Influencia del índice de masa corporal en los resultados a largo plazo del trasplante hepático

Resumo

SUMMARY: Background. The worldwide increase in the prevalence of obesity in the general population over recent years has also been observed among patients with chronic liver disease who are candidates for liver transplantation (LT). At the same time, a widening of the indications for LT and a reduction in optimal organ donors has increased the utilization of marginal donors, including those with a high body mass index (BMI). However, the influence of the obesity of donor and recipient on the morbidity, mortality, and survival outcomes of LT has yet to be fully elucidated in the scientific literature. Objectives. To analyze the influence of obesity, considering the BMI of recipients pre-LT and the BMI of donors pre-extraction, on the long-term morbidity and mortality of LT recipients at the Virgen de las Nieves University Hospital (HUVN) between 2002 and 2014. Material and methods. A retrospective cohort study was conducted in liver transplant patients of the HUVN between January 2002 and December 2014, collecting data on sociodemographic variables of recipients and donors, on the surgery and treatments, and on postoperative variables related to morbidity and mortality, including: onset of arterial, biliary, or venous complications, requirement for blood products, need for re-transplantation, graft rejection, and length of hospital and ICU stays, among others. Information was also gathered on the post-transplantation survival time of recipients/grafts (in months) and the cause of death. LT recipients were followed up for at least 24 months. Results. The results generated in this Doctoral Thesis work, published in four original scientific papers, show that: • The rate of pre-transplant portal thrombosis was higher in recipients with BMI >35 kg/m² than those with BMI of 20-25 kg/m² (36.5% vs. 13.9%, p = 0.041), but no between-group differences were found in the onset of other post-transplant complications studied, such as post-reperfusion syndrome, hospital and ICU stay, wound infection, or biliary, arterial, or portal complications. Mortality was also higher in the group with BMI >35 kg/m² than in those with BMI of 20-25 kg/m² (72.7% vs. 38.9%, p = 0.032). [Complications Associated with Liver Transplantation in Recipients with Body Mass Index >35 kg/m². Would it be a poor prognosis predictive factor? Transplantation Proceedings 2015; 47: 2650-2]. • No differences were observed between recipients with BMI ≥ 35 kg/m² and those with BMI < 35 kg/m² in biliary, portal, or artery complications, need for retransplantation or reoperation, intraoperative requirement for blood products, onset of post-reperfusion syndrome, development of rejection, or in hospital or ICU stay. However, the groups significantly differed in graft and recipient survival. The group with BMI ≥ 35 kg/m² had a higher mortality rate (26.5% vs. 62.5%, p = 0.041), with a 3.54-fold higher mortality risk (OR) (95% CI; 39-9.03), and a shorter graft survival time (61 vs. 21 months, p = 0.001) in comparison to patients with lower BMI. According to the multivariate analysis results, the variables related to mortality were the BMI (OR: 6.131 [95% CI; 1.25-29.95], p = 0.025), post-transplant portal vein thrombosis (OR: 5.311 [95% CI; 1.707-16.524], p = 0.004), HCV infection (OR: 3.017 [95% CI; 1.39-6.55], p = 0.005), and biliary complications (OR: 2,726 [95% CI; 1,109-6,698], p = 0.029). [Influence of Obesity on Liver Transplantation Outcomes. Transplantation Proceedings 2016; 48: 2503-5]. • When the patients in the series were compared by BMI according to the categories established by the World Health Organization (WHO), no statistically significant differences were found in venous complications (portal thrombosis before or after transplant, deep vein thrombosis, or pulmonary thromboembolism) or in the survival of the graft and recipient. However, the survival rate was lower for obese patients with BMI ≥ 35 kg/m² than for patients in the other BMI categories (19 months vs. 84 months). [Influence of body mass index on venous thrombotic complications of liver transplants. Transplantation Proceedings 2016; 48: 3017-20]. • The ICU stay was longer for LT recipients with grafts from obese donors (BMI ≥30 kg/m²) than for those receiving grafts from donors with BMI <30 kg/m² (p = 0.006). There were no differences in post-transplantation complications or in patient or graft survival; however, differences close to significance were found for the presence of high blood pressure in obese donors (16% vs. 28%, p = 0.086) and the onset of biliary complications (16% vs. 28%, p = 0.086). In the multivariate analysis, the mortality of recipients with grafts from obese donors was associated with the age of the donor (p = 0.043) or the presence of HCV in the recipient (p = 0.001) [Influence of donor obesity on long-term liver transplantation outcomes. Transplantation Proceedings 2018; (in press)]. Conclusions. According to the results obtained in this study population, we can conclude that obesity, especially a BMI ≥ 35 kg/m² , is a poor prognostic factor for LT recipients, mainly with respect to the mortality risk. Nevertheless, we cannot conclude in the study population that a high BMI (≥ 35 kg/m²) is an absolute contraindication for liver transplantation, because not more post-transplantation complications were observed among recipients with this characteristic. Mortality in LT recipients of grafts from donors with BMI > 30 kg/m² , increases with higher age of the donor or with HCV-positivity of the recipient. However, there was no difference in post-transplantation complications or survival outcomes between patients receiving grafts from donors with BMI ≥ 30 kg/m² and those receiving grafts from donors with lower BMI values, except for a longer ICU stay in the former. These findings support the desirability of preventive measures to reduce the BMI of obese LT candidates, thereby improving post-transplantation morbidity and mortality outcomes and reducing associated health costs.