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2018-03-10 - Colloque/Abstract - Anglais - 1 page(s)

Carlier Stéphane , Saussez Julien, Scalia Alessandro, Chodzynski Kamil , Nishio Shunji, Thayse Kathleen , Brunner Philippe, Zouaoui Boudjeltia Karim , Coussement Grégory , "IN VIVO, IN VITRO AND IN SILICO COMPARISON OF TWO DEVICES TO MEASURE FRACTIONAL FLOW RESERVE" in AMERICAN COLLEGE OF CARDIOLOGY , 71, 1115-276, Orlando, USA, 2018

  • Codes CREF : Cardiologie et circulation (DI3321), Mécanique des fluides (DI1244)
  • Unités de recherche UMONS : Cardiologie (M106), Fluides-Machines (F702)
  • Instituts UMONS : Institut des Sciences et Technologies de la Santé (Santé)
Texte intégral :

Abstract(s) :

(Anglais) Background: Fractional flow reserve (FFR) can be measured with a wire or a microcatheter with built-in pressure-sensor. We sought 1) to quantify the impact on the pressure gradient (ΔP) of each device in silico in a modeled coronary artery stenosis validated by in vitro measurements and 2) to assess our clinical experience with both systems. Methods: In a validated test bench mimicking any blood flow rate pattern, 50 mm-long tubes with a inner lumen diameter of 2.5 mm (3D printed in polylactic acid) with or without a 15 mm-long 60 % diameter stenosis (DS) were studied. Measured ΔP at flow rate (Q) up to 100 ml/min with or without a FFR device inserted were compared with computational fluid dynamic (CFD software FineOpen™, Numeca) solving the Navier-Stokes equations in a mesh of ~1.106 nodes reproducing the in vitro setup. Clinical cases from our cathlab were also reviewed over the last 2 years (1009 coronary angiography and 315 PCI). Results: Without a stenosis, ΔP at Q=100 ml/min was 7, 8 and 9 mmHg respectively without any device, with a 0.014” Boston Scientific Comet™ FFR-wire and with a Acist Navvus™ 0.022” microcatheter. CFD gave the same values when each system was placed close to the wall, but gradients twice larger with the FFR device simulated in the center. In the tube with a 60% stenosis, ΔP at Q=50 ml/min was 17, 30 and 74 mmHg respectively. In silico, other geometries demonstrated a decreased influence of any device on ΔP with a larger residual lumen: in a 2.5 mm tube with a 50% DS, ΔP for Q=50 ml/min was 11, 15 and 25 mmHg, respectively a true FFR of 0.89, a wire-FFR of 0.85 and a microcatheter-FFR of 0.75, for a 100 mmHg proximal pressure. Conceptually, a pressure-wire might not cross difficult lesions while a workhorse wire would, on which a FFR-microcatheter could be advanced. However, we found in our clinical data base that we tried to measure FFR with 41 Navvus™ and failed to cross 3 lesions, while we crossed all 71 attempted stenosis with a Comet™ wire. Conclusion: We demonstrate in vitro and in silico in small diseased coronary arteries that clinically significantly higher ΔP are added by a FFR-microcatheter than by a FFR wire. In our daily practice, these microcatheters had also a higher failure rate to cross tortuous lesions.