title: Discrepancy between morphologic and functional criteria of optimal stent deployment using intravascular ultrasound and pressure derived myocardial fractional flow reserve.
abstract: BACKGROUND
  Pressure derived myocardial FFR, a functional index of epicardial stenosis has been proposed for the assessment of optimal stent deployment. The following study evaluated the potential of serial fractional flow reserve (FFR) measurements in comparison to the 'gold standard' intravascular ultrasound (IVUS) for optimal stent deployment and its long-term outcome.
  
  
  METHODS
  35 patients with a single de novo lesion underwent PTCA followed by stent implantation with an initial inflation pressure of 12 atm. If optimal stent expansion using IVUS-criteria were not fulfilled, re-dilatation at 16 atm as well as additional inflations with larger balloon sizes were performed to reach the procedural end-point. IVUS and FFR were performed after each dilatation (n = 136). Angiography was repeated after 6 months.
  
  
  RESULTS
  In 30 pts who fulfilled IVUS criteria, mean lumen area (2.9+/-1.3 mm2) increased after PTCA and stent implantation to 10.0+/-3.0 mm2. In six pts, optimum stent deployment according to a value of FFR0.94 was not reached. Four of six pts reached the IVUS criteria at 12 atm and two pts at 16 atm, respectively. Positive and negative predictive values of FFR were 26 and 64%. Three of the 30 pts (10%) revealed a restenosis at three months follow-up. One of these restenosis was seen in a patient with a post-procedural FFR<0.94.
  
  
  CONCLUSIONS
  FFR was not valid to predict optimal stent expansion according to IVUS criteria but could delineate under-expanded stents despite a reasonable angiographic appearance. Morphologic (IVUS) and functional criteria (FFR) for optimal stent deployment revealed a comparably low restenosis rate.
authors.affiliation: Medizinische Poliklinik-Innenstadt, Department of Cardiology, University of Munich, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Stempfle
authors.forename: Andreas
authors.initials: A
authors.lastname: König
authors.forename: Eva
authors.initials: E
authors.lastname: Drescher
authors.forename: Uwe
authors.initials: U
authors.lastname: Siebert
authors.forename: Volker
authors.initials: V
authors.lastname: Klauss
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015607:Stents; D018084:Ultrasonography, Interventional