Dynamic microvascular blood flow analysis during post-occlusive reactive hyperemia test in patients with...

Patients suffering from schizophrenia have an increased mortality risk due to cardiovascular events. Recently the analysis of peripheral circulation has revealed interesting results in the study of vascular pathological conditions assuming that the state of microcirculation of the skin is at least partly representative for the constitution of other vascular beds including those of the cardiac muscle and arteries. The objective of this study was to investigate the microcirculation in patients with acute schizophrenia (PAT, n = 15, mean age 33.0 years, 7 male, 8 female) to identify whether spectral features from blood flow signals derived through laser Doppler spectrometry are significantly altered compared to healthy subjects (CON, n = 15, mean age 32.4 years, 7 male, 8 female) by means of the post-occlusive reactive hyperemia test. It was also explored if a segmentation of the post-ischemic stage can disclose more detailed and additional information about the dynamic behavior of the blood flow during hyperemic response. For this reason, time-frequency analyses were performed to observe the course of the blood flow frequency components over time. Our results indicate significant differences in the patients group, already detectable under baseline conditions but also in the hyperemic phase. The main modifications affect the respiratory (p = 0.006) as well as the cardiac (p = 0.001) activity. It was further shown that the application of a segmented analysis of the post-ischemic state considerably improves the differentiation between both groups. Only with the introduced segmentation algorithm using a window length of 2048 samples and a shift of 128 and 256 samples we could demonstrate influences of the disease on the endothelial (p = 0.029), the sympathetic (p = 0.019) and the myogenic (p = 0.029) mechanisms. These information provide further insights into the appearance of schizophrenia and could lead to an improvement of the patients' treatment to avoid the occurrence of cardiovascular events.