Clinical Research Evaluation of the Angiosome Concept Using Near-Infrared Fluorescence Imaging with Indocyanine Green Floris P. Tange, 1 Bien R. Ferrari, 1 Pim van den Hoven, 1 Jan van Schaik, 1 Abbey Schepers, 1 Catharina S.P. van Rijswijk, 2 Rutger W. van der Meer, 2 Hein Putter, 3 Alexander L. Vahrmeijer, 1 Jaap F. Hamming, 1 and Joost R. van der Vorst, 1 Leiden, The Netherlands Background: The angiosome concept is defined as the anatomical territory of a source artery within all tissue layers. When applying this theory in vascular surgery, direct revascularization (DR) is preferred to achieve increased blood flow toward the targeted angiosome of the foot in patients with lower extremity arterial disease (LEAD). This study evaluates the applicability of the angiosome concept using quantified near-infrared (NIR) fluorescence imaging with indoc- yanine green (ICG). Methods: This study included patients undergoing an endovascular- or surgical revasculariza- tion of the leg between January 2019 and December 2021. Preinterventional and postinterven- tional ICG NIR fluorescence imaging was performed. Three angiosomes on the dorsum of the foot were determined: the posterior tibial artery (hallux), the anterior tibial artery (dorsum of the foot) and the combined angiosome (second to fifth digit). The angiosomes were classified from the electronic patient records and the degree of collateralization was classified based on preprocedural computed tomography angiography and/or X-ray angiography. Fluorescence in- tensity was quantified in all angiosomes. A subgroup analysis based on endovascular or surgical revascularized angiosomes, and within critical limb threatening ischemia (CLTI) patients was performed. Results: ICG NIR fluorescence measurements were obtained in 52 patients (54 limbs) including a total of 157 angiosomes (121 DR and 36 indirect revascularizations [IR]). A signifi- cant improvement of all perfusion parameters in both the directly and indirectly revascularized angiosomes was found (P-values between <0.001e0.007). Within the indirectly revascularized angiosomes, 90.6% of the scored collaterals were classified as significant. When comparing the percentual change in perfusion parameters between the directly and indirectly revascularized angiosomes, no significant difference was seen in all perfusion parameters (P-values between 0.253 and 0.881). Similar results were shown in the CLTI patients subgroup analysis, displaying a significant improvement of perfusion parameters in both the direct and indirect angiosome The first two authors contributed equally and share first authorship. Declarations of interest: none. Funding: This work is co-funded by the PPP Allowance made avail- able by Health w Holland, Top Sector Life Sciences & Health, to stim- ulate public-private partnerships; and by the H2020 project Photonics grant agreement id: 871908. 1 Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands. 2 Department of Interventional Radiology, Leiden University Medical Centre, Leiden, The Netherlands. 3 Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands. Correspondence to: Dr. J.R. Van Der Vorst, Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; E-mail: j.r.van_der_vorst@lumc.nl Ann Vasc Surg 2023; -: 1–8 https://doi.org/10.1016/j.avsg.2023.01.006 Ó 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/ 4.0/). Manuscript received: October 23, 2022; manuscript accepted: January 6, 2023; published online: --- 1