The value of near-infrared spectroscopy for the assessment of calf muscle function in venous patients.

Abstract

Near-infrared spectroscopy (NIRS) is a noninvasive technique with the potential to determine the degree of tissueoxygenation. The aim of the current study was to investigate the use of NIRS as a reliable method of detecting calf muscle pump dysfunction in groups of patients with venous disease. Patients with superficial venous insufficiency (SVI) orhistory of deep venous thrombosis (DVT) were classified according to the comprehensive classification system for chronic venous disorders (clinical class, etiology, anatomy, andpathophysiology) and compared with controls (GROUP variable). A 10-stage evaluation of ambulatory venous function was performed, and corresponding values of calf regional oxygen saturation (crSaO2, %) at each phase were recorded (TIME variable). Thereafter, the percentage changes of crSaO2 values (Δ scores, %) between a given phase and the reference phase were estimated. Differences among groups and phases were evaluated using analysis of variance. Subgroup analysis between C0-C2 and C3-C6 patients was performed. The receiver operating characteristic curve analysis was used todetect the best predictive capability for SVI and DVT. A total of 30 patients with SVI, 31 patients with DVT, and 34 controls were included in the study. A statistically significant effect of TIME (F= 382.4; P< .001) andTIME×GROUP interaction (F= 6.3; P< .001) was recorded. Concerning prediction, we found a statistically significant area under the curve (AUC) for SVI (AUC= 0.72; 95% confidence interval, 0.58-0.83; P= .003) and forDVT (AUC= 0.83; 95% confidence interval, 0.71-0.92; P< .0001) patients. The measurement of crSaO2 using NIRS detected alterations in calf muscle pump oxygenation during exercise and differences in tissue oxygenation among SVI patients, DVT patients, and controls. NIRS may represent a reliable noninvasive tool for the study of calf muscle dysfunction in venous disease and a useful vehicle for generating testable hypotheses in the laboratory setting.