Indocyanine green dye (ICG) fluorescence lymphography represents a suitable method of providing information on the effectiveness of intermittent pneumatic compression (IPC) during the treatment of leg oedema (an excess of fluid around the limb), according to a study conducted with patients after surgery. Moreover, IPC was compared to other modalities for the therapy of limb oedema, including manual lymphatic drainage and bandaging.
Results of the trial, in addition to an analysis of its findings, were presented at the International Union of Phlebology chapter meeting (UIP 2019; 25–27 August, Krakow, Poland) by Marzanna Zaleska (Polish Academy of Sciences and Central Clinical Hospital MSW, Warsaw, Poland), who explained that “tissue oedema develops with the insufficiency of both the venous and lymphatic systems”.
Zaleska, who conducted the investigation with Waldemar Olszewski (Central Clinical Hospital MSW, Warsaw, Poland), also underlined that “the oedema which develops with venous stasis affects lymphatic flow, while lymphatic stasis affects the venous capacity, so these two situations should be treated and excess fluid should be removed”. The aim of compression therapy is to move mobile oedema tissue fluid towards the extremities, where it can be absorbed, while the effectiveness of a compression method can be evaluated according to changes in limb circumference or volume.
However, as Zaleska reminded those in attendance, these methods do not show where oedema fluid has been moved, nor do they reveal whether there is a post-compression oedema fluid backflow for patients in an upright position. “All of this necessitates the visualisation of fluid movement,” Zaleska argued, detailing the several methods currently available for monitoring the condition of both the lymphatic and venous systems; these include lymphoscintigraphy, which traces areas in which there is an accumulation of fluid, and x-ray phlebography.
“Our aim was to visualise oedema fluid movement during high-pressure pneumatic compression, using ICG fluorescence lymphography,” said Zaleska, who outlined that “we investigated patients with lymphoedema of the limbs after hysterectomy and patients with venous leg ulcers and oedema.” In addition to this, ICG fluorescence lymphography was used to visualise tissue and oedema fluid flow during manual drainage and bandaging.
As part of the study, 20 patients with post-surgical lymphoedema of lower and upper limbs, 10 patients with post-thrombotic leg oedema and five cases with venous ulcers were enrolled, with the investigation carried out across three treatment groups: i) manual lymphatic drainage (thumb or hand); ii) intermittent pneumatic compression (eight-chamber sleeve, each chamber inflated to 50, 80, 100, and 120mmHg for 50 seconds); iii) bandaging generating interface pressure of 40-50mmHg. For each type of compression, ICG fluorescence lymphography was performed at a known force.
The findings of the investigation demonstrated that a threshold pressure of 80mmHg in the compression is needed to move oedema fluid, and over 40mmHg for tissue fluid. Furthermore, ICG fluorescence lymphography was successful in demonstrating that IPC is an effective therapy of limb oedema.
Zaleska commented: “These are pictures before and after compression, and you can see that even after one minute of compression there is less dye, which means there is less fluid. Before IPC, we measured fluorescence intensity in this area and it was 62%, and after three minutes with 50mmhg the fluorescence intensity decreased to 42%. After additional minutes with higher compression, the fluorescence intensity decreased to 36% and 34%, so the compression was effective.”
As well as visualising the accumulation of fluid in one area of the limb, ICG fluorescence lymphography was also able to show this accumulation of fluid along the whole limb: from the foot to the groin. “As you can see, some fluid was moved from the foot and calf to the knee (origin) and to the thigh. We can also see that some fluid moved to the proximal part of the limb,” Zaleska added. These observations point to the need for ICG fluorescence lymphography before and after compression therapy in each patient.
She concluded: “Using this method, it is possible show how large the oedema is around the ulcer; here we can see a small necrotic area and a large accumulation of fluid. ICG lymphography provides information on the stagnant oedema fluid in the dermis and subepidermal plexus and the effects of pneumatic compression.”