title: Coronary Artery Axial Plaque Stress and its Relationship With Lesion Geometry: Application of Computational Fluid Dynamics to Coronary CT Angiography.
abstract: OBJECTIVE
  The purpose of this study was to characterize the hemodynamic force acting on plaque and to investigate its relationship with lesion geometry.
  
  
  BACKGROUND
  Coronary plaque rupture occurs when plaque stress exceeds plaque strength.
  
  
  METHODS
  Computational fluid dynamics was applied to 114 lesions (81 patients) from coronary computed tomography angiography. The axial plaque stress (APS) was computed by extracting the axial component of hemodynamic stress acting on stenotic lesions, and the axial lesion asymmetry was assessed by the luminal radius change over length (radius gradient [RG]). Lesions were divided into upstream-dominant (upstream RG > downstream RG) and downstream-dominant lesions (upstream RG < downstream RG) according to the RG.
  
  
  RESULTS
  Thirty-three lesions (28.9%) showed net retrograde axial plaque force. Upstream APS linearly increased as lesion severity increased, whereas downstream APS exhibited a concave function for lesion severity. There was a negative correlation (r = -0.274, p = 0.003) between APS and lesion length. The pressure gradient, computed tomography-derived fractional flow reserve (FFRCT), and wall shear stress were consistently higher in upstream segments, regardless of the lesion asymmetry. However, APS was higher in the upstream segment of upstream-dominant lesions (11,371.96 ± 5,575.14 dyne/cm(2) vs. 6,878.14 ± 4,319.51 dyne/cm(2), p < 0.001), and in the downstream segment of downstream-dominant lesions (7,681.12 ± 4,556.99 dyne/cm(2) vs. 11,990.55 ± 5,556.64 dyne/cm(2), p < 0.001). Although there were no differences in FFRCT, % diameter stenosis, and wall shear stress pattern, the distribution of APS was different between upstream- and downstream-dominant lesions.
  
  
  CONCLUSIONS
  APS uniquely characterizes the stenotic segment and has a strong relationship with lesion geometry. Clinical application of these hemodynamic and geometric indices may be helpful to assess the future risk of plaque rupture and to determine treatment strategy for patients with coronary artery disease. (Evaluation of FFR, WSS, and TPF Using CCTA; NCT01857687).
authors.affiliation: HeartFlow, Redwood City, California; Department of Surgery, Stanford University Medical Center, Stanford, California.
authors.forename: Gilwoo
authors.initials: G
authors.lastname: Choi
authors.affiliation: Department of Medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Joo Myung
authors.initials: JM
authors.lastname: Lee
authors.affiliation: HeartFlow, Redwood City, California.
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Jun-Bean
authors.initials: JB
authors.lastname: Park
authors.affiliation: HeartFlow, Redwood City, California.
authors.forename: Sethuraman
authors.initials: S
authors.lastname: Sankaran
authors.affiliation: Department of Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Otake
authors.affiliation: Department of Medicine, Inje University Ilsan Paik Hospital, Goyang, South Korea.
authors.forename: Joon-Hyung
authors.initials: JH
authors.lastname: Doh
authors.affiliation: Department of Medicine, Keimyung University Dongsan Medical Center, Daegu, South Korea.
authors.forename: Chang-Wook
authors.initials: CW
authors.lastname: Nam
authors.affiliation: Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea.
authors.forename: Eun-Seok
authors.initials: ES
authors.lastname: Shin
authors.affiliation: HeartFlow, Redwood City, California; Department of Bioengineering, Stanford University, Stanford, California.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Taylor
authors.affiliation: Department of Medicine, Seoul National University Hospital, Seoul, South Korea; Institute on Aging, Seoul National University, Seoul, South Korea. Electronic address: bkkoo@snu.ac.kr.
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
mesh_terms: D000368:Aged; D003198:Computer Simulation; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012422:Rupture, Spontaneous; D012720:Severity of Illness Index; D013314:Stress, Mechanical
keywords: axial plaque stress; computational fluid dynamics; coronary artery disease; coronary computed tomography angiography; coronary plaque; pressure; wall shear stress