title: First experience in analysing pulsatile retinal capillary flow and arteriolar structural parameters measured noninvasively in hypertensive patients.
abstract: OBJECTIVE
  Increased pulsatile pressure induces as well as aggravates microvascular damage. Scanning laser Doppler flowmetry allows the noninvasive assessment of both retinal capillary flow (RCF) and arteriolar structural parameters of the retinal circulation. Moreover, pulsatile characteristics of the retinal arterioles can be assessed.
  
  
  METHODS
  In study 1, reliability of pulsatile RCF and structural parameters were examined in randomly selected patients. In study 2, pulsatile RCF as well as the structural parameters of retinal arterioles were assessed in hypertension grade 1-2 (HT1-2; n = 20) and treatment-resistant hypertension (TRH; n = 19).
  
  
  RESULTS
  In study 1, test-retest, interobserver and intraobserver reliability of all parameters showed coefficients of variation of less than 10%. In study 2, it was shown that patients with TRH had higher pulse pressure (P = 0.003) and pulsed RCF values (P < 0.001) as patients with HT1-2. Patients with HT1-2 had no change in the vessel diameter, but a significant difference in lumen diameter, resulting in an altered wall thickness (P = 0.001) between systole and diastole. In contrast, patients with TRH showed differences in vessel diameter (P = 0.005) as well as lumen diameter (P = 0.001), resulting in an unaltered wall thickness between systole and diastole. Hence, wall thickness change as a result of pulsed flow regulation observed in HT1-2 was missing in TRH.
  
  
  CONCLUSIONS
  We suggest a new reliable tool for evaluating the pulsatility in the retinal circulation in humans, and found significant differences in pulsatile RCF and structural parameters between patients with HT1-2 and those with TRH.
authors.affiliation: aDepartment of Nephrology and Hypertension, University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany bDepartment of Pathophysiology cDepartment of Nephrology and Hypertension, University of Warmia and Masury, Olsztyn, Poland dDepartment of Ophthalmology, University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Harazny
authors.forename: Christian
authors.initials: C
authors.lastname: Ott
authors.forename: Ulrike
authors.initials: U
authors.lastname: Raff
authors.forename: Jürgen
authors.initials: J
authors.lastname: Welzenbach
authors.forename: Norbert
authors.initials: N
authors.lastname: Kwella
authors.forename: Georg
authors.initials: G
authors.lastname: Michelson
authors.forename: Roland E
authors.initials: RE
authors.lastname: Schmieder
mesh_terms: D000328:Adult; D001160:Arterioles / Q000503:physiopathology*; D002196:Capillaries / Q000503:physiopathology; D003971:Diastole; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow; D015203:Reproducibility of Results; D012160:Retina / Q000503:physiopathology; D012171:Retinal Vessels / Q000503:physiopathology*; D013599:Systole