[Evaluation of liver function with 13C-labelled amino acid using hepatectomized rat model]

Comparison of clinical value of IRIS 13C-methacetin breath test and ICG test in assessment of liver function in cirrhosis

AIM: To compare the clinical value of ¹³C-methacetin breath test and ICG test in the assessment of liver function in patients with cirrhosis.

METHODS: Fifty-nine patients with liver cirrhosis received ¹³C-methacetin breath test after an overnight fast. Breath samples were taken before and at different time within 120 min after administration. ¹³CO₂ enrichment was measured by infrared isotope spectrometry (IRIS). The ¹³CO₂ maximum excretive rate before 40 min (mv_max40), ¹³CO₂ cumulative excretion at 40 min (cum₄₀) and ¹³CO₂ cumulative excretion at 120 min (cum₁₂₀) were determined. Plasma retention rate of indocyanine green at 15 min (R_{15 ICG}) was also measured.

RESULTS: ¹³C mv_max40, cum₄₀ and cum₁₂₀ were significantly different between the cirrhosis patients with different Child-Pugh grades (A, B, C). (mv_max40 A-B, B-C and A-C: 2.80, 4.82 and 10.38; cum₄₀ A-B, B-C and A-C: 3.85, 3.39 and 8.64; cum₁₂₀ A-B, B-C and A-C: 4.52, 3.75 and 12.36, P<0.01). The differences of R_{15 ICG} of patients with different Child-Pugh grades were also significant (A-B and B-C: -4.72,-1.27, P<0.01) except between Child-Pugh B and C group (A-C: -5.85, P>0.05).¹³C mv_max40, cum₄₀, cum₁₂₀ and R_{15 ICG} significantly correlated with Child-Pugh classification score (r = -0.562, -0.614, -0.716 and 0.555, P<0.001). For the evaluation of liver function in patients with cirrhosis, the consistence of 13C-methacetin breath test with Child-Pugh classification (Kappa: 0.69, P<0.05) was better than that of ICG test (Kappa: 0.47, P<0.05).

CONCLUSION: ICG test is a good quantitative method for the evaluation of the liver function in cirrhosis. ¹³C-methacetin breath test can be used to measure immediate hepatocyte injure and liver functional reserve. It is more sensitive than ICG test in the evaluation of liver function in cirrhosis, especially in uncompensated patients.

Evaluation of hepatic function with 13C-methacetin breath test in patients with liver cirrhosis

AIM: To investigate the characteristics of the ¹³C-methacetin breath test (¹³C-MBT) as a tool to monitor hepatic function of patients with liver cirrhosis.

METHODS: Forty-two patients with liver cirrhosis and thirty-one age- and sex-matched healthy controls underwent ¹³C-MBT.¹³C-methacetin (75 mg) was given orally, and the levels of ¹³CO₂ delta over baseline (DOB), metabolisation velocity (MV) and cumulative percentage doses (CD) before and 10, 20, 30, 40, 50, 60, 80, 100 and 120 min after substrate administration breath samples was determined and compared, by non-dispersive infrared spectrometry.

RESULTS: The ¹³CO₂ peak percent doses of healthy controls, Child class A and Child class B patients were 20.3 ±3.5%, 7.5±1.8% or 6.5±3.3% and 4.5±1.3%, and occurred at 20 min, 20 or 80 min and 40 min, respectively. The differences of¹³CO₂ peak percent doses among healthy controls, Child class A and Child class B patients were obvious (P <0.05). No ¹³CO₂peak percent doses occurred in Child class C patients. The differences of ¹³CO₂ peak metabolic velocity were obvious (P <0.05) between healthy controls (28.8±5.3%) and Child class A patients (9.4±2.4%). No ¹³CO₂ peak metabolic velocity occurred in Child class B and Child class C patients. The ¹³CO₂ cumulative percentage doses of healthy controls, Child class A , Child class B and Child class C patients at 120 min after substrate administration were 31.2±4.5%, 13.8±3.7%, 8.2±2.2% and 2.4±0.8% (P <0.05), respectively.

CONCLUSION: The severity of liver damage can be directly and effectively evaluated by ¹³C-MBT in patients with cirrhosis.