High-Intensity Helical Flow: A Double-Edged Sword in Coronary Artery Haemodynamics

TL;DR

This study investigates how high-intensity helical flow influences shear stress in coronary arteries, revealing that it can both mitigate and exacerbate conditions linked to atherosclerosis, challenging previous beliefs about its protective role.

Contribution

It provides new insights into the dual role of helical flow in coronary artery haemodynamics, highlighting its complex impact on plaque development and vulnerability.

Findings

HF correlates with higher TAESS in all vessel segments

High HF reduces areas of low TAESS in stenosed arteries

High HF increases areas of high TAESS, potentially increasing plaque vulnerability

Abstract

The role of Helical Flow (HF) in human coronary arteries remains uncertain, yet its understanding promises unprecedented insights into atherosclerotic processes. In this study, we investigated the effects of HF and key haemodynamic descriptors in 39 patient-specific left coronary artery trees from the ASOCA dataset, including 20 non-stenosed and 19 stenosed cases. Absolute HF intensity $h_2$ correlated with higher Time-Averaged Endothelial Shear Stress (TAESS) in all vessel segments regardless of stenosis (p < 0.05). In stenosed cases, this correlation was so prominent that the vessel area exposed to adversely low TAESS was reduced (< 0.5 Pa, p = 0.0001), while areas of adversely high TAESS increased (> 4.71 Pa, p < 0.05), coinciding with high $h_2$ regions. This suggests that HF in coronary arteries is not always protective as previously thought. It not only mitigates low TAESS, which is associated with long-term plaque development and restenosis, but also exacerbates adversely high TAESS, which is linked to increased plaque vulnerability and acute events. Our findings redefine the current understanding of helical blood flow's role in cardiovascular atherosclerotic disease processes.