Abstract 302: The PAT Ratio is Reduced by Beta-blockers

Background: Flow-mediated dilatation (FMD) of the brachial artery and Peripheral arterial tonometry (PAT) are both methods for assessing endothelial vascular function. FMD measures predominantly nitric oxide mediated vasodilation whereas PAT measures a more complex range of mechanisms. The recent study showed that the sympathetic nervous system plays a significant role in this response. Methods: The study involved 176 subjects (mean age66 ±12 years). Based on the medication of beta-blockers, they were divided into 2 groups: beta-blocker group (n=37) and control group (n=139). Flow mediated vasodilatation (FMD) and nitroglycerine-induced vasodilatation (NID) in the brachial artery was measured by using UNEXEF18G (UNEX CO, Japan), and nitroglycerin mediated vasodilatation (NMD) was used as a control test for FMD. At the same time, PAT ratio was measured by using Endo-PAT 2000 (Itamar Medical, Israel) Results: PAT ratio was significantly impaired in beta-blocker group compared to that in control group (1.5±0.4% vs. 1.9±0.6%, respectively; P<0.05). However, FMD and NMD had no deference in both groups. Multivariable analysis revealed that blood sugar and medication of beta-blockers were independent variables for PAT ratio. Conclusion: These result show that beta-blockers is associated with a tendency towards reduced PAT ratio. PAT needs to be further studied, including the assessment of non-endothelial factor