title: Computational study of the risk of restenosis in coronary bypasses.
abstract: Coronary artery disease, caused by the buildup of atherosclerotic plaques in the coronary vessel wall, is one of the leading causes of death in the world. For high-risk patients, coronary artery bypass graft is the preferred treatment. Despite overall excellent patency rates, bypasses may fail due to restenosis. In this context, the purpose of this work was to perform a parametric computational study of the fluid dynamics in patient-specific geometries with the aim of investigating a possible relationship between coronary stenosis degree and risk of graft failure. Firstly, we propose a strategy to prescribe realistic boundary conditions in the absence of measured data, based on an extension of Murray's law to provide the flow division at bifurcations in case of stenotic vessels and non-Newtonian blood rheology. Then, we carry out numerical simulations in three patients affected by severe coronary stenosis and treated with a graft, in which the stenosis degree is virtually varied in order to compare the resulting fluid dynamics in terms of hemodynamic indices potentially involved in restenosis development. Our findings suggest that low degrees of coronary stenosis produce a more disturbed fluid dynamics in the graft, resulting in hemodynamic conditions that may promote a higher risk of graft failure.
authors.affiliation: MOX, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy. bruno.guerciotti@polimi.it.
authors.forename: Bruno
authors.initials: B
authors.lastname: Guerciotti
authors.affiliation: MOX, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Vergara
authors.affiliation: Radiology Unit, Ospedale L. Sacco, via G.B. Grassi 74, 20157, Milan, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ippolito
authors.affiliation: SB MATHICSE CMCS, EPFL, av. Piccard, Bat. MA, Sec. B2-C2, Station 8, 1015, Lausanne, Switzerland.
authors.forename: Alfio
authors.initials: A
authors.lastname: Quarteroni
authors.affiliation: Cardiosurgery Unit, Ospedale L. Sacco, via G.B. Grassi 74, 20157, Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Antona
authors.affiliation: Cardiosurgery Unit, Ospedale L. Sacco, via G.B. Grassi 74, 20157, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Scrofani
mesh_terms: D001783:Blood Flow Velocity; D003198:Computer Simulation; D001026:Coronary Artery Bypass; D023903:Coronary Restenosis; D003331:Coronary Vessels / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D008954:Models, Biological; D012306:Risk
keywords: Computational fluid dynamics; Coronary bypass; Murray’s law; Non-Newtonian rheology; Restenosis