Liver transplantation is recognized as a viable treatment modality for PROP, as the liver is the major site of branched-chain amino acid (BCAA) metabolism and propionic acid (PA) production. Indications for liver transplant have included neonatal onset, frequent metabolic decompensation, uncontrolled hyperammonemia, poor growth, and sibling death, with consideration of risks and benefits of medical treatment for the patient who is a potential candidate. The metabolic team input, including contributions from the metabolic RD, is integral in the pre-transplant planning, peri-transplant period, and the post-transplant era for the individual with PROP. 

The goal for nutritional management of the individual with PROP undergoing liver transplant is to establish and maintain good metabolic control prior to, during, and after surgery. The nutrient recommendations for the pre-transplant period do not change from the individual’s usual intake.  The transplant and metabolic teams should prepare for possible surgical and other complications that may impact metabolic control.  During the surgery, continuous IV access for appropriate D10 and sodium bicarbonate infusion is recommended.  Protein intake post-transplant is less restrictive when compared to pre-transplant, with the goal of meeting the DRI for protein with intact protein, and possibly advancing protein intake while monitoring individual tolerance. Use of medical food as a protein source post-transplant was infrequent.  Continuation of carnitine supplementation was common but not universal.

Liver transplantation in PROP is only partially curative.  As there are extrahepatic sources of PA production, some individuals continue to experience periods of acidosis and/or remain at risk of central nervous system metabolic crises. However, liver transplantation appears beneficial for severely affected individuals with PROP by significantly reducing the number of episodes of decompensation. Improved metabolic control following transplant has been shown to slow and stabilize neurological decline, improve cardiac function, growth and quality of life. 

Definitions of the protein terminology used throughout this guideline are listed in Appendix B.