title: Effect of myocardial contractility on hemodynamic end points under concomitant microvascular disease in a porcine model.
abstract: In this study, coronary diagnostic parameters, pressure drop coefficient (CDP: ratio of trans-stenotic pressure drop to distal dynamic pressure), and lesion flow coefficient (LFC: ratio of % area stenosis (%AS) to the CDP at throat region), were evaluated to distinguish levels of %AS under varying contractility conditions, in the presence of microvascular disease (MVD). In 10 pigs, %AS and MVD were created using angioplasty balloons and 90-μm microspheres, respectively. Simultaneous measurements of pressure drop, left ventricular pressure (p), and velocity were obtained. Contractility was calculated as (dp/dt)max, categorized into low contractility <900 mmHg/s and high contractility >900 mmHg/s, and in each group, compared between %AS <50 and >50 using analysis of variance. In the presence of MVD, between the %AS <50 and >50 groups, values of CDP (71 ± 1.4 and 121 ± 1.3) and LFC (0.10 ± 0.04 and 0.19 ± 0.04) were significantly different (P < 0.05), under low-contractility conditions. A similar %AS trend was observed under high-contractility conditions (CDP: 18 ± 1.4 and 91 ± 1.4; LFC: 0.08 ± 0.04 and 0.25 ± 0.04). Under MVD conditions, similar to fractional flow reserve, CDP and LFC were not influenced by contractility.
authors.affiliation: School of Dynamic Systems, Department of Mechanical Engineering, University of Cincinnati, 593 Rhodes Hall, Cincinnati, OH, 45220, USA.
authors.forename: Srikara Viswanath
authors.initials: SV
authors.lastname: Peelukhana
authors.forename: Kranthi K
authors.initials: KK
authors.lastname: Kolli
authors.forename: Massoud A
authors.initials: MA
authors.lastname: Leesar
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Effat
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Helmy
authors.forename: Imran
authors.initials: I
authors.lastname: Arif
authors.forename: Eric W
authors.initials: EW
authors.lastname: Schneeberger
authors.forename: Paul
authors.initials: P
authors.lastname: Succop
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Banerjee
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000503:physiopathology*; D023921:Coronary Stenosis / Q000175:diagnosis / Q000503:physiopathology*; D003331:Coronary Vessels / Q000503:physiopathology*; D004195:Disease Models, Animal; D053805:Fractional Flow Reserve, Myocardial; D006439:Hemodynamics; D008833:Microcirculation; D009200:Myocardial Contraction; D012720:Severity of Illness Index; D013552:Swine; D016277:Ventricular Function, Left; D017725:Ventricular Pressure