Correlation between 24-Hour Blood Pressure Parameters and Optic Nerve Damage in Primary Open-Angle Glaucoma

Abstract

Objective: To study the correlation between the 24-hour blood pressure parameters and optic nerve damage in primary open-angle glaucoma (POAG). Methods: In this case control study, 60 patients with POAG were assigned to POAG group, and 55 normal subjects were assigned to control group. Synchronous monitoring of 24-hour intraocular pressure (IOP) and blood pressure was conducted in both groups. Blood pressure parameters, optic perfusion pressure, and intraocular pressure for the two groups were compared. We also evaluated the connections among the blood pressure parameters, optic perfusion pressure, and IOP with visual function. Inter-group comparisons were made by independent samples t-tests and multiple linear regression. Results: ①The average IOP, IOP fluctuation, the ocular perfusion pressure fluctuation, and pulse pressure fluctuation of POAG group were significantly higher than those of control group (t=3.22, 6.57, 2.29, 2.39, respectively, all P<0.05). ②The mean systolic blood pressure of POAG group was significantly higher than that of control group (t=3.02, P=0.003). The highest systolic blood pressure, systolic blood pressure fluctuations, nighttime average systolic blood pressure, highest nighttime systolic blood pressure value and fluctuation of POAG group were also significantly higher than those of control group (t=4.38, 5.27, 4.13, 4.13, 4.14, all P<0.001). ③The mean 24-hour diastolic pressure, the maximum diastolic pressure, the mean nighttime diastolic pressure, and the maximum nighttime diastolic pressure of POAG group were significantly higher than those of control group (t=2.22, 2.50, 2.29, 2.10, all P<0.05). ④In POAG group, the mean IOP was negatively correlated with the visual field mean defect in POAG (b=-0.44, P=0.004), and the RNFL thickness was negatively correlated with mean IOP (b=-0.956, P=0.001), IOP fluctuation (b=-1.125, P=0.003). The mean nighttime diastolic pressure (b=0.395, P<0.001) and the mean nighttime arterial pressure (b=0.046, P=0.001) were positively correlated with AP100 and AP50 values, respectively. Conclusions: ①There was a correlation between the blood pressure parameters and the optic nerve damage in POAG. ②The nighttime optic perfusion pressure, the nighttime diastolic blood pressure, and the nighttime arterial pressure may be influential factors affecting optic nerve damage of POAG. ③In the treatment of POAG, a stable normal blood pressure and stable target IOP are beneficial to maintain an effective and stable optic perfusion pressure. This suggests that we should pay attention to the treatment of POAG with IOP reduction and changes of blood pressure at the same time. Key words: 24-hour blood pressure; blood pressure parameters; primary open-angle glaucoma; optic nerve damage