Abstract
Purpose: :
Structural alterations of small subcutaneous arteries predict cardio-cerebrovascular events. It was found recently that subjects with an increase in wall cross sectional area of small subcutaneous arteries are at high risk for cardio-cerebrovascular events. We investigated the structural alteration of retinal arterioles in patients with a history of a recent cerebrovascular event (transitory ischemic attack or lacunar cerebral infarction) compared to arterial normotensive and hypertensive controls.
Methods: :
Wall cross sectional area and arteriole-to-venule-ratio (AV-ratio) of retinal vessels, body mass index, arterial blood pressure and intima-media-thickness (IMT) of the carotid artery were measured in 24 subjects (57±9 years) with an acute history of a cerebrovascular event within 1-7 days prior to examination, in 83 subjects with arterial hypertension (53±5 years, daytime SBP >= 135 mmHg and DBP >= 85 mmHg) and in 15 normotensive controls (53±8 years). The structure of retinal arterioles was assessed by Scanning Laser Doppler Flowmetry (Heidelberg Retina Flowmeter). Analyses were performed with AFFPIA. Outer diameter (AD) of retinal arterioles was measured in reflection images and lumen diameter (LD) in perfusion images. Wall-to-lumen ratio (WLR), wall thickness (WTH) and wall cross sectional area (WCSA) were calculated according to the formulas (AD-LD)/LD, (AD-LD)/2 and (Pi/4)*(AD²-LD²), respectively. Assessing digital fundus photographs the AV-ratio was calculated. Statistical comparison between groups was performed using Kruskal-Wallis-test (SPSS software, release 14.0). Data are given as mean±SD.
Results: :
WCSA of retinal arterioles were significantly increased in patients with cerebrovascular events (5310±1888 µm²) compared to hypertensive subjects (4097±1488 µm²) or normotensive controls (3849±1296 µm²), p<0.05. WLR, WTH and IMT showed similar significant changes (p<0.001). We found no significant differences between groups concerning age, BMI and AV-ratio.
Conclusions: :
The wall cross sectional area of retinal arterioles was highest in the cerebrovascular event group compared to arterial hypertensive subjects and normotensive controls, indicating vascular hypertrophy. In contrast, the AV-ratio did not differ significantly in the cerebrovascular group from the others. Sophisticated examination of retinal arterioles might be a future tool for cerebrovascular risk stratification.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • imaging/image analysis: clinical • retina