title: Impact of Aortic Valve Stenosis on Coronary Hemodynamics and the Instantaneous Effect of Transcatheter Aortic Valve Implantation.
abstract: BACKGROUND
  Aortic valve stenosis (AS) induces compensatory alterations in left ventricular hemodynamics, leading to physiological and pathological alterations in coronary hemodynamics. Relief of AS by transcatheter aortic valve implantation (TAVI) decreases ventricular afterload and is expected to improve microvascular function immediately. We evaluated the effect of AS on coronary hemodynamics and the immediate effect of TAVI.
  
  
  RESULTS
  Intracoronary pressure and flow velocity were simultaneously assessed at rest and at maximal hyperemia in an unobstructed coronary artery in 27 patients with AS before and immediately after TAVI and in 28 patients without AS. Baseline flow velocity was higher and baseline microvascular resistance was lower in patients with AS as compared with controls, which remained unaltered post-TAVI. In patients with AS, hyperemic flow velocity was significantly lower as compared with controls (44.5±14.5 versus 54.3±18.6 cm/s; P=0.04). Hyperemic microvascular resistance (expressed in mm Hg·cm·s(-1)) was 2.10±0.69 in patients with AS as compared with 1.80±0.60 in controls (P=0.096). Coronary flow velocity reserve in patients with AS was lower, 1.9±0.5 versus 2.7±0.7 in controls (P<0.001). Improvement in coronary hemodynamics after TAVI was most pronounced in patients without post-TAVI aortic regurgitation. In these patients (n=20), hyperemic flow velocity increased significantly from 46.24±15.47 pre-TAVI to 56.56±17.44 cm/s post-TAVI (P=0.003). Hyperemic microvascular resistance decreased from 2.03±0.71 to 1.66±0.45 (P=0.050). Coronary flow velocity reserve increased significantly from 1.9±0.4 to 2.2±0.6 (P=0.009).
  
  
  CONCLUSIONS
  The vasodilatory reserve capacity of the coronary circulation is reduced in AS. TAVI induces an immediate decrease in hyperemic microvascular resistance and a concomitant increase in hyperemic flow velocity, resulting in immediate improvement in coronary vasodilatory reserve.
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Esther M A
authors.initials: EM
authors.lastname: Wiegerinck
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Tim P
authors.initials: TP
authors.lastname: van de Hoef
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Rolandi
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: ZeYie
authors.initials: Z
authors.lastname: Yong
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Floortje
authors.initials: F
authors.lastname: van Kesteren
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Karel T
authors.initials: KT
authors.lastname: Koch
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Marije M
authors.initials: MM
authors.lastname: Vis
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Bas A J M
authors.initials: BA
authors.lastname: de Mol
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Piek
authors.affiliation: From the AMC Heartcenter, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. J.baan@amc.uva.nl.
authors.forename: Jan
authors.initials: J
authors.lastname: Baan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000503:physiopathology* / Q000601:surgery; D006328:Cardiac Catheterization; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000502:physiology*; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: aortic valve stenosis; coronary circulation; coronary microvascular function; coronary microvascular resistance; coronary physiology; transcatheter aortic valve implantation