Noninvasive Near-Infrared Spectroscopic Evaluation Of Calf Muscle Oxygenation In Patients With Advanced Chronic Venous Insufficiency Associated With Tricuspid Regurgitation

BACKGROUND: Near-infrared spectroscopy (NIRS) allows continuous noninvasive monitoring of changes in the tissue levels of oxygenated hemoglobin (O(2)Hb) and deoxygenated hemoglobin (HHb), and can clarify the severity of chronic venous disease. Severe tricuspid regurgitation (TR) has occasionally been known to lead to advanced symptoms of chronic venous insufficiency (CVI) and impaired wound healing. The purpose of this study was to investigate changes in the calf muscle O(2)Hb and HHb levels during standing and exercise using NIRS and to compare discriminative NIRS-derived parameters between patients with advanced CVI associated with TR and those without.METHODS: Forty-eight limbs in 46 patients with CEAP (clinical-etiology-anatomy-pathophysiology) C4a-C6 were studied. Thirteen of the limbs had CVI associated with TR and the remaining 35 had primary valvular insufficiency (PVI) with no evidence of TR. To assess the severity of CVI, the revised Venous Clinical Severity Score (VCSS) was employed. NIRS was used to measure changes in the levels of O(2)Hb and HHb in the calf muscle. On standing, increases in O(2)Hb and HHb were calculated by subtracting the baseline value from the maximum value (Delta O(2)Hb(st) and Delta HHb(st)). The times taken for the O(2)Hb and HHb concentrations to become maximal ((T)O(2)Hb(st), and (T)HHb(st)) were also measured. During 10 tiptoe movements, the relative change in O(2)Hb was calculated by subtracting the value measured at the end of exercise from that measured at the beginning of exercise (Delta O(2)Hb(ex)). On the other hand, 10 tiptoe movements produced venous expulsion (Delta HHbE(ex)) and a subsequent retention (Delta HHbR(ex)). The oxygenation index (HbD; HbD=O(2)Hb-HHb) was also calculated at the end of standing and at the end of 10 tiptoe movements (Delta HbD(st) and Delta HbD(ex)).RESULTS: There were no significant differences in mean age, gender distribution and VCSS between the two groups. However, body mass index was significantly lower in patients with TR (19.8 +/- 3.0 vs. 24.2 +/- 2.9, P=0.01). On standing, the Delta HHb(st) increased significantly in patients with TR relative to those without (21 +/- 24 vs. 8 +/- 3, P=0.04). Similarly, Delta HbD(st) decreased significantly in patients with TR relative to those without (1 +/- 33 vs. 22 +/- 19, P=0.04). During ten tiptoe movements, the fall in Delta HbD(ex) was significantly more pronounced in patients with TR (-38 +/- 37 vs. -4 +/- 13, P=0.01). There were no significant differences in the remaining parameters between the two groups.CONCLUSIONS: Our previous studies had shown that (T)O(2)Hb(st) was the best parameter for discriminating early from advanced chronic venous disease. In the present study, however, (T)O(2)Hb(st) was similar among patients with >= CEAP C4 regardless of tricuspid valve insufficiency. A significant increase in Delta HHb(st) and a decrease in Delta HbD(st) on standing, and a significant decrease in Delta HbD(ex) during exercise were important parameters that allowed discrimination between patients with TR and those without.