António Fiarresga1, Mafalda Selas2, Eunice Oliveira2, Sandra Cavaco-Gonçalves3, Duarte Cacela2, Belmira Carrapiço4, Nuno Cardim5, Rui Cruz Ferreira2. 1. Serviço de Cardiologia, Hospital de Santa Marta, Centro Hospitalar de Lisboa Central, EPE, Lisboa, Portugal. Electronic address: antoniojosefiarresga@spc.pt. 2. Serviço de Cardiologia, Hospital de Santa Marta, Centro Hospitalar de Lisboa Central, EPE, Lisboa, Portugal. 3. Instituto Nacional de Investigação Agrária e Veterinária, IP, Lisboa, Portugal. 4. Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Lisboa, Portugal. 5. Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
Abstract
INTRODUCTION: The index of microcirculatory resistance (IMR) enables/provides quantitative, invasive, and real-time assessment of coronary microcirculation status. AIMS: The primary aim of this study was to validate the assessment of IMR in a large animal model, and the secondary aim was to compare two doses of intracoronary papaverine, 5 and 10 mg, for induction of maximal hyperemia and its evolution over time. METHODS: Measurements of IMR were performed in eight pigs. Mean distal pressure (Pd) and mean transit time (Tmn) were measured at rest and at maximal hyperemia induced with intracoronary papaverine, 5 and 10 mg, and after 2, 5, 8 and 10 minutes. Disruption of the microcirculation was achieved by selective injection of 40-μm microspheres via a microcatheter in the left anterior descending artery. RESULTS: In each animal 14 IMR measurements were made. There were no differences between the two doses of papaverine regarding Pd response and IMR values - 11 ± 4.5 U with 5 mg and 10.6 ± 3 U with 10 mg (p=0.612). The evolution of IMR over time was also similar with the two doses, with significant differences from resting values disappearing after five minutes of intracoronary papaverine administration. IMR increased with disrupted microcirculation in all animals (41 ± 16 U, p=0.001). CONCLUSIONS: IMR provides invasive and real-time assessment of coronary microcirculation. Disruption of the microvascular bed is associated with a significant increase in IMR. A 5-mg dose of intracoronary papaverine is as effective as a 10-mg dose in inducing maximal hyperemia. After five minutes of papaverine administration there is no significant difference from resting hemodynamic status.
INTRODUCTION: The index of microcirculatory resistance (IMR) enables/provides quantitative, invasive, and real-time assessment of coronary microcirculation status. AIMS: The primary aim of this study was to validate the assessment of IMR in a large animal model, and the secondary aim was to compare two doses of intracoronary papaverine, 5 and 10 mg, for induction of maximal hyperemia and its evolution over time. METHODS: Measurements of IMR were performed in eight pigs. Mean distal pressure (Pd) and mean transit time (Tmn) were measured at rest and at maximal hyperemia induced with intracoronary papaverine, 5 and 10 mg, and after 2, 5, 8 and 10 minutes. Disruption of the microcirculation was achieved by selective injection of 40-μm microspheres via a microcatheter in the left anterior descending artery. RESULTS: In each animal 14 IMR measurements were made. There were no differences between the two doses of papaverine regarding Pd response and IMR values - 11 ± 4.5 U with 5 mg and 10.6 ± 3 U with 10 mg (p=0.612). The evolution of IMR over time was also similar with the two doses, with significant differences from resting values disappearing after five minutes of intracoronary papaverine administration. IMR increased with disrupted microcirculation in all animals (41 ± 16 U, p=0.001). CONCLUSIONS: IMR provides invasive and real-time assessment of coronary microcirculation. Disruption of the microvascular bed is associated with a significant increase in IMR. A 5-mg dose of intracoronary papaverine is as effective as a 10-mg dose in inducing maximal hyperemia. After five minutes of papaverine administration there is no significant difference from resting hemodynamic status.
Keywords:
Animal model; Coronary microcirculation; Index of microcirculation resistance; Microcirculação coronária; Modelo animal; Índice de resistência da microcirculação
Authors: Elisa McAlindon; Maria Pufulete; Jessica Harris; Chris Lawton; Tom Johnson; Julian Strange; Andreas Baumbach; Chiara Bucciarelli-Ducci Journal: PLoS One Date: 2018-11-13 Impact factor: 3.240
Authors: Annette M Maznyczka; Keith G Oldroyd; John P Greenwood; Peter J McCartney; James Cotton; Mitchell Lindsay; Margaret McEntegart; J Paul Rocchiccioli; Richard Good; Keith Robertson; Hany Eteiba; Stuart Watkins; Aadil Shaukat; Colin J Petrie; Aengus Murphy; Mark C Petrie; Colin Berry Journal: Circ Cardiovasc Interv Date: 2020-05-15 Impact factor: 6.546