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Near-Infrared Indocyanine Green Florescence as a Viability Measure During Ex vivo Normothermic Limb Perfusion (EVNLP)
Robert Craig Clark, Varun Kopparthy, Payam Sadeghi, Abby Meyers, Antonio Rampazzo, Bahar Bassiri Gharb
CCF Department of Plastic and Reconstructive Surgery
2022-01-15
Presenter: Robert Clark BS
Affidavit:
I certify that the material proposed for presentation in this abstract has not been published in any scientific journal or previously presented at a major meeting. The program director is responsible for making a statement within the confines of the box below specific to how much of the work on this project represents the original work of the resident. All authors/submitters of each abstract should discuss this with their respective program director for accurate submission of information as well as the program director's approval for inclusion of his/her electronic signature.
Director Name: Bahar Bassiri Gharb
Author Category: Medical Student
Presentation Category: Basic Science Research
Abstract Category: General Reconstruction
Purpose:
Ex vivo normothermic limb perfusion (EVNLP) is practicable for prolonged limb preservation. Multifactorial post-perfusion viability assessment is not established. This study correlates quantitative indocyanine green (ICG) florescence data with demonstrated viability measures.
Methods:
Nine Yorkshire pig forelimbs underwent prolonged EVNLP. At perfusion endpoint, ICG (7.5mg/3ml) was administered and florescence recorded. Six images were cropped from each recording. Median pixel brightness was determined utilizing ImageJ and normalized to account for recording variation. Normalized outputs were compared with weight gain, extensor and flexor compartment pressures, and change in vascular resistance.
Results:
EVNLP continued 21±3 hours with endpoint weight gain of 22.2±17%, extensor and flexor compartment pressures of 51.1±34.2mmHg and 51.1±31.9mmHg respectively, and increase in vascular resistance of 49.5±37.3%. Initial limb weight significantly correlated with normalized limb florescence [Forelimb: (r=0.728, p=0.03), Foot: (r=0.734, p=0.02)]. Flexor compartment pressure significantly correlated with extensor compartment pressure (r=0.906, p<.001) and weight gain (r = 0.671, p=0.05).
Normalized limb florescence significantly correlated with weight gain [Forelimb: (r=-0.769, p=0.02), foot (r=-0.801, p=0.01)] but did not correlate significantly with other variables. Controlling for initial limb weight, normalized limb florescence correlated significantly with weight gain [forelimb: (r=-0.823, p=0.01), foot: (r=-0.786, p=0.01)], and normalized foot florescence correlated significantly with flexor compartment pressure (r=-0.692, p=0.04).
Conclusions:
Decreasing endpoint limb florescence significantly correlated with increasing weight gain and compartment pressure, which are described markers of muscle injury. This indicates that decreased ICG florescence could be an indicator of limb injury during EVNLP. ICG fluorescence may be valuable for limb viability assessment before transplantation.
