# Investigating Delayed Rupture of Flow Diverter-Treated Giant Aneurysm Using Simulated Fluid–Structure Interactions

## TL;DR

This study uses simulations to explore why giant brain aneurysms treated with flow diverters sometimes rupture later, challenging existing theories.

## Contribution

A novel fluid–structure interaction simulation of a flow diverter-treated giant aneurysm is presented.

## Key findings

- Wall compliance causes a phase shift and dampening in pressure cycles.
- Aneurysmal flow increases when wall compliance is considered.
- Existing delayed-rupture hypotheses may need reevaluation based on these findings.

## Abstract

Giant intracranial aneurysms are frequently treated shortly after discovery due to their increased risk of rupture and commonly symptomatic nature. Among available treatments, flow diverters are often the sole viable option, though they carry a rare but serious risk of delayed post-operative rupture. The underlying mechanisms of these ruptures remain unknown, due to the biomechanical complexity of giant aneurysms and challenges in replicating in vivo hemodynamic conditions within numerical simulation frameworks. This study presents a novel fluid–structure interaction simulation of a giant intracranial aneurysm treated with a flow diverter, based on high-resolution rotational angiography imaging. The resulting hemodynamics are compared to three established delayed-rupture hypotheses involving pressure rises, chaotic flow and autolysis. When considering wall compliance, the analysis reveals a consistent phase shift, dampening in pressure cycles, and an increased aneurysmal flow. These findings highlight the need for revisiting existing hypotheses and provide a foundation for advancing both computational modelling and clinical management strategies for giant intracranial aneurysms.