Pulse-waveform and laser-doppler indices for identifying colorectal-cancer patients

This study aimed to determine the effectiveness of using noninvasive arterial pulse-wave and laser-Doppler flowmetry (LDF) measurements to discriminate between colorectal-cancer (CC) patients and healthy control subjects. Radial-artery blood pressure waveform (BPW), finger photoplethysmography (PPG), and skin-surface LDF signals were measured noninvasively in 12 CC patients and 25 control subjects. Beat-to-beat, spectral, and variability analyses were applied to 20-minute-long recorded signals. Significant intergroup differences were found. In BPW, C1-C4 amplitude indices were significantly larger while P2-P8 phase-angle indices were significantly smaller in the CC patients than in the controls. The PPG and LDF variability indices were significantly larger and smaller, respectively, in CC patients. The relative energy contributions of the endothelial-, neural-, and myogenic-related frequency bands in LDF were significantly smaller in CC patients. The present findings indicate that pulse and LDF waveform analysis can be used to evaluate the arterial pulse-wave transmission condition, the responses of the blood-flow perfusion, and its regulatory activities in CC patients. There could be some similarities and differences in the present indices for different types of cancer. These findings could be utilized in the development of a rapid, noninvasive, and objective technique for evaluating the CC-induced blood-flow responses.