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Abstract #10347 Published in IGR 6-1
Autoregulative behavior of retinal arteries and veins during changes of perfusion pressure: a clinical study
Nagel E; Vilser WGraefe's Archive for Clinical and Experimental Ophthalmology 2004; 242: 13-17
PURPOSE: To investigate the autoregulative response of large retinal vessels to artificial reduction of perfusion pressure. METHODS: The diameters of a venous and an arterial segment (each approximately 1.5 mm in length) in one eye of each of 13 healthy volunteers (aged 54.5 ± 18 years) were measured continuously using the Retinal Vessel Analyzer (Imedos, Weimar, Germany). The intraocular pressure (IOP; mean before examination 13.7 ± 2.9 mmHg) was increased by 21.2 ± 3.5 mmHg by means of a suction cup in order to produce temporary reduction of the retinal perfusion pressure. The RVA measurements were taken for two minutes without artificial intervention (baseline), for 100 sec during IOP elevation, and for up to ten minutes after removal of the suction cup. RESULTS: A significant response of arterial and venous diameters to the provocation was found (p < 0.02, ANOVA). The arterial and venous responses were opposite: While the artificially elevated IOP increased the arterial diameter by +1.9 ± 4.5%, the venous vessel diameter decreased by -2.6 ± 3.5% (p < 0.02, Mann-Whitney U test). After normalization of the IOP the arterial diameter fell slightly below the baseline value, while the veins underwent temporary dilation by +5.9 ± 3.3% (p < 0.001). The mean systemic blood pressure did not change significantly during the investigation. CONCLUSIONS: Retinal arteries and veins of healthy volunteers exhibited opposite autoregulative behavior in response to perfusion pressure changes. This is believed to be due to the different regulative functions of arteries and veins.
Dr. E. Nagel, Rudolstadt Ophthalmology Practice, Anton-Sommer-Strasse 55, 07407 Rudolstadt, Germany. e_a_nagel@t-online.de
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)