title: Functional assessment of jailed side branches in coronary bifurcation lesions using fractional flow reserve.
abstract: OBJECTIVE
  This study was designed to assess the functional significance of side branches after stent implantation in main vessels using fractional flow reserve (FFR).
  
  
  BACKGROUND
  Little is known about the functional significance of side branches after stent implantation in main vessels in coronary bifurcation lesions.
  
  
  METHODS
  Between May 2007 and January 2011, 230 side branches in 230 patients after stent implantation in main vessels were assessed by FFR and were consecutively enrolled.
  
  
  RESULTS
  Median FFR at the side branch was 0.91 (interquartile range: 0.85 to 0.95). There was a negative correlation between the diameter stenosis (DS) by quantitative coronary angiography (QCA) and FFR of side branch (r=-0.21, p=0.002), but only 41 (17.8%) side branches were functionally significant after stent implantation in the main vessel. Among 67 side branches with >50% DS by QCA, 19 (28.4%) had FFR≤0.80, and among 163 side branches with ≤50% DS by QCA, 22 (13.5%) had FFR≤0.80 after stent implantation in main vessels. On the basis of receiver-operating characteristic curves, the optimal cutoff value of DS by QCA of the side branch was 54.9%, and the area under the curve was 0.64 (95% confidence interval [CI]: 0.58 to 0.71, p<0.001) with a 41.5% sensitivity, an 83.1% specificity, a 34.7% positive predictive value, an 86.3% negative predictive value, and a 75.7% accuracy. Multivariate binary logistic regression analysis identified DS by QCA (odds ratio [OR]: 1.04, 95% CI: 1.02 to 1.06, p=0.001) and reference vessel diameter (OR: 0.28, 95% CI: 0.10 to 0.77, p=0.014) before stent implantation as independent predictors of the side branches with FFR≤0.80 after stent implantation.
  
  
  CONCLUSIONS
  Most side branch lesions do not have functional significance after stent implantation in the main vessel, and quantitative coronary angiography is unreliable in assessing the functional severity of these lesions.
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Ahn
authors.forename: Jong-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Kang
authors.forename: Young-Hak
authors.initials: YH
authors.lastname: Kim
authors.forename: Hae-Geun
authors.initials: HG
authors.lastname: Song
authors.forename: Jun-Hyok
authors.initials: JH
authors.lastname: Oh
authors.forename: Jong Seon
authors.initials: JS
authors.lastname: Park
authors.forename: Won-Jang
authors.initials: WJ
authors.lastname: Kim
authors.forename: Seung-Whan
authors.initials: SW
authors.lastname: Lee
authors.forename: Cheol Whan
authors.initials: CW
authors.lastname: Lee
authors.forename: Jae-Joong
authors.initials: JJ
authors.lastname: Kim
authors.forename: Seong-Wook
authors.initials: SW
authors.lastname: Park
authors.forename: Seung-Jung
authors.initials: SJ
authors.lastname: Park
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation*; D016001:Confidence Intervals; D017023:Coronary Angiography / Q000295:instrumentation; D003324:Coronary Artery Disease / Q000473:pathology / Q000628:therapy*; D003331:Coronary Vessels / Q000473:pathology*; D054855:Drug-Eluting Stents; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006439:Hemodynamics; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011446:Prospective Studies; D012042:Registries; D018709:Statistics, Nonparametric