Most publications available either deal with the outcomes of endoscopic drainage of extrahepatic bile ducts being achieved by means of choledochoduodenostomy/cholecystoduodenostomy or presenting combined outcomes of transmural biliary drainage from extra- and intrahepatic access.[11,12,14−16] This makes it difficult to compare the results of this study with those obtained by others. This prospective study showed that transgastric drainage of intrahepatic bile ducts (EUS-guided endoscopic hepaticogastrostomy) in patients with malignant biliary obstruction following ERCP failure is an effective endotherapeutic modality with an acceptable complication rate, and may be an alternative method for minimally invasive treatment for these patients. Notably, all patients in the study had cancer within the biliopancreatic area, which increased complication risk as well as periprocedural mortality. The prognosis was further worsened by cancer comorbidities, mainly cancer-related cachexia. However, the good results of endoscopic treatment support the efficacy of extra-anatomical transmural biliary tract anastomoses.
In most institutions, PTBD remains the treatment of choice when a transpapillary approach proves ineffective.[5, 20]However, PTBD is less effective and is associated with higher complication rates than the transpapillary approach.[5] In addition, external percutaneous drainage remains a persistent problem in long-term palliative care as it often adds to the patient’s discomfort.[5] Compared to conventional percutaneous biliary drainage, endoscopic transmural anastomoses between the biliary and gastrointestinal tracts are characterized by similar technical and clinical success rates of more than 90%, but with complication rates being significantly higher in the external drainage group.[20, 21] In their systematic review and meta-analysis of nine studies, Sharaiha et al. demonstrated no difference in technical success rates between endoscopic extra-anatomical bile duct anastomoses and external percutaneous drainage in patients following ERCP.[22] The same study revealed a better clinical success rate as well as a lower number of complications and reinterventions for transmural endoscopic anastomoses compared to percutaneous drainage.[22] In addition to the reduction of the above-mentioned discomfort in palliative care, the superiority of endoscopic bile duct anastomoses over percutaneous drainage consists mainly of its reduction in post-procedural risk for infections, which frequently require reinterventions and hospitalizations in patients with percutaneous drainage.[22]
Four meta-analyses available in the literature on the subject of EUS-guided extra-anatomical bile duct anastomoses revealed high technical (90–94.7%) and clinical success (87–94%) rates, with an acceptable complication rate of 16–29%.[11,14−16] When comparing extrahepatic biliary tract access, via choledochoduodenostomy/cholecystoduodenostomy, to intrahepatic access, via hepaticogastrostomy, the technical and clinical success rates are similar. Whereas a higher number of complications are observed in patients with intrahepatic access.[11, 17] On the other hand, a systematic review and meta-analysis carried out by Uemura et al. did not reveal any differences in the efficacy and safety of endoscopic hepaticogastrostomy compared to endoscopic choledochoduodenostomy/cholecystoduodenostomy.[18]
When making a choice regarding the type and technique for extra-anatomical transmural biliary drainage, one should take into consideration the treatment center experience and the estimated complication risks that are frequently related to anatomical conditions and cancer stage.[19] Intrahepatic access to the biliary tract via hepaticogastrostomy is generally considered to be technically more challenging than extrahepatic access via choledochoduodenostomy/cholecystoduodenostomy. Consequently, endoscopic hepaticogastrostomy is reserved for patients in whom choledochoduodenostomy/ cholecystoduodenostomy is considered impossible.[19] On the other hand, of all the techniques for extra-anatomical transmural endoscopic biliary drainage, hepaticogastrostomy has the broadest range of clinical indications.[14–16] Neither duodenal obstruction, biliary obstruction at the hilar level, nor alterations of gastrointestinal anatomy following previous surgical procedures preventing transduodenal drainage of extrahepatic bile ducts, are contraindications for endoscopic hepaticogastrostomy.[14–16]
Endoscopic hepaticogastrostomy is an extra-anatomical transmural endoscopic biliary drainage modality that is most frequently performed at our center, not only because of our experience, but also because of its high efficacy combined with a relatively low complication rate. The results of our study suggest that endoscopic hepaticogastrostomy is not only an alternative to be used following failed attempts at ERCP, but may also be used as first-line treatment in the endotherapy of irresectable malignant biliary obstruction.
In experienced institutions, endoscopic hepaticogastrostomy in patients with obstructive jaundice secondary to malignant biliary obstruction has an efficacy rate similar to that of ERCP.[23] Three randomized studies compared the results of patients with malignant biliary obstruction involving transpapillary drainage treated with ERCP vs EUS-guided transmural biliary drainage.[24–26] No differences in the efficacy or safety of both treatments were observed in two studies.[24, 25] In contrast, the study by Paik et al. also failed to reveal any differences in the efficacy of treatment, but demonstrated that extra-anatomical transmural anastomoses were associated with lower complication rates compared to ERCP.[26] In theory, EUS-guided extra-anatomical transmural anastomoses between the biliary and gastrointestinal tracts, compared to transpapillary drainage via ERCP, may prevent injuries to the major duodenal papilla, thus reducing acute pancreatitis risk.[27, 28] There is also less contact between the endoprosthesis and tumor tissues, reducing the risk of the transmural stent becoming overgrown and obstructed by cancer tissue. Thus, the transmural self-expandable stents used in endoscopic hepaticogastrostomy should remain patent longer than self-expandable stents introduced via the transpapillary route in the course of ERCP procedures. This is particularly important in cases of distal malignant bile duct stenosis, where transmural prostheses are usually not in direct contact with neoplastic tissue. On the other hand, this is not valid for of Bismuth type II–IV hilar tumors, where the transmural stents installed to drain the right liver lobe splint the malignant stricture. In our study, it was in patients with bile duct malignancies involving the liver hilum where increased rates of repeated endoscopic interventions were observed as the result of self-expandable transmural stent obstructions. In reinterventions, stent patency was restored using another fully coated self-expandable stent introduced into the lumen of the occluded stent. In addition, obstruction of the transmural stents frequently led to suppurative cholangitis. As a result, nasobiliary drainage had to be temporarily installed within the transmural stent in some patients for active drainage of bile during the course of reintervention.
This study found negative predictors for the efficacy of endoscopic hepaticogastrostomy including, in addition to the aforementioned technical conditions of the procedure itself. These were: Bismuth type II–IV cholangiocarcinoma, hepatic metastases, ascites, suppurative cholangitis, and high blood bilirubin levels exceeding 30 mg/dL. Bismuth type II–IV cholangiocarcinoma was a negative predictive factor for endoscopic procedure efficacy and was not related to the lack of adequate drainage in our patients. In all patients whose malignant lesion involved the liver hilum, access to the right intrahepatic duct was gained via the stricture being splinted by a stent introduced into the left intrahepatic duct via the stomach, as previously described.[29, 30] The presence of metastatic lesions in the liver and high blood bilirubin levels also had a negative effect on treatment outcomes. Both findings might have had a common denominator. The high blood bilirubin level may have been due to hepatic parenchyma being damaged secondary to the presence of metastatic lesions rather than by bile duct obstruction alone. Ascites was another negative predictor of endotherapeutic success. The presence of ascitic fluid between the gastric wall and the liver not only makes it technically difficult to perform a transgastric puncture of the enlarged bile ducts due to the increased distance between the bile ducts and the gastrointestinal tract, but also makes it difficult to maintain the transmural stent in a correct and stable position, increasing the risk of stent migration and consequently, bile leakage from the anastomosis into the peritoneum.
Based on these factors, it appears that the best treatment results can be obtained in patients with distal biliary stricture, no intrahepatic metastatic lesions, blood bilirubin levels < 30 mg/dL, and no signs of cholangitis or ascites.
Our study has some limitations which should be considered when interpreting our findings. The main limitations of this study include the lack of randomization and the fact that the study was performed only on a selected group of patients from a single center.
The current literature does not provide a unified standard for the therapeutic management regarding EUS-guided endoscopic transmural biliary drainage due to inefficacy or failure of transpapillary drainage attempted in the course of ERCP in patients with obstructive jaundice secondary to irresectable malignant biliary obstruction. Consequently, further studies on the management of these patients are recommended. As suggested by our results, in the event of transpapillary biliary drainage proving ineffective, extra-anatomical bile duct anastomoses to the gastrointestinal tract provides an effective method in patients with malignant biliary obstruction. Furthermore, in experienced sites, the efficacy of EUS-guided endoscopic hepaticogastrostomy is similar to that of transpapillary drainage in the course of ERCP. Compared to the latter, EUS-guided endoscopic hepaticogastrostomy has a wider range of indications in patients with obstructive jaundice secondary to irresectable malignant biliary obstruction and can be used as the first-line treatment in these patients. Nevertheless, further studies are now necessary in order to evaluate the efficacy of this treatment strategy in detail.