Abstract
Purpose: :
There is little knowledge on systolodiastolic pulse amplitude of retinal microvessels, despite its potential interest in retinal and general vascular diseases as a marker of vascular stiffness. We underwent this preliminary study to explore the reproducibility and variations of vessel pulse amplitude in health and diseases.
Methods: :
The amplitude of systolodiastolic variations of the diameters of temporal arterioles and venules (diameter >110 µm, 1 disc diameter from the disc) were recorded using the Retinal Vessel Analyzer (RVA®; Imedos, Ilmenau, Germany) in 37 normal eyes, 19 eyes of arterial hypertensive patients, 16 eyes that had recovered from CRVO (visual acuity > 20/25, central retinal thickness <250 µm, no glaucoma, no arterial hypertension) and 9 fellow normal eyes. A minimum of 20 cardiac cycles (outlined by a r-wave generator) were averaged.
Results: :
In control eyes, the mean (±SD) pulse amplitude over the cardiac cycle was 1.9% (± 0.5) for arterioles and 3.3% (± 1.1) for venules. Reproducibility (mean (±SD) intersession difference; n=14) was 3% (± 0.4) for arterioles ( ICCs: ) and 2.5% (± 0.5) for venules, with ICCs of 0.94 (± 0.2) and 0.94 (± 0.3), respectively. There was a significant positive correlation between arterial pressure and venular relative pulse (r: 0.49; p < 0.01) but not with arteriolar pulse (r: -0.004; p= 0.9). The venular pulse amplitude was significantly lower in post-CRVO eyes (1.4% ± 0.9; p<0.002). There was no correlation of pulse amplitude with age (r: -0.19; p = 0.3) or with intraocular pressure (r: 0.16; p = 0.5).
Conclusions: :
Measurement of retinal vessel pulse amplitude is highly reproducible. Pulse amplitude of retinal venules, but not of arterioles, is positively correlated with arterial hypertension, and negatively correlated with CRVO history. While it is conceivable that a certain degree of venular stiffness accounts for the decreased venous pulsatility following CRVO, the mechanisms linking arterial pressure to venular pulse remains unclear. Additional basic and epidemiological studies are needed in order to determine if the measure of retinal vessel pulse amplitude is of interest for management or follow-up of cardiovascular and eye diseases.
Keywords: blood supply • clinical (human) or epidemiologic studies: systems/equipment/techniques