Report from a consensus conference on the sensitized patient awaiting heart transplantation

IgM marks persistent IgG anti-human leukocyte antigen antibodies in highly sensitized heart transplant patients

BACKGROUND

Sensitization to human leukocyte antigens (HLA) is a persistent problem in heart transplant (HT) candidates. We sought to characterize the anti-HLA antibody and circulating B cell repertoire in a cohort of highly sensitized HT candidates.

METHODS

We assessed immunoglobulin G (IgG) and immunoglobulin M (IgM) anti-HLA antibodies using Luminex single antigen bead assays in a cohort of 11 highly sensitized (HS; calculated panel reactive antibody ≥ 90%) and 3 mildly sensitized (MS) candidates. We also performed B cell receptor repertoire sequencing (BCRseq) in HS candidates and 33 non-candidate controls. HLA antibody strength was measured by mean fluorescence intensity (MFI).

RESULTS

We found that IgM anti-HLA antibodies were present in all HS candidates, but with a lower breadth and strength as compared to IgG. When anti-HLA IgG specificities intersected with IgM, binding strength was higher. In contrast, there were IgM but no intersecting IgG specificities for the MS group. In four candidates in the HS group, IgG anti-HLA antibodies decreased in both breadth and strength after HT, but the decrease in strength was smaller if the IgG possessed a specificity that intersected with pre-transplant IgM. BCRseq revealed larger B cell clonotypes in HS candidates but similar diversity as compared to controls.

CONCLUSIONS

IgM marks IgG anti-HLA antibodies with higher strength before HT and persistence after HT. The presence of IgM intersecting IgG for an anti-HLA specificity may be a useful approach to determine which donor HLA should be avoided for a sensitized candidate.

Rejection Requiring Treatment within the First Year following Heart Transplantation: The UNOS Insight

(1) Background: Heart failure is an extremely impactful health issue from both a social and quality-of-life point of view and the rate of patients with this condition is destined to rise in the next few years. Transplantation remains the mainstay of treatment for end-stage heart failure, but a shortage of organs represents a significant problem that prolongs time spent on the waiting list. In view of this, the selection of donor and recipient must be extremely meticulous, considering all factors that could predispose to organ failure. One of the main considerations regarding heart transplants is the risk of graft rejection and the need for immunosuppression therapy to mitigate that risk. In this study, we aimed to assess the characteristics of patients who need immunosuppression treatment for rejection within one year of heart transplantation and its impact on mid-term and long-term mortality. (2) Methods: The United Network for Organ Sharing (UNOS) Registry was queried to identify patients who solely underwent a heart transplant in the US between 2000 and 2021. Patients were divided into two groups according to the need for anti-rejection treatment within one year of heart transplantation. Patients' characteristics in the two groups were assessed, and 1 year and 10 year mortality rates were compared. (3) Results: A total of 43,763 patients underwent isolated heart transplantation in the study period, and 9946 (22.7%) needed anti-rejection treatment in the first year. Patients who required treatment for rejection within one year after transplant were more frequently younger (49 ± 14 vs. 52 ± 14 years, p < 0.001), women (31% vs. 23%, p < 0.001), and had a higher CPRA value (14 ± 26 vs. 11 ± 23, p < 0.001). Also, the rate of prior cardiac surgery was more than double in this group (27% vs. 12%, p < 0.001), while prior LVAD (12% vs. 11%, p < 0.001) and IABP (10% vs. 9%, p < 0.01) were more frequent in patients who did not receive anti-rejection treatment in the first year. Finally, pre-transplantation creatinine was significantly higher in patients who did not need treatment for rejection in the first year (1.4 vs. 1.3, p < 0.01). Most patients who did not require anti-rejection treatment underwent heart transplantation during the new allocation era, while less than half of the patients who required treatment underwent transplantation after the new allocation policy implementation (65% vs. 49%, p < 0.001). Patients who needed rejection treatment in the first year had a higher risk of unadjusted 1 year (HR: 2.25; 95% CI: 1.88-2.70; p < 0.001), 5 year (HR: 1.69; 95% CI: 1.60-1.79; p < 0.001), and 10 year (HR: 1.47; 95% CI: 1.41-1.54, p < 0.001) mortality, and this was confirmed at the adjusted analysis at all three time-points. (4) Conclusions: Medical treatment of acute rejection was associated with significantly increased 1 year mortality compared to patients who did not require anti-rejection therapy. The higher risk of mortality was confirmed at a 10 year follow-up. Further studies and newer follow-up data are required to investigate the role of anti-rejection therapy in the heart transplant population.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Management of the sensitized heart transplant candidate

PURPOSE OF REVIEW

For sensitized heart transplant candidates who have antibodies to human leukocyte antigens (HLA), finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting heart transplantation has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease.

RECENT FINDINGS

Advances in the assessment of HLA antibodies allow for identification of heart transplant candidates who may benefit from desensitization strategies to widen the donor pool and mitigate the risk of adverse posttransplant outcomes.

SUMMARY

Antibody sensitization is a barrier to successful heart transplantation and strategies to identify sensitized patients, stratify their risk, and mitigate this risk through desensitization is crucial to optimize the quality of life and survival of HT recipients.

Three year post heart transplant outcomes of desensitized durable mechanical circulatory support patients

BACKGROUND

The risks and benefits of desensitization therapy (DST) in highly sensitized mechanical circulatory support (MCS) patients are not well known. We investigated 3 year post-transplant outcomes of desensitized durable MCS patients.

METHODS

Among 689 consecutively enrolled heart transplantation recipients between 2010 and 2016, we categorized them into Group A (desensitized MCS patients, n = 21), Group B (desensitized non-MCS patients, n = 28) and Group C (all nondesensitized patients, n = 640). Post-transplant outcomes included the incidence of primary graft dysfunction, 3-year survival, freedom from cardiac allograft vasculopathy, nonfatal major adverse cardiac events, any treated rejection, acute cellular rejection, antibody mediated rejection (AMR) and infectious complications.

RESULTS

The types of DST in Groups A and B were similar and included combinations of rituximab/intravenous immunoglobulin and plasmapheresis/bortezomib. Group A, compared with Group B, showed significantly higher pre-DST panel reactive antibody (PRA) (92.2 ± 9.8 vs. 83.3 ± 15.6, P = 0.007) and higher PRA reduction after DST (-22.2 ± 26.9 vs. -6.3 ± 7.5, P = 0.015). Groups A and C showed comparable primary graft dysfunction, 3-year survival, freedom from cardiac allograft vasculopathy, nonfatal major adverse cardiac events, any treated rejection, acute cellular rejection, and AMR. Although statistically not significant, Group A showed numerically higher 3-year freedom from AMR than Group B. Infectious complications were similar in both Groups A and B.

CONCLUSIONS

DST for MCS patients showed significant PRA reduction, resulting in an expansion of the donor pool. The post-transplant outcome of desensitized MCS patients showed comparable clinical outcomes to non-desensitized control patients in the same study period, revealing the safety and efficacy of DST.

Multidisciplinary Care in Heart Failure Services

The American College of Cardiology/American Heart Association/Heart Failure Society of American 2022 guidelines for heart failure (HF) recommend a multidisciplinary team approach for patients with HF. The multidisciplinary HF team-based approach decreases the hospitalization rate for HF and health care costs and improves adherence to self-care and the use of guideline-directed medical therapy. This article proposes the optimal multidisciplinary team structure and each team member's delineated role to achieve institutional goals and metrics for HF care. The proposed HF-specific multidisciplinary team comprises cardiologists, surgeons, advanced practice providers, clinical pharmacists, specialty nurses, dieticians, physical therapists, psychologists, social workers, immunologists, and palliative care clinicians. A standardized multidisciplinary HF team-based approach should be incorporated to optimize the structure, minimize the redundancy of clinical responsibilities among team members, and improve clinical outcomes and patient satisfaction in their HF care.

Detection and management of HLA sensitization in candidates for adult heart transplantation

Heart transplantation (HT) remains the preferred therapy for patients with advanced heart failure. However, for sensitized HT candidates who have antibodies to human leukocyte antigens , finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting HT has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease. This State-of-the-Art review discusses the assessment of human leukocyte antigens antibodies, potential desensitization strategies including mechanisms of action and specific protocols, the approach to a potential donor including the use of complement-dependent cytotoxicity, flow cytometry, and virtual crossmatches, and peritransplant induction management.

An Analysis of 183 Heart Transplants for Pediatric or Congenital Heart Disease-Impact of High Panel Reactive Antibody

BACKGROUND

We reviewed our management strategy and outcome data for all 179 patients with pediatric and/or congenital heart disease who underwent 183 heart transplants from January 1, 2011, to December 31, 2021, and evaluated the impact of elevated panel reactive antibody (PRA).

METHODS

High PRA was defined as PRA >10%. Univariate associations with long-term survival were assessed with Cox proportional hazards models. Impact of high PRA on survival was estimated with multivariable models.

RESULTS

PRA >10% was present in 60 of 183 transplants (32.8%), who were more likely to have prior cardiac surgery, higher number of prior cardiac operations, prior sternotomy, prior heart transplant, and positive crossmatch (24 of 60 [40.0%] vs 11 of 123 [8.9%], P < .0001). Univariate associations with long-term survival include acquired heart disease vs congenital or retransplant (hazard ratio [HR], 0.18; 95% CI, 0.053-0.593; P = .005), prior cardiac surgery (HR, 5.6; 95% CI, 1.32-23.75; P = .020), number of prior cardiac operations (HR, 1.3 for each additional surgery; 95% CI, 1.12-1.50; P = .0004), single ventricle (HR, 2.4; 95% CI, 1.05-5.48; P = .038), and preoperative renal dysfunction (HR, 3.4; 95% CI, 1.43-7.49; P = .002). In multivariate analysis, high PRA does not impact survival when controlling for each of the factors shown in univariable analysis to be associated with long-term survival. The Kaplan-Meier method provided the following survival estimates at 1 year (95% CI) and 5 years (95% CI) after cardiac transplantation: All patients, 93.6% (89.9%-97.3%) and 85.8% (80.0%-92.1%); PRA <10%, 96.6% (93.4%-99.9%) and 86.7% (79.6%-94.3%); and PRA >10%, 86.7% (78.0%-96.4%) and 83.8% (74.0%-95.0%). Despite high PRA being associated with higher mortality at 1 year (14.9% vs 3.8%, P = .035), no significant difference exists in Kaplan-Meier overall survival at 5 years posttransplant in patients with and without high PRA (log-rank P = .4).

CONCLUSIONS

In our cohort, 5-year survival in patients with high PRA (PRA >10%) is similar to that in patients without high PRA (PRA <10%), despite the presence of more risk factors in those with high PRA. Individualized immunomodulatory strategies can potentially mitigate the risk of high PRA.

Preoperative Evaluation and Care of Heart Transplant Candidates

Heart transplantation is recommended for patients with advanced heart failure refractory to medical and device therapy, and who do not have absolute contraindications. When patients become eligible for heart transplantation, they undergo comprehensive evaluation and preparation to optimize their posttransplantation outcomes. This review provides an overview of the processes that are employed to enable the candidates to be transplant-ready when donor hearts are available.

A standardized definition for right ventricular failure in cardiac surgery patients

Right ventricular failure (RVF) is a significant cause of mortality and morbidity after cardiac surgery. Despite its prognostic importance, RVF remains under investigated and without a universally accepted definition in the perioperative setting. We foresee that the provision of a standardized perioperative definition for RVF based on practical and objective criteria will help to improve quality of care through early detection and facilitate the generalization of RVF research to advance this field. This article provides an overview of RVF aetiology, pathophysiology, current diagnostic modalities, as well as a summary of existing RVF definitions. This is followed by our proposal for a standardized definition of perioperative RVF, one that captures RV structural and functional abnormalities through a multimodal approach based on anatomical, echocardiographic, and haemodynamic criteria that are readily available in the perioperative setting (Central Image).

Cefazolin plus ertapenem and heart transplantation as salvage therapy for refractory LVAD infection due to methicillin-susceptible Staphylococcus aureus: A case series

The use of left ventricular assist devices (LVADs) is increasingly more common as the availability of donor organs in relation to failing hearts is outstandingly limited. Infections are the most common complications in LVAD recipients, particularly those caused by Staphylococcus spp. Refractory LVAD-related infections are not uncommon as achieving adequate source control is often not feasible before heart transplantation. Evidence suggest that cefazolin plus ertapenem is effective in refractory methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, but this approach has not been described in LVAD recipients. In this article, we report two cases of refractory MSSA bacteremia in LVAD recipients that were successfully treated with salvage therapy with cefazolin plus ertapenem and subsequent heart transplantation. This treatment strategy should be considered in patients with refractory LVAD-associated infection due to MSSA that are not responding to standard treatment.

Outcomes of pre- heart transplantation desensitization in a series of highly sensitized patients bridged with left ventricular assist devices

Desensitization therapy for heart transplantation (HT) candidates can shorten transplant wait times and broaden the donor pool. Specific evidence-based recommendations on both protocols and indications are lacking. We retrospectively assessed left ventricular assist devices-bridged candidates who received pre-HT desensitization therapy. The therapeutic protocol consisted of intravenous immunoglobulin and rituximab followed by bortezomib and plasmapheresis if an insufficient response was achieved. Desensitization was attempted in 10 patients; only 7 tolerated therapy and underwent transplant. For those patients, median decrease in unacceptable calculated panel reactive antibody was 11%; there was no significant decrease for 3 patients. Post-desensitization adverse events were observed in all patients which included coagulopathy, bone marrow suppression, and infection. Median time to first infection was 16 days. One patient had clinically significant rejection and 3 patients had uptrending donor-specific antibodies. Decisions to proceed with desensitization should be individualized understanding potential risks and benefits.

Ivabradine plus conventional treatment vs conventional treatment alone in reducing the mean heart rate in heart transplant recipients: A randomized clinical trial

The absence of afferent nerves for heart rate (HR) regulation leaves the transplanted heart under the influence of its internal and hormonal control. The HR of heart transplantation (HTx) recipients varies from to 90-110 bpm, indicating a lack of vagal parasympathetic tone. We hypothesized that the reduction in mean HR using an If-channel antagonist (ivabradine) could be effective and safe in HTx recipients. The primary objective of this open-label randomized clinical trial was to compare the mean HR at 3, 6, 12, 18, 24, 30, and 36 months after randomization between an ivabradine plus conventional treatment group (IG) and conventional treatment alone group (CG). The secondary objectives were reduction in mortality, graft dysfunction, and ventricular mass. All patients were randomized between 1 and 12 months after HTx. Ivabradine started at randomization. Of the 35 patients, 54.28% were in the CG and 45.72% in the IG. There were no significant between-group differences in demographics. Over time, the HR differences between the groups became significant (P < .01). There were no significant between-group differences in mortality, graft dysfunction, and ventricular mass. We conclude that ivabradine could effectively and consistently reduce the HR in HTx recipients.

Heart transplantation candidacy

PURPOSE OF REVIEW

Timely referral of eligible candidates for consideration of advanced therapies, such as a heart transplantation or mechanical circulatory support is essential. The characteristics of heart transplantation candidates have changed significantly over the years, leading to a more complex evaluation process. The present review summarizes recent advances in the evaluation process for heart transplantation eligibility.

RECENT FINDINGS

The heart transplantation allocation policy was recently reviewed in the USA in an effort to reduce waitlist mortality and to ensure fair geographic allocation of organs to the sickest patients. Moreover, patients with chronic infectious diseases, as well as malignancies, are being currently considered acceptable candidates for transplantation. Listing practices for heart transplantation vary between programmes, with a greater willingness to consider high-risk candidates at higher-volume centres.

SUMMARY

The ultimate decision to place high-risk candidates on the heart transplantation waitlist should be based on a combination of quantitative and qualitative data analysis informed by clinical judgement, and the chronic shortage of organ donors makes this process an important ethical concern for any society. Future guidelines should discuss approaches to achieve fair organ allocation while preserving improved outcomes after transplantation.

Heart Transplant Immunosuppression Strategies at Cedars-Sinai Medical Center

Heart transplant is the optimal treatment for selected patients with end-stage heart failure. Immunosuppression after heart transplantation has significantly reduced the incidence of rejection and improved patient outcomes with the routine use of calcineurin inhibitors. Antimetabolites and proliferation signal inhibitors add to the improvement in patient outcomes as well. The goal of induction therapy is to provide intense immunosuppression when the risk of allograft rejection is highest. Most maintenance immunosuppressive protocols employ a 3-drug regimen consisting of a calcineurin inhibitor, an antimetabolite agent and glucocorticoids. The management of rejection proceeds in a stepwise fashion based on the severity of rejection detected on biopsy and the patient's clinical presentation. This review will cover induction, maintenance, rejection therapy and some special considerations including sensitization, renal sparing protocol, and corticosteroid weaning. It will end in consideration of potential future directions in immunosuppressive strategies to promote patient and graft survival.

Gender differences in heart transplantation: Twenty-five year trends in the nationwide Spanish heart transplant registry

The study of gender differences may lead into improvement in patient care. We have aimed to identify the gender differences in heart transplantation (HT) of adult HT recipients in Spain and their evolution in a study covering the years 1993-2017 in which 6740 HT (20.6% in women) were performed. HT indication rate per million inhabitants was lower in women, remaining basically unchanged during the 25-year study period. HT rate was higher in men, although this decreased over the 25-year study period. Type of heart disease differed in men versus women (p < .001): ischemic heart disease 47.6% versus 22.5%, dilated cardiomyopathy 41.3% versus 34.6%, or other 36% versus 17.8%, respectively. Men were more frequently diabetics (18% vs. 13.1% p < .001), hypertensives (33.1% vs. 24% p < .001), and smokers (21.7% vs. 12.9% p < .001), respectively. Women had more pre-HT malignancies (7.1% vs. 2.8% p < .001), and their clinical status was worse at HT due to renal function and mechanical ventilation. Adjusted survival (p = .198) and most of the mortality-related variables were similar in men and women. Death occurred more frequently in women due to rejection (7.9% vs. 5.1% p < .001) and primary failure (18.2% vs. 12.5% p < .001) and in men due to malignancies (15.1% vs. 6.6% p < .001).

Genomic study of dilated cardiomyopathy in a group of Mexican patients using site-directed next generation sequencing

Background

Dilated cardiomyopathy (DCM) is a major cause of nonischemic heart failure and death in young adults. Next generation sequencing (NGS) has become part of the diagnostic workup in idiopathic and familial DCM. More than 50 DCM genes have been identified, revealing great molecular heterogeneity and variable diagnostic yield. Interpretation of variant pathogenicity is challenging particularly in underrepresented populations, as pathogenic variant databases include studies mainly from European/Caucasian populations. To date, no studies on genomic diagnosis of DCM have been conducted in Mexico.

Methods

We recruited 55 unrelated DCM patients, 22 familial (F‐DCM), and 33 idiopathic (I‐DCM), and performed site‐directed NGS seeking causal mutations. Diagnostic yield was defined as the proportion of individuals with at least one pathogenic (P) or likely pathogenic (LP) variant in DCM genes.

Results

Overall diagnostic yield was 47.3%, and higher in F‐DCM (63.6%) than in I‐DCM (36.4%, p = 0.047). Overall, NGS disclosed 41 variants of clinical interest (61.0% novel), 27 were classified as P/LP and 14 of unknown clinical significance. Of P/LP variants, 10 were A‐band region TTN truncating variants, five were found in DSP (18.5%), five in MYH7 (18.5%), two in LMNA (7.4%), and one in RBM20, ABCC9, FKTN, ACTA1, and TNNT2. NGS findings suggested autosomal recessive inheritance in three families, two with DSP loss of function mutations in affected individuals. The increasing number of mutation reports in DCM, increasing knowledge on the functional consequences of mutations, mutational hotspots and functional domains of DCM‐related proteins, the recent refinement ACMG/ClinGen Guidelines, and co‐segregation analysis in DCM families helped increase the diagnostic yield.

Conclusion

This is the first NGS study performed in a group of Mexican DCM patients, contributing to understand the mutational spectrum and complexity of DCM molecular diagnosis.

Impact of pretransplant antibodies on outcomes after heart transplantation

Purpose of review

Since the discovery of human leukocyte antigen (HLA) in the 1950s, there has been great interest in the role of antibodies in posttransplant rejection. The development of the lymphocyte toxicity test by Terasaki et al. in the 1960s was the first step toward understanding the role of antibodies in posttransplant rejection.

Recent findings

Subsequently, various organs have been transplanted and improving posttransplant outcomes have become a focus of research. In particular, methods to measure antibodies that affect posttransplant outcomes, including anti-HLA antibodies, and methods to desensitize patients from specific antibodies have been explored. One recent method for measuring antibodies is called the solid-phase assay, which uses purified HLA fixed to microbeads. This assay does not use donor lymphocytes and allows clinicians to test the reactivity of patient serum against a panel of antibodies. It has also enabled the identification of specific anti-HLA antibodies using a single HLA.

Summary

In addition to advances in methods to measure and analyze anti-HLA antibodies, the clinical impact of non-HLA antibodies has also received much attention recently.

The meaning of donor-specific antibodies after heart transplant

PURPOSE OF REVIEW

Antibody-mediated rejection (AMR) is a major contributor of impaired long-term survival after heart transplantation (HTx). The presence of circulating donor-specific antihuman leukocyte antigen (HLA) antibodies (DSAs) is considered as a mandatory criterion for AMR after HTx. DSA are known prognostic biomarkers of outcome, for example, recipients with de-novo DSA have a three-fold increased risk of mortality.

RECENT FINDINGS

Although the awareness of the impact and prognosis of DSA on the survival has been increased in the HTx community over the last decade, the management of DSA pre and posttransplant varies among centers and is mainly based on the experience of transplant physicians. Thus, firm consensus strategies for each HTx recipient should be established by a center advisory board of experts in the field of HLA genetics, transplantation immunology, and HTx to evaluate the immunological risk preoperatively and also continuously during the posttransplant course. Consequently, the recent advances of invasive and noninvasive diagnostic tools should be applied, according to the risk, laboratory findings, and clinical events of the recipient. Such individual strategy will result in tailored therapeutic options.

SUMMARY

Novel standards for the management of DSA in HTx recipients on the basis of an interdisciplinary approach of experts will improve diagnostics for personalized medicine.

Management of the sensitized pediatric heart transplant patient

Despite advancements in transplant immunosuppression and techniques for managing critically ill patients awaiting heart transplantation, children who are immunologically sensitized to human leukocyte antigen remain at increased risk for morbidity and mortality, both while awaiting and after heart transplant. In this review we will discuss the epidemiology of sensitization, review the immunologic basis and methods of human leukocyte antigen antibody detection, describe outcomes for sensitized pediatric transplant candidates, and consider both pre- and post-transplant management options for sensitized patients.

Emerging role of cardiac computed tomography in heart failure

Despite medical advancements, the prognosis of patients with heart failure remains poor. While echocardiography and cardiac magnetic resonance imaging remain at the forefront of diagnosing and monitoring patients with heart failure, cardiac computed tomography (CT) has largely been considered to have a limited role. With the advancements in scanner design, technology, and computer processing power, cardiac CT is now emerging as a valuable adjunct to clinicians managing patients with heart failure. In the current manuscript, we review the current applications of cardiac CT to patients with heart failure and also the emerging areas of research where its clinical utility is likely to extend into the realm of treatment, procedural planning, and advanced heart failure therapy implementation.

Strain-encoded magnetic resonance: a method for the assessment of myocardial deformation

This study aims to assess the usefulness of strain‐encoded magnetic resonance (SENC) for the quantification of myocardial deformation (‘strain’) in healthy volunteers and for the diagnostic workup of patients with different cardiovascular pathologies. SENC was initially described in the year 2001. Since then, the SENC sequence has undergone several technical developments, aiming at the detection of strain during single‐heartbeat acquisitions (fast‐SENC). Experimental and clinical studies that used SENC and fast‐SENC or compared SENC with conventional cine or tagged magnetic resonance in phantoms, animals, healthy volunteers, or patients were systematically searched for in PubMed. Using ‘strain‐encoded magnetic resonance and SENC’ as keywords, three phantom and three animal studies were identified, along with 27 further clinical studies, involving 185 healthy subjects and 904 patients. SENC (i) enabled reproducible assessment of myocardial deformation in vitro, in animals and in healthy volunteers, (ii) showed high reproducibility and substantially lower time spent compared with conventional tagging, (iii) exhibited incremental value to standard cine imaging for the detection of inducible ischaemia and for the risk stratification of patients with ischaemic heart disease, and (iv) enabled the diagnostic classification of patients with transplant vasculopathy, cardiomyopathies, pulmonary hypertension, and diabetic heart disease. SENC has the potential to detect a wide range of myocardial diseases early, accurately, and without the need of contrast agent injection, possibly enabling the initiation of specific cardiac therapies during earlier disease stages. Its one‐heartbeat acquisition mode during free breathing results in shorter cardiovascular magnetic resonance protocols, making its implementation in the clinical realm promising.

Temporal expression of cytokines and B-cell phenotypes during mechanical circulatory support

BACKGROUND

Allosensitization during mechanical circulatory support (MCS) is a well-described phenomenon, although its mechanism remains unknown. Although immune-mediated interactions from devices or blood transfusions have been proposed, the role of inflammation in this development is less clear. This study was undertaken to further investigate the temporal association of cytokines and B-cell phenotypes in the MCS population.

METHODS

Adult patients who received the Heartmate II (Thoratec, Pleasanton, Calif) at our center between September 2012 and March 2015 were prospectively followed after device implantation. Blood draws for anti-human leukocyte antigen (HLA) antibody, cytokine expression, and B-cell immunophenotyping were performed before implantation and for 3 weeks postoperatively. Time courses for cytokines and B-cell subsets were expressed using visual representations of median levels as heat maps, and mixed modeling analysis was used to model changes with time and patient factors.

RESULTS

Twenty patients who received the Heartmate II (Thoratec) were analyzed during the study period. Four patients showed measureable levels of anti-HLA antibody during the follow-up period, although 3 of these had evidence of antibodies preoperatively. Analysis of cytokine trends revealed early (interleukin [IL]-6, IL-8, and IL-10) and late peaking (IL-3, IL-4, fibroblast growth factor 2, and CD40L) patterns. Upregulation of switched memory, transitional, and plasma blast B cells occurred over time. Right ventricular assist device use and low Interagency Registry for Mechanically Assisted Circulatory Support score were associated with decreased mature naive and increased antibody-secreting cells.

CONCLUSIONS

MCS device implantation was associated with increased inflammatory cytokines and maturation of B-cell phenotypes. No patients developed de novo HLA antibodies, whereas several showed increases in anti-HLA antibody levels detected before implantation. This suggests that inflammation and maturation of existing sensitized B cells might play an important role in the pathogenesis of allosensitization in MCS.

Sensitization in Heart Transplantation: Emerging Knowledge: A Scientific Statement From the American Heart Association

Sensitization, defined as the presence of circulating antibodies, presents challenges for heart transplant recipients and physicians. When present, sensitization can limit a transplantation candidate’s access to organs, prolong wait time, and, in some cases, exclude the candidate from heart transplantation altogether. The management of sensitization is not yet standardized, and current therapies have not yielded consistent results. Although current strategies involve antibody suppression and removal with intravenous immunoglobulin, plasmapheresis, and antibody therapy, newer strategies with more specific targets are being investigated.

Double-Valve Surgery After Cardiac Retransplantation

We provide an update on Canada's first neonatal heart transplant recipient who, after cardiac retransplantation, underwent a mitral valve replacement and tricuspid valve repair. Twenty-seven years after his initial heart surgery and 13 years after his most recent transplant, this patient developed heart failure with severe mitral regurgitation secondary to a calcified mitral valve. The patient was highly sensitized with no evidence of allograft rejection; therefore, mitral and tricuspid surgery was performed. The patient did well perioperatively and remains well 18 months after surgery. To our knowledge, this novel case represents the first double-valve surgery in a patient who underwent cardiac retransplantation.

Recent advances in heart transplantation

Despite advances in medical and electrical therapies for heart failure, morbidity and mortality remain high and patients often progress to end-stage heart failure. Over the last five decades, heart transplantation is considered a standard therapy for select patients with end-stage heart failure. However, while heart transplantation has become a treatment of choice for end-stage heart failure, challenges still exist for improvement in the short- and long-term outcomes. While there is an increase in the number of patients with end-stage heart failure, the number of donor organs remains a major limiting factor. Heart transplantation candidates in the current era are also more complex: older, antigen-sensitized, and on mechanical circulatory support at the time of listing and transplant. Such potential heart transplant recipients have an increased chance of problems, including antibody-mediated rejection and primary graft dysfunction. Recent advances could address the current challenges and include: 1) attempts to expand the pool of donor hearts; 2) changes in heart transplantation allocation policy allowing for more equitable organ distribution; and 3) advances in the management of antibody sensitization. Developments in these areas could result in improved survival and quality of life for heart transplantation recipients.

The management of antibodies in heart transplantation: An ISHLT consensus document

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.

The Past, Present and Future of Heart Transplantation

Heart transplantation (HTx) has become standard treatment for selected patients with end-stage heart failure. Improvements in immunosuppressant, donor procurement, surgical techniques, and post-HTx care have resulted in a substantial decrease in acute allograft rejection, which had previously significantly limited survival of HTx recipients. However, limitations to long-term allograft survival exist, including rejection, infection, coronary allograft vasculopathy, and malignancy. Careful balance of immunosuppressive therapy and vigilant surveillance for complications can further improve long-term outcomes of HTx recipients.

Use of Anti-Thymocyte Globulin for Induction Therapy in Cardiac Transplantation: A Review

The most common causes of death after heart transplantation (HTx) include acute rejection and multi-organ failure in the early period and malignancy and cardiac allograft vasculopathy (CAV) in the late period. Polyclonal antibody preparations such as rabbit anti-thymocyte globulin (ATG) may reduce early acute rejection and the later occurrence of CAV after HTx. ATG therapy depletes T cells, modulates adhesion and cell-signaling molecules, interferes with dendritic cell function, and induces B-cell apoptosis and regulatory and natural killer T-cell expansion. Evidence from animal studies and from retrospective clinical studies in humans indicates that ATG can be used to delay calcineurin inhibitor (CNI) exposure after HTx, thus benefiting renal function, and to reduce the incidence of CAV and ischemia-reperfusion injury in the transplanted heart. ATG may reduce de novo antibody production after HTx. ATG does not appear to increase cytomegalovirus infection rates with longer prophylaxis (6-12 months). In addition, ATG may reduce the risk of lymphoproliferative disease and does not appear to confer an additive effect on acquiring lymphoma after HTx. Randomized, controlled trials may provide stronger evidence of ATG association with patient survival, graft rejection, renal protection through delayed CNI initiation, as well as other benefits. It can also help establish optimal dosing and patient criteria to maximize treatment benefits.

Ventricular assist device elicits serum natural IgG that correlates with the development of primary graft dysfunction following heart transplantation

BACKGROUND

Pre-transplant sensitization is a limiting factor in solid-organ transplantation. In heart transplants, ventricular assist device (VAD) implantation has been associated with sensitization to human leukocyte antigens (HLA). The effect of VAD on non-HLA antibodies is unclear. We have previously shown that polyreactive natural antibodies (Nabs) contribute to pre-sensitization in kidney allograft recipients. Here we assessed generation of Nabs after VAD implantation in pre-transplant sera and examined their contribution to cardiac allograft outcome.

METHODS

IgM and IgG Nabs were tested in pre-transplant serum samples collected from 206 orthotopic heart transplant recipients, including 128 patients with VAD (VAD patients) and 78 patients without VAD (no-VAD patients). Nabs were assessed by testing serum reactivity to apoptotic cells by flow cytometry and to the generic oxidized epitope, malondialdehyde, by enzyme-linked immunosorbent assay.

RESULTS

No difference was observed in serum levels of IgM Nabs between VAD and no-VAD patients. However, serum IgG Nabs levels were significantly increased in VAD compared with no-VAD patients. This increase was likely due to the presence of the VAD, as revealed by lower serum IgG Nabs levels before implantation. Elevated pre-transplant IgG Nabs level was associated with development of primary graft dysfunction (PGD).

CONCLUSIONS

Our study demonstrates that VAD support elicits IgG Nabs reactive to apoptotic cells and oxidized epitopes. These findings further support broad and non-specific B-cell activation by VAD, resulting in IgG sensitization. Moreover, the association of serum IgG Nabs levels with development of PGD suggests a possible role for these antibodies in the inflammatory reaction accompanying this complication.

Research priority setting in organ transplantation: a systematic review

Barriers to access and long-term complications remain a challenge in transplantation. Further advancements may be achieved through research priority setting with patient engagement to strengthen its relevance. We evaluated research priority setting in solid organ transplantation and described stakeholder priorities. Databases were searched to October 2016. We synthesized the findings descriptively. The 28 studies (n = 2071 participants) addressed kidney [9 (32%)], heart [7 (25%)], liver [3 (11%)], lung [1 (4%)], pancreas [1 (4%)], and nonspecified organ transplantation [7 (25%)] using consensus conferences, expert panel meetings, workshops, surveys, focus groups, interviews, and the Delphi technique. Nine (32%) reported patient involvement. The 336 research priorities addressed the following: organ donation [43 priorities (14 studies)]; waitlisting and allocation [43 (10 studies)]; histocompatibility and immunology [31 (8 studies)]; immunosuppression [21 (10 studies)]; graft-related complications [38 (13 studies)]; recipient (non-graft-related) complications [86 (14 studies)]; reproduction [14 (1 study)], psychosocial and lifestyle [49 (7 studies)]; and disparities in access and outcomes [10 (4 studies)]. The priorities identified were broad but only one-third of initiatives engaged patients/caregivers, and details of the process were lacking. Setting research priorities in an explicit manner with patient involvement can guide investment toward the shared priorities of patients and health professionals.