Introduction: Brain hypoperfusion causing the syncope may lead to changes in the brain tissue. The question is how differ the response to brain hypoperfusion in relation to age of patients with syncope.
The aim of study: analysis of influence of age on cerebral regional oxygen saturation (rSO2) measured by near infra-red spectroscopy (NIRS) during head-up tilt test (HUTT) in patients with vasovagal syncope (VVS).
Study population: we observed 1270 adult patients (786 women), aged 17-82 yrs. (median of age 40 yrs.) with VVS referred to HUTT.
Methods:All pts. underwent HUTT according standard Westminster protocol. During HUTT rSO2 of frontal lobes of brain was measured using INVOS cerebral oxim eter in all pts. Baseline value of rSO2 was evaluated during 15 min. supine phase before HUTT. Changes of rSO2 during HUTT was expressed as a relative decrease (in%) of rSO2 in left and right channels. Area limited by curve of rSO2 and baseline level of rSO2 during HUTT (rSO2-AUC), mean (rSO2-mean) and maximal (rSO2-max) desaturation during the test was also analyzed in all patients. Patients were divided into 4 groups according to quartiles of age. Measured parameters of brain saturation were compared quartiles of patients’ age
Results: HUTT was positive in 1027 pts. (80,8%) Significant desaturation preceded syncope induction during HUTT in all pts. in comparison to pts. with negative test (32,5 and 33,1 % vs -10,8 and -11,4 % p< 0,00001). Higher values of both mean and maximal desaturation and area limited by the desaturation curves were observed in the youngest (17-25 yrs.) and the oldest (60-82 yrs.) quartiles of pts. with vasovagal syncope induced by HUTT in comparison to the subjects with age between 25-60 yrs. (II and III quartiles).
Conclusions: 1. The brain saturation changes induced by syncope during HUTT are related to the age of patients with vasovagal faints. 2. The youngest and the oldest patients are more sensitive to brain hypoperfusion related to the vasovagal syncope. 3. Lower degree of desaturation induced by syncope in the middle aged pts. with vasovagal syncope may reflect the more feasible autoregulation of brain perfusion or other mechanism, i.e. kind of preconditioning.