Impact of Aortic Valve Stenosis on Coronary Hemodynamics and the Instantaneous Effect of Transcatheter Aortic Valve Implantation

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. METHODS AND 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) 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