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.
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.
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.
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.
To read this article in full you will need to make a payment
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to Heart, Lung and Circulation
Already a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
- Direct measurement of microvascular pressures in the isolated perfused dog lung.Science. 1980; 210: 327-328
- Pathologic assessment of vasculopathies in pulmonary hypertension.J Am Coll Cardiol. 2004; 43: 25S-32S
- Pulmonary microvascular disease in chronic thromboembolic pulmonary hypertension.Proc Am Thorac Soc. 2006; 3: 571-576
- Measurement of pulmonary flow reserve in higher primates.Clin Exp Pharmacol Physiol. 2009; 36: 797-802
- Measurement of pulmonary flow reserve and pulmonary index of microcirculatory resistance for detection of pulmonary microvascular obstruction.PLoS ONE. 2010; 5: e9601
- Comparison of coronary thermodilution and Doppler velocity for assessing coronary flow reserve.Circulation. 2003; 108: 2198-2200
- Direct demonstration of 25- and 50-microm arteriovenous pathways in healthy human and baboon lungs.Am J Physiol Heart Circ Physiol. 2007; 292: H1777-H1781
- Intracoronary papaverine: an ideal coronary vasodilator for studies of the coronary circulation in conscious humans.Circulation. 1986; 73: 444-451
Accepted: June 28, 2010
Received: June 4, 2010
© 2010 Published by Elsevier Inc.