Discussion
TIPS, OHE, liver function injury
REGRESSION, POSTOPERATIVE COMPLICATIONS
With continuous improvement of hardware facilities and technical concepts, effects of TIPS on PHT therapy have becoming more and more remarkable, however, its postoperative complications remain challenging. For example, HE caused by biochemical disturbance of brain functions as a result of liver function injury and portal-systemic shunt greatly affects the quality of lifeIn this study, we have identified that age, creatinine, blood ammonia, ICG-R15, and percentage of PPG decline were independent risk factors for OHE after TIPS in PHT patients based on multivariate logistic regression models. Several risk factors were related to OHE after TIPS in previous studies. For example, age was associated with HE after TIPSCurrently, Child–Pugh scoring system and MELD scoring system have certain predictive value in predicting OHE after TIPS. However, some indicators in Child–Pugh score are subjective or interrelated, so Child–Pugh score cannot accurately predict OHE after TIPS. The MELD score may predict the mortality of patients after TIPS. Presently, MELD is the most widely applied index for evaluating liver function before liver transplantationThe nomogram is an intuitive statistical tool that can provide information for decision-making in clinical practice. Therefore, we combined 5 risk factors to illustrate a combinatory value in predicting OHE after TIPS. Compared with Child–Pugh score and MELD score, our novel model had a better predictive value for OHE after TIPS. The nomogram prediction model, Child–Pugh score and MELD ROC curves were drawn to calculate C-index values. The predictive ability of our nomogram model vs. conventional models in predicting OHE after TIPS was compared. The C-index value of our novel prediction model was the highest in training cohort and validation cohort, indicating that this nomogram prediction model had a better predictive capability. In terms of validation, Bootstrap self-sampling method was used to calculate consistency index. This prediction model had good accuracy. The calibration curve fit well with the ideal curve, indicating that this nomogram prediction model had a good prediction capability for OHE after TIPS. Traditionally, nomograms have been assessed by diagnostic performance indices, and its clinical value cannot be determined. DCA can assess the benefits of various patient-preferred diagnostic tests to identify the risks of undertreatment and overtreatment, in order to facilitate decision-making. The DCA demonstrated that our nomograms provided more benefits than other models in both training and validation cohorts. Therefore, our nomograms can be applied in clinical practice. However, this study still has some limitations: (1) this study used the change value of PPG as one of the model parameters, so the model cannot predict the occurrence of OHE before TIPS; (2) as a retrospective study, there is a certain selection bias; (3) this study only carried out internal verification, but lacked external verification.In conclusion, we have demonstrated that age, creatinine, ammonia, ICG-R15, and percentage of PPG decline are independent risk factors for predicting OHE after TIPS. When TIPS is performed for PHT patients, in order to reduce the incidence of postoperative OHE, in addition to routine preoperative assessment, attentions should be paid to age and renal function. Furthermore, blood ammonia and ICG-R15 results should be assessed before the surgery. Therapeutic effects attributed to decreased portal venous pressure and the possible increased risk of HE should be balanced during the surgery. In this study, we have proposed a novel predictive nomogram for HE after TIPS. The nomogram harbors good predictive performance and would be a conventional tool to facilitate clinical decision-making.