24-h blood pressure monitoring in normal tension glaucoma: night-time blood pressure variability.
Systemic arterial hypotension, hypertension and altered ocular blood flow are known risk factors in glaucoma. In this study, 24-h ambulatory blood pressure monitoring was performed in patients with normal tension glaucoma (NTG) and controls to evaluate blood pressure variability. In all, 51 patients with NTG and 28 age-matched controls were included in this prospective study. A 24-h ambulatory blood pressure monitoring (SpaceLabs Medical Inc., Redmond, USA) was performed and systolic, diastolic and mean arterial blood pressures were measured every 30 min during daytime (0800-2000) and night time (0000-0600). To evaluate blood pressure variability a variability index was defined as the s.d. of blood pressure measurements. Night-time blood pressure depression ('dip') was calculated (in percent of the daytime blood pressures). Patients with NTG exhibited higher night-time diastolic (P = 0.01) and mean arterial blood pressure values (P = 0.02) compared to controls, whereas systolic blood pressure data were not significantly different. The variability indices of night-time systolic, diastolic and mean arterial blood pressure measurements were significantly increased in patients with NTG compared to controls (P < 0.05). The night-time blood pressure depression of systolic (P = 0.47), diastolic (P = 0.11) and mean arterial blood pressures (P = 0.28) was not significantly different between patients with NTG and controls. In conclusion, patients with NTG showed increased variability of night-time blood pressure measurements compared to controls. Increased fluctuation of blood pressure may lead to ocular perfusion pressure fluctuation and may cause ischaemic episodes at the optic nerve head.
Plange
N
N
Augenklinik des Universitätsklinikum Aachen, Germany. nplange@ukaachen.de
Kaup
M
M
Daneljan
L
L
Predel
H G
HG
Remky
A
A
Arend
O
O
D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D005123:Eye / Q000098:blood supply; D005260:Female; D005901:Glaucoma / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology; D013599:Systole / Q000502:physiology