title: Evaluation of local flow conditions in jailed side branch lesions using computational fluid dynamics.
abstract: OBJECTIVE
  Lesions of vascular bifurcation and their treatment outcomes have been evaluated by anatomical and physiological methods, such as intravascular ultrasound and fractional flow reserve (FFR). However, local changes in flow dynamics in lesions of bifurcation have not been well evaluated. This study aimed at evaluating changes in the local flow patterns of bifurcation lesions.
  
  
  METHODS
  Eight (n=8) representative simulation-models were constructed: 1 normal bifurcation, 5 main-branch (MB) stenting models with various side-branch (SB) stenoses (ostial or non-ostial 75% diameter stenosis with 1- or 2-cm lesion lengths, ostial 75% diameter stenosis caused by carina shift), and 2 post-kissing models (no or 50% SB residual stenosis). Pressure, velocity, and wall shear stress (WSS) profiles around the bifurcation sites were investigated using computational fluid dynamics.
  
  
  RESULTS
  Post-stenting models revealed significant pressure drop in the SB (FFR<0.75), excluding the carina shift model (FFR=0.89). In the post-kissing models, there was no significant pressure drop. All post-stenting models revealed eccentric low velocity flow patterns and areas of low WSS, primarily in the lateral wall on distal MB. Post-kissing angioplasty improved pressure drop in the SB but resulted in alteration of flow distribution in the MB. In the carina shift model, kissing ballooning resulted in deteriorated local flow conditions due to increased area of low velocity and WSS.
  
  
  CONCLUSIONS
  This study suggests that the most commonly used bifurcation intervention strategy may cause local flow disturbances, which may partially explain high restenosis and event rates in patients with bifurcation lesions.
authors: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors: Sang-Hoon
authors: SH
authors: Na
authors: Bon-Kwon
authors: BK
authors: Koo
authors: Jeong Chul
authors: JC
authors: Kim
authors: Han-Mo
authors: HM
authors: Yang
authors: Kyung-Woo
authors: KW
authors: Park
authors: Hyun-Jae
authors: HJ
authors: Kang
authors: Hyo-Soo
authors: HS
authors: Kim
authors: Byung-Hee
authors: BH
authors: Oh
authors: Young-Bae
authors: YB
authors: Park