Data from: Retinal capillary rarefaction in patients with untreated mild-moderate hypertension

Background: Microvascular rarefaction influences peripheral vascular
resistance, perfusion and metabolism by affecting blood pressure and flow
pattern. In hypertension microvascular rarefaction has been described in
experimental animal studies as well as in capillaroscopy of skin and
biopsies of muscle tissue in patients. Retinal circulation mirrors
cerebral microcirculation and allows non-invasive investigations. We
compared capillary rarefaction of retinal vessels in hypertensive versus
normotensive subjects. Methods: In this study retinal capillary
rarefaction in 70 patients with long time (more than 67 month of disease
duration) and 64 patients with short time hypertension stage 1 or 2 has
been compared to 55 healthy control subjects, who participated in clinical
trials in our Clinical Research Center (www.clinicaltrials.gov:
NCT01318395, NCT00627952, NCT00152698, NCT01319344). Retinal vascular
parameters have been measured non-invasively and in vivo in perfusion
image by scanning laser Doppler flowmetry (Heidelberg Engineering,
Germany). Capillary rarefaction was assessed by capillary area (CapA) (in
pixel-number) and intercapillary distance (ICD) (in μm). Additionally
retinal capillary flow (RCF) was measured. Results: ICD was greater in the
long time hypertensive group compared to healthy individuals (24.2 ± 6.3
μm vs 20.1 ± 4.2 μm, p = 0.001) and compared to short time hypertensive
patients (22.2 ± 5.2 μm, p = 0.020). Long time hypertensive patients
showed less CapA compared to healthy people (1462 ± 690 vs 1821 ± 652,
p = 0.005). Accordingly, RCF was significantly lower in the long time
hypertensive group compared to the healthy control group (282 ± 70 AU vs
314 ± 60 AU, p = 0.032). Our data indicate a lower level of retinal
capillary density in hypertensive patients, especially in those with long
time hypertension. Conclusion: Patients with hypertension stage 1 or 2
showed retinal capillary rarefaction in comparison to healthy normotensive
subjects. Retinal capillary rarefaction was intensified with duration of
disease.