Author + information
- Miao Chu1,
- Clemens von Birgelen2,
- Yingguang Li3,
- Jelmer Westra4,
- Junqing Yang5,
- Niels Holm6,
- William Wijns7 and
- Shengxian Tu8
- 1Shangha Jiaotong University, Shanghai, Shanghai, China
- 2Thoraxcentrum Twente, Enschede, Netherlands
- 3Leiden University Medical Center, Leiden, Netherlands
- 4Aarhus University Hospital, Aarhus, Denmark
- 5Guangdong General Hospital, Guagnzhou, Guangdong, China
- 6Aarhus University Hospital, Aarhus N, Denmark
- 7The Lambe Institute for Translational Medicine and Curam, and Saolta University Healthcare Group, Galway, Galway, Ireland
- 8Shanghai Jiao Tong University, Shanghai, Shanghai, China
Disturbed flow patterns are associated with the localization of atherosclerotic lesion, where recirculation and secondary flows are usually present. However, there is no metric to quantify the extent of flow disturbance. And the relation between fractional flow reserve (FFR) and local coronary flow patterns is incompletely understood.
Three-dimensional angiographic reconstruction and computational fluid dynamics were applied to simulate individual’s pulsatile blood flow. A novel parameter, disturbed vorticity index (DVI), was derived to quantify stenosis-induced flow disturbance. We assessed the relation between DVI, flow patterns and pressure drop in 9 virtual vessel models with different obstructed characteristcs. The correlation between DVI, FFR, other hemodynamic and antomical parameters, were evalueated using data of an international multicenter FFR-study.
In our obstructed virtual vessel models, heterogeneous flow vorticity accompanied disturbed flow patterns. DVI increased with the extent of flow disturbance influenced by factors of flow rate, stenosis severity, lesion length and obstuction eccentricity. DVI was also found to correlated with pressure drop for all modeled stenoses (R2 = 0.85, p<0.001). For patients, we assessed a total of 84 coronary arteries from 73 patients with intermediate coronary lesions and pressure-wire derived FFR of 0.84±0.08 (FFR≤0.80 in 27(32%) arteries). DVI increased with lesion length (ρ=0.44, p<0.001) and percent diameter stenosis (ρ=0.23, p=0.037). Furthermore, DVI had a stronger correlation with FFR (ρ=-0.74, p<0.001) when compared with flow velocity (ρ=-0.27, p=0.015), percent diameter stenosis (ρ=-0.40, p<0.001) and lesion length (ρ=-0.36, p=0.001).
DVI, a novel index to quantify disturbed flow, reflects in-vivo the accumulated effect of disturbed flows along the stenotic segments of a vessel, influenced by DS%, LL, perfused flow, and other geometrical and hemodynamic variables. DVI was better correlated with FFR than flow. It provides a new metric to advance our understanding of the relation between local hemodynamics, FFR and perhaps atherosclerosis progression.
IMAGING: FFR and Physiologic Lesion Assessment