Development of a liver graft assessment expert machine-learning system: when the artificial intelligence helps liver transplant surgeons

BackgroundThe complex process of liver graft assessment is one point for improvement in liver transplantation. The main objective of this study is to develop a tool that supports the surgeon who is responsible for liver donation in the decision-making process whether to accept a graft or not using the initial variables available to it.Material and methodLiver graft samples candidate for liver transplantation after donor brain death were studied. All of them were evaluated “in situ” for transplantation, and those discarded after the “in situ” evaluation were considered as no transplantable liver grafts, while those grafts transplanted after “in situ” evaluation were considered as transplantable liver grafts. First, a single-center, retrospective and cohort study identifying the risk factors associated with the no transplantable group was performed. Then, a prediction model decision support system based on machine learning, and using a tree ensemble boosting classifier that is capable of helping to decide whether to accept or decline a donor liver graft, was developed.ResultsA total of 350 liver grafts that were evaluated for liver transplantation were studied. Steatosis was the most frequent reason for classifying grafts as no transplantable, and the main risk factors identified in the univariant study were age, dyslipidemia, personal medical history, personal surgical history, bilirubinemia, and the result of previous liver ultrasound (p < 0.05). When studying the developed model, we observe that the best performance reordering in terms of accuracy corresponds to 76.29% with an area under the curve of 0.79. Furthermore, the model provides a classification together with a confidence index of reliability, for most cases in our data, with the probability of success in the prediction being above 0.85.ConclusionThe tool presented in this study obtains a high accuracy in predicting whether a liver graft will be transplanted or deemed non-transplantable based on the initial variables assigned to it. The inherent capacity for improvement in the system causes the rate of correct predictions to increase as new data are entered. Therefore, we believe it is a tool that can help optimize the graft pool for liver transplantation

Management of Large, Spontaneous Portosystemic Shunts in Liver Transplantation: Case Report and Review of Literature

The presence of collateral circulation in liver cirrhosis patients with portal hypertension is quite frequent due to re-permeabilization of closed embryonic channels. In some cases, these shunts could measure over 1 cm wide, therefore, containing a significative blood flow. Its management during liver transplantation could be challenging due to possible complications resulting from either ligation of the shunts or from ignoring them. We present the case of a patient with recurrent hepatic encephalopathy (HE) and a large spontaneous portosystemic shunt (SPSS) who submitted to liver transplant and review the literature identifying options, complications, and outcomes with the aim of facilitating decision making. A 68-year-old, Spanish man diagnosed with liver cirrhosis with portal hypertension and recurrent episodes of HE is proposed for LT. The patient's Child-Pugh score was A6-B7, and the Model for End-stage Liver Disease score was 12. Preoperatively, a computed tomography scan showed a large SPSS running to the inferior cava vein. During the surgery, a small-sized portal vein and a large shunt measuring almost 3 cm wide were identified. After reperfusion, portal vein flow was 1000 to 1100 mL/min. Owing to the previous HE and the risk of low portal flow, the shunt was closed increasing the portal flow to 1800 mL/min. The patient was discharged without any complications. The presence of large SPSSs are frequent during LT. Decision making intraoperatively can be challenging due to possible complications derived from ligation of the SPSS or from ignoring it. Either preoperative assessment of a further HE risk or portal vein flow measurement after reperfusion are essential to achieve a correct resolution

Radiofrequency-assisted transection of the pancreas versus stapler in distal pancreatectomy: study protocol for a multicentric randomised clinical trial (TRANSPAIRE).

To date, no pancreatic stump closure technique has been shown to be superior to any other in distal pancreatectomy. Although several studies have shown a trend towards better results in transection using a radiofrequency device (radiofrequency-assisted transection (RFT)), no randomised trial for this purpose has been performed to date. Therefore, we designed a randomised clinical trial, with the hypothesis that this technique used in distal pancreatectomies is superior in reducing clinically relevant postoperative pancreatic fistula (CR-POPF) than mechanical closures. TRANSPAIRE is a multicentre randomised controlled trial conducted in seven Spanish pancreatic centres that includes 112 patients undergoing elective distal pancreatectomy for any indication who will be randomly assigned to RFT or classic stapler transections (control group) in a ratio of 1:1. The primary outcome is the CR-POPF percentage. Sample size is calculated with the following assumptions: 5% one-sided significance level (α), 80% power (1-β), expected POPF in control group of 32%, expected POPF in RFT group of 10% and a clinically relevant difference of 22%. Secondary outcomes include postoperative results, complications, radiological evaluation of the pancreatic stump, metabolomic profile of postoperative peritoneal fluid, survival and quality of life. Follow-ups will be carried out in the external consultation at 1, 6 and 12 months postoperatively. TRANSPAIRE has been approved by the CEIM-PSMAR Ethics Committee. This project is being carried out in accordance with national and international guidelines, the basic principles of protection of human rights and dignity established in the Declaration of Helsinki (64th General Assembly, Fortaleza, Brazil, October 2013), and in accordance with regulations in studies with biological samples, Law 14/2007 on Biomedical Research will be followed. We have defined a dissemination strategy, whose main objective is the participation of stakeholders and the transfer of knowledge to support the exploitation of activities. ClinicalTrials.gov Registry (NCT04402346)