Clinical and radiological risk factors for rupture of vertebral artery dissecting aneurysm: significance of the stagnation sign

Risk factors for the rupture of intracranial aneurysms: a systematic review and meta-analysis

Purpose

The study aimed to identify potential risk factors for aneurysm rupture by performing a systematic review and meta-analysis.

Materials and methods

We systematically searched the PubMed, Embase, and Cochrane Library electronic databases for eligible studies from their inception until June 2023.

Results

Eighteen studies involving 17,069 patients with unruptured intracranial aneurysm (UIA) and 2,699 aneurysm ruptures were selected for the meta-analysis. Hyperlipidemia [odds ratio (OR): 0.47; 95% confidence interval (CI): 0.39-0.56; p < 0.001] and a family history of subarachnoid hemorrhage (SAH) (OR: 0.81; 95% CI: 0.71-0.91; p = 0.001) were associated with a reduced risk of aneurysm rupture. In contrast, a large-size aneurysm (OR: 4.49; 95% CI: 2.46-8.17; p < 0.001), ACA (OR: 3.34; 95% CI: 1.94-5.76; p < 0.001), MCA (OR: 2.16; 95% CI: 1.73-2.69; p < 0.001), and VABA (OR: 2.20; 95% CI: 1.24-3.91; p = 0.007) were associated with an increased risk of aneurysm rupture. Furthermore, the risk of aneurysm rupture was not affected by age, sex, current smoking, hypertension, diabetes mellitus, a history of SAH, and multiple aneurysms.

Conclusion

This study identified the predictors of aneurysm rupture in patients with UIAs, including hyperlipidemia, a family history of SAH, a large-size aneurysm, ACA, MCA, and VABA; patients at high risk for aneurysm rupture should be carefully monitored.

Systematic Review Registration

Our study was registered in the INPLASY platform (INPLASY202360062).

Significance of headache in intracranial vertebrobasilar artery dissections: an observational study

Headache may represent acute phase of intracranial vertebrobasilar artery dissection (iVBAD). We aimed to evaluate its clinical significance in iVBAD. Consecutive acute iVBAD patients were grouped into ruptured iVBAD, unruptured iVBAD with no headache, isolated headache, or concurrent headache with neurological symptoms. Composite hemorrhagic/ischemic endpoints, and dynamic arterial changes were graded. Clinical characteristics of the four groups, and association between headache and composite outcomes was evaluated. Headaches were precedent in 79% of the ruptured iVBAD patients (maximal delay, 10D). In unruptured iVBAD, when patients with no headache (N = 69), concurrent headache (N = 111), and isolated headache (N = 126) were compared, concurrent headache was associated with ischemic endpoints (isolated headache as reference, adjusted odds ratio: 6.40, 95% confidence interval [2.03-20.19]). While there were no differences in hemorrhagic endpoints, dynamic arterial changes were higher in the isolated headache group (aOR: 3.98, 95% CI [1.72-9.18]) but not for the concurrent headache group (aOR: 1.59 [0.75-3.38]) compared to no headache group. Headache was more commonly severe (48.4% vs. 17.3%, p < 0.001) and ipsilateral (59.7% vs. 45.5%, p = 0.03) for isolated headache compared to concurrent headache, indicating a higher causal relationship. In iVBAD, isolated headache may be considered an acute-phase biomarker, associated with dynamic arterial changes.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Computational fluid dynamics-based virtual angiograms for the detection of flow stagnation in intracranial aneurysms

The goal of this study was to test if CFD-based virtual angiograms could be used to automatically discriminate between intracranial aneurysms (IAs) with and without flow stagnation. Time density curves (TDC) were extracted from patient digital subtraction angiography (DSA) image sequences by computing the average gray level intensity inside the aneurysm region and used to define injection profiles for each subject. Subject-specific 3D models were reconstructed from 3D rotational angiography (3DRA) and computational fluid dynamics (CFD) simulations were performed to simulate the blood flow inside IAs. Transport equations were solved numerically to simulate the dynamics of contrast injection into the parent arteries and IAs and then the contrast retention time (RET) was calculated. The importance of gravitational pooling of contrast agent within the aneurysm was evaluated by modeling contrast agent and blood as a mixture of two fluids with different densities and viscosities. Virtual angiograms can reproduce DSA sequences if the correct injection profile is used. RET can identify aneurysms with significant flow stagnation even when the injection profile is not known. Using a small sample of 14 IAs of which seven were previously classified as having flow stagnation, it was found that a threshold RET value of 0.46 s can successfully identify flow stagnation. CFD-based prediction of stagnation was in more than 90% agreement with independent visual DSA assessment of stagnation in a second sample of 34 IAs. While gravitational pooling prolonged contrast retention time it did not affect the predictive capabilities of RET. CFD-based virtual angiograms can detect flow stagnation in IAs and can be used to automatically identify aneurysms with flow stagnation even without including gravitational effects on contrast agents.

Flow diverters in the treatment of unruptured vertebral artery dissecting aneurysm: A single-center experience

Objective

To evaluate the efficacy and safety of flow diverters (FD) in the treatment of vertebral artery dissecting aneurysm (VADA).

Methods

A total of 16 patients with 17 unruptured VADAs treated with FD from January 2017 to May 2021 were included. Data of clinical outcomes and radiographic examination were collected and assessed by the modified Rankin Scale (mRS) and O'Kelly-Marotta (OKM) grading scale.

Results

All patients were treated with a single FD. No perioperative complications occurred. The mean age was 55.1 years old. The mean size of the aneurysm was 10.4 mm. All patients had a favorable occlusion (OKM D + C3) result and the complete occlusion rate in the 6th month was 66.7% (OKM D). The mean clinical follow-up time was 7.8 months, and all patients had a good clinical outcome (mRS = 0). No procedure-related complication occurred at the last follow-up time.

Conclusion

FD is an effective and safe tool for treating unruptured VADA. Long-term prospective studies with a large sample are still needed to confirm these findings in the future.

Spontaneous healing and complete disappearance of an intracranial vertebral artery dissecting aneurysm: A case report

RATIONALE

Intracranial vertebrobasilar dissecting aneurysms (VBDAs) are associated with a greater tendency to rupture and a greater risk of worse outcomes than anterior circulation aneurysms. Spontaneous healing of a VBDA is very rare, and there have been very few case reports of spontaneous healing of an aneurysm. We describe a case of intracranial vertebral artery dissecting aneurysm that healed spontaneously and disappeared completely on follow-up images.

PATIENT CONCERNS

A 40-years-old woman was referred to the neurology department because of a persistent headache, especially in the left occiput.

DIAGNOSES

Magnetic resonance angiography and computed tomography angiography showed a left vertebral artery dissection-like aneurysm (4.5 × 2.0 × 2.5 mm in size) with proximal parent artery mild stenosis (40%).

INTERVENTIONS

Flunarizine hydrochloride was administered for symptomatic treatment and follow-up angiography was performed.

OUTCOMES

Digital subtraction angiography and magnetic resonance angiography showed that the aneurysm had completely disappeared at 3 months follow-up. High-resolution magnetic resonance vessel wall imaging revealed intimal thickening and mild stenosis in the left intracranial vertebral artery without an aneurysm signal. In addition, enhancement scanning revealed that the aneurysm area was moderately enhanced. MR-vessel wall imaging at 7 months follow-up showed that the enhancement was slightly reduced compared with the previous time.

LESSONS

This case illustrates the relatively plastic nature of a vertebral dissecting aneurysm, indicating that spontaneous healing remains possible.