A novel infrared fluorescence method to identify regions of superficial microvenous reflux in patients with chronic venous disease

TL;DR

This study introduces a new imaging technique using near-infrared fluorescence to detect microvenous reflux in chronic venous disease patients, linking it to disease severity and skin changes.

Contribution

The first in vivo application of near-infrared fluorescence imaging to assess superficial microvenous reflux in chronic venous disease.

Findings

NIRF imaging revealed various microvenous reflux patterns in vivo, including focal and diffuse skin fluorescence.

The extent of fluorescence was associated with the severity of venous disease (CEAP classification).

Observed reflux patterns correlate with venous incompetence, such as perforator vein or saphenofemoral junctional issues.

Abstract

Reflux within the superficial microvenous network may play a critical role in the development of skin changes associated with chronic venous insufficiency. This study aimed to extend previous ex vivo observations to determine the in vivo utility of near infrared fluorescence (NIRF) imaging to assess superficial venous reflux in the leg.

A total of 28 limbs were examined in 17 participants. These included limbs with (CEAP C2, n = 6; C3, n = 1; and C4, n = 15) and without (CEAP C0, n = 6) venous disease. Indocyanine green (5 mL at 0.1 mg/mL) was infused via an (antegrade) cannula in the distal great saphenous vein and the medial leg imaged using NIRF. Venous reflux was assessed using the Valsalva maneuver, with or without superficial outflow obstruction (thigh cuff inflated to 50 mmHg).

Consistent with our previous ex vivo study, NIRF imaging visualized a wide range of different microvenous reflux patterns in vivo. These included focal and diffuse regions of fluorescence within the skin, the extent of which appeared to be associated with venous disease (CEAP C classification) severity. The observed reflux patterns also appeared to be functional correlates of perforator vein or saphenofemoral junctional incompetence.

This preliminary in vivo study provides proof-of-principle observations suggesting a potential novel method for investigating microvenous reflux in superficial venous disease.

This study reports the first in vivo use of near-infrared fluorescence (NIRF) imaging with indocyanine green to assess superficial microvenous reflux within intact limbs. This preliminary data suggests that the extent and distribution of skin fluorescence may be associated with venous disease severity (CEAP Clinical classification). It also provides potential mechanistic insight, identifying reflux patterns that appear to be functional correlates of venous incompetence. This study suggests that NIRF imaging could provide a novel tool for investigating microvenous contributions to chronic venous disease and its skin manifestations.

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