title: Hemodynamics in Transplant Renal Artery Stenosis and its Alteration after Stent Implantation Based on a Patient-specific Computational Fluid Dynamics Model.
abstract: BACKGROUND
  Accumulating studies on computational fluid dynamics (CFD) support the involvement of hemodynamic factors in artery stenosis. Based on a patient-specific CFD model, the present study aimed to investigate the hemodynamic characteristics of transplant renal artery stenosis (TRAS) and its alteration after stent treatment.
  
  
  METHODS
  Computed tomography angiography (CTA) data of kidney transplant recipients in a single transplant center from April 2013 to November 2014 were reviewed. The three-dimensional geometry of transplant renal artery (TRA) was reconstructed from the qualified CTA images and categorized into three groups: the normal, stenotic, and stented groups. Hemodynamic parameters including pressure distribution, velocity, wall shear stress (WSS), and mass flow rate (MFR) were extracted. The data of hemodynamic parameters were expressed as median (interquartile range), and Mann-Whitney U-test was used for analysis.
  
  
  RESULTS
  Totally, 6 normal, 12 stenotic, and 6 stented TRAs were included in the analysis. TRAS presented nonuniform pressure distribution, adverse pressure gradient across stenosis throat, flow vortex, and a separation zone at downstream stenosis. Stenotic arteries had higher maximal velocity and maximal WSS (2.94 [2.14, 3.30] vs. 1.06 [0.89, 1.15] m/s, 256.5 [149.8, 349.4] vs. 41.7 [37.8, 45.3] Pa at end diastole, P= 0.001; 3.25 [2.67, 3.56] vs. 1.65 [1.18, 1.72] m/s, 281.3 [184.3, 364.7] vs. 65.8 [61.2, 71.9] Pa at peak systole, P= 0.001) and lower minimal WSS and MFRs (0.07 [0.03, 0.13] vs. 0.52 [0.45, 0.67] Pa, 1.5 [1.0, 3.0] vs. 11.0 [8.0, 11.3] g/s at end diastole, P= 0.001; 0.08 [0.03, 0.19] vs. 0.70 [0.60, 0.81] Pa, 2.0 [1.3, 3.3] vs. 16.5 [13.0, 20.3] g/s at peak systole, P= 0.001) as compared to normal arteries. Stent implantation ameliorated all the alterations of the above hemodynamic factors except low WSS.
  
  
  CONCLUSIONS
  Hemodynamic factors were significantly changed in severe TRAS. Stent implantation can restore or ameliorate deleterious change of hemodynamic factors except low WSS at stent regions.
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Hong-Yang
authors.initials: HY
authors.lastname: Wang
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Long-Shan
authors.initials: LS
authors.lastname: Liu
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Hai-Ming
authors.initials: HM
authors.lastname: Cao
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Rong-Hai
authors.initials: RH
authors.lastname: Deng
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Huan-Xi
authors.initials: HX
authors.lastname: Zhang
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Ji-Guang
authors.initials: JG
authors.lastname: Fei
authors.affiliation: Organ Transplant Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080; Guangdong Provincial Key Laboratory on Organ Donation and Transplant Immunology, Guangzhou, Guangdong 510080, China.
authors.forename: Chang-Xi
authors.initials: CX
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001807:Blood Vessel Prosthesis; D003198:Computer Simulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D057446:Hydrodynamics; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D012078:Renal Artery Obstruction / Q000503:physiopathology / Q000601:surgery*; D013314:Stress, Mechanical; D055815:Young Adult