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Background: The problem of AMR remains unsolved because standardized schemes for diagnosis and treatment remains contentious. Therefore, a consensus conference was organized to discuss the current status of antibody-mediated rejection (AMR) in heart transplantation. Methods: The conference included 83 participants (transplant cardiologists, surgeons, immunologists and pathologists) representing 67 heart transplant centers from North America, Europe, and Asia who all participated in smaller break-out sessions to discuss the various topics of AMR and attempt to achieve consensus. Results: A tentative pathology diagnosis of AMR was established, however, the pathologist felt that further discussion was needed prior to a formal recommendation for AMR diagnosis. One of the most important outcomes of this conference was that a clinical definition for AMR (cardiac dysfunction and/or circulating donor-specific antibody) was no longer believed to be required due to recent publications demonstrating that asymptomatic (no cardiac dysfunction) biopsy-proven AMR is associated with subsequent greater mortality and greater development of cardiac allograft vasculopathy. It was also noted that donor-specific antibody is not always detected during AMR episodes as the antibody may be adhered to the donor heart. Finally, recommendations were made for the timing for specific staining of endomyocardial biopsy specimens and the frequency by which circulating antibodies should be assessed. Recommendations for management and future clinical trials were also provided. Conclusions: The AMR Consensus Conference brought together clinicians, pathologists and immunologists to further the understanding of AMR. Progress was made toward a pathology AMR grading scale and consensus was accomplished regarding several clinical issues. [ABSTRACT FROM AUTHOR]

The development of cardiac allograft vasculopathy remains the Achilles heel of cardiac transplantation. Unfortunately, the definitions of cardiac allograft vasculopathy are diverse, and there are no uniform international standards for the nomenclature of this entity. This consensus document, commissioned by the International Society of Heart and Lung Transplantation Board, is based on best evidence and clinical consensus derived from critical analysis of available information pertaining to angiography, intravascular ultrasound imaging, microvascular function, cardiac allograft histology, circulating immune markers, non-invasive imaging tests, and gene-based and protein-based biomarkers. This document represents a working formulation for an international nomenclature of cardiac allograft vasculopathy, similar to the development of the system for adjudication of cardiac allograft rejection by histology. [Copyright &y& Elsevier]

Background: Lymphoma after heart transplantation (HT) has been associated with induction therapy and herpesvirus infection. It is not known whether anti-viral agents administered immediately after HT can reduce the incidence of lymphoma. Methods: This study was a retrospective review of 3,393 patients who underwent HT in Spain between 1984 and December 2003. Variables examined included development of lymphoma and, as possible risk factors, recipient gender and age, induction therapies (anti-thymocyte globulin, OKT3 and anti–interleukin-2 receptor antibodies) and anti-viral prophylaxis (acyclovir or ganciclovir). To study the effect of evolving treatment strategy, three HT eras were considered: 1984 to 1995; 1996 to 2000; and 2001 to 2003. Results: Induction therapy was employed in >60% of HTs, and anti-viral prophylaxis in >50%. There were 62 cases of lymphoma (3.1 per 1,000 person-years, 95% confidence interval: 2.4 to 4.0). Univariate analyses showed no influence of gender, age at transplant, HT era, pre-HT smoking or the immunosuppressive maintenance drugs used in the first 3 months post-HT. The induction agent anti-thymocyte globulin (ATG) was associated with increased risk of lymphoma, and prophylaxis with acyclovir with decreased risk of lymphoma. Multivariate analyses (controlling for age group, gender, pre-HT smoking and immunosuppression in the first 3 months with mycophenolate mofetil and/or tacrolimus) showed that induction increased the risk of lymphoma if anti-viral prophylaxis was not used (regardless of induction agent and anti-viral agent), but did not increase the risk if anti-viral prophylaxis was used. Conclusions: Induction therapies with ATG or OKT3 do or do not increase the risk of lymphoma depending on whether anti-viral prophylaxis with acyclovir or ganciclovir is or is not employed, respectively. [Copyright &y& Elsevier]

We previously reported a microarray-based diagnostic system for heart transplant endomyocardial biopsies (EMBs), using either 3-archetype (3AA) or 4-archetype (4AA) unsupervised algorithms to estimate rejection. In the present study we examined the stability of machine-learning algorithms in new biopsies, compared 3AA vs 4AA algorithms, assessed supervised binary classifiers trained on histologic or molecular diagnoses, created a report combining many scores into an ensemble of estimates, and examined possible automated sign-outs. We studied 889 EMBs from 454 transplant recipients at 8 centers: the initial cohort (N = 331) and a new cohort (N = 558). Published 3AA algorithms derived in Cohort 331 were tested in Cohort 558, the 3AA and 4AA models were compared, and supervised binary classifiers were created. A'lgorithms derived in Cohort 331 performed similarly in new biopsies despite differences in case mix. In the combined cohort, the 4AA model, including a parenchymal injury score, retained correlations with histologic rejection and DSA similar to the 3AA model. Supervised molecular classifiers predicted molecular rejection (areas under the curve [AUCs] >0.87) better than histologic rejection (AUCs <0.78), even when trained on histology diagnoses. A report incorporating many AA and binary classifier scores interpreted by 1 expert showed highly significant agreement with histology (p < 0.001), but with many discrepancies, as expected from the known noise in histology. An automated random forest score closely predicted expert diagnoses, confirming potential for automated signouts. Molecular algorithms are stable in new populations and can be assembled into an ensemble that combines many supervised and unsupervised estimates of the molecular disease states. [ABSTRACT FROM AUTHOR]

Despite the successes from refined peri-operative management techniques and immunosuppressive therapies, antibodies remain a serious cause of morbidity and mortality for patients both before and after heart transplantation. Patients awaiting transplant who possess antibodies against human leukocyte antigen are disadvantaged by having to wait longer to receive an organ from a suitably matched donor. The number of pre-sensitized patients has been increasing, a trend that is likely due to the increased use of mechanical circulatory support devices. Even patients who are not pre-sensitized can go on to produce donor-specific antibodies after transplant, which are associated with worse outcomes. The difficulty in managing antibodies is uncertainty over which antibodies are of clinical relevance, which patients to treat, and which treatments are most effective and safe. There is a distinct lack of data from prospective trials. An international consensus conference was organized and attended by 103 participants from 75 centers to debate contentious issues, determine the best practices, and formulate ideas for future research on antibodies. Prominent experts presented state-of-the-art talks on antibodies, which were followed by group discussions, and then, finally, a reconvened session to establish consensus where possible. Herein we address the discussion, consensus points, and research ideas. [ABSTRACT FROM AUTHOR]

Background New biomarkers are necessary to improve detection of the risk of infection in heart transplantation. We performed a multicenter study to evaluate humoral immunity profiles that could better enable us to identify heart recipients at risk of severe infections. Methods We prospectively analyzed 170 adult heart recipients at 8 centers in Spain. Study points were before transplantation and 7 and 30 days after transplantation. Immune parameters included IgG, IgM, IgA and complement factors C3 and C4, and titers of specific antibody to pneumococcal polysaccharide antigens (anti-PPS) and to cytomegalovirus (CMV). To evaluate potential immunologic mechanisms leading to IgG hypogammaglobulinemia, before heart transplantation we assessed serum B-cell activating factor (BAFF) levels using enzyme-linked immunoassay. The clinical follow-up period lasted 6 months. Clinical outcome was need for intravenous anti-microbials for therapy of infection. Results During follow-up, 53 patients (31.2%) developed at least 1 severe infection. We confirmed that IgG hypogammaglobulinemia at Day 7 (defined as IgG <600 mg/dl) is a risk factor for infection in general, bacterial infections in particular, and CMV disease. At Day 7 after transplantation, the combination of IgG <600 mg/dl + C3 <80 mg/dl was more strongly associated with the outcome (adjusted odds ratio 7.40; 95% confidence interval 1.48 to 37.03; p = 0.014). We found that quantification of anti-CMV antibody titers and lower anti-PPS antibody concentrations were independent predictors of CMV disease and bacterial infections, respectively. Higher pre-transplant BAFF levels were a risk factor of acute cellular rejection. Conclusion Early immunologic monitoring of humoral immunity profiles proved useful for the identification of heart recipients who are at risk of severe infection. [ABSTRACT FROM AUTHOR]

Background: Primary graft failure (PGF) is the leading cause of early heart transplantation (HT) mortality. Our aim was to analyze PGF currently and explore the ability of a dedicated score for PGF risk stratification. Methods: After applying a dedicated PGF definition, we analyzed its incidence, mortality, and associated factors in a multicenter cohort of 857 HTs performed in 2006 to 2009. We used the following criteria: recipient right (R) atrial pressure ≥ 10 mm Hg; age (A) ≥ 60 years; diabetes (D) mellitus, and inotrope (I) dependence; donor age (A) ≥ 30 years, and length (L) of ischemia ≥ 240 minutes to calculate the RADIAL score for PGF risk prediction. Results: PGF incidence was 22%. The right ventricle was almost always affected, alone (45%) or as part of biventricular failure (47%). Mechanical circulatory support was used in 55%. Mortality attributable to PGF was 53% and extended through the third month after HT, but thereafter, PGF had little influence in long-term outcome. The RADIAL score was higher in PGF patients (2.78 ± 1.1 vs 2.42 ± 1.1, p = 0.001) and stratified 3 groups with incremental PGF incidence: low risk (12.1%), intermediate risk (19.4%), and high risk (27.5%, p = 0.001). Conclusions: PGF had a strong impact, with an incidence of 22% and a mortality exceeding 50% that extends through the third post-HT month. The RADIAL score classified patients into 3 groups with incremental risk for PGF and may be useful for its prevention and early therapy. [ABSTRACT FROM AUTHOR]

It is unclear whether the usual criteria for implantation of implantable cardioverter defibrillators in patients at risk of sudden death can be generalized to heart transplant recipients. We describe sudden death in 2 heart transplant recipients despite correctly functioning implantable cardioverter defibrillators. The scant relevant literature is reviewed. We conclude that implantable cardioverter defibrillators are unlikely to assist heart transplant recipients with severe coronary allograft vasculopathy and poor ventricular systolic function, the group with the highest incidence of sudden death. [Copyright &y& Elsevier]