The physical origin of aneurysm growth, dissection, and rupture

TL;DR

This study uncovers the physical mechanisms behind aneurysm growth, dissection, and rupture through in-vitro experiments, establishing a predictive framework based on flutter instability that can improve clinical prognosis.

Contribution

It introduces a first-principles-based flutter instability parameter to predict aneurysm progression and rupture, linking physical dynamics to clinical outcomes.

Findings

Flutter instability predicts transition from stable to unstable flow.

Low-level instability can cause permanent aneurysm growth.

Large flutter induces strain localization leading to rupture.

Abstract

Rupture of aortic aneurysms is by far the most fatal heart disease, with a mortality rate exceeding 80%. There are no reliable clinical protocols to predict growth, dissection, and rupture because the fundamental physics driving aneurysm progression is unknown. Here, via in-vitro experiments, we show that a blood-wall, fluttering instability manifests in synthetic arteries under pulsatile forcing. We establish a phase space to prove that the transition from stable flow to unstable aortic flutter is accurately predicted by a flutter instability parameter derived from first principles. Time resolved strain maps of the evolving system reveal the dynamical characteristics of aortic flutter that drive aneurysm progression. We show that low level instability can trigger permanent aortic growth, even in the absence of material remodeling. Sufficiently large flutter beyond a secondary threshold localizes strain in the walls to the length scale clinically observed in aortic dissection. Lastly, significant physical flutter beyond a tertiary threshold can ultimately induce aneurysm rupture via failure modes reported from necropsy. Resolving the fundamental physics of aneurysm progression directly leads to clinical protocols that forecast growth as well as intercept dissection and rupture by pinpointing their physical origin.