Utility of flow diverters in treatment of acutely ruptured uncoilable aneurysms of the posterior circulation of the brain

Treatment of ruptured intracranial aneurysms with parent artery flow diverter devices: A comprehensive systematic review and meta-analysis

BACKGROUND

Surgical clipping and endovascular coiling are well-established treatments for acutely ruptured intracranial aneurysms leading to acute subarachnoid hemorrhage (aSAH). However, these modalities have limitations, particularly in cases involving wide-necked, bifurcating, or dissecting aneurysms. Flow diverter (FD) devices, initially used for unruptured aneurysms, have emerged as an alternative treatment for ruptured aneurysms despite concerns about hemorrhagic complications.

AIMS

This study aimed to perform a comprehensive systematic review and meta-analysis to assess the efficacy and safety of parental artery FD devices in treating ruptured intracranial aneurysms.

METHODS

A systematic search was conducted in Medline, Embase, and Cochrane databases from inception to July 2024. The inclusion criteria focused on studies involving patients with acutely ruptured aneurysms treated with parental artery FDs, with or without adjunctive coiling. Studies were required to report clear, stratified data specific to the population of interest, and include more than five patients. Exclusion criteria included studies on non-ruptured aneurysms, intrasaccular flow diversion devices, or previously clipped aneurysms treated with FD. Data extraction was performed independently by two authors, and statistical analysis included single proportion analysis with 95% confidence intervals under a random-effects model, using R Studio. The primary outcome was the rate of aneurysm occlusion at follow-up.

SUMMARY OF REVIEW

A total of 60 studies encompassing 1300 patients were included. The primary outcome analysis revealed a 90% (95% CI: 87-92%; I2 = 51%) rate of total occlusion at follow-up. Subgroup analysis indicated an occlusion rate of 89% for anterior circulation aneurysms and 96% for posterior circulation aneurysms. Intraoperative complications occurred in 6% of cases, while postoperative complications were observed in 13%. Rebleeding rates were low at 1%, with a 2% need for retreatment. Good functional outcomes (mRS ⩽ 2) were achieved in 82% of patients, and the overall mortality rate was 4%.

CONCLUSIONS

FD devices demonstrated high rates of aneurysm occlusion and favorable functional outcomes in patients with acutely ruptured intracranial aneurysms. However, the low mortality rate and favorable outcomes observed may reflect selection bias toward patients with less severe SAH. Despite a modest complication rate, the overall safety and efficacy of FD devices suggest they may be a viable alternative to traditional treatments for specific aneurysm types. Further studies, including a broader spectrum of SAH severities, are warranted to optimize their use in clinical practice.

Cranial and spinal computed tomography (CT) angiography with photon-counting detector CT: comparison with angiographic and operative findings

The clinical imaging features of photon-counting detector (PCD) computed tomography (CT) are mainly known as dose reduction, improvement of spatial resolution, and reduction of artifacts compared to energy-integrating detector CT (EID-CT). The utility of cranial and spinal PCD-CT and PCD-CT angiography (CTA) has been previously reported. CTA is a widely used technique for noninvasive evaluation. Cranial CTA is important in brain tumors, especially glioblastoma; it evaluates whether the tumor is highly vascularized prior to an operation and helps in the diagnosis and assessment of bleeding risk. Spinal CTA has an important role in the estimation of feeders and drainers prior to selective angiography in the cases of spinal epidural arteriovenous fistulas and spinal tumors, especially in hemangioblastoma. So far, EID-CTA is commonly performed in an adjunctive role prior to selective angiography; PCD-CTA with high spatial resolution can be an alternative to selective angiography. In the cases of cerebral aneurysms, flow diverters are important tools for the treatment of intracranial aneurysms, and postoperative evaluation with cone beam CT with angiography using diluted contrast media is performed to evaluate stent adhesion and in-stent thrombosis. If CTA can replace selective angiography, it will be less invasive for the patient. In this review, we present representative cases with PCD-CT. We also show how well the cranial and spinal PCD-CTA approaches the accuracy of angiographic and intraoperative findings.

Predicting the O'Kelly-Marotta scale score after flow-diverter stent placement using silent MRA

PURPOSE

Flow-diverter (FD) stents were developed to treat aneurysms that are difficult to treat with conventional coiling or surgery. This study aimed to compare usefulness of Silent MRA and TOF (time of flight) -MRA in patients with aneurysms after FD placement.

MATERIALS AND METHODS

We retrospectively collected images from 22 patients with 23 internal carotid artery aneurysms treated with FD. Two radiologists conducted MRA and DSA experiments. In the first reading experiment, the radiologists evaluated the aneurysm filling by employing Silent MRA and TOF-MRA and utilizing the modified O'Kelly-Marotta (OKM) scale, a four-class classification system for aneurysms after FD placement. We then calculated the agreement between the modified OKM scale on MRA and the original OKM scale on DSA. In the second reading experiment, the radiologists rated blood flow within the FD using a five-point scale.

RESULTS

The weighted kappa value of the OKM scale between DSA and TOF-MRA was 0.436 (moderate agreement), and that between DSA and Silent MRA was 0.943 (almost perfect agreement). The accuracies for the four-class classification were 0.435 and 0.870 for TOF-MRA and Silent MRA, respectively. The mean score of blood flow within FD for TOF-MRA was 2.43 ± 0.90 and that for Silent MRA was 3.04 ± 1.02 (P < 0.001).

CONCLUSION

Silent MRA showed a higher degree of agreement than TOF-MRA in aneurysm filling with DSA. In addition, Silent MRA was significantly superior to TOF-MRA in depicting blood flow within the FD. Therefore, Silent MRA is clinically useful for the follow-up of patients after FD placement.

Endovascular treatment of ruptured basilar artery trunk aneurysms: complications and long-term outcomes

OBJECT

Treatment of ruptured basilar artery trunk (BAT) aneurysms is challenging, and is associated with high complication and mortality rates. Herein, we analyzed the complications, long-term outcomes, and outcome predictors of endovascular treatment for ruptured BAT aneurysms.

METHODS

Between January 2011 and July 2023, 36 patients with 36 ruptured BAT aneurysms underwent endovascular treatment at our institution. The postprocedural complications and clinical and angiographic outcomes were subsequently reviewed, and the risk factors for postprocedural complications were evaluated.

RESULTS

All 36 aneurysms in 36 patients were treated successfully. The median clinical follow-up time was 47.0 (IQR: 10.5, 84.5) months. Overall, complications occurred in 10 (27.8%) patients, including 3 (8.3%) deaths. Ischemic events occurred in seven (19.4%) patients, while three (8.3%) patients had shunt-dependent hydrocephalus, of whom one (2.8%) patient had both shunt-dependent hydrocephalus and ischemic events. The cumulative survival rates at 3 and 5 years were 94.1% and 87.8%, respectively. The cumulative 3- and 5-year complication-free survival rates were 75.0% and 70.0%, respectively. Multivariate Cox regression analysis revealed that diabetes mellitus (HR:8.76, 95%CI:2.35-32.69, p=0.001), and Glasgow coma scale score ≤ 12 before the procedure (HR:5.04, 95%CI:1.40-18.12, p=0.013) were associated with overall postprocedural complications. The complete aneurysm occlusion rate was 61.5% at a median angiography follow-up time of 6.0 (IQR: 5.0, 6.0) months.

CONCLUSIONS

Endovascular treatment is a safe and feasible option for treating ruptured BAT aneurysms. The rate of favorable outcomes at the final follow-up was satisfactory. However, postprocedural complications, particularly ischemic events, should be carefully considered.

Current research status and future of endovascular treatment for basilar artery aneurysms

Aneurysms occurring along the basilar artery (BA) account for <1% of all intracranial aneurysms. Endovascular treatment (EVT) in particular is recommended for large unruptured BA aneurysms and ruptured BA aneurysms. Given that EVT techniques vary, a detailed review of EVT for BA aneurysms is necessary. In this review, the following issues were discussed: the anatomy and anomalies of the BA, the classification of BA aneurysms, the natural history of BA aneurysms, the status of open surgery, the use of EVT for various types of BA aneurysms and the deployment of new devices. According to the findings of this review and based on our experience in treating BA aneurysms, traditional coiling EVT is still the optimal therapy for most BA aneurysms. However, in some BA aneurysms, flow diverter (FD) deployment can be used. In addition, there are also some new devices, such as intrasaccular flow disruptors and stent-like devices that can be used to treat BA aneurysms. In general, EVT can yield good clinical and angiographic outcomes for patients with BA aneurysms. In addition, recent new devices and techniques, such as new-generation FDs generated via surface modification and virtual reality simulation techniques, show promise for EVT for BA aneurysms. These devices and techniques may further improve EVT outcomes for BA aneurysms.

Ruptured basilar artery perforator aneurysm mimicking superior cerebellar artery aneurysm

BACKGROUND AND IMPORTANCE

The diagnosis of basilar artery perforator aneurysm is difficult due to their small size, with high rates of negative angiography. Furthermore, due to the considerable variation of basilar artery perforator (BAP), even if an aneurysm originates from a BAP, it is often difficult to clearly identify its origin on angiography.

CLINICAL PRESENTATION

A 46-female patient presented with World Federation of Neurological Surgeons Scale 1 subarachnoid hemorrhage. Initial imaging study, including digital subtraction angiography (DSA), revealed no vascular lesions. Two-week after admission, DSA revealed an aneurysm arising from the left superior cerebellar artery (SCA). Endovascular coil embolization was planned first. However, aneurysm selection using microcatheter was failed. Then, surgical approach was done via pre-temporal approach. We identified SCA, but there was no aneurysm. Further dissection revealed an aneurysm arising from basilar artery perforator, which was overlapped by SCA. The parent artery of the aneurysm arose from juxtaproximal to the orifice of left SCA, and crossed SCA at the juxtadistal to the aneurismal sac. Complete clip occlusion was done preserving BAP. After the surgery, the patient developed diplopia without extraoccular movement limitations. Two-month after the surgery, she was fully recovered without any neurologic deficits.

CONCLUSION

It is crucial to adequately consider the possibility of open surgery as a viable option in case that endovascular treatment of aneurysms originated from the distal segment of basilar artery proves unsuccessful.