Background
Despite increasing evidence implicating the pulmonary microcirculation in the pathogenesis
of lung conditions such as pulmonary vascular disease, there remain few methods for
its evaluation in vivo. We recently demonstrated that the novel index of Doppler-derived pulmonary flow
reserve (PFRdopp = maximal hyperaemic/basal pulmonary flow) could be reliably measured in high primates.
Noting that the microvasculature is the chief regulator of pulmonary blood flow, we
hypothesised that PFRdopp may detect microcirculatory loss. We therefore studied the relationship between PFRdopp and experimentally induced pulmonary microvascular obstruction using microspheres
in higher primates.
Methods
Under ketamine anaesthesia, Doppler sensor-guidewires were placed in the segmental
pulmonary artery of three adult baboons. Doppler flow velocity and haemodynamics were
recorded at rest and during hyperaemia [as induced by intrapulmonary artery adenosine
(200 μg/kg/min)]. Serial PFRdopp evaluations were made after cumulative intrapulmonary artery ceramic microspheres
administration.
Results
Cumulative microsphere administration progressively reduced PFRdopp (1.54 ± 0.26, 1.48 ± 0.20, 1.12 ± 0.04 and 1.18 ± 0.09; baseline, 104, 105 and 106 microspheres boluses; p < 0.02) without affecting pulmonary artery pressure, systemic artery pressure or heart
rate.
Conclusions
Doppler-derived PFR can detect partial, progressive pulmonary microvascular obstruction
in higher primates. PFRdopp may thus have a potential role in the assessment of the pulmonary microcirculation
in vivo.
Keywords
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Article info
Publication history
Accepted:
June 28,
2010
Received:
June 4,
2010
Identification
Copyright
© 2010 Published by Elsevier Inc.
