title: Disturbed coronary hemodynamics in vessels with intermediate stenoses evaluated with fractional flow reserve: a combined analysis of epicardial and microcirculatory involvement in ischemic heart disease.
abstract: BACKGROUND
  In chronic ischemic heart disease, focal stenosis, diffuse atherosclerotic narrowings, and microcirculatory dysfunction (MCD) contribute to limit myocardial flow. The prevalence of these ischemic heart disease levels in fractional flow reserve (FFR) interrogated vessels remains largely unknown.
  
  
  RESULTS
  Using intracoronary measurements, 91 coronaries (78 patients) with intermediate stenoses were classified in 4 FFR and coronary flow reserve (CFR) agreement groups, using FFR>0.80 and CFR<2 as cutoffs. Index of microcirculatory resistance (IMR) and atherosclerotic burden (Gensini score) were also assessed. MCD was assumed when IMR≥29.1 (75(th) percentile). Fifty-four (59.3%) vessels had normal FFR, from which only 20 (37%) presented both normal CFR and IMR. Among vessels with FFR>0.80, most (63%) presented disturbed hemodynamics: abnormal CFR in 28 (52%) and MCD in 18 (33%). Vessels with FFR>0.80 presented higher IMR [adjusted mean 27.6 (95% confidence interval, 23.4-31.8)] than those with FFR≤0.80 [17.3 (95% confidence interval, 13.0-21.7), p=0.001]. Atherosclerotic burden was inversely correlated with CFR (r=-0.207, P=0.055), and in vessels with FFR>0.80 and CFR<2 (n=28, 39%), IMR had a wide dispersion (7-72.7 U), suggesting a combination of diffuse atherosclerotic narrowings and MCD. Vessels with FFR≤0.80 and normal CFR presented the lowest IMR, suggesting a preserved microcirculation.
  
  
  CONCLUSIONS
  A substantial number of coronary arteries with stenoses showing an FFR>0.80 present disturbed hemodynamics. Integration of FFR, CFR, and IMR supports the existence of differentiated patterns of ischemic heart disease that combine focal and diffuse coronary narrowings with variable degrees of MCD.
authors.affiliation: Cardiovascular Institute, Hospital Clinico San Carlos, Madrid, Spain (M.E.-P., J.E., E.M., M.M., N.G., P.J.-Q., R.H., R.M. B.I., I.J.N.-G., F.A., C.B., E.G., A.F.-O., C.M.); Centro Nacional de Investigaciónes Cardiovasculares Carlos III (CNIC), Madrid, Spain (M.E.-P., J.E., B.I., A.F.-O.); Imperial College Healthcare and NHS Trust, London, UK (R.P., S.S., J.D.); and Clinical Epidemiology Unit, Hospital Clinico San Carlos, Madrid, Spain (C.F.).
authors.forename: Mauro
authors.initials: M
authors.lastname: Echavarria-Pinto
authors.forename: Javier
authors.initials: J
authors.lastname: Escaned
authors.forename: Enrico
authors.initials: E
authors.lastname: Macías
authors.forename: Miguel
authors.initials: M
authors.lastname: Medina
authors.forename: Nieves
authors.initials: N
authors.lastname: Gonzalo
authors.forename: Ricardo
authors.initials: R
authors.lastname: Petraco
authors.forename: Sayan
authors.initials: S
authors.lastname: Sen
authors.forename: Pilar
authors.initials: P
authors.lastname: Jimenez-Quevedo
authors.forename: Rosana
authors.initials: R
authors.lastname: Hernandez
authors.forename: Rafael
authors.initials: R
authors.lastname: Mila
authors.forename: Borja
authors.initials: B
authors.lastname: Ibañez
authors.forename: Ivan J
authors.initials: IJ
authors.lastname: Nuñez-Gil
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernández
authors.forename: Fernando
authors.initials: F
authors.lastname: Alfonso
authors.forename: Camino
authors.initials: C
authors.lastname: Bañuelos
authors.forename: Eulogio
authors.initials: E
authors.lastname: García
authors.forename: Justin
authors.initials: J
authors.lastname: Davies
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández-Ortiz
authors.forename: Carlos
authors.initials: C
authors.lastname: Macaya
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D003251:Constriction, Pathologic / Q000503:physiopathology; D003324:Coronary Artery Disease / Q000453:epidemiology / Q000503:physiopathology; D003326:Coronary Circulation / Q000502:physiology; D023921:Coronary Stenosis / Q000145:classification / Q000503:physiopathology*; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000145:classification / Q000503:physiopathology*; D010496:Pericardium / Q000503:physiopathology*; D015995:Prevalence; D011446:Prospective Studies
keywords: coronary disease; microcirculation; physiology