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Assessing Renal Blood Flow Hemodynamics And Autoregulation In Humans Using Intrarenal Doppler Flow Velocity Measurement
Author(s) -
Braam Branko,
Kiepas Alex,
Nath Ermin,
Mitrou Nick,
Cupples Will,
Kim Daniel
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.808.23
Subject(s) - autoregulation , hemodynamics , renal blood flow , cardiology , medicine , renal circulation , blood flow , renal artery , tubuloglomerular feedback , kidney , blood pressure
Renal hemodynamics studied in experimental animals (rats, mice, dogs) has revealed that autoregulation of renal blood flow (RBF) is established by myogenic response (MR) and tubuloglomerular feedback (TGF). However, this data has not been available in humans. In this pilot study, we directly measure RBF in humans allowing analysis of MR and TGF characteristics. We assessed RBF at 50 Hz using Doppler‐based flow velocity measurements by introducing a FloWire (Volcano) catheter into the renal artery of 5 human subjects who were undergoing cardiac catheterization. RBF was derived from Doppler velocities over 5‐10 minutes and renal artery diameter. Renal artery pressure (RAP) was measured in the abdominal aorta at the root of the renal artery. The 5 subjects displayed substantial variations in RAP, allowing assessment of MR and TGF by time series analysis. Overall, RBF showed autoregulatory behaviour (see example).MR and TGF signatures could be identified in the Gain, Coherence and Phase plots. A newly developed method to assess autoregulation efficiency established by MR revealed highly variable efficiency among these 5 individuals. In sum, this approach makes it possible to investigate RBF dynamics, MR and TGF and efficiency of autoregulation in humans. Further studies are directed to develop the analytical methodology for these human samples further and to compare patients with and without heart failure with respect to RBF dynamics. Grant support received from the Univ. of Alberta Hospital Foundation.