Definition and classification of negative outcomes in solid organ transplantation. Application in liver transplantation.

OBJECTIVE: This study defined negative outcomes of solid organ transplantation, proposed a new classification of complications by severity, and applied the classification to evaluate the results of orthotopic liver transplantation (OLT). SUMMARY AND BACKGROUND DATA: The lack of uniform reporting of negative outcomes has made reports of transplantation procedures difficult to interpret and compare. In fact, only mortality is well reported; morbidity rates and severity of complications have been poorly described.
METHODS: Based on previous definition and classification of complications for general surgery, a new classification for transplantation in four grades is proposed. Results including risk factors of the first 215 OLTs performed at the University of Toronto have been evaluated using the classification.
RESULTS: All but two patients (99%) had at least one complication of any kind, 92% of patients surviving more than 3 months had grade 1 (minor) complications, 74% had grade 2 (life-threatening) complications, and 30% had grade 3 (residual disability or cancer) complications. Twenty-nine per cent of patients had grade 4 complications (retransplantation or death). The most common grade 1 complications were steroid responsive rejection (69% of patients) and infection that did not require antibiotics or invasive procedures (23%). Grade 2 complications primarily were infection requiring antibiotics or invasive procedures (64%), postoperative bleeding requiring > 3 units of packed red cells (35%), primary dysfunction (26%), and biliary disease treated with antibiotics or requiring invasive procedures (18%). The most frequent grade 3 complication was renal failure, which is defined as a permanent rise in serum creatinine levels > or = twice the pretransplantation values (11%). Grade 4 complications (retransplantation or death) mainly were infection (14%) and primary dysfunction (11%). Comparison between the first and last 50 OLTs of the series indicates a significant decrease in the mean number of grade 1 and 2 complications. This was partially a result of better medical status of patients at the time of transplantation. Using univariate and multivariate analyses of risk factors, the best predictor of grade 1 complications was donor obesity; for grade 2 complications, the best predictor was a donor liver rewarming time of > 90 minutes, and for grade 3 and 4 complications, the best predictor was the APACHE II scoring system and donor cardiac arrest.
CONCLUSIONS: Standardized definitions and classifications of complications of transplantation will allow us to better evaluate and compare results of transplantation among centers and over time, and better compare effectiveness of new therapies. Orthotopic liver transplantation still is a procedure with high morbidity that requires careful analysis of risk factors to optimize selection of patients and organ sharing.