Use of indocyanine green for liver function assessment and its role in predicting the risk of postoperative liver failure

Postoperative liver failure (POLF) is one of the most serious complications in abdominal surgery, as its appearance is often associated with an unfavorable outcome.OBJECTIVE: To investigate the role of Indocyanine Green (ICG) and Indocyanine Green Retention rate (ICG-R15) for assessment of liver function in order to predict the risk of POLF.MATERIAL AND METHODS: In 06.2021 – 11.2022, a prospective study was conducted, including 20 patients admitted in University Hospital "Alexandrovska" for malignant liver neoplasms. Liver function was assessed by static biochemical parameters and intravenous ICG administration (0.5 mg/kg), aiming to measure the residual blood concentration at the 15th minute (ICG-R15). The results and the probable correlation with clinico-morphological features were processed statistically.RESULTS AND DISCUSSION: The study included 13 men (65%) and 7 women (35%) with primary (5) and metastatic (15) liver tumors. 13 minor (<3 segments) and 7 major liver resections were performed. ICG-R15 ranged in 2-40%. Mean T-Bil in patients with abnormal ICG-R15 were higher than those with normal. There is no significant relationship between the other static parameters and ICG-R15. Early postoperative mortality was 0%. Transient POLF (15%) was observed only in patients with elevated ICG-R15 (p=0.001). There is a significant relationship between elevated ICG-R15 and complications. For ICGR15>15%, major liver interventions were not undertaken (p=0.001). In the ICG-R15 <15% group, regardless of major resection performed, POLF was not observed. The lack of significant deviations in static liver indicators with marked differences in ICGR15 clearly shows the need to combine methods for a precise liver function assessment. POLF was rapidly controlled due to consideration of the resection volume in context of ICG-R15.CONCLUSION: The ICG-R15 is an easy, safe, and valuable tool for assessing liver function and identifying patients at risk of POLF. Additional studies are needed, as the present study is initial for Bulgaria.