Endoscopic management of post-liver transplant billiary complications: A prospective study from tertiary centre in India

Background

Liver transplantation has become common in India over the last decade and biliary strictures after the procedure cause a significant morbidity. Endoscopic retrograde cholangiopancreatography (ERCP) is a safe and effective treatment modality for post-transplant biliary strictures so we decided to evaluate prospectively the outcomes of endoscopic treatment in post-living donor liver transplantation (LDLT) biliary strictures.

Methods

We studied ten consecutive patients who had developed biliary strictures (out of 312 who had undergone liver transplantation between June 2009 and June 2013) and had been referred to the Department of Gastroenterology for management. All patients underwent liver function tests, ultrasound of the abdomen, magnetic resonance cholangiography and liver biopsy, if this was indicated.

Results

Of these 312 patients who underwent liver transplantation, 305 had living donors (LDLT) and 7 deceased donors (DDLT). Ten patients in the LDLT group (3.3 %) developed biliary strictures. There were seven males and three females who had median age of 52 years (range 4–60 years). The biliary anastomosis was duct-to-duct in all patients with one patient having an additional duct-to-jejunum anastomosis. The mode of presentation was cholangitis in four patients (40 %), asymptomatic elevation of liver enzymes in four (40 %) and jaundice in two patients (20 %). The median time from transplantation to the detection of the stricture was 12 months (2–42.5 months). ERCP was attempted as initial therapy in all patients: seven were managed entirely by endoscopic therapy, and three required a combined percutaneous and endoscopic approach. Cholangiography demonstrated anastomotic stricture in all patients. A total of 32 sessions of ERCP were done with mean of 3.2 (2–5) endoscopic sessions and 3.4 (1–6) stents required to resolve the stricture. The median time from the first intervention to stricture resolution was 4 months (range 2–12 months). In four patients, the stents were removed after one session and in two patients each after two, three and four sessions. In six patients more than one stent was placed and all of them required dilatation of stricture. Seven patients completed treatment and are off stents at a median follow up period of 9.5 months (7–11 months). Two patients developed recurrence of their stricture after 7.5 months. Both had long strictures and required a combined endoscopic and percutaneous approach. There was one mortality due to sepsis secondary to cholangitis.

Conclusions

Post-LDLT biliary strictures can be successfully treated with ERCP, and most patients remain well on follow up (median 9.5 months). A combined endoscopic and percutaneous approach is useful when ERCP alone fails.

     

Conservative versus liberal oxygenation targets in critically ill children: the randomised multiple-centre pilot Oxy-PICU trial

Background

Oxygen saturation monitoring for children receiving respiratory support is standard worldwide. No randomised clinical trials have compared peripheral oxygen saturation (SpO₂) targets for critically ill children. The harm of interventions to raise SpO₂ to >?94% may exceed their benefits.

Methods

We undertook an open, parallel-group randomised trial of children >?38 weeks completed gestation and <?16 years of age receiving invasive or non-invasive respiratory support and supplemental oxygen who were admitted urgently to one of three paediatric intensive care units. A ‘research without prior consent’ approach was employed. Children were randomly assigned to a liberal oxygenation group (SpO₂ targets >?94%) or a conservative oxygenation group (SpO₂ = 88–92% inclusive). Outcomes were measures of feasibility: recruitment rate, protocol adherence and acceptability, between-group separation of SpO₂ and safety. The Oxy-PICU trial was registered before recruitment: ClinicalTrials.gov identifier NCT03040570.

Results

A total of 159 children met the inclusion criteria, of whom 119 (75%) were randomised between April and July 2017, representing a rate of 10 patients per month per site. The mean time to randomisation from first contact with an intensive care team was 1.9 (SD 2.2) h. Consent to continue in the study was obtained in 107 cases (90%); the children’s parents/legal representatives were supportive of the consent process. The median (interquartile range, IQR) of time-weighted individual mean SpO₂ was 94.9% (92.6–97.1) in the conservative oxygenation group and 97.5% (96.2–98.4) in the liberal group [difference 2.7%, 95% confidence interval (95% CI) 1.3–4.0%, p?<?0.001]. Median (IQR) time-weighted individual mean FiO₂ was 0.28 (0.24–0.37) in the conservative group and 0.37 (0.30–0.42) in the liberal group (difference 0.08, 95% CI 0.03–0.13, p?<?0.001). There were no significant between-group differences in length of stay, duration of organ support or mortality. Two prespecified serious adverse events (cardiac arrests) occurred, both in the liberal oxygenation group.

Conclusion

A definitive clinical trial of peripheral oxygen saturation targets is feasible in critically ill children.

     

Complicated Perianal Sepsis

Management of benign anorectal conditions like abscesses and haemorrhoids is usually uneventful. However, complicated perianal complications can result and have sparsely been reported in literature. Hereby, we report a series of seven patients who presented with rare sequelae like necrotising fasciitis, intraperitoneal or retroperitoneal involvement. All patients responded well to surgical management. Accordingly, complicated perianal sepsis warrants a timely and aggressive surgical intervention.     

Readmission after living donor liver transplantation: Predictors,causes, and outcomes

Background

Complications following liver transplantation requiring readmission may be serious and potentially life threatening. Most reports on readmission have been about after deceased donor liver transplantation (DDLT). We hypothesized that readmission after living donor liver transplantation (LDLT) is due to different reasons and analyzed our experience.

Methods

We retrospectively analyzed the records of 172 consecutive patients who underwent liver transplantation at our institute between January 2010 and June 2012. The primary outcome measure was readmission. We classified readmission into early (<3 months after discharge) and late (>3 months).

Results

The study population was 140 after excluding pediatric patients (12), DDLT recipients (2), and those who died during the index admission (18). Their median age was 42 years, and there were 117 males and 23 females. Thirty-eight patients were readmitted (56 episodes) after LDLT. There were 35 early and 21 late readmission episodes. The most common cause for early readmissions was infection (46 %) and that for late readmissions was biliary stricture (62 %). On univariate analysis, pretransplant portal vein thrombosis, more than one bile duct in the liver graft, revised arterial anastomosis or two arteries in the graft, and higher serum alkaline phosphatase levels at discharge were significantly associated with readmission. Readmission was also significantly associated with a higher overall mortality than non-readmission in which there was no mortality.

Conclusion

Pretransplant portal vein thrombosis, more than one bile duct in the liver graft, revision of the arterial anastomosis or two arteries in the graft, and higher serum alkaline phosphatase levels at discharge were significantly associated with readmission. Infective and biliary complications were the commonest causes of early and late readmission after LDLT.     

Live donor liver transplantation for acute liver failure: A single center experience

Introduction

Acute liver failure (ALF) is an indication for emergency liver transplantation (LT). Although centers performing only deceased donor liver transplants (DDLT) have shown improved outcomes in this situation, they still have relatively long waiting lists. An alternative would be living donor liver transplantation (LDLT), which has shown equivalent outcomes in the elective situation but there is limited evidence of its results in ALF.

Aim

The purpose of this study was to assess the outcomes in patients with ALF undergoing emergency LDLT in our center in Delhi, India.

Methods

We prospectively collected data on 479 patients who underwent LT in our hospital between January 2009 and December 2015 to evaluate the outcomes of those with ALF. The ALF patients were listed for transplantation after they met the Kings’ College criteria and rapid evaluation was done following a protocol consisting of three phases. Patients with grade III/IV encephalopathy were put on mechanical ventilation. Data regarding their postoperative course, morbidity, and mortality were analyzed.

Results

Thirty-six (7.5%) out of the 479 patients underwent emergency LT for ALF. Their mean age was 27.5 years (range 4–59 years) and the male to female ratio of 2:3. Preoperative intubation was required in 15 of 25 patients who had encephalopathy. Wilson’s disease was the most common cause of ALF in children while in adults, it was acute viral hepatitis. The time interval between listing and transplantation was a mean of 36?±?12.4 h. The mean graft to recipient weight ratio (GRWR) was 1.06?±?0.3. The recipients were extubated postoperatively after a mean period of 2.6 days and their mean ICU stay was 6.3 days. Postoperative infection was the most common complication and required upgradation of antifungal and antibiotic treatments. Neurological complications occurred in five patients. Thirty-one of 36 (86.1%) patients survived and progressive cerebral edema and sepsis were the most common causes of mortality. Patients who died had higher model for end-stage liver disease scores, longer cold ischemia time (CIT), and higher grades of encephalopathy (though 80% patients with encephalopathy survived). There was no donor mortality. At long-term follow up of a median of 56 months, 29 (80.5%) of 36 patients were still alive.

Conclusions

In our experience, LDLT is an alternative procedure to DDLT in patients with ALF and is associated with good outcomes even in patients with high grades of encephalopathy.

     

Spontaneous massive gastrointestinal hemorrhage in patients with pancreatitis

Spontaneous massive gastrointestinal hemorrhage occurring in patients with pancreatitis is an uncommon and difficult clinical problem, especially in a tropical third world country where the underlying causes of pancreatitis and facilities for its diagnosis and management are different from those in the developed West. Of 7 such cases seen by us in 3 years, 2 were due to hemosuccus pancreaticus, 2 were due to gastric variceal hemorrhage consequent to splenic vein obstruction, and one each due to contiguous pancreatic inflammation involving the duodenum, an aneurysmal bleed from the left gastric artery and a pseudocyst rupturing into the transverse colon. A fiberoptic endoscopic examination was helpful in all the 7 cases and delineated the cause of bleeding, whereas angiography, performed in 4 patients contributed little to management. The mortality rate was 14%. It is suggested that a timely endoscopic examination during active bleeding, which may be repeated if necessary, is extremely rewarding in the diagnosis and management of such patients and often obviates the necessity of angiography which is a time-consuming and cumbersome investigation in a critically ill patient and facilities for which are usually not available in most third world country hospitals.     

Using the Opportunity Estimator tool to improve engagement in a quality and safety intervention

Teams throughout the United States participating in a program to reduce central line-associated bloodstream infections (CLABSIs) are using the Opportunity Estimator. This web-based tool translates CLABSI-related data into "opportunity estimates" of the patient lives and money that could be saved by reducing these infections.     

Functional requirements of AID’s higher order structures and their interaction with RNA-binding proteins

Activation-induced cytidine deaminase (AID) is essential for the somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes. Although both the N and C termini of AID have unique functions in DNA cleavage and recombination, respectively, during SHM and CSR, their molecular mechanisms are poorly understood. Using a bimolecular fluorescence complementation (BiFC) assay combined with glycerol gradient fractionation, we revealed that the AID C terminus is required for a stable dimer formation. Furthermore, AID monomers and dimers form complexes with distinct heterogeneous nuclear ribonucleoproteins (hnRNPs). AID monomers associate with DNA cleavage cofactor hnRNP K whereas AID dimers associate with recombination cofactors hnRNP L, hnRNP U, and Serpine mRNA-binding protein 1. All of these AID/ribonucleoprotein associations are RNA-dependent. We propose that AID’s structure-specific cofactor complex formations differentially contribute to its DNA-cleavage and recombination functions.Activation-induced cytidine deaminase (AID), which is expressed in antigen-stimulated mature B cells, is essential for Ig somatic hypermutation (SHM) and class-switch recombination (CSR) (1, 2). AID induces DNA breaks at the variable (V) and switch (S) regions during SHM and CSR, respectively (3, 4). Although both processes are initiated by AID-induced DNA cleavage, point mutations at the V region are executed mostly by error-prone DNA repair whereas CSR is accomplished by recombination of cleaved ends at donor and acceptor S regions (5, 6). However, the detailed mechanisms by which AID carries out the two mechanistically distinct functions for SHM and CSR have yet to be uncovered (7). Studies on AID mutants revealed that AID’s N- and C-terminal domains are distinctly required for its DNA-cleavage and recombination functions, respectively (8–10). Mutations at the N terminus of AID impair SHM as well as CSR whereas those at the C terminus abrogate CSR only and show increased SHM activity. Recent studies demonstrated that the CSR process after DNA cleavage, including the synapsis formation between cleaved ends, is impaired with the C-terminally defective AID, indicating that AID’s C terminus confers a CSR-specific recombination function, independent of AID’s DNA cleavage function, by an unknown mechanism (11, 12).AID belongs to the APOBEC (apolipoprotein B mRNA-editing enzyme catalytic polypeptide) family of cytidine deaminases (CDDs) and shows high sequence homology with APOBEC1 (A1) (1, 13, 14), which edits apolipoprotein B (APOB) mRNA. The APOB mRNA editing ability of A1 is highly dependent on its cofactors, A1CF/ACF (15, 16) and RBM47 (17), both of which belong to the heterogeneous nuclear ribonucleoprotein (hnRNP) family. Recently, two A1CF-like hnRNPs, hnRNP K and hnRNP L, were identified as the cofactors of AID and found to be involved in the cleavage and recombination of DNA, respectively (18). Because the N and C termini of AID differentially regulate two functions of AID—cleavage and recombination, respectively—we speculated that the AID termini would be critical for function-coupled cofactor association. For instance, the N or C terminus of AID may function as a molecular switch that induces an AID–AID interaction, enabling AID to exert distinct physiological functions through its association with cofactors. Regrettably, however, there is little structural information available that can explain any of AID’s regulatory modes of action, including its cofactor association mechanisms, in the context of its physiological functions.Although a significant amount of structural information is available for a number of APOBEC family members, the 3D structures of A1 and AID are yet to be resolved (19, 20). The CDD family of enzymes exists in nature in a variety of structural forms, including monomeric, dimeric, and tetrameric forms, and comparative structural modeling using the yeast CDD structure predicts a dimeric structure for both A1 and AID (21, 22). On the other hand, homology modeling with the APOBEC2 (A2) crystal structure, which seems to be a tetramer composed of two head-to-head interacting dimers, predicts that AID forms a tetramer (23). Notably, A2 was later reported to exist as a monomer in solution (24). Similarly, an atomic force microscopic (AFM) study found that AID exists in the cell predominantly as a monomer associated with a single-strand DNA substrate (25). However, the same AFM dataset was interpreted differently by another group of investigators, who concluded that AID probably forms an A2-like tetramer in solution (26). The modeling of AID’s catalytic pocket in reference to eight APOBEC family members suggested that most of the AID–DNA complex remains in an inactive state due to occlusion by the substrate DNA, which may explain its weak catalytic activity for cleaving DNA in vitro (27).One of the limitations of the computational modeling of AID’s structure is that AID’s N-and C-terminal sequences are substantially different from those of other APOBEC members and thus reside outside the modeling template. Although the structural outcome of a protein can differ by a variety of reasons, including the methods applied (28), none of the AID studies mentioned above explain why the C-terminal deletion of AID leads to the loss of CSR function only. Therefore, model-based computational simulation may not explain the physiological structure–function relationship of AID in B cells.Here, we explored AID’s structure–function relationship using a bimolecular fluorescence complementation (BiFC) assay, which detects homo- or heteromeric protein–protein interactions in live cells (29, 30). For the homomeric interaction assay, the target protein is fused to two nonfluorescent halves of a green or red fluorescent protein. An interaction between two of the target proteins brings the two nonfluorescent halves of the fluorescent protein into close proximity, reconstituting the fluorescence. The BiFC assay thus allows a rapid analysis of the dimerization of a protein of interest in live cells.By combining this assay with other biochemical approaches, such as coimmunoprecipitation (co-IP) and glycerol gradient sedimentation, we revealed the presence of both monomeric and dimeric forms of AID in analyzed cells. Intriguingly, C-terminal AID mutants that lost CSR function showed a severe dimerization defect, suggesting that AID’s C terminus is required to stabilize the dimeric structure that is required for CSR. We also showed that the AID monomer and dimer associate with different RNA-binding proteins (RBPs) to form ribonucleoprotein (RNP) complexes. Based on these findings, we propose that the monomeric AID–RNP complex includes hnRNP K (18) and contributes to the DNA cleavage function of AID whereas the dimeric AID–RNP complexes include hnRNP L (18), hnRNP U (31), or Serpine mRNA-binding protein 1 (SERBP1) (32) and contribute to the recombination step of CSR.     

The effect of the modified puestow procedure on diabetes in patients with tropical chronic pancreatitis--a prospective study

OBJECTIVES: Surgical decompression of the pancreatic duct in patients with chronic pancreatitis relieves pain in 80-90% of subjects, but its effect on exocrine and endocrine pancreatic function is not clear. We sought to further examine such effects. METHODS: We performed the modified Puestow procedure (lateral pancreaticojejunostomy) in 53 patients with chronic tropical pancreatitis. Pain evaluation was done subjectively and objectively, and the fasting and postprandial blood glucose, insulin requirements, and 72-h fecal fat levels were estimated before and at 3 months and 5 yr after operation. We compared 46 operated patients who completed 5 yr of follow-up with 40 patients who did not undergo operation. RESULTS: Forty-one patients (89%) had complete pain relief. The mean fasting (209 mg/dl) and postprandial (320 mg/dl) blood glucose and insulin requirements (40 U/day) decreased postoperatively (fasting, 162 mg/dl; postprandial blood glucose, 254mg/dl; insulin requirement, 18.2 U/day; p < 0.01), and steatorrhea improved in one of six patients. In the nonoperated group, endocrine and exocrine pancreatic function remained unchanged. CONCLUSIONS: Patients with tropical chronic pancreatitis who undergo the Puestow procedure not only have relief from pain but also improvement of diabetes.