can reduce the risk of medullary infarction. The risk of medullary infarction is high in cases with proximal VA stumps, but the symptoms are mild. A shorter length of trapping, although less likely to lead to complications, cannot prevent medullary infarction because the total length depends on the anatomical location of the PICA and not on the surgical technique. Reconstructive therapy should be indicated for patients with ruptured VADAs at high risk of severe ischemic complications (e.g., patients with hypoplasia of the contralateral VA or cases involving the PICA or anterior spinal artery, which are inappropriate for partial internal trapping) or for patients with unruptured VADAs.

Surgical Management of Intracranial Artery Dissection

Intracranial artery dissection (IAD) is a relatively rare cause of stroke, but it has been recognized increasingly with recent advances of the neuroimaging technique. Since rebleeding occurs frequently in the acute stage in the ruptured IAD, urgent surgical treatment should be performed to prevent rebleeding. On the other hand, surgical treatment for unruptured IAD is controversial because it has little risk for bleeding. However, surgical treatment for unruptured IAD may be considered if the formation or enlargement of the aneurysmal dilatation has been confirmed. Since there are several proposed surgical strategies for IAD, it is important to select an appropriate strategy on a case-by-case basis. If the risk of infarction due to vessel occlusion is high, combined bypass surgery should be considered.

Therapeutic Progress in Treating Vertebral Dissecting Aneurysms Involving the Posterior Inferior Cerebellar Artery

Among the variations of vertebral artery dissecting aneurysms (VDAs), VDAs involving the posterior inferior cerebellar artery (PICA), especially ruptured and high-risk unruptured aneurysms, are the most difficult to treat. Because the PICA is an important structure, serious symptoms may occur after its occlusion. Retained PICAs are prone to re-bleeding because VDAs are difficult to completely occlude. There is therefore confusion regarding the appropriate treatment for VDAs involving the PICA. Here, we used the PubMed database to review recent research concerning VDAs that involve the PICA, and we found that treatments for VDAs involving the PICA include (i) endovascular treatment involving the reconstruction of blood vessels and blood flow, (ii) occluding the aneurysm using an internal coil trapping or an assisted bypass, (iii) inducing reversed blood flow by occluding the proximal VDA or forming an assisted bypass, or (iv) the reconstruction of blood flow via a craniotomy. Although the above methods effectively treat VDAs involving the PICA, each method is associated with both a high degree of risk and specific advantages and disadvantages. The core problem when treating VDAs involving the PICA is to retain the PICA while occluding the aneurysm. Therefore, the method is generally selected on a case-by-case basis according to the characteristics of the aneurysm. In this study, we summarize the various current methods that are used to treat VDAs involving the PICA and provide schematic diagrams as our conclusion. Because there is no special field of research concerning VDAs involving the PICA, these cases are hidden within many multiple-cases studies. Therefore, this study does not review all relevant documents and may have some limitations. Thus, we have focused on the mainstream treatments for VDAs that involve the PICA.

Effect of coil packing proximal to the dilated segment on postoperative medullary infarction and prognosis following internal trapping for ruptured vertebral artery dissection

INTRODUCTION

Medullary infarction is an important complication of internal trapping for vertebral artery dissection. This study investigated risk factors for medullary infarction following internal trapping of ruptured vertebral artery dissection.

METHODS

We retrospectively studied 26 patients with ruptured vertebral artery dissection who underwent endovascular treatment and postoperative magnetic resonance imaging between April 2001 and March 2013. Clinical and radiological findings were analyzed to identify factors associated with postoperative medullary infarction.

RESULTS

Ten of the 26 patients (38%) showed postoperative lateral medullary infarction on magnetic resonance imaging. Multivariate logistic regression analysis revealed that medullary infarction was independently associated with poor clinical outcome (odds ratio (OR) 17.01; 95% confidence interval (CI) 1.68-436.81; p=0.032). Univariate analysis identified vertebral artery dissection on the right side and longer length of the entire trapped area as risk factors for postoperative medullary infarction. When the trapped area was divided into three segments (dilated, distal, and proximal segments), proximal segment length, but not dilated segment length, was significantly associated with medullary infarction (OR 1.55 for a 1-mm increase in proximal segment length; 95% CI 1.15-2.63; p=0.027). Receiver operating characteristic analysis showed that proximal segment length offered a good predictor of the risk of postoperative medullary infarction, with a cut-off value of 5.8 mm (sensitivity 100%; specificity 82.3%).

CONCLUSIONS

Longer length of the trapped area, specifically the segment proximal to the dilated portion, is associated with a higher incidence of medullary infarction following internal trapping, indicating that this complication may be avoidable.

Endovascular interventional therapy and classification of vertebral artery dissecting aneurysms

The current study aimed to summarise the clinical features and classifications of vertebral artery dissecting aneurysms (VADAs) to optimise strategies for endovascular interventional therapy. The clinical features and results of 31 inpatients with VADA were retrospectively analysed. The aneurysms were classified according to their location and association between the aneurysm and posterior inferior cerebellar artery (PICA), and into subtypes according to the developmental state of the contralateral vertebral artery. Different endovascular interventional therapy strategies were selected for each classification. Three types of aneurysm with two subtypes each were identified. An aneurysm located distally to the PICA was termed type I (10/31 patients). Aneurysms with a contralateral vertebral artery were denoted as subtype a (type Ia, 6/31 patients) and aneurysms with hypoplasia of the contralateral vertebral artery were denoted as subtype b (type Ib, 4/31 patients). An aneurysm located at the origin of the PICA was termed type II (13/31 patients), with seven cases classified as IIa and six cases as IIb. An aneurysm located proximally to the PICA was termed type III (8/31 patients), with five cases classified as IIIa and three cases as IIIb. Among the 31 patients, 18 received stent-assisted coiling, two received coiling, 10 received coiling with parent artery occlusion and one patient received conservative treatment. Among the 31 patients with VADA, 21 were occluded completely, nine were partially occluded and one was not occluded. One patient developed a coma following coiling; however, the other 30 patients recovered well. Thus, the classification of an aneurysm based on its location and the developmental state of the contralateral vertebral arteries appears to be an effective and safe approach for the selection of appropriate endovascular interventional therapy strategies.

Endovascular treatment for ruptured vertebral artery dissecting aneurysms: results from Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2

In treating ruptured vertebral artery dissecting aneurysms (VADAs), neuroendovascular therapy (NET) represented by coil obliteration is considered to be a reliable intervention. However, there has been no multi-center based study in this setting so far. In this article, results of NET for ruptured VADA obtained from Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2 were assessed to elucidate the factors associated with favorable outcome. A total of 213 in JR-NET1 and 381 patients in JR-NET2 with ruptured VADA were included, and they were separately analyzed because several important datasets such as vasospasm and site of dissecting aneurysms in relation to the posterior inferior cerebellar artery (PICA) were collected only in JR-NET1. The ratio of poor World Federation of Neurosurgical Societies (WFNS) grade (4 and 5) was 48.8% and 53.9%, and the ratio of favorable outcome (modified Rankin scale, mRS 0 to 2) at 30 days after onset was 61.1 % and 49.1% in JR-NET1 and 2, respectively. In both studies, poor WFNS grade and procedural complication were independently correlated as negative factors for favorable outcome. In JR-NET1, PICA-involved lesion was also designated as a negative factor while elderly age and absence of postprocedural antithrombotic therapy was detected as other negative factors in JR-NET2. The ratios of favorable outcome in poor grade patients were 25.4% in JR-NET1 and 31.3% in JR-NET2, which seemed compatible with the previous studies. These results may provide a baseline data for the NET in this disease and could be useful for validating the benefits of novel devices.

Flow-diverting stent for ruptured intracranial dissecting aneurysm of vertebral artery

BACKGROUND

The treatment of ruptured dissecting aneurysms of the intracranial vertebral artery (VA) with parent vessel preservation is a challenge for neurosurgeons and interventional neuroradiologists.

OBJECTIVE

To propose an indication for flow-diverting treatment for reconstruction of a dissecting VA with acute subarachnoid hemorrhage.

METHODS

Two male patients transferred after acute subarachnoid hemorrhage and dissecting aneurysm on the V4 segment of the dominant VA. An occlusion test was not performed because of their poor clinical state. A flow-diverting stent represented by the Pipeline embolization device was suggested to both patients.

RESULTS

Three Pipeline embolization devices were deployed in each VA. One dissecting aneurysm was excluded immediately after 3 stents, and 1 patient had complete exclusion demonstrated at the 48-hour control. No morbidity directly related to the procedure was observed. No recanalization and no rebleeding occurred during the 3 months of follow-up.

CONCLUSION

A flow-diverting stent may be considered an option to treat ruptured dissecting aneurysms of the VA, providing remodeling of the parent vessel and complete exclusion of the aneurysm.

Intracranial aneurysms associated with a double origin of the posterior inferior cerebellar artery

The posterior inferior cerebellar artery (PICA) frequently has a variable course and target territory. However, double origin PICA is a rare finding. Its significance is uncertain, but it has been associated with intracranial aneurysms localized at the PICA proper or at a distant site. The presence of this variation imposes specific challenges. We describe two cases of double origin PICA, one of them associated with an ipsilateral PICA aneurysm. The role of this finding was critically reviewed. A literature search identified 23 cases of double origin PICA, including both cases reported in this paper. Intracranial aneurysms were strongly associated with double origin PICA (71% in 21 detailed cases of double origin PICA). The current patient harboring a PICA aneurysm was successfully treated by endovascular trapping. In the setting of double origin PICA aneurysms, this variation beneficially affects the treatment choice once the two limbs enable the safe sacrifice of the channel involved, with preservation of blood flow through the other channel.

Endovascular treatment for cerebral aneurysms using stents

Endovascular stent placement combined with coil embolization is an established procedure for the treatment of intracranial aneurysms. We describe lesion outcome using stents for the treatment of intracranial aneurysms. Sixty-nine patients (30 females and 39 males; age range 12-78 years) treated with stent placement at Beijing Tiantan Hospital over a six-year period. Seventy- six cerebral aneurysms were encountered and 74 lesions were treated with 79 stents. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 32 months. Of the 74 stented aneurysms, 34 (45.9%) were located in the anterior circulation and 40 (54.1%) in the posterior circulation. Forty-eight (64.9%) aneurysms were small and 26 (35.1%) were large or giant. In 67 (90.5%) aneurysms embolization was completed by packing the aneurysm sac with platinum coils. In five small fusiform and four saccular aneurysms, the stent was used alone. Six procedure-related complications were observed and a cause of death in 7.2% of the patients. Follow-up angiography obtained at three months to one year in 68 (91.9%) aneurysms demonstrated complete occlusion in 43 aneurysms with a progressive thrombosis rate of 19.4% (six out of 31 aneurysms). Aneurysm recurrence occurred in four (5.8%) patients, three were treated with coil embolization and one with placement of another stent. Overall long-term outcome was good (GOS Score 4 or 5) in 92.8%, and fatal (GOS Score 1) in 7.2% of the patients. Intracranial stents can be a useful addition to coil embolization for complex broad-based aneurysms. Favorable overall long-term outcome can be achieved in 92.8% of patients when using endovascular stent placement techniques.

Endovascular treatment using stents for vertebral artery fusiform aneurysms

BACKGROUND

To report our experience with 12 ruptured and 12 unruptured vertebral artery (VA) fusiform aneurysms treated endovascularly using stents.

METHODS

Three patients were female and 20 patients were male; their mean age was 43·7 (17-77) years. Altogether, 25 stents were placed in 23 patients for 24 fusiform VA aneurysms.

RESULTS

All patients were successfully treated using stents; in 19 patients, we also coil-embolized the aneurysmal lumen. One aneurysm was treated by the placement of two stents covering the dissection site. No technical complications were encountered. According to the Glasgow outcome scale, at follow-up after treatment, 22 patients (95·7%) made a good recovery and one (4·3%) died due to rebleeding during the procedure.

CONCLUSION

Endovascular therapy using stents may be a useful treatment in patients with fusiform VA aneurysms involving the posterior inferior cerebellar artery or hypoplasia of the contralateral VA or unruptured VA aneurysms.

Angiographic and clinical outcomes of stent-alone treatment for spontaneous vertebrobasilar dissecting aneurysm

PURPOSE

Spontaneous vertebrobasilar dissecting aneurysm (VBD) is a very challenging disease with an unpredictable clinical course and controversies on treatment strategy. The present study reports radiological and clinical outcomes of stent-alone treatment (SAT) for VBD.

METHODS

Twenty-four VBDs treated with SAT are included in the present study. Clinical and angiographic data were reviewed retrospectively.

RESULTS

A total of 24 lesions in 22 patients with a mean follow-up period of 16.21 months were included. Of the 24 individual lesions, 23 were intracranial vertebral artery lesions and 1 lesion was located in the basilar artery. There were six cases of ruptured dissections with the other cases having various symptoms. The immediate post-SAT angiographic outcomes included 5 lesions with good remodeling over 90% recovery and 19 poorly remodeled lesions. The latest angiographic outcomes included 17 cases of good remodeling (remodeling rate over 90%), 6 cases of poor remodeling (remodeling rate below 70%), and 1 case with morphological aggravation. The overlapping stent technique was used in seven cases and it was significantly associated with good angiographic results. None of the rupture cases underwent re-rupture post SAT. There was one case of a symptomatic complication of a femoral arteriovenous fistula.

CONCLUSIONS

The SAT could be a feasible alternative for the treatment of VBD. The overlapping technique was significantly associated with good angiographic outcome. We expect that technological development of the intracranial stent will allow better procedural outcomes of SAT.