Perioperative characteristics and management of liver transplantation for isolated methylmalonic acidemia-the largest experience in China.

There are few detailed consensus and guidelines on perioperative clinical characteristics of liver transplantation (LT) in patients with methylmalonic acidemia (MMA). This retrospective study investigated details of the clinical course and individualized treatment plan of the center with largest experience in China.A total of 7 MMA patients undergoing LT in Beijing Friendship Hospital from June 2013 to December 2017 were enrolled in the study, whose clinical data (clinical characteristics, laboratory findings, chronological changes in urine MMA levels, treatment, etc.) during perioperative period were analyzed retrospectively. All the patients received strict postoperative management.All the 7 cases were confirmed to have isolated MMA, among which, 3 cases received living donor liver transplantation (LDLT), 4 cases received deceased donor liver transplantation (DDLT). A wild fluctuate of metabolic condition was observed within the first few days after surgery and two weeks after LT, the mean base excess of blood value (BE-B) restored to normal whereas plasma bicarbonate (HCO) was still below normal value even with intermittent sodium bicarbonate correction. It also showed marked reduction in propionylcarnitine (C3) and C3/C2 level and the mean urine MMA by gas chromatography-mass spectrometry (GC-MS) was reduced by 81.7% (P<0.01) but remained >72× higher than upper limit of normal. The metabolism-correcting medications were administered as before. The renal function of one case with renal insufficiency before LT (serum creatinine rising) maintained stable by adjusting the immunosuppressive regimen during the observation period. All patients survive to date.LT is an effective treatment to prevent metabolic crisis, but patients with MMA tend to be metabolically fragile even after surgery. During perioperative period, close monitoring should be given for acidosis episodes so as to implement sodium bicarbonate correction. Metabolism-correcting medications are still needed. Special immunosuppressive regimen is an effective way of maintaining renal function for those with kidney dysfunction.