Single-operator cholangioscopy for biliary complications in liver transplant recipients

AIM To evaluate cholangioscopy in addition to endoscopic retrograde cholangiopancreatography(ERCP) for management of biliary complications after liver transplantation(LT).METHODS Twenty-six LT recipients with duct-to-duct biliary reconstruction who underwent ERCP for suspected biliary complications between April and December2016 at the university hospital of Muenster were consecutively enrolled in this observational study. After evaluating bile ducts using fluoroscopy, cholangioscopy using a modern digital single-operator cholangioscopy s y s t e m(S py G la s s D S ?) wa s pe r fo r me d dur ing the same procedure with patients under conscious sedation. All patients received peri-interventional antibiotic prophylaxis and bile was collected during the intervention for microbial analysis and for antibiotic susceptibility testing.RESULTS Thirty-three biliary complications were found in a total of 22 patients, whereas four patients showed normal bile ducts. Anastomotic strictures were evident in 14(53.8%) patients, non-anastomotic strictures in seven(26.9%), biliary cast in three(11.5%), and stones in six(23.1%). A benefit of cholangioscopy was seen in 12(46.2%) patients. In four of them, cholangioscopy was crucial for selective guidewire placement prior to planned intervention. In six patients, biliary cast and/or stones failed to be diagnosed by ERCP and were only detectable through cholangioscopy. In one case, a bile duct ulcer due to fungal infection was diagnosed by cholangioscopy. In another case, signs of bile duct inflammation caused by acute cholangitis were evident. One patient developed post-interventional cholangitis. No further procedure-related complications occurred. Thirty-seven isolates were found in bile. Sixteen of these were gram-positive(43.2%), 12(32.4%) were gram-negative bacteria, and Candida species accounted for 24.3% of all isolated microorganisms. Interestingly, only 48.6% of specimens were sensitive to prophylactic antibiotics.CONCLUSION Single-operator cholangioscopy can provide important diagnostic information, helping endoscopists to plan and perform interventional procedures in LT-related biliary complications.

Influence of tacrolimus metabolism rate on renal function after solid organ transplantation

The calcineurin inhibitor(CNI) tacrolimus(TAC) is an integral part of the immunosuppressive regimen after solid organ transplantation. Although TAC is very effective in prevention of acute rejection episodes, its highly variable pharmacokinetic and narrow therapeutic window require frequent monitoring of drug levels and dose adjustments. TAC can cause CNI nephrotoxicity even at low blood trough levels(4-6 ng/m L). Thus, other factors besides the TAC trough level might contribute to CNI-related kidney injury. Unfortunately, TAC pharmacokinetic is determined by a whole bunch of parameters. However, for daily clinical routine a simple application strategy is needed. To address this problem, we and others have evaluated a simple calculation method in which the TAC blood trough concentration(C) is divided by the daily dose(D). Fast TAC metabolism(C/D ratio < 1.05) was identified as a potential risk factor for an inferior kidney function after transplantation. In this regard, we recently showed a strong association between fast TAC metabolism and CNI nephrotoxicity as well as BKV infection. Therefore, the TAC C/D ratio may assist transplant clinicians in a simple way to individualize the immunosuppressive regimen.