Predictors of survival after in vivo split liver transplantation: Analysis of 110 consecutive patients

Orthotopic liver transplantation (OLT) has become a well-established modality for treatment of previously fatal liver disease. The advent of new immunosuppressive agents and refinement of surgical techniques have accounted for remarkable progress in the years since the first OLT was performed in 1963. 1,2 The past decade has also witnessed an exponential increase in the number of patients awaiting liver transplantation. Currently, it is estimated that more than 14,500 patients are listed for liver transplantation, with only 4,500 cadaveric livers available annually. With more than 4 million Americans affected with hepatitis C, 25% to 35% of whom will develop cirrhosis, the transplant community is anticipating an epidemic of patients requiring transplantation. Such an increasing discrepancy between donor supply and demand has resulted in an increasing death rate for adult and pediatric patients awaiting OLT. In addition, in the past 5 years, there has been an increase in the number of livers transplanted into critically ill patients, with a higher rate of complications and death after OLT. To maximize donor organ use in children and adults, four procedures have evolved from the fundamental principle that a portion of the liver with a suitable vascular pedicle, bile duct, and venous drainage, along with sufficient functional hepatocyte mass, can sustain hepatic function in a patient as well as a whole organ. Reduced-size liver transplantation 3–9 was the wellspring for this effort, followed by adult-to-pediatric living-related transplantation, 10,11 cadaveric split liver transplantation (SLT), 12–32 and more recently adult-to-adult living donor transplantation. 33 Pichlmayr et al 12 in 1988 reported the first clinical attempt at an ex vivo SLT. One year later, Bismuth et al 13 described two patients with fulminant hepatic failure, each receiving a split graft. Broelsch et al 15 reported the first series of 30 SLTs in 21 children and 5 adults. In this early experience, patient survival was inferior to that reported in series of cadaveric whole-liver transplants. 28 Despite skepticism as to the lasting role of SLT, several European centers, faced with increasing waiting list death rates because of donor scarcity, pursued the split liver option. The results of a collective experience of 50 donor livers, providing 100 grafts during a 5-year period, from the European Split Liver Registry, demonstrated no significant difference from the results of conventional whole-organ orthotopic liver transplantation during the same period. 16 Such results renewed interest in SLT, as evidenced by more recent series of ex vivo SLT. 14,19,24 Despite marked improvements of outcome in these series, high-risk patients appeared to have a worse outcome than nonurgent recipients. A modification of the ex vivo splitting technique is in vivo splitting, which involves an extension of the techniques for living-related donor liver procurement that is completed in the heart-beating cadaver donor. At UCLA, we first attempted in vivo SLT in 1992. Our first experience was not favorable, but after establishing a living-related liver program and accruing experience in 30 cases, we resumed the in vivo split liver program in 1996. In that same year, Rogiers et al 30 reported their initial experience with split grafts, which demonstrated superior results compared with ex vivo split liver techniques. There have been only a few published reports of in vivo SLT 29–35 because the procedure has been performed only during the past 4 years. Initial results from these few series, which involved a limited number of patients, suggested an improvement over the ex vivo experience, with higher patient and graft survival rates and a lower incidence of complications. However, larger series of in vivo SLT are required to confirm these results. Further, a better understanding of the factors that influence the outcome of SLT is critical for the successful application of SLT to expand a severely depleted cadaveric donor pool. This report examined the outcome of in vivo SLT and analyzed the factors affecting patient survival in a large number of recipients.