Redefining the molecular rejection states in 3230 heart transplant biopsies: Relationships to parenchymal injury and graft survival.

The first-generation Molecular Microscope (MMDx) system for heart transplant endomyocardial biopsies used expression of rejection-associated transcripts (RATs) to diagnose not only T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR) but also acute injury. However, the ideal system should detect rejection without being influenced by injury, to permit analysis of the relationship between rejection and parenchymal injury. To achieve this, we developed a new rejection classification in an expanded cohort of 3230 biopsies: 1641 from INTERHEART (ClinicalTrials.gov NCT02670408), plus 1589 service biopsies added to improve the power of the machine learning algorithms. The new system used 6 rejection classifiers instead of RATs and generated 7 rejection archetypes: No rejection, 48%; Minor, 24%; TCMR1, 2.3%; TCMR2, 2.7%; TCMR/mixed, 2.7%; early-stage ABMR, 3.9%; and fully developed ABMR, 16%. Using rejection classifiers eliminated cross-reactions with acute injury, permitting separate assessment of rejection and injury. TCMR was associated with severe-recent injury and late atrophy-fibrosis and rarely had normal parenchyma. ABMR was better tolerated, seldom producing severe injury, but in later biopsies was often associated with atrophy-fibrosis, indicating long-term risk. Graft survival and left ventricular ejection fraction were reduced not only in hearts with TCMR but also in hearts with severe-recent injury and atrophy-fibrosis, even without rejection.

Right ventricular dysfunction in left ventricular assist device candidates: is it time to change our prospective?

The use of left ventricular assist devices (LVAD) has significantly increased in the last years, trying to offer a therapeutic alternative to heart transplantation, in light also to the significant heart donor shortage compared to the growing advanced heart failure population. Despite technological improvements in the devices, LVAD-related mortality is still fairly high, with right heart failure being one of the predominant predictors. Therefore, many efforts have been made toward a thorough right ventricular (RV) evaluation prior to LVAD implant, considering clinical, laboratory, echocardiographic, and invasive hemodynamic parameters. However, there is high heterogeneity regarding both which predictor is the strongest as well as the relative cut-off values, and a consensus has not been reached yet, increasing the risk of facing patients in which the distinction between good or poor RV function cannot be surely reached. In parallel, due to technological development and availability of mechanical circulatory support of the RV, LVADs are being considered even in patients with suboptimal RV function. The aim of our review is to analyze the current evidence regarding the role of RV function prior to LVAD and its evaluation, pointing out the extreme variability in parameters that are currently assessed and future prospective regarding new diagnostic tools. Finally, we attempt to gather the available information on the therapeutic strategies to use in the peri-operative phase, in order to reduce the incidence of RV failure, especially in patients in which the preoperative evaluation highlighted some conflicting results with regard to ventricular function.

European Society for Organ Transplantation (ESOT) Consensus Statement on the Use of Non-invasive Biomarkers for Cardiothoracic Transplant Rejection Surveillance.

While allograft rejection (AR) continues to threaten the success of cardiothoracic transplantation, lack of accurate and repeatable surveillance tools to diagnose AR is a major unmet need in the clinical management of cardiothoracic transplant recipients. Endomyocardial biopsy (EMB) and transbronchial biopsy (TBBx) have been the cornerstone of rejection monitoring since the field's incipience, but both suffer from significant limitations, including poor concordance of biopsy interpretation among pathologists. In recent years, novel molecular tools for AR monitoring have emerged and their performance characteristics have been evaluated in multiple studies. An international working group convened by ESOT has reviewed the existing literature and provides a series of recommendations to guide the use of these biomarkers in clinical practice. While acknowledging some caveats, the group recognized that Gene-expression profiling and donor-derived cell-free DNA (dd-cfDNA) may be used to rule out rejection in heart transplant recipients, but they are not recommended for cardiac allograft vasculopathy screening. Other traditional biomarkers (NT-proBNP, BNP or troponin) do not have sufficient evidence to support their use to diagnose AR. Regarding lung transplant, dd-cfDNA could be used to rule out clinical rejection and infection, but its use to monitor treatment response is not recommended.

Relationship Between Immune Response to Severe Acute Respiratory Syndrome Coronavirus 2 Vaccines and Development of Breakthrough Infection in Solid Organ Transplant Recipients: The CONTRAST Cohort.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in solid organ transplant (SOT) recipients is associated with poorer antibody response (AbR) compared with non-SOT recipients. However, its impact on the risk of breakthrough infection (BI) has yet to be assessed. METHODS: Single-center prospective longitudinal cohort study enrolling adult SOT recipients who received SARS-CoV-2 vaccination during a 1-year period (February 2021 - January 2022), end of follow-up April 2022. Patients were tested for AbR at multiple time points. The primary end-point was BI (laboratory-confirmed SARS-CoV-2 infection ≥14 days after the second dose). Immunization (positive AbR) was considered an intermediate state between vaccination and BI. Probabilities of being in vaccination, immunization, and BI states were obtained for each type of graft and vaccination sequence using multistate survival analysis. Then, multivariable logistic regression was performed to analyze the risk of BI related to AbR levels. RESULTS: 614 SOT (275 kidney, 163 liver, 137 heart, 39 lung) recipients were included. Most patients (84.7%) received 3 vaccine doses. The first 2 consisted of BNT162b2 and mRNA-1273 in 73.5% and 26.5% of cases, respectively. For the third dose, mRNA-1273 was administered in 59.8% of patients. Overall, 75.4% of patients reached immunization and 18.4% developed BI. Heart transplant recipients showed the lowest probability of immunization (0.418) and the highest of BI (0.323); all mRNA-1273 vaccine sequences showed the highest probability of immunization (0.732) and the lowest of BI (0.098). Risk of BI was higher for non-high-level AbR, younger age, and shorter time from transplant. CONCLUSIONS: SOT patients with non-high-level AbR and shorter time from transplantation and heart recipients are at highest risk of BI.

Does therapeutic drug monitoring (TDM) of trough concentrations suffice for optimizing preemptive therapy with ganciclovir of cytomegalovirus infections in non-renal solid organ transplant recipients?

OBJECTIVES: The aim of this study is to explore the relationship between ganciclovir exposure and clinical efficacy and/or safety in non-renal solid organ transplant (SOT) recipients receiving preemptive therapy with ganciclovir/valganciclovir and undergoing therapeutic drug monitoring (TDM)-guided dosing optimization. METHODS: Non-renal SOT recipients admitted to IRCCS Azienda Ospedaliero-Universitaria of Bologna receiving preemptive therapy with ganciclovir or valganciclovir for active cytomegalovirus (CMV) infection and who underwent at least one TDM were included. Desired ganciclovir Cmin range was set at 1-3 mg/L, and average ganciclovir trough concentrations (Cmin ) were calculated for each patient. Reduced CMV viral load below the lower limit of quantification (LLQ) at 30 days and occurrence of myelotoxicity were selected as the primary outcome. Univariate analysis was performed by comparing patients with average Cmin below or above 1 or 3 mg/L. Receiver operating characteristic (ROC) curve analysis was performed to identify the average ganciclovir Cmin cut-off predictive for clinical efficacy or toxicity. RESULTS: Twenty-nine out of 89 retrieved patients met the inclusion criteria, with a median (interquartile [IQR]) baseline CMV viral load of 27,163 copies/mL (IQR 13 159.75-151 340.25 copies/mL). Reduced CMV viral load below the LLQ at 30 days was found in 17 patients (58.6%). No difference was found in the primary outcome between patients showing average Cmin below or above 1 mg/L (100.0% vs. 53.8%; p = .25) and/or 3 mg/L (65.2% vs. 33.3%; p = .20). ROC analysis did not allow to identify an average Cmin cut-off predictive of clinical efficacy or toxicity. CONCLUSIONS: No clear relationship between ganciclovir Cmin and neither CMV eradication nor safety issues was identified.

Heart transplantation: focus on donor recovery strategies, left ventricular assist devices, and novel therapies.

Heart transplantation is advocated in selected patients with advanced heart failure in the absence of contraindications. Principal challenges in heart transplantation centre around an insufficient and underutilized donor organ pool, the need to individualize titration of immunosuppressive therapy, and to minimize late complications such as cardiac allograft vasculopathy, malignancy, and renal dysfunction. Advances have served to increase the organ donor pool by advocating the use of donors with underlying hepatitis C virus infection and by expanding the donor source to use hearts donated after circulatory death. New techniques to preserve the donor heart over prolonged ischaemic times, and enabling longer transport times in a safe manner, have been introduced. Mechanical circulatory support as a bridge to transplantation has allowed patients with advanced heart failure to avoid progressive deterioration in hepato-renal function while awaiting an optimal donor organ match. The management of the heart transplantation recipient remains a challenge despite advances in immunosuppression, which provide early gains in rejection avoidance but are associated with infections and late-outcome challenges. In this article, we review contemporary advances and challenges in this field to focus on donor recovery strategies, left ventricular assist devices, and immunosuppressive monitoring therapies with the potential to enhance outcomes. We also describe opportunities for future discovery to include a renewed focus on long-term survival, which continues to be an area that is under-studied and poorly characterized, non-human sources of organs for transplantation including xenotransplantation as well as chimeric transplantation, and technology competitive to human heart transplantation, such as tissue engineering.

Pretransplant Right Ventricular Dysfunction Is Associated With Increased Mortality After Heart Transplantation: A Hard Inheritance to Overcome.

BACKGROUND: Right ventricular dysfunction (RVD) is a major issue in patients with advanced heart failure because it precludes the implantation of left ventricular assist device, usually leaving heart transplantation (HTx) as the only available treatment option. The pulmonary artery pulsatility index (PAPi) is a hemodynamic parameter integrating information of right ventricular function and of pulmonary circulation. Our aim is to evaluate the association of preoperative RVD, hemodynamically defined as a low PAPi, with post-HTx survival. METHODS AND RESULTS: Consecutive adult HTx recipient at 2 Italian transplant centers between 2000 and 2018 with available data on pre-HTx right heart catheterization were included retrospectively. RVD was defined as a value of PAPi lower than the 25th percentile of the study population. The association of RVD with the 1-year post-HTx mortality and other secondary end points were evaluated. Multivariate logistic regression was used to adjust for clinical and hemodynamic variables. Analyses stratified by pulmonary vascular resistance (PVR) status (≥3 Woods units vs <3 Woods units) were also performed. Among 657 HTx recipients (female 31.1%, age 53 ± 11 years), patients with pre-HTx RVD (PAPi of <1.68) had significantly lower 1-year survival rates (77.8% vs 87.1%, P = .005), also after adjusting for estimated glomerular filtration rate, total bilirubin, PVR, serum sodium, inotropes, and mechanical circulatory support at HTx (hazard ratio 2.0, 95% confidence interval, 1.3-3.1). RVD was also associated with post-HTx renal replacement therapy (hazard ratio 2.0, 95% confidence interval 1.05-3.30) and primary graft dysfunction (hazard ratio 1.7, , 95% confidence interval 1.02-3.30). When stratifying patients by estimated PVR status, RVD was associated with worse 1-year survival among patients with normal PVR (76.9% vs 88.3%, P = .003), but not in those with increased PVR (78.6% vs 83.2%, P = .49). CONCLUSIONS: Preoperative RVD, evaluated through PAPi, is associated with mortality and morbidity after HTx, providing incremental prognostic value over traditional clinical and hemodynamic parameters.

Cytomegalovirus Management in Solid Organ Transplant Recipients: A Pre-COVID-19 Survey From the Working Group of the European Society for Organ Transplantation.

Infections are leading causes of morbidity/mortality following solid organ transplantation (SOT) and cytomegalovirus (CMV) is among the most frequent pathogens, causing a considerable threat to SOT recipients. A survey was conducted 19 July-31 October 2019 to capture clinical practices about CMV in SOT recipients (e.g., how practices aligned with guidelines, how adequately treatments met patients' needs, and respondents' expectations for future developments). Transplant professionals completed a ∼30-minute online questionnaire: 224 responses were included, representing 160 hospitals and 197 SOT programs (41 countries; 167[83%] European programs). Findings revealed a heterogenous approach to CMV diagnosis and management and, sometimes, significant divergence from international guidelines. Valganciclovir prophylaxis (of variable duration) was administered by 201/224 (90%) respondents in D+/R- SOT and by 40% in R+ cases, with pre-emptive strategies generally reserved for R+ cases: DNA thresholds to initiate treatment ranged across 10-10,000 copies/ml. Ganciclovir-resistant CMV strains were still perceived as major challenges, and tailored treatment was one of the most important unmet needs for CMV management. These findings may help to design studies to evaluate safety and efficacy of new strategies to prevent CMV disease in SOT recipients, and target specific educational activities to harmonize CMV management in this challenging population.

ESOT Consensus Platform for Organ Transplantation: Setting the Stage for a Rigorous, Regularly Updated Development Process.

The European Society for Organ Transplantation (ESOT) has created a platform for the development of rigorous and regularly updated evidence based guidelines for clinical practice in the transplantation field. A dedicated Guideline Taskforce, including ESOT-council members, a representative from the Centre for Evidence in Transplantation, editors of the journal Transplant International has developed transparent procedures to guide the development of guidelines, recommendations, and consensus statements. During ESOT's first Consensus Conference in November 2022, leading experts will present in-depth evidence based reviews of nine themes and will propose recommendations aimed at reaching a consensus after public discussion and assessment by an independent jury. All recommendations and consensus statements produced for the nine selected topics will be published including the entire evidence-based consensus-finding process. An extensive literature review of each topic was conducted to provide final evidence and/or expert opinion.

Multiple organ retrieval in a brain dead left ventricular assist device donor.

Left ventricular assist device (LVAD) support in donors may contribute in preserving proper haemodynamics and systemic perfusion during organ retrieval thus decreasing the risk of multiple organ injury. This is an option to expand the current organ supply. We report on intra-abdominal organs procurement strategy in a selected LVAD recipient who suffered a fatal cerebrovascular accident at the time of COVID-19 pandemic outbreak. The liver and kidneys grafts have been successfully transplanted.

Impact of prior sternotomy on survival and allograft function after heart transplantation: A single center matched analysis.

BACKGROUND: Orthotopic heart transplantation (OHT) remains the gold standard for the treatment of end-stage heart failure. The number of patients who have had at least one prior sternotomy while awaiting transplantation has increased over the years reaching 50% in the last ISHLT registry report. We analysed our institutional transplant activity focusing on prior-sternotomy setting to identify the real burden of this preoperative variable and its potential consequences. METHODS: Between 2000 and 2020, a total of 512 consecutive adult patients underwent OHT. We divided them into two groups according to the previous sternotomy variable: a prior sternotomy group (PS-group, n = 131, 25.6%) and a heart transplant as first sternotomy group (FS-group, n = 381, 74.4%). After propensity score matching, a total of 106 matched-pairs were identified for the final analysis. RESULTS: The overall 30-day mortality was similar in the two groups (7.5% vs. 5.7%, p = .58). The prior sternotomy was not an independent risk factor for 90-day mortality (odds ratio: 0.89, p = .81). In the matched sample, prior cardiac surgery was not predictive for any major postoperative complication: primary graft failure, AKI, bleeding, acute respiratory insufficiency, need for extra-corporeal life support (p > .05). The log-rank test revealed no significant difference between the two groups in the unmatched and matched pools (p = .93 and 0.69 respectively. At univariable analysis prior sternotomy was not associated with an increased risk of posttransplant mortality (hazard ratio: 0.87, p = .599). CONCLUSIONS: Despite it increases surgical complexity, the reoperation alone does not represent a proper risk factor and among different co-variates that may affect post-OHT outcomes.

Overcoming challenges in patient selection and monitoring in combined heart and kidney transplantation.

Combined heart-kidney transplantation (HKT) is a growing therapeutic strategy in patients with advanced heart failure (HF) and concomitant chronic kidney disease (CKD). Although patients with advanced HF and need for chronic haemodialysis have a clear indication for combined HKT, challenges to current practice lie in identifying those patients with severely depressed kidney function, which will not recover kidney function after restoration of appropriate haemodynamic conditions following heart transplantation (HT) alone. Because of the paucity of available organs, maximisation of kidney graft utility whilst minimising the operative risks associated with combined transplantation is mandatory. The benefits of HKT go beyond the mere restoration of kidney function. Data from registry analysis show that HKT improves overall survival in patients with CKD, as compared to heart transplant only, and it is associated with reduced incidence of heart allograft rejection, likely through the promotion of host immune tolerance mechanisms. In patients not requiring chronic dialysis, kidney-after-heart strategy may be explored, instead of combined HKT, in particular when the aetiology of CKD is unclear. This indeed allows for monitoring and gaging of indications for combined transplantation in the postoperative period. This approach however should be matched with priority listing for kidney transplantation given the high waitlist mortality in heart transplant recipients with associated CKD. The use of kidney machine perfusion may represent an additional tool to optimise the outcome of HKT, allowing more time to stabilise the patient after HT surgery.

miR-21 antagonism reprograms macrophage metabolism and abrogates chronic allograft vasculopathy.

Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.

COVID-19 and education: restructuring after the pandemic.

COVID-19 challenges to keep a valuable educational offer with lockdown measures and social distancing are reviewed. Scientific Societies had to think of new alternatives to maintain meetings with conversion to a virtual format and development of online resources, rapidly available and broadly accessible. Other in person activities as face-to-face clinics have been substituted by telemedicine; the same happened with surgical training in theatre, given the suspension of most of the operations. Finally, the need to share and communicate in a continuous evolving scenario, has impacted negatively the integrity of peer review process, not following the normal procedures to ensure scientific integrity and reproducibility in the earliest phases of the pandemic.

Longest reported support (7.5 years) with postauricular type of Jarvik 2000 axial-flow left ventricular assist device.

Mechanical circulatory supports with left ventricular assist devices (LVAD) are nowadays an established treatment in end-stage heart failure for those patients who are waiting for an organ donation or are unsuitable for transplantation. The duration of LVAD support is variable, depending on the device, the intention to treat and the issues occurring during treatment, which can change the purpose treatment or accelerate the transplantation. Moreover, length of reported supports in the literature is heterogenous. In here, we present the clinical and surgical case of the longest LVAD support reported in the literature, as a bridge to transplantation, with axial pump Jarvik 2000 (Jarvik Heart, Inc, New York, NY).

Right Heart Catheterization in Patients with Advanced Heart Failure: When to Perform? How to Interpret?

Right heart catheterization is an established cornerstone of advanced heart failure management, as a clear understanding of the patient's hemodynamic status offers insight into diagnosis, prognosis, and management. In this review, the authors will describe the role of right heart catheterization in the diagnosis and management of shock, in the context of left ventricular assist devices, in the assessment of heart transplant candidacy, and also explore future directions of implantable monitoring devices for pulmonary artery and left atrial pressure monitoring.

Postoperative outcomes following rehabilitation in patients with left ventricular assist devices.

Postoperative rehabilitation is a cornerstone of the recovery pathway following left ventricular assist device implantation (LVAD), and patients are expected to conduct an autonomous life thanks to improved technology and increased knowledge of mechanical circulatory support. The primary purpose of the present study was to quantify clinical changes related to rehabilitation, in patients with LVAD: functional capacity, disability, and quality of life were identified as reliable outcomes to detect such changes. The current study was a scoping review conducted searching three primary databases, namely PubMed, Scopus, and Cochrane Library, from their inception until January 2020. After the selection process was completed, 12 citations were included in the present study. Three hundred eight three patients were included in the current analysis. Functional capacity, disability, and quality of life were investigated in 157, 215, 18 patients, respectively. Significant differences were found before and after rehabilitation. The mean walked distance at 6-Minute Walk Test improved from 319±96 to 412.8±86.2 metres (p<0.001), the mean score of the Functional Independence Measure from 68.4±11.8 to 92.5±10.8 points (p<0.001), the mean score of the Short Form-36 physical component from 32.7±29.9 to 55.5±24.7 points (p=0.009) and the mental component from 55.8±19.8 to 75.4±21.4 points (p=0.002). Postoperative rehabilitation is effective at improving functional capacity, disability, and quality of life in patients with left ventricular assist device; all these three domains are particularly expressive of the entity of patients' functional recovery.

Does the antibody mediated rejection grading scale have prognostic prediction? Yes, but the picture is still blurry.

PURPOSE OF REVIEW: Antibody-mediated rejection (ABMR) is a condition difficult to diagnose and treat, which may significantly impair the outcome of heart transplant recipients. In clinical practice, diagnosis is based on immunopathology grading of endomyocardial biopsies (EMB). Despite its value, the current diagnostic system has several pitfalls that have been addressed in recent literature. RECENT FINDINGS: Pathology grading of ABMR (pAMR) has a relevant prognostic factor. However, it does not capture several nuances, such as chronic vs. acute ABMR, mixed rejection or microvascular inflammation. Molecular biology-based assays are shedding new light on the mechanisms of ABMR, which could improve the precision of ABMR diagnosis. SUMMARY: These new findings have the potential to rearrange EMB grading system and to guide more precisely decision-making, but studies validating the therapeutic management based on molecular-pathology coupling are still missing.

Monitoring of Cytomegalovirus (CMV)-Specific Cell-Mediated Immunity in Heart Transplant Recipients: Clinical Utility of the QuantiFERON-CMV Assay for Management of Posttransplant CMV Infection.

The clinical utility of the QuantiFERON-CMV (QFN-CMV) assay in heart transplant recipients was assessed. Forty-four cytomegalovirus (CMV)-seropositive patients were enrolled: 17 received antiviral prophylaxis, and 27 were managed preemptively. CMV-DNAemia monitoring was performed by the use of a quantitative real-time PCR assay. The QFN-CMV assay was retrospectively performed on blood samples collected at five posttransplant time points. A higher proportion of patients with an indeterminate QFN-CMV result after the suspension of prophylaxis than of patients who showed a global T-cell responsiveness developed CMV infection (P = 0.036). Patients who reconstituted a CMV-specific response following the first CMV-DNAemia-positive result (42.9%) showed a median CMV-DNAemia peak 1 log of magnitude lower than that seen with patients with indeterminate results, and all controlled viral replication spontaneously. The 25% of patients with an indeterminate result developed CMV disease. In the preemptive strategy group, no differences in the development of subsequent infection, magnitude of viral load, and viral control were observed on the basis of QFN-CMV measurements performed before and after the first CMV-DNAemia-positive result. Considering both CMV prevention strategies, viral relapse was associated with the failure to reconstitute CMV-specific cell-mediated immunity (CMI) after the resolution of the first episode of CMV infection (P = 0.032). QFN-CMV measurements can be a useful tool for identifying patients (i) at higher risk of developing infection after discontinuing antiviral prophylaxis, (ii) with late CMV infection who would benefit from appropriate antiviral interventions, and (iii) at higher risk of viral relapses. QFN-CMV measurements taken within 1 month posttransplantation (early period) are not revealing.