title: Preprocedural fractional flow reserve and microvascular resistance predict increased hyperaemic coronary flow after elective percutaneous coronary intervention.
abstract: BACKGROUND
  Epicardial focal coronary artery stenosis, diffuse coronary disease, and microvascular resistance (MR) may limit coronary flow. The purpose of percutaneous coronary intervention (PCI) is to increase coronary flow by targeting epicardial lesions. After PCI, MR might change and affect coronary flow. We investigated whether PCI influences MR using the index of microcirculatory resistance (IMR) and if pre-PCI fractional flow reserve (FFR) or MR predicts the post-PCI change in hyperaemic coronary flow.
  
  
  RESULTS
  This prospective study included 245 vessels from 229 patients with stable angina pectoris undergoing elective PCI. FFR and IMR were measured before and after PCI. Post-PCI increase in hyperaemic coronary flow was assessed using the change in thermodilution-derived transit time (pre-PCI Tmn- post-PCI Tmn). IMR significantly decreased after PCI (median 1.9; interquartile range, -4.9 to 10.1) and was significantly associated with pre-PCI IMR (r = 0.70, P < 0.001). Increased coronary flow was significantly correlated with pre-PCI IMR (r = 0.62, P < 0.001) and pre-PCI FFR (r = 0.51, P < 0.001). In multivariate analysis, factors significantly associated with decreased post-PCI IMR were pre-PCI IMR (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08-1.19; P < 0.001) and angiographic reference diameter (OR, 2.44; 95% CI; 1.09-5.48; P = 0.03). Factors significantly associated with increased coronary flow post-PCI were pre-PCI IMR (OR, 1.15; 95% CI, 1.08-1.23; P < 0.001) and pre-PCI FFR (OR, <0.001; 95% CI, 0.000-0.003; P < 0.001).
  
  
  CONCLUSIONS
  PCI affected MR. Pre-PCI FFR and MR were independent predictors of post-PCI changes in hyperaemic coronary flow. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Murai
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kanaji
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Yonetsu
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Tetsumin
authors.initials: T
authors.lastname: Lee
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Matsuda
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Usui
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Araki
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Niida
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
authors.affiliation: Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Tsunekazu
authors.initials: T
authors.lastname: Kakuta
mesh_terms: D000368:Aged; D060050:Angina, Stable / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006328:Cardiac Catheterization / Q000295:instrumentation; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013815:Thermodilution; D014160:Transducers, Pressure; D016896:Treatment Outcome; D014655:Vascular Resistance
keywords: cardiovascular disease; coronary flow; coronary microvascular resistance; percutaneous coronary intervention