Development of a novel method of assessing lymph function in human extremities and its clinical application

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Lymph transportation is controlled, at least in part, by the intrinsic pumping of lymphatic vessels. Although an understanding of this process is important for medical application, little is currently known because it is difficult to measure. Here, weintroduce an easy, safe, and cost-effective technique for measuring lymphatic pumping in leg superficial lymphatic vessels. We compared readings obtained with this technique with values obtained by performing dynamic lymphoscintigraphy, a more difficult and expensive technique. Further, we investigated differences in lymphatic pumping between healthy patients and patients with lymphedema. Indocyanine green (ICG) fluorescence lymphography was performed by subcutaneously injecting 0.3 ml of ICG (0.5%) into the dorsum of the foot. Real-time fluorescence images of lymph propulsion were obtained with an infrared-light camera system in a supine or a sitting position. A custom-made transparent sphygmomanometer cuff was wrapped around the lower le … More g and connected to a standard mercury sphygmomanometer. The cuff was inflated to 60 mm Hg, then gradually deflated at 5-min intervals to lower the pressure by 10 mm Hg steps until the fluorescence dye exceeded the upper border of the cuff (indicating that the lymphatic contraction had overcome the cuff pressure). Lymph pumping pressure (Ppump) was defined as the value of the cuff pressure when the dye exceeded the upper border of the cuff. Among healthy, supine subjects, Ppump was 25.2 ± 16.7 mm Hg (mean ± SD). Healthy subjects (Ppump = 29.3 ± 16.0) showed higher Ppumthan those for lymphedematous subjects (13.2 ± 14.9). Our method of measuring lymphatic pumping may develop as a vital tool for diagnosing lymphatic malfunctions.T o evaluate the influences of age and gender on leg lymphatic pumping pressure. A total of 399 subjects between the ages of 20 and 91 years (199 males and 200 females) volunteered to participate in this study. Lymphatic pumping was measured in 798 legs of the 399 participants. Indocyanine green (ICG) fluorescence lymphography was performed, and the real-time fluorescence images of lymph propulsion were obtainedin a sitting position using an infrared-light camera system. A custom-made transparent sphygmomanometer cuff was wrapped around the lower leg and connected to astandard mercury sphygmomanometer. The cuff was inflated, and then gradually deflated until the fluorescent dye exceeded the upper border of the cuff. Lymph pumping pressure was defined as the value of the cuff pressure when the dye exceeded the upper border of the cuff. There was a significant correlation between the leg lymphatic pumping and age: r = -0.34 (p < 0.0001). Comparison of lymphatic pumping between males and females indicated that the age-related decrease in lymphatic pumping pressure was more marked in females of postmenopausal age. Less