title: Impaired microvascular properties in uncomplicated type 1 diabetes identified by Doppler ultrasound of the ocular circulation.
abstract: OBJECTIVE
  Quantification of Doppler flow velocity waveforms has been shown to predict adverse cardiovascular outcomes and identify altered downstream haemodynamics and vascular damage in a number of organ beds. We employed novel techniques to quantify Doppler flow velocity waveforms from the retro bulbar circulation.
  
  
  RESULTS
  In total, 39 patients with uncomplicated Type 1 diabetes mellitus, and no other significant cardiovascular risk factors were compared with 30 control subjects. Flow velocity waveforms were captured from the ophthalmic artery (OA), central retinal artery (CRA) and the common carotid artery. The flow velocity profiles were analysed in the time domain to calculate the resistive index (RI), and time-frequency domain using novel discrete wavelet transform methods for comparison. Analysis of flow waveforms from the OA and CRA identified specific frequency band differences between groups, occurring independently of potential haemodynamic or metabolic confounding influences. No changes were identified in the calculated RI from any arterial site.
  
  
  CONCLUSIONS
  Novel analysis of the arterial flow velocity waveforms recorded from the retro bulbar circulation identified quantifiable differences in Doppler flow velocity waveform morphology in patients with diabetes prior to the development of overt retinopathy. The technique may be useful as an additional marker of cardiovascular risk.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lockhart
authors.forename: Aaron
authors.initials: A
authors.lastname: McCann
authors.forename: Christina A
authors.initials: CA
authors.lastname: Agnew
authors.forename: Paul K
authors.initials: PK
authors.lastname: Hamilton
authors.forename: Cathy E
authors.initials: CE
authors.lastname: Quinn
authors.forename: Vivienne
authors.initials: V
authors.lastname: McClenaghan
authors.forename: Christopher
authors.initials: C
authors.lastname: Patterson
authors.forename: R
authors.initials: R
authors.lastname: Canice McGivern
authors.forename: Mark T
authors.initials: MT
authors.lastname: Harbinson
authors.forename: Gary E
authors.initials: GE
authors.lastname: McVeigh
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D042241:Early Diagnosis; D005123:Eye / Q000098:blood supply*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D009660:Northern Ireland; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color; D018617:Ultrasonography, Doppler, Pulsed