A system to assess endothelial dysfunction by combining peripheral arterial tonometry with digital thermal monitoring

Endothelial dysfunction is a well-known indication of the early stages of cardio vascular diseases. Various non-invasive methods have been developed to estimate the level of endothelial dysfunction. This study presents a combined non-invasive endothelial function assessment method which acquires a Peripheral Arterial Tonometry (PAT) signal simultaneously with a digital thermal monitoring (DTM) signal. The developed hardware platform acquire, preprocess and transmit the PAT and DTM signals to a software platform implemented in a Personal computer where further processing, real time visualization, calculation of signal parameters and a classification to assess the level of endothelial health is performed. The endothelium is stimulated to induce reactive hyperemia by occluding the upper arm using a blood pressure cuff. The test was carried out on 11 diabetes and 21 non-diabetes participants. Statistical analysis showed a significant correlation between the Reflection Index calculated from the PAT signal and the TEMP-AUC, TMP-fall and Rise/fall parameters calculated from the DTM signal. A one way ANOVA carried out on the collected multivariate data set shows that the Reflection Index, TEMP-AUC, TMP-fall and Rise/fall parameters are significant and a classification carried out based on linear discriminant analysis shows promising results in differentiating nondiabetes subjects from participants with diabetes.