Pancreas and Islet Transplantation: Comparative Outcome Analysis of a Single-centre Cohort Over 20-years.

OBJECTIVE: To provide the largest single-center analysis of islet (ITx) and pancreas (PTx) transplantation. SUMMARY BACKGROUND DATA: Studies describing long-term outcomes with ITx and PTx are scarce. METHODS: We included adults undergoing ITx (n=266) and PTx (n=146) at the University of Alberta from January 1999 to October 2019. Outcomes include patient and graft survival, insulin independence, glycemic control, procedure-related complications, and hospital readmissions. Data are presented as medians (interquartile ranges, IQR) and absolute numbers (percentages, %) and compared using Mann-Whitney and χ2 tests. Kaplan-Meier estimates, Cox proportional hazard models and mixed main effects models were implemented. RESULTS: Crude mortality was 9.4% and 14.4% after ITx and PTx, respectively ( P= 0.141). Sex-adjusted and age-adjusted hazard-ratio for mortality was 2.08 (95% CI, 1.04-4.17, P= 0.038) for PTx versus ITx. Insulin independence occurred in 78.6% and 92.5% in ITx and PTx recipients, respectively ( P= 0.0003), while the total duration of insulin independence was 2.1 (IQR 0.8-4.6) and 6.7 (IQR 2.9-12.4) year for ITx and PTx, respectively ( P= 2.2×10 -22 ). Graft failure ensued in 34.2% and 19.9% after ITx and PTx, respectively ( P =0.002). Glycemic control improved for up to 20-years post-transplant, particularly for PTx recipients (group, P= 7.4×10 -7 , time, P =4.8×10 -6 , group*time, P= 1.2×10 -7 ). Procedure-related complications and hospital readmissions were higher after PTx ( P =2.5×10 -32 and P= 6.4×10 -112 , respectively). CONCLUSIONS: PTx shows higher sex-adjusted and age-adjusted mortality, procedure-related complications and readmissions compared with ITx. Conversely, insulin independence, graft survival and glycemic control are better with PTx. This study provides data to balance risks and benefits with ITx and PTx, which could improve shared decision-making.

A single nucleotide polymorphism genetic risk score to aid diagnosis of coeliac disease: a pilot study in clinical care.

BACKGROUND: Single nucleotide polymorphism-based genetic risk scores (GRS) model genetic risk as a continuum and can discriminate coeliac disease but have not been validated in clinic. Human leukocyte antigen (HLA) DQ gene testing is available in clinic but does not include non-HLA attributed risk and is limited by discrete risk stratification. AIMS: To accurately characterise both HLA and non-HLA coeliac disease genetic risk as a single nucleotide polymorphism-based GRS and evaluate diagnostic utility. METHODS: We developed a 42 single nucleotide polymorphism coeliac disease GRS from a European case-control study (12 041 cases vs 12 228 controls) using HLA-DQ imputation and published genome-wide association studies. We validated the GRS in UK Biobank (1237 cases) and developed direct genotyping assays. We tested the coeliac disease GRS in a pilot clinical cohort of 128 children presenting with suspected coeliac disease. RESULTS: The GRS was more discriminative of coeliac disease than HLA-DQ stratification in UK Biobank (receiver operating characteristic area under the curve [ROC-AUC] = 0.88 [95% CIs: 0.87-0.89] vs 0.82 [95% CIs: 0.80-0.83]). We demonstrated similar discrimination in the pilot clinical cohort (114 cases vs 40 controls, ROC-AUC = 0.84 [95% CIs: 0.76-0.91]). As a rule-out test, no children with coeliac disease in the clinical cohort had a GRS below 38th population centile. CONCLUSIONS: A single nucleotide polymorphism-based GRS may offer more effective and cost-efficient testing of coeliac disease genetic risk in comparison to HLA-DQ stratification. As a comparatively inexpensive test it could facilitate non-invasive coeliac disease diagnosis but needs detailed assessment in the context of other diagnostic tests and against current diagnostic algorithms.

HLA Alloimmunization Following Ventricular Assist Device Support Across the Age Spectrum.

BACKGROUND: Ventricular assist device (VAD) therapy has become an important tool for end-stage heart failure. VAD therapy has increased survival but is associated with complications including the development of human leukocyte antigen (HLA) antibodies. We sought to determine the incidence of HLA antibody development post-VAD insertion, across the age spectrum, in patients receiving leukocyte-reduced blood products, with standardized HLA antibody detection methods and to investigate factors associated with antibody development. METHODS: This was a retrospective analysis of all patients who underwent durable VAD placement between 2005 and 2014. Inclusion criteria included availability of pre- and post-VAD HLA antibody results. Associations between HLA antibody development in the first-year postimplant and patient factors were explored. RESULTS: Thirty-nine adult and 25 pediatric patients made up the study cohort. Following implant, 31% and 8% of patients developed new class I and class II antibodies. The proportion of newly sensitized patients was similar in adult and pediatric patients. The class I HLA panel reactive antibody only significantly increased in adults. Pre-VAD sensitization, age, sex (pediatrics), and transfusion were not associated with the development of HLA antibodies. CONCLUSIONS: In a cohort of VAD patients receiving leukocyte-reduced blood products and standardized HLA antibody testing, roughly one-third developed new class I antibodies in the first-year postimplant. Adults showed significantly increased class I panel reactive antibody following VAD support. No patient-related factors were associated with HLA antibody development. Larger prospective studies are required to validate these findings and determine the clinical impact of these antibodies following VAD insertion.

Comparison of the effects of standard vs low-dose prolonged-release tacrolimus with or without ACEi/ARB on the histology and function of renal allografts.

Targeting the renin-angiotensin system and optimizing tacrolimus exposure are both postulated to improve outcomes in renal transplant recipients (RTRs) by preventing interstitial fibrosis/tubular atrophy (IF/TA). In this multicenter, prospective, open-label controlled trial, adult de novo RTRs were randomized in a 2 × 2 design to low- vs standard-dose (LOW vs STD) prolonged-release tacrolimus and to angiotensin-converting enzyme inhibitors/angiotensin II receptor 1 blockers (ACEi/ARBs) vs other antihypertensive therapy (OAHT). There were 2 coprimary endpoints: the prevalence of IF/TA at month 6 and at month 24. IF/TA prevalence was similar for LOW vs STD tacrolimus at month 6 (36.8% vs 39.5%; P = .80) and ACEi/ARBs vs OAHT at month 24 (54.8% vs 58.2%; P = .33). IF/TA progression decreased significantly with LOW vs STD tacrolimus at month 24 (mean [SD] change, +0.42 [1.477] vs +1.10 [1.577]; P = .0039). Across the 4 treatment groups, LOW + ACEi/ARB patients exhibited the lowest mean IF/TA change and, compared with LOW + OAHT patients, experienced significantly delayed time to first T cell-mediated rejection. Renal function was stable from month 1 to month 24 in all treatment groups. No unexpected safety findings were detected. Coupled with LOW tacrolimus dosing, ACEi/ARBs appear to reduce IF/TA progression and delay rejection relative to reduced tacrolimus exposure without renin-angiotensin system blockade. ClinicalTrials.gov identifier: NCT00933231.

Baseline Functional Class and Therapeutic Efficacy of Common Heart Failure Interventions: A Systematic Review and Meta-analysis.

BACKGROUND: New York Heart Association (NYHA) functional class provides important prognostic information and is often used to select patients for cardiovascular therapies, yet, the effect of NYHA class on therapeutic efficacy has not been systematically studied. METHODS: In this systematic review and meta-analysis we compared the relative and absolute mortality benefit of 5 common heart failure interventions (angiotensin-converting enzyme [ACE] inhibitors, ß-blockers, mineralocorticoid receptor antagonists [MRAs], implantable cardioverter defibrillator [ICD], and cardiac resynchronization therapy [CRT]) across NYHA class. We included 26 randomized clinical trials of these interventions that reported all-cause mortality stratified according to baseline NYHA class in 36,406 patients. RESULTS: Pooled relative risk for NYHA I/II vs. III/IV strata were similar for ACE inhibitors (0.90 vs. 0.88), ß-blockers (0.72 vs. 0.79), MRA (0.79 vs. 0.75), and CRT (0.80 vs. 0.80), with all heterogeneity P > 0.8. Conversely, ICD efficacy was greater for class I/II (relative risk, 0.65 vs 0.86, heterogeneity P = 0.02). The pooled absolute risk difference was smaller for NYHA I/II vs III/IV with ACE inhibitors (-0.02 vs. -0.06, P = 0.12), ß-blockers (-0.02 vs. -0.05, P = 0.047), MRA (-0.03 vs. -0.11, P = 0.001), and CRT (-0.01 vs. -0.04, P = 0.036), but was similar across NYHA class for the ICD (-0.07 vs. -0.05; P = 0.27). CONCLUSIONS: Relative mortality reductions with most interventions were independent of baseline NYHA class. However, ICD efficacy was greater with NYHA I/II vs. III/IV limitation, and absolute benefit was greater with higher NYHA class. For interventions other than the ICD, there is little evidence supporting use of NYHA class as a rigid criterion for selecting heart failure therapies.

Islet-after-failed-pancreas and pancreas-after-failed islet transplantation: Two complementary rescue strategies to control diabetes.

For selected patients with type 1 diabetes, ß-cell replacement is the treatment of choice, either by islet transplantation (ITX) or whole pancreas transplantation (PTX). When either modality fails, current practice is to consider retransplantation, or return to exogenous insulin. We investigate outcomes with PTX after failed ITX (PAI), and ITX after failed PTX (IAP). All patients receiving PAI or IAP at a single institution were identified. Donor and recipient variables were documented, including transplant outcomes analyzed for insulin requirement and metabolic control. Five subjects were listed for PAI, and 2 received transplants. Of the 4 listed for IAP, 3 have received transplants. The mean waitlist time was 4.5 ± 4.1 y for PAI and 0.35 ±0 .4 y for IAP (p = 0.08). Metabolic control was excellent after PAI, with 2/2 insulin-independent. After IAP, 1/2 achieved insulin independence and good metabolic control after 2 islet infusions. The third could not receive 2(nd) infusion and presented c-peptide levels < 0.1 nmol/L. Both strategies are feasible. The outcomes after PAI in our center must be offset by much longer waitlist time due to the sensitization status of these patients. Data from multicentre experience will allow more robust comparative outcomes to be made, the current observations being restricted to a limited patient set.

The worst symptom as defined by patients during heart failure hospitalization: implications for response to therapy.

BACKGROUND: Patients perceive different symptoms of heart failure decompensation. It is not known whether the nature of the worst symptom relates to hemodynamic profile, response to therapy, or improvement in clinical trials. METHODS AND RESULTS: Patients in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial were hospitalized with advanced heart failure, ejection fraction ≤30%, and at least 1 sign and 1 symptom of elevated filling pressures. Visual analog scales (VAS) for symptoms were completed by 371 patients, who selected their worst symptom as difficulty breathing, fatigue, abdominal discomfort, or body swelling and also scored breathing and global condition at baseline and discharge. The dominant symptom identified was difficulty breathing by 193 (52%) patients, fatigue by 118 (32%), and abdominal discomfort and swelling each by 30 (8%) patients, combined as right-sided congestion for analysis. Clinical and hemodynamic assessments were not different between groups except that right-sided congestion was associated with more hepatomegaly, ascites, third heart sounds, and jugular venous distention. This group also had greater reduction in jugular venous distention and trend toward higher blood urea nitrogen after therapy. By discharge, average improvements in worst symptom and global score were 28 points and 24 points. For those with ≥10 points in improvement in worst symptom, 84% also improved global assessment ≥10 points. Initial fatigue was associated with less improvement (P = .002) during and after hospitalization, but improvements in symptom scores were sustained when re-measured during 6 months after discharge. CONCLUSION: In most patients hospitalized with clinical congestion, therapy will improve symptoms regardless of the worst symptom perceived, with more evidence of baseline fluid retention and reduction during therapy for worst symptoms of abdominal discomfort or edema. Improvement in trials should be similar when tracking worst symptom, dyspnea, or global assessment.

Functionally competent cardiac stem cells can be isolated from endomyocardial biopsies of patients with advanced cardiomyopathies.

RATIONALE: Two categories of cardiac stem cells (CSCs) with predominantly myogenic (mCSC) and vasculogenic (vCSC) properties have been characterized in the human heart. However, it is unknown whether functionally competent CSCs of both classes are present in the myocardium of patients affected by end-stage cardiac failure, and whether these cells can be harvested from relatively small myocardial samples. OBJECTIVE: To establish whether a clinically relevant number of mCSCs and vCSCs can be isolated and expanded from endomyocardial biopsies of patients undergoing cardiac transplantation or left ventricular assist device implantation. METHODS AND RESULTS: Endomyocardial biopsies were collected with a bioptome from the right side of the septum of explanted hearts or the apical LV core at the time of left ventricular assist device implantation. Two to 5 biopsies from each patient were enzymatically dissociated, and, after expansion, cells were sorted for c-kit (mCSCs) or c-kit and KDR (vCSCs) and characterized. mCSCs and vCSCs constituted 97% and 3% of the c-kit population, respectively. Population doubling time averaged 27 hours in mCSCs and vCSCs; 5×10(6) mCSCs and vCSCs were obtained in 28 and 41 days, respectively. Both CSC classes possessed significant growth reserve as documented by high telomerase activity and relatively long telomeres. mCSCs formed mostly cardiomyocytes, and vCSCs endothelial and smooth muscle cells. CONCLUSIONS: The growth properties of mCSCs and vCSCs isolated from endomyocardial biopsies from patients with advanced heart failure were comparable to those obtained previously from larger myocardial samples of patients undergoing elective cardiac surgery.

Failure of prophylactic intravenous immunoglobulin to prevent sensitization to cryopreserved allograft tissue used in congenital cardiac surgery.

OBJECTIVE: Cryopreserved allograft tissue used in the Norwood procedure for infants with hypoplastic left heart syndrome causes profound immunologic sensitization, which may complicate future transplantation. Intravenous immunoglobulin has been shown to reduce sensitization after it has developed, allowing successful transplantation. The purpose of this pilot trial was to determine whether intravenous immunoglobulin given before and after the procedure could prevent sensitization to cryopreserved allograft patches used in the initial repair of hypoplastic left heart syndrome. METHODS: Intravenous immunoglobulin (2 g/kg) was given preoperatively, 3 weeks postoperatively, and 4 months postoperatively to 7 infants undergoing the Norwood procedure. Panel-reactive antibodies were measured with flow cytometry preoperatively and at 1, 4, 6, and 12 months postoperatively and compared with values from a contemporary cohort of 12 infants undergoing the Norwood procedure who did not receive intravenous immunoglobulin. RESULTS: The groups were well matched for length and weight at time of surgery. Control infants were somewhat younger than the cohort receiving intravenous immunoglobulin (8 +/- 5 vs 17 +/- 14 days, P = .021). There were no differences in transfusion requirements. There was no difference in the degree of sensitization between control and intravenous immunoglobulin groups at 1 month (class I panel-reactive antibodies 20% +/- 30% vs 4% +/- 9%, P = .443, class II panel-reactive antibodies 17% +/- 27% vs 20% +/- 17%, P = .400), 4 months (class I panel-reactive antibodies 62% +/- 40% vs 73% +/- 41%, P = .813, class II panel-reactive antibodies 49% +/- 42% vs 54% +/- 41%, P = .706), and 12 months (class I panel-reactive antibodies 49% +/- 42% vs 58% +/- 39%, P = .686, class II panel-reactive antibodies 44% +/- 36% vs 49% +/- 42%, P = .651). CONCLUSION: Despite studies showing intravenous immunoglobulin to reduce sensitization, we were unable to demonstrate that intravenous immunoglobulin prevented sensitization after exposure to allograft tissue in neonates undergoing congenital cardiac surgery.

Use of an allograft patch in repair of hypoplastic left heart syndrome may complicate future transplantation.

OBJECTIVE: Cryopreserved allograft tissue used in the Norwood procedure for infants with hypoplastic left heart syndrome (HLHS) has the potential to cause marked immunologic sensitization which may complicate potential future heart transplantation, if required. The purpose of this study was to assess the anti-HLA antibody response to allograft patches used in the initial repair of HLHS. METHODS: A prospective cohort study was conducted comparing the panel-reactive antibody levels (PRA) in 12 infants undergoing repair of HLHS with cryopreserved allograft patch to 10 infants undergoing arterial switch for transposition of the great arteries (no allograft tissue used). PRA for Class I (HLA-A, B, C) and Class II (HLA-DR, DQ) antibodies were assessed preoperatively and postoperatively using flow cytometry. RESULTS: The two groups were well matched at the time of surgery (age, weight, gender). Infants in both groups received blood from multiple donors; however, the allograft group received significantly more (12+/-10 vs. 5+/-1 units; P<0.001). By 4 months, most infants receiving allograft tissue had become highly sensitized for both Class I PRA (62+/-40 vs. 0; P=0.002) and Class II PRA (49+/-42 vs. 2+/-3; P=0.022). This response continued to increase at 12 months: Class I PRA (79+/-21 vs. 0; P=0.008) and Class II PRA (66+/-27 vs. 5+/-6; P=0.008). Specificity analysis confirmed antibodies were specific for the donor allograft HLA type. In addition, infants who were coincidently HLA-matched with their allograft did not develop an elevated PRA. CONCLUSIONS: Allograft tissue used in the repair of HLHS is associated with profound donor specific immunologic sensitization in the majority of recipients and may complicate or jeopardize future transplantation. Methods to reduce the immunogenicity of cryopreserved allograft tissue used for arch reconstruction requires further investigation.

Peritubular capillary changes and C4d deposits are associated with transplant glomerulopathy but not IgA nephropathy.

We examined our renal transplant population for glomerular diseases demonstrated on biopsy between January 1993 and April 2002, focusing on transplant glomerulopathy (TGP). Of 1156 patients followed in our clinics during this period, glomerular disease was diagnosed in 132 cases (11.4%). Glomerulonephritis was diagnosed in 86 transplants (7.4%), with IgA nephropathy (IgAN) being the commonest diagnosis [32 cases (2.8%)]. Thirty-one cases (2.7%) of biopsy-proven TGP were analyzed for associated factors compared with 27 cases (2.3%) of recurrent IgAN. Transplant glomerulopathy was less frequent with mycophenolate mofetil (MMF) and/or tacrolimus, whereas recurrent IgAN showed no such tendency (P= 0.02). Peritubular capillary (PTC) C4d deposition was observed in six of 24 cases (25%) with TGP but none with recurrent IgAN (P= 0.02). Peritubular capillary basement membrane (BM) multilayering was significantly greater in TGP (4.92 +/- 2.94) than in recurrent IgAN (1.86 +/- 1.04) (P < 0.001). The graft survival of TGP was worse than recurrent IgAN (P= 0.05). The association of TGP with BM multilayering and C4d deposits in PTC suggests a generalized disorder of the graft microcirculation and its BM, owing to antibody-mediated rejection in at least some cases. Transplant glomerulopathy has a serious prognosis but is less frequent in patients on newer immunosuppression, unlike recurrent IgAN.

Do cardiac troponins provide prognostic insight in hemodialysis patients?

BACKGROUND: The diagnosis of myocardial necrosis in patients with chronic renal failure is often difficult because biochemical markers of cardiac damage such as creatine kinase MB (CKMB) and cardiac troponin T (cTnT) may be spuriously elevated. Recent small studies also report unexplained elevations in cardiac troponin I (cTnI) in chronic renal failure patients undergoing hemodialysis. The relative incidence of elevated cardiac troponins in this population and their relationship to clinical events remain unknown. OBJECTIVE: To determine the incidence and prognostic significance of asymptomatic elevations of cTnT and cTnI in patients undergoing hemodialysis for chronic renal failure. DESIGN: Prospective cohort study. SETTING: University tertiary care teaching hospital. PATIENTS: One hundred thirteen patients over 21 years of age undergoing onsite hemodialysis were enrolled between December 1997 and February 1998. MEASUREMENTS: All-cause and cardiovascular mortality, hospitalization for acute myocardial infarction, unstable angina or congestive heart failure, new onset sustained arrhythmia or need for unscheduled emergency hemodialysis due to volume overload at 30 days and six months. RESULTS: The incidence of abnormal results for cTnT, cTnI and CKMB were 42%, 15% and 4%, respectively. Independent predictors of mortality at six months were median age greater than 63 years (odds ratio 14.3, 95% CI 1.5 to 130.3, P=0.019) and positive cTnT (odds ratio 13.6, 95% CI 2.5 to 73.2, P=0.002). Diabetics were more likely to have positive cTnI and cTnT results than nondiabetics (P<0.001 and P=0.023, respectively). CONCLUSIONS: cTnT is commonly elevated in patients with chronic renal failure even in the absence of acute coronary syndromes. cTnT may be an important independent prognostic marker in patients on hemodialysis for chronic renal failure. While less common, elevations of cTnI are more frequent than CKMB elevations. The basis of these cardiac troponin elevations is unclear. These findings may represent, in part, a subclinical myocardial injury, an inflammatory response to chronic renal failure or a chronically volume overloaded state.

Antibody-mediated rejection criteria - an addition to the Banff 97 classification of renal allograft rejection.

Antibody-mediated rejection (AbAR) is increasingly recognized in the renal allograft population, and successful therapeutic regimens have been developed to prevent and treat AbAR, enabling excellent outcomes even in patients highly sensitized to the donor prior to transplant. It has become critical to develop standardized criteria for the pathological diagnosis of AbAR. This article presents international consensus criteria for and classification of AbAR developed based on discussions held at the Sixth Banff Conference on Allograft Pathology in 2001. This classification represents a working formulation, to be revisited as additional data accumulate in this important area of renal transplantation.