# Flow diverter treatment for saccular unruptured intracranial aneurysms: A systematic review focussing on study quality and initial outcomes

## TL;DR

This review evaluates the quality and outcomes of flow-diverting stent treatments for unruptured brain aneurysms, finding limited high-quality evidence and notable complications.

## Contribution

The study provides an updated systematic review with a focus on methodological quality and financial bias in flow-diverting stent research.

## Key findings

- Most studies on flow-diverting stents for aneurysms had poor or moderate methodological quality.
- Complications and neurological worsening occurred in a significant proportion of patients within 3 months.
- Financial conflicts of interest were reported in nearly half of the included studies.

## Abstract

Flow-diverting (FD) stents are increasingly used to treat small, unruptured intracranial aneurysms (UIA), but high-quality, unbiased data on initial complications and clinical outcomes were limited in previous literature reviews. We updated the literature review to assess quality, potential bias, complications and short-term outcomes in studies on FD-stents for UIAs.

We systematically searched PubMed, Embase and Cochrane Library until January 9, 2025 for studies on FD-stents for UIAs. We assessed methodological quality using the methodological index for non-randomised studies (poor: 0–9, moderate: 10–13, good: 14–16), and financial conflicts of interest. The primary outcome was neurological outcome according to a validated outcome scale at 1–3 months after treatment. Secondary outcomes were clinical worsening and complications.

We included 13 studies with 743 patients and 806 UIAs, of which 88.4% (95% CI: 85.7%–91.2%) were <10 mm. All studies were uncontrolled. The methodological quality was poor in six and moderate in seven studies. Financial conflicts of interest were reported in six studies. At 1–3 months after treatment, the proportion of patients were for mRS ⩾1 13.3% (95% CI: 10.0%–16.6%), mRS ⩾2 5.3% (95% CI: 3.2%–7.5%), mRS ⩾3 2.4% (95% CI: 0.1%–3.9%) and neurological worsening 3.1% (95% CI: 1.5%–4.6%). Complications within 3 months occurred in 12.7% (95% CI: 10.3%–15.0%).

The literature on FD-stents is methodologically weak and potentially biased by financial interests but still shows relevant proportions of complications and post-treatment morbidity. Currently, there are no good data supporting the use of FD-stents for UIAs where standard treatment options are available. Randomised-controlled trials are needed to compare safety, efficacy and durability between FD-stents and coiling or clipping.

Graphical abstract