Relationship of blood pressure to retinal vessel diameter in type 1 diabetes mellitus.
OBJECTIVE
To examine the relationship of blood pressure (BP) and use of angiotensin-receptor blocker or angiotensin-converting enzyme inhibitor to retinal vessel diameter in normotensive, normoalbuminuric persons with type 1 diabetes mellitus.


METHODS
In a randomized, controlled clinical trial, clinic and 24-hour ambulatory BPs were measured in persons with type 1 diabetes mellitus and gradable fundus photographs both at baseline (n = 147) and at 5-year follow-up (n = 124). Retinal arteriole and venule diameters were measured by a computer-assisted technique. Individual arteriole and venule measurements were combined into summary indexes that reflect the average retinal arteriole (central retinal arteriole equivalent [CRAE]) and venule (central retinal venule equivalent [CRVE]) diameter of an eye, respectively.


RESULTS
While controlling for age, study site, glycosylated hemoglobin level, and ambulatory pulse rate, the daytime ambulatory systolic (-0.29-microm effect per 1 mm Hg; P = .02), daytime ambulatory diastolic (-0.44-microm effect per 1 mm Hg; P = .04), nighttime ambulatory systolic (-0.27-microm effect per 1 mm Hg; P = .03), and 24-hour ambulatory systolic (-0.31-microm effect per 1 mm Hg; P = .03) BPs were cross-sectionally associated with a smaller CRAE. While controlling for age, study site, glycosylated hemoglobin level, ambulatory pulse rate, and baseline CRAE, no BP measure was associated with a change in CRAE or CRVE during 5 years of follow-up. Treatment with losartan potassium or enalapril maleate was not associated with a statistically significant change in CRAE or CRVE.


CONCLUSIONS
Angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker therapy does not affect retinal arteriole or venule diameter in normotensive persons with type 1 diabetes mellitus. Trial Registration clinicaltrials.gov Identifier: NCT00143949.
Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 610 N Walnut St, 417 WARF, Madison, WI 53726-2336, USA. kleinr@epi.ophth.wisc.edu
Ronald
R
Klein
Chelsea E
CE
Myers
Barbara E K
BE
Klein
Bernard
B
Zinman
Robert
R
Gardiner
Samy
S
Suissa
Alan R
AR
Sinaiko
Sandra M
SM
Donnelly
Paul
P
Goodyer
Trudy
T
Strand
Michael
M
Mauer
D000293:Adolescent; D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D001160:Arterioles / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D004311:Double-Blind Method; D004656:Enalapril / Q000494:pharmacology; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019808:Losartan / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000187:drug effects / Q000502:physiology*; D014699:Venules / Q000502:physiology
D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D006442:Glycated Hemoglobin; D019808:Losartan