Retinal arteriolar remodeling is an early marker of subclinical target organ damage in arterial hypertension. Through adaptive optics which is totally noninvasive and highly accurate, it is possible to measure changes in arteriolar diameter within 1 μm accuracy. The aim of this study was to evaluate a new marker describing internal diameter variability of the supero-temporal arteriole in hypertensive patients before and after blood pressure control.
Design and method:
Adaptive Optics RTX1® Camera (ImagineEye, Orsay, France) was used to capture three consecutive images along the supero-temporal arteriole. Wall Thickness (WT) and internal diameter (ID) were measured to calculate Wall-to-Lumen Ratio (WLR) and Wall Cross-Sectional Area (WCSA). A coefficient of variation (CV) for ID was calculated for each group by the following formula: (standard deviation ID/mean ID)*100 over three consecutive measurements. Subjects with a CV ID > 75% were classified as irregular. Uncontrolled hypertensive subjects in the irregular group were given an antihypertensive pharmacological treatment and were reevaluated 1 month after.
44 patients were analyzed (mean age 47.7 ± 11). Median CV ID in the irregular group was 11% [IQR 9.0–15.0] as compared to 2.0% (regular group) [IQR 1.0–4.0], p < 0.001. Patients in the arteriolar irregular group had an increase in home blood pressure (148.3/96.3 vs 130.7/ 82.6 mmHg, p < 0.01). They had significantly decreased ID (82.24 ± 13.5 vs 89.9 ± 14.8, p = 0.01) and increased WLR (0.311 ± 0.07 vs 0.262 ± 0.04, p = 0.025) whereas no differences were observed in WT and WCSA.
At one-month follow-up, along with a significant blood pressure reduction, which was associated with arteriolar enlargement and WLR reduction, a decrease in median ID CV was observed (11%[IQR 9.0–15.0] to 4.2% [IQR 1.8–6.05], p = 0.014).
Arteriolar micro-constrictions are observed in a subset of hypertensive patients with the use of adaptive optics camera. A decrease in blood pressure is accompanied with their disappearance. Beyond classical retinal microvascular remodeling indexes, Adaptive Optics may allow the definition of novel markers of microvascular remodeling that are associated with hypertension.