Abstract
Purpose: :
Recently, we have shown that the spectral index (SI) derived from the first and third harmonic oscillation of the blood flow velocity envelope of the ophthalmic artery is sensitive to age and gender. The ocular cold pressor test (OCPT) was used to examine SI for differences in the response to provocation in dependency on these parameters.
Methods: :
Twenty-eight healthy men (age 46.2 ± 15.7 years) and women (age 46.0 ± 15.9 years, p = 0.961) each were selected from a data set of 296 subjects according to age and their blood pressure (SBP/DBP ≤ 140/90 mmHg) during the first 300 sec before implementation of OCPT with positioning of the subjects’ hand in 4°C water for further 300 sec. The blood flow velocity of the contralateral ophthalmic artery was measured every 30 sec during the entire 900 sec lasting test using pulsed Doppler sonography, and blood pressure and heart rate were measured every 60 sec. The SI course was calculated from the blood flow velocity envelope and related to blood pressure.
Results: :
Cronbach’s alpha reliability for SI was at least 0.973 during OCPT. Absolute values for areas under curves (AUC, 300 to 600 sec) of SI were significantly lower reduced in women than in men but percentage changes did not differ (men, -18.4 ± 8.9 %; women, -17.8 ± 14.1 %). Absolute and percentage AUCs of SBP and DBP were increased significantly lower in women (SBP, 6.4 ± 4.9 %; DBP 4.9 ± 6.2%) compared to men (SBP, 10.0 ± 5.8 %; p = 0.011; DBP 9.4 ± 6.5 %, p = 0.006). Absolute AUC of SI (360 to 540 sec) was lower in older men (53 to 67 years) than in younger men (15 to 52 years), p = 0.039, but not in older women (50 to 67 years) compared to younger women (15 to 49 years), p = 0.051, n = 14 each. Also neither percentage change of the AUC of SI differed between age groups nor absolute and percentage blood pressure. The heart rate was not different in all evaluated groups.
Conclusions: :
The spectral index of the ophthalmic artery may detect different responses of an altered vessel constitution to cold provocation in consideration of age and gender.
Keywords: aging • blood supply • imaging/image analysis: clinical