A new method for the assessment of venous insufficiency in primary varicose veins using near-infrared spectroscopy

Purpose: Patients with chronic venous insufficiency (CVI) were evaluated from the aspect of ambulatory venous function using near-infrared spectroscopy (NIRS). Methods: Seventy-two primary varicose veins of 59 patients (varicose group) and 20 normal limbs of 13 volunteers (normal group) were studied. The affected limbs of the patients were divided into three groups according to the classification advocated by an International Consensus Committee in 1995: mild CVI with class 2 or 3 (50 Limbs); moderate CVI with class 4 (11 limbs); and severe CVI with class 5 or 6 (11 limbs). All of the patients underwent a treadmill walking test, during which NIRS was applied. Oxygenated hemoglobin (OxyHb) and deoxygenated hemoglobin (DeoHb) were continuously measured by NIRS during exercise. The ambulatory venous retention index (AVRI) obtained from serial changes in DeoHb was assessed comparatively in the four groups (normal and mild to severe CVI). In addition, 19 limbs in 13 patients were evaluated with air plethysmography for comparison with the data obtained by NIRS. Results: Two distinct patterns of DeoHb change were observed. During exercise, the DeoHb level decreased in the normal group as a result of calf muscle contraction, whereas in the varicose group the DeoHb level rose because of an apparent venous reflux into the calf muscles. AVRI studies demonstrated a significant difference (p < 0.0001) among groups. Although there was no apparent relationship between AVRI and ejection fraction, AVRI showed a significant correlation with the venous filling index (r = 0.61) and a weak correlation with the residual volume fraction (r = 0.41). Conclusion: NIRS is useful for accurately assessing ambulatory venous dysfunction in patients with primary varicose veins.