Vascular dysregulation in the choroid of subjects with acral vasospasm

To assess the relationship between ocular perfusion pressure and blood flow in the choroid in subjects with acral vasospasm.

Twenty otherwise healthy subjects with acral vascular dysregulation and 55 age-matched nonvasospastic healthy volunteers were recruited. After a 20-minute rest in a sitting position, intraocular pressure and choroidal blood flow were determined by means of applanation tonometry and choroidal laser Doppler flowmetry, respectively. The laser Doppler flowmetry variables velocity, volume, and flux were assessed. The correlations between mean ocular perfusion pressure ([23 x [(23 x diastolic blood pressure) + (13 x systolic blood pressure)]] -intraocular pressure) and blood flow measures were determined by means of the Pearson linear correlation factor. The t test was used to evaluate differences between normal subjects and patients with vasospasm.

Apart from a slight difference in systolic blood pressure (mean +/- SD, 113.70 +/- 11.88 mm Hg in the vasospastic group and 121.09 +/- 14.58 mm Hg in the control group; P =.05), the 2 study groups were completely comparable. Velocity and flux correlated significantly with the mean ocular perfusion pressure (r = 0.76, P<.001; r = 0.64, P =.002, respectively) in vasospastic subjects. Such correlations did not occur in the control group, and the difference between vasospastic patients and control subjects with regard to these correlations was statistically significant (P<.001 and P =.003, respectively).

Choroidal blood flow seems, to some degree, to be independent of perfusion pressure, but not in subjects with acral vasospasm.