Latner Thoracic Surgery Research Laboratories, Toronto General Research Hospital Institute, University Health Network, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Latner Thoracic Surgery Research Laboratories, Toronto General Research Hospital Institute, University Health Network, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
J Thorac Cardiovasc Surg. 2022 Nov;164(5):e185-e203. doi: 10.1016/j.jtcvs.2022.02.048. Epub 2022 Mar 11.
Ex vivo lung perfusion (EVLP) is an excellent platform to evaluate donor lung function before transplantation, but novel methods are needed to accurately confirm transplant quality. Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) has been used in various clinical perioperative applications to evaluate tissue perfusion. We used NIRF imaging during pig and human EVLP to evaluate donor lung perfusion and edema.
Pig lungs with various degrees of lung injury (n = 10) and human lungs rejected from clinical transplantation (n = 3) were imaged during EVLP using intravascular ICG and a SPY Elite (Stryker) NIRF imaging unit. Optimal ICG and imaging conditions, and perfusion and edema quantification methods, were established. Pig lung transplants with extended graft preservation (n = 5) and control native lungs (n = 6) were also imaged.
A single ICG dose resulted in sustained donor lung NIRF throughout the EVLP. Even and homogenous ICG signal was demonstrated in areas of normal lung. Low NIRF was present in regions with poor tissue perfusion, and rapid, intense ICG accumulation occurred in damaged and edematous areas. Segmental perfusion defects were common in the peripheral and elevated regions of the lungs, and serial imaging showed gradual perfusion recovery during EVLP. Impaired microvascular reperfusion, indicated by a decreased NIRF ingress rate, was detected in transplanted pig lungs early after reperfusion.
NIRF imaging enables noninvasive real-time evaluation of lung perfusion and edema during EVLP. Prospective clinical studies are needed to determine the role of NIRF imaging in donor lung assessment and selection, and prediction of posttransplant outcomes.
体外肺灌注（EVLP）是评估供肺移植前功能的绝佳平台，但需要新的方法来准确确认移植质量。近红外荧光（NIRF）成像结合吲哚菁绿（ICG）已在各种临床围手术期应用中用于评估组织灌注。我们在猪和人 EVLP 期间使用 NIRF 成像来评估供肺灌注和水肿。
对具有不同程度肺损伤的猪肺（n=10）和临床移植中被拒绝的人肺（n=3）进行 EVLP 时，使用血管内 ICG 和 SPY Elite（Stryker）NIRF 成像单元进行成像。确定了最佳的 ICG 和成像条件以及灌注和水肿定量方法。还对具有延长供体肺保存的猪肺移植（n=5）和对照原生肺（n=6）进行了成像。
单次 ICG 剂量可使供体肺的 NIRF 在整个 EVLP 过程中持续存在。正常肺区域显示出均匀一致的 ICG 信号。在组织灌注不良的区域存在低 NIRF，而在受损和水肿区域则会迅速、强烈地积累 ICG。在肺的外周和高处区域常见节段性灌注缺陷，连续成像显示 EVLP 期间灌注逐渐恢复。在再灌注后早期，移植猪肺中的微血管再灌注受损，表现为 NIRF 进入率降低。
NIRF 成像可在 EVLP 期间对肺灌注和水肿进行非侵入性实时评估。需要进行前瞻性临床研究，以确定 NIRF 成像在供肺评估和选择以及预测移植后结局中的作用。
