Assessment by Pulse Dye-densitometry Indocyanine Green (ICG) Clearance Test of Hepatic Function of Patients Before Cardiac Surgery: Its Value As a Predictor of Serious Postoperative Liver Dysfunction

Objective: Patients with preoperative liver dysfunction occasionally have a poor prognosis after cardiac surgery because the liver condition is aggravated. The pulse dye-densitometry indocyanine green (ICG) clearance test was used as a preoperative evaluation technique.

Design: Prospective, clinical evaluation.

Setting: Surgical intensive care unit of a national cardiovascular center.

Subjects: Twenty-seven patients with preoperative liver dysfunction were studied. They were divided into four groups depending on the cause of their liver dysfunction.

Interventions: With the patient's informed consent, a bolus of ICG, 20 mg, was injected, and the disappearance of ICG was measured noninvasively by pulse dye-densitometry.

Measurements And Main Results: The ICG retention rate at 15 minutes (ICG-R15) was calculated for the regression time. The patients were assessed in terms of ICG-R15 and the cause of liver dysfunction. The ICG-R15 values obtained for all 27 patients were 30% +/- 16% (mean +/- standard deviation). The 21 survivors had ICG-R15 values of 24% +/- 12%, whereas the 6 patients who died after surgery had significantly greater ICG-R15 values of 50% +/- 13% (p < 0.05). The mean values of ICG-R15 in patients with congestive liver, viral hepatitis accompanied by congestive liver, viral hepatitis, and cirrhosis were 34%, 23%, 13%, and 42%, respectively. The 6 of 27 patients who died after surgery had ICG-R15 values greater than 40%. Five of the seven patients with cirrhosis died.

Conclusion: These results suggest that (1) compared with Child-Pugh classification, the value of ICG-R15 provides a more accurate surgical indication; and (2) liver dysfunction from cirrhosis causes postoperative deterioration of liver function, especially when the ICG-R15 value exceeds 40%.