Outcomes after Flow Diverter Treatment in Subarachnoid Hemorrhage: A Meta-Analysis and Development of a Clinical Prediction Model (OUTFLOW).

BACKGROUND: patients with a subarachnoid hemorrhage (SAH) might need a flow diverter (FD) placement for complex acutely ruptured intracranial aneurysms (IAs). We conducted a meta-analysis and developed a prediction model to estimate the favorable clinical outcome after the FD treatment in acutely ruptured IAs. METHODS: a systematic literature search was performed from 2010 to January 2021 in PubMed and Embase databases. Studies with more than five patients treated with FDs within fifteen days were included. In total, 1157 studies were identified. The primary outcome measure was the favorable clinical outcome (mRS 0-2). Secondary outcome measures were complete occlusion rates, aneurysm rebleeding, permanent neurologic deficit caused by procedure-related complications, and all-cause mortality. A prediction model was constructed using individual patient-level data. RESULTS: 26 retrospective studies with 357 patients and 368 aneurysms were included. The pooled rates of the favorable clinical outcome, mortality, and complete aneurysm occlusion were 73.7% (95% CI 64.7-81.0), 17.1% (95% CI 13.3-21.8), and 85.6% (95% CI 80.4-89.6), respectively. Rebleeding occurred in 3% of aneurysms (11/368). The c-statistic of the final model was 0.83 (95% CI 0.76-0.89). All the studies provided a very low quality of evidence. CONCLUSIONS: FD treatment can be considered for complex ruptured IAs. Despite high complication rates, the pooled clinical outcomes seem favorable. The prediction model needs to be validated by larger prospective studies before clinical application.

Limitations of Flow Diverters in Posterior Communicating Artery Aneurysms.

BACKGROUND: Treatment of intracranial aneurysms with flow diverters (FDs) showed promising results. However, a subset of patients treated for posterior communicating artery (PComA) aneurysms has variable occlusion rates. Especially the fetal type-associated PComA aneurysms seemed to respond differently to treatment. We analyze our series of fetal type PComA aneurysms treated with a FD. The literature on this subject is reviewed. METHODS: Data from patients treated with FD for all PComA aneurysms at the RadboudUMC Nijmegen were retrospectively analysed. Primary end-point was complete aneurysm occlusion at six months. Secondary end-points were clinical outcome, treatment safety, and results of secondary treatment after non-closure. The results for the fetal PComA aneurysms were compared to the literature. RESULTS: Nineteen consecutive patients harboring 21 PComA aneurysms were treated. Three aneurysms had ipsilateral fetal type PCA (14.3%). Overall, none of the fetal type PcomA aneurysm showed complete occlusion versus 77.8% of the others (p = 0.03). Mortality and permanent morbidity rates were respectively 5.3% and 0%. CONCLUSIONS: FD treatment for PComA aneurysm with fetal type circulation seemed to be less effective compared to other types of PComA aneurysms. Flow characteristics at the PComA bifurcation are thought to be causative Alternative strategies should be considered as first line treatment.

Flow diversion treatment for acutely ruptured aneurysms.

BACKGROUND AND PURPOSE: Flow diverters are sometimes used in the setting of acutely ruptured aneurysms. However, thromboembolic and hemorrhagic complications are feared and evidence regarding safety is limited. Therefore, in this multicenter study we evaluated complications, clinical, and angiographic outcomes of patients treated with a flow diverter for acutely ruptured aneurysms. METHODS: We conducted a retrospective observational study of 44 consecutive patients who underwent flow diverter treatment within 15 days after rupture of an intracranial aneurysm at six centers. The primary end point was good clinical outcome, defined as modified Rankin Scale score (mRS) 0-2. Secondary endpoints were procedure-related complications and complete aneurysm occlusion at follow-up. RESULTS: At follow-up (median 3.4 months) 20 patients (45%) had a good clinical outcome. In 20 patients (45%), 25 procedure-related complications occurred. These resulted in permanent neurologic deficits in 12 patients (27%). In 5 patients (11%) aneurysm re-rupture occurred. Eight patients died resulting in an all-cause mortality rate of 18%. Procedure-related complications were associated with a poor clinical outcome (mRS 3-6; OR 5.1(95% CI 1.0 to 24.9), p=0.04). Large aneurysms were prone to re-rupture with rebleed rates of 60% (3/5) vs 5% (2/39) (p=0.01) for aneurysms with a size ≥20 mm and <20 mm, respectively. Follow-up angiography in 29 patients (median 9.7 months) showed complete aneurysm occlusion in 27 (93%). CONCLUSION: Flow diverter treatment of ruptured intracranial aneurysms was associated with high rates of procedure-related complications including aneurysm re-ruptures. Complications were associated with poor clinical outcome. In patients with available angiographic follow-up, a high occlusion rate was observed.

NeuroForm Atlas Stent-Assisted Coiling: Preliminary Results.

BACKGROUND: Stent-assisted coiling (SAC) is increasingly being performed as intervention for wide-neck intracranial aneurysms. The NeuroForm Atlas Stent (CE-marked; Stryker, Kalamazoo, Michigan) is relatively new. OBJECTIVE: To evaluate the effectiveness and safety of NeuroForm Atlas SAC for intracranial aneurysms in the first such study. METHODS: We retrospectively analyzed data from all patients treated with the NeuroForm Atlas SAC of an intracranial aneurysm, both ruptured and unruptured, between June 2015 and December 2016. Primary end-points were favorable clinical outcomes (modified Rankin scale score 0-2) and successful aneurysm occlusion (Raymond-Roy class I/II), both at 6-mo follow-up. Secondary end-points were the occurrence of intervention-related complications leading to permanent neurological deficit, the occurrence of intervention-related stroke and neurological death, immediate aneurysm occlusion, rupture (or rerupture) of the aneurysm, and recanalization. RESULTS: Twenty-seven consecutive patients, 10 with ruptured saccular wide-neck aneurysms, were treated with NeuroForm Atlas SAC. At 6-mo follow-up, 18/26 (69.2%) survivors had successful aneurysm occlusion and 22/26 (84.6%) had favorable clinical outcome. One patient had died of a cause unrelated to treatment. No intervention-related complications leading to permanent neurological deficit occurred. However, intraprocedural thromboembolic complications occurred in 4/27 patients (14.8%), and ischemic stroke related to treatment occurred in 4/26 (15.4%). No hemorrhagic complications were observed. CONCLUSION: NeuroForm Atlas SAC is a feasible way to treat ruptured and unruptured wide-neck aneurysms that are not amenable to conventional coiling or clipping. Aneurysm occlusion and favorable clinical outcome are consistent with previously reported rates for SAC of wide-neck aneurysms with other devices.