Graft Risk Index After Liver Transplant: Internal and External Validation of a New Spanish Indicator.

OBJECTIVES: Scarcity of liver grafts has led to the use of marginal donors, consequently increasing the number of complications posttransplant. To prevent this situation, several indicators have been developed. However, important differences remain among countries. Here, we compared an early-risk liver transplant indicator based on the Spanish Liver Transplant Registry, called the Graft Risk Index, versus the US donor risk index and the Eurotransplant donor risk index. MATERIALS AND METHODS: The new indicator was based on prospectively collected data from 600 adult liver transplants performed in our center. We considered 2 events to compare the indexes: graft survival and rejection-free graft survival, with Cox proportional regression for analyses. Power to predict graft survival was evaluated by calculating the receiver operating characteristic area under the curve. RESULTS: We found no differences between the US and Eurotransplant donor risk indexes in prediction of patients with and without early graft failure. With regard to early survival, only the Graft Risk Index allowed better survival discrimination, in which survival progressively decreased with values ≥ 3 (with probability of graft survival at 1 month of 68%; 95% confidence interval, 46.2-82.5). This increase in risk was significant compared with the standard group (hazard ratio of 10.15; 95% confidence interval, C 3.91- 26.32; P < .001). We calculated powers of prediction of 0.52 (95% confidence interval, 0.43-0.62), 0.54 (95% confidence interval, 0.45-0.65), and 0.69 (95% confidence interval, 0.61-0.77) for donor risk index, Eurotransplant donor risk index, and early Graft Risk Index, respectively. CONCLUSIONS: Neither the US donor risk index nor the Eurotransplant donor risk index was valid for our Spanish liver donation and transplant program. Therefore, an indicator to predict posttransplant graft survival that is adapted to our environment is necessary. This national Graft Risk Index can be a useful tool to optimize donor-recipient matching.

Supervivencia del injerto tras trasplante hepático: aproximación a un nuevo índice de riesgo español / Graft survival after liver transplantation: an approach to a new Spanish risk index

Introducción: existen diversos indicadores para la valoración de la supervivencia del injerto hepático (DRI americano y ET-DRI europeo, entre otros), pero existen diferencias importantes entre los programas de trasplante de los diferentes países y podría ser que dichos indicadores no sean válidos en nuestro medio. Objetivos: el objetivo de este estudio es describir un nuevo indicador nacional de riesgo del injerto hepático a partir de los resultados del Registro Español de Trasplante Hepático (RETH) y validar el DRI y el ET-DRI. Metodología: el RETH incluye un análisis de Cox de los factores relacionados con la supervivencia del injerto. En base a sus resultados se define el indicador graft risk index (GRI). Las variables que contempla dependen del proceso de donación: edad, causa de muerte, compatibilidad sanguínea y tiempo de isquemia fría; y del receptor: edad, enfermedad de base, virus C, número de trasplante, estado UNOS y técnica quirúrgica. Se obtuvo la curva de la regresión logística y se calcularon las curvas de supervivencia del injerto por estratificación. La precisión se evaluó mediante el área ROC. Resultados: un GRI de 1 se corresponde con una probabilidad de pérdida del injerto del 23,25%; cada punto de aumento del GRI supone que la probabilidad se multiplica por 1,33. El GRI mostró la mejor discriminación por estratificación. El área ROC del DRI fue 0,54 (95% IC, 0,50-0,59) y del ET-DRI, 0,56 (95% IC, 0,51-0,61), frente al GRI 0,70 (95% IC, 0,65-0,73) (p < 0,0001). Conclusiones: el DRI y el ET-DRI no parecen útiles en nuestro medio y sería necesario disponer de un indicador propio. El GRI requiere un estudio nacional que perfile más el indicador y realice una validación más amplia

Introduction: several indicators are available to assess liver graft survival, including the American DRI and the European ET-DRI. However, there are significant differences between transplant programs of different countries, and the previously mentioned indicators might be not valid in our setting. Objectives: the aim of the study was to describe a new national liver graft risk indicator based on the results obtained from the Registro Español de Trasplante Hepático (RETH) and to validate the DRI and ET-DRI indicators. Methods: the RETH includes a Cox analysis of factors associated with graft survival; the graft risk index (GRI) indicator was defined based on these results. The variables considered are dependent upon the donation conditions (age, cause of death, blood compatibility and cold ischemia time) and the transplant recipient (age, underlying disease, hepatitis C virus, transplant number, UNOS status and surgical technique). A logistic regression curve was obtained and graft survival curves were calculated by stratification. Precision was assessed using the ROC analysis. Results: a GRI of 1 represents a probability of graft loss of 23.25%; each point increase in the GRI score multiplies this probability by 1.33. The best discrimination of GRI was obtained by stratification. The DRI ROC area was 0.54 (95% CI, 0.50-0.59) and the ET-DRI ROC area was 0.56 (95% CI, 0.51-0.61), compared to 0.70 (95% CI, 0.65-0.73) (p < 0.0001) for the GRI. Conclusions: both the DRI and ET-DRI do not seem to be useful in our setting. Hence a national indicator is more desirable. The GRI requires a national study in order to further streamline and assess this indicator

Graft survival after liver transplantation: an approach to a new Spanish risk index.

INTRODUCTION: several indicators are available to assess liver graft survival, including the American DRI and the European ET-DRI. However, there are significant differences between transplant programs of different countries, and the previously mentioned indicators might be not valid in our setting. OBJECTIVES: the aim of the study was to describe a new national liver graft risk indicator based on the results obtained from the Registro Español de Trasplante Hepático (RETH) and to validate the DRI and ET-DRI indicators. METHODS: the RETH includes a Cox analysis of factors associated with graft survival; the graft risk index (GRI) indicator was defined based on these results. The variables considered are dependent upon the donation conditions (age, cause of death, blood compatibility and cold ischemia time) and the transplant recipient (age, underlying disease, hepatitis C virus, transplant number, UNOS status and surgical technique). A logistic regression curve was obtained and graft survival curves were calculated by stratification. Precision was assessed using the ROC analysis. RESULTS: a GRI of 1 represents a probability of graft loss of 23.25%; each point increase in the GRI score multiplies this probability by 1.33. The best discrimination of GRI was obtained by stratification. The DRI ROC area was 0.54 (95% CI, 0.50-0.59) and the ET-DRI ROC area was 0.56 (95% CI, 0.51-0.61), compared to 0.70 (95% CI, 0.65-0.73) (p < 0.0001) for the GRI. CONCLUSIONS: both the DRI and ET-DRI do not seem to be useful in our setting. Hence a national indicator is more desirable. The GRI requires a national study in order to further streamline and assess this indicator.

Disfunción endotelial, enfermedad coronaria y diabetes mellitus / Endothelial dysfunction, coronary heart disease and diabetes mellitus

Fundamento y objetivo: La diabetes mellitus es un factor de riesgo cardiovascular que propicia la aparición de una lesión endotelial, fundamental en la fisiopatología de la cardiopatía isquémica, por lo que sería útil la investigación de marcadores que indiquen la lesión en pacientes diabéticos. Pacientes y método: Estudio observacional, realizado con 25 pacientes diagnosticados de cardiopatía isquémica y alteración endotelial confirmada mediante coronario grafía, cuyo único factor de riesgo cardiovascular es la diabetes mellitus (grupo I). Tomamos 2 grupos control, uno de 10 sujetos diabéticos sin más factores de riesgo ni clínica de cardiopatía isquémica (grupo II), y otro de 17 sujetos sanos sin factores de riesgo cardiovascular (grupo III). Comparamos entre los grupos la actividad del factor de von Willebrand (FvW) antigénico, como marcador de lesión endotelial. Empleamos como herramientas estadísticas la prueba de la t de Student y la de la 2, el coeficiente de correlación y análisis de regresión múltiple, con un intervalo de confianza del 95%.Resultados: Los pacientes diabéticos tienen mayores concentraciones de FvW que los sujetos sanos; además, los sujetos con cardiopatía isquémica presentan valores más elevados que los diabéticos sin complicaciones vasculares. Se comprueba cierto grado de relación entre las concentraciones de FvW y fibrinógeno en el grupo I. Conclusiones: El FvW es un factor de riesgo de lesión endotelial en diabéticos, y un marcador de riesgo de complicaciones vasculares (AU)

Background and objective: Diabetes mellitus is a cardiovascular risk factor that promotes the development of endothelial injury, which is fundamental in the physiopathology of ischemic heart disease. Therefore, investigation of markers indicating the presence of endothelial injury in diabetic patients would be useful. Patients and method: We performed an observational study of 25 patients with ischemic heart disease and coronary atherosclerosis, diagnosed by coronary angiography, whose only cardiovascular risk factor was diabetes mellitus (group I). There were 2 control groups, one with 10 diabetic controls without ischemic heart disease or other cardiovascular risk factors (group II) and another group with 17 healthy controls (group III). Activity of von Willebrand factor (vWf) antigen, as a marker of endothelial injury, was compared among the groups. Student’s ttest, the 2 test, the coefficient of correlation, and multiple regression analysis, with a 95% confidence interval, were used in the statistical analysis. Results: Diabetic patients had higher vWf levels than healthy controls. Diabetic patients with coronary atherosclerosis had higher vWf levels than diabetics without vascular complications. There was a correlation between vWF and fibrinogen concentrations in group I. Conclusions: vWf is a risk factor for the development of endothelial injury in diabetics and is also a marker of risk for the development of vascular complications in these patients (AU)