Age determines vascular reactivity as measured by optical rhinometry

Endonasal blood volume depends on autonomous nervous system activation and ultimately vascular reactivity. It can be measured by optical rhinometry, a simple- to-use, subject-compliance independent method. We investigated endonasal perfusion following postural change to determine predictors of vascular response.

Optical rhinometry was performed in 52 healthy subjects (25 women) with an age range of 21-80 years. Subjects were placed in supine position after 5 min of standing. Optical density (OD) as marker of endonasal blood volume was continuously measured for 30 min after postural change. In addition to age, data on other risk factors for impaired vascular reactivity, such as gender, smoking, level of physical activity, resting heart rate and blood pressure were obtained. To evaluate raw-data curves, integrals over defined time-periods were calculated.

The OD initially increased following the intervention (t(max) at 207 +/- 12 s, mean +/- SEM). Thereafter, a gradual return to baseline levels was observed in young but not in elderly subjects. In multivariate models, age was the most influential parameter for vascular response followed by body mass index. The defined integrals as indicators of curve structure were all significantly influenced by age (P < 0.01 for each interval). Other measured risk factors had no effect on curve characteristics.

Age is an important predictor of endonasal perfusion. Evaluation of optical rhinometry needs to take age-dependency of results into account. Studies in patients with cardiovascular disease are needed to show if optical rhinometry can provide information about vascular responsiveness as a predictor of cardiovascular morbidity.