Measurement of Pulmonary Flow Reserve and Pulmonary Index of Microcirculatory Resistance for Detection of Pulmonary Microvascular Obstruction

PLoS One

Chirapan Chawantanpipat¹  Kim H. Chan²  Martin K. C. Ng²  Rahn Ilsar²  Annemarie Hennessy²  Timothy A. Dobbins²  Richard Waugh³  David S. Celermajer⁴ 

[1] Department of Medicine, University of Sydney, Sydney, New South Wales, Australia;Royal Prince Alfred Hospital, Sydney, New South Wales, Australia;School of Public Health, University of Sydney, Sydney, New South Wales, Australia;University of Western Sydney, Sydney, New South Wales, Australia

关键词: Blood flow;    Adenosine;    Pulmonary arteries;    Hemodynamics;    Primates;    Baboons;    Blood pressure;    Microcirculation;   

DOI  :  10.1371/journal.pone.0009601

学科分类：医学（综合）

来源: Public Library of Science

【 摘 要 】

Background The pulmonary microcirculation is the chief regulatory site for resistance in the pulmonary circuit. Despite pulmonary microvascular dysfunction being implicated in the pathogenesis of several pulmonary vascular conditions, there are currently no techniques for the specific assessment of pulmonary microvascular integrity in humans. Peak hyperemic flow assessment using thermodilution-derived mean transit-time (Tmn) facilitate accurate coronary microcirculatory evaluation, but remain unvalidated in the lung circulation. Using a high primate model, we aimed to explore the use of Tmn as a surrogate of pulmonary blood flow for the purpose of measuring the novel indices Pulmonary Flow Reserve [PFR = (maximum hyperemic)/(basal flow)] and Pulmonary Index of Microcirculatory Resistance [PIMR = (maximum hyperemic distal pulmonary artery pressure)×(maximum hyperemic Tmn)]. Ultimately, we aimed to investigate the effect of progressive pulmonary microvascular obstruction on PFR and PIMR.Methods and Results Temperature- and pressure-sensor guidewires (TPSG) were placed in segmental pulmonary arteries (SPA) of 13 baboons and intravascular temperature measured. Tmn and hemodynamics were recorded at rest and following intra-SPA administration of the vasodilator agents adenosine (10–400 µg/kg/min) and papaverine (3–24 mg). Temperature did not vary with intra-SPA sensor position (0.010±0.009 v 0.010±0.009°C; distal v proximal; p = 0.1), supporting Tmn use in lung for the purpose of hemodynamic indices derivation. Adenosine (to 200 µg/kg/min) & papaverine (to 24 mg) induced dose-dependent flow augmentations (40±7% & 35±13% Tmn reductions v baseline, respectively; p<0.0001). PFR and PIMR were then calculated before and after progressive administration of ceramic microspheres into the SPA. Cumulative microsphere doses progressively reduced PFR (1.41±0.06, 1.26±0.19, 1.17±0.07 & 1.01±0.03; for 0, 104, 105 & 106 microspheres; p = 0.009) and increased PIMR (5.7±0.6, 6.3±1.0, 6.8±0.6 & 7.6±0.6 mmHg.sec; p = 0.0048).Conclusions Thermodilution-derived mean transit time can be accurately and reproducibly measured in the pulmonary circulation using TPSG. Mean transit time-derived PFR and PIMR can be assessed using a TPSG and adenosine or papaverine as hyperemic agents. These novel indices detect progressive pulmonary microvascular obstruction and thus have with a potential role for pulmonary microcirculatory assessment in humans.

【 授权许可】

CC BY