The International Consortium on Primary Graft Dysfunction: Redefining Clinical Risk Factors in the Contemporary Era of Heart Transplantation.

BACKGROUND: Primary graft dysfunction (PGD) is the leading cause of morbidity and mortality early after heart transplantation (HT). The International Consortium on PGD is a multicenter collaboration dedicated to identifying the clinical risk factors for PGD in the contemporary era of HT. The objectives of the current report were (1) to assess the incidence of severe PGD in an international cohort; (2) to evaluate the performance of the most strongly validated PGD risk tool, the RADIAL score, in a contemporary cohort; and (3) to redefine clinical risk factors for severe PGD in the current era of HT. METHODS: This is a retrospective, observational study of consecutive adult HT recipients between 2010 and 2020 in 10 centers in the United States, Canada and Europe. Patients with severe PGD were compared to those without severe PGD (comprising those with no, mild and moderate PGD). The RADIAL score was calculated for each transplant recipient. The discriminatory power of the RADIAL score was evaluated using receiver operating characteristic (ROC) analysis, and its calibration was assessed by plotting the percentage of PGD predicted vs that which was observed. To identify clinical risk factors associated with severe PGD, we performed multivariable mixed-effects logistic regression modeling to account for among-center variability. RESULTS: A total of 2746 patients have been enrolled in the registry to date, including 2015 (73.4%) from North America, and 731 (26.6%) from Europe; 215 participants (7.8%) met the criteria for severe PGD. There was an increase in the incidence of severe PGD over the study period (P value for trend by difference sign test = 0.004). The Kaplan-Meier estimate for 1-year survival was 75.7% (95% CI 69.4-80.9%) in patients with severe PGD as compared to 94.4% (95% CI 93.5-95.2%) in those without severe PGD (log-rank P value < 0.001). The RADIAL score performed poorly in our contemporary cohort and was not associated with severe PGD; it had an AUC of 0.53 (95% CI 0.48-0.58). In the multivariable regression model, acute preoperative dialysis (OR 2.41, 95% CI 1.31-4.43), durable left ventricular assist device support (OR 1.77, 95% CI 1.13-2.77), and total ischemic time (OR 1.20 for each additional hour, 95% CI 1.02-1.41) were associated with an increased risk of severe PGD. CONCLUSIONS: Our consortium has identified an increasing incidence of PGD in the modern transplant era. We identified contemporary risk factors for this early post-transplant complication, which confers a high mortality risk. These results may enable the identification of patients at high risk for developing severe PGD in order to inform peri-transplant donor and recipient management practices.

The XIIIth Banff Conference on Allograft Pathology: The Banff 2015 Heart Meeting Report: Improving Antibody-Mediated Rejection Diagnostics: Strengths, Unmet Needs, and Future Directions.

The 13th Banff Conference on Allograft Pathology was held in Vancouver, British Columbia, Canada from October 5 to 10, 2015. The cardiac session was devoted to current diagnostic issues in heart transplantation with a focus on antibody-mediated rejection (AMR) and small vessel arteriopathy. Specific topics included the strengths and limitations of the current rejection grading system, the central role of microvascular injury in AMR and approaches to semiquantitative assessment of histopathologic and immunophenotypic indicators, the role of AMR in the development of cardiac allograft vasculopathy, the important role of serologic antibody detection in the management of transplant recipients, and the potential application of new molecular approaches to the elucidation of the pathophysiology of AMR and potential for improving the current diagnostic system. Herein we summarize the key points from the presentations, the comprehensive, open and wide-ranging multidisciplinary discussion that was generated, and considerations for future endeavors.

Inflammatory cell burden and phenotype in endomyocardial biopsies with antibody-mediated rejection (AMR): a multicenter pilot study from the AECVP.

This multicenter case-controlled pilot study evaluated myocardial inflammatory burden (IB) and phenotype in endomyocardial biopsies (EMBs) with and without pathologic antibody-mediated rejection (pAMR). Sixty-five EMBs from five European heart transplant centers were centrally reviewed as positive (grade 2, n = 28), suspicious (grade 1, n = 7) or negative (n = 30) for pAMR. Absolute counts of total, intravascular (IV) and extravascular (EV) immunophenotyped mononuclear cells were correlated with pAMR grade, capillary C4d deposition, donor specific antibody (DSA) status and acute cellular rejection (ACR). In pAMR+ biopsies, equivalent number of IV CD3+ T lymphocytes (23 ± 4/0.225 mm(2) ) and CD68+ macrophages (21 ± 4/0.225 mm(2) ) were seen. IB and cell phenotype correlated with pAMR grade, C4d positivity and DSA positivity (p < 0.0001). High numbers of IV T lymphocytes were associated with low grade ACR (p = 0.002). In late-occurring AMR EV plasma cells occurring in 34% of pAMR+ EMBs were associated with higher IB. The IB in AMR correlated with pAMR+, C4d positivity and DSA positivity. In pAMR+ equivalent numbers of IV T lymphocytes and macrophages were found. The presence of plasma cells was associated with a higher IB and occurrence of pAMR late after transplantation.

Differential effect of everolimus on progression of early and late cardiac allograft vasculopathy in current clinical practice.

Randomized trials showed that mTOR inhibitors prevent early development of cardiac allograft vasculopathy (CAV). However, the action of these drugs on CAV late after transplant is controversial, and their effectiveness for CAV prevention in clinical practice is poorly explored. In this observational study we included 143 consecutive heart transplant recipients who underwent serial intravascular ultrasound (IVUS), receiving either everolimus or mycophenolate as adjunctive therapy to cyclosporine. Ninety-one recipients comprised the early cohort, receiving IVUS at weeks 3-6 and year 1 after transplant, and 52 the late cohort, receiving IVUS at years 1 and 5 after transplant. Everolimus independently reduced the odds for early CAV (0.14 [0.01-0.77]; p = 0.02) but it did not appear to influence late CAV progression. High-dose statins were found to be associated with reduced CAV progression both early and late after transplant (p ≤ 0.05). Metabolic abnormalities, such as high triglycerides, were associated with late, but not with early CAV progression. By highlighting a differential effect of everolimus and metabolic abnormalities on early and late changes of graft coronary morphology, this observational study supports the hypothesis that everolimus may be effective for CAV prevention but not for CAV treatment, and that risk factors intervene in a time-dependent sequence during CAV development.

Everolimus versus mycophenolate mofetil in heart transplantation: a randomized, multicenter trial.

In an open-label, 24-month trial, 721 de novo heart transplant recipients were randomized to everolimus 1.5 mg or 3.0 mg with reduced-dose cyclosporine, or mycophenolate mofetil (MMF) 3 g/day with standard-dose cyclosporine (plus corticosteroids ± induction). Primary efficacy endpoint was the 12-month composite incidence of biopsy-proven acute rejection, acute rejection associated with hemodynamic compromise, graft loss/retransplant, death or loss to follow-up. Everolimus 1.5 mg was noninferior to MMF for this endpoint at month 12 (35.1% vs. 33.6%; difference 1.5% [97.5% CI: -7.5%, 10.6%]) and month 24. Mortality to month 3 was higher with everolimus 1.5 mg versus MMF in patients receiving rabbit antithymocyte globulin (rATG) induction, mainly due to infection, but 24-month mortality was similar (everolimus 1.5 mg 10.6% [30/282], MMF 9.2% [25/271]). Everolimus 3.0 mg was terminated prematurely due to higher mortality. The mean (SD) 12-month increase in maximal intimal thickness was 0.03 (0.05) mm with everolimus 1.5 mg versus 0.07 (0.11) mm with MMF (p < 0.001). Everolimus 1.5 mg was inferior to MMF for renal function but comparable in patients achieving predefined reduced cyclosporine trough concentrations. Nonfatal serious adverse events were more frequent with everolimus 1.5 mg versus MMF. Everolimus 1.5 mg with reduced-dose cyclosporine offers similar efficacy to MMF with standard-dose cyclosporine and reduces intimal proliferation at 12 months in de novo heart transplant recipients.

Everolimus is associated with a reduced incidence of cytomegalovirus infection following de novo cardiac transplantation.

BACKGROUND: Cytomegalovirus (CMV) causes several complications following cardiac transplantation including cardiac allograft vasculopathy. Previous studies suggested that immunosuppressive treatment based on everolimus might reduce CMV infection. Aiming to better characterize the action of everolimus on CMV and its interplay with patient/recipient serology and anti-CMV prophylaxis, we analyzed data from 3 large randomized studies comparing various everolimus regimens with azathioprine (AZA)- and mycophenolate mofetil (MMF)-based regimens. METHODS: CMV data were analyzed from 1009 patients in 3 trials of de novo cardiac transplant recipients who were randomized to everolimus 1.5 mg/day, everolimus 3 mg/day, or AZA 1-3 mg/kg/day, plus standard-dose (SD) cyclosporine (CsA; study B253, n = 634); everolimus 1.5 mg/day plus SD- or reduced-dose (RD)-CsA (study A2403, n = 199); and everolimus 1.5 mg/day plus RD-CsA or MMF plus SD-CsA (study A2411, n = 176). RESULTS: In study B253, patients allocated to everolimus experienced almost a 70% reduction in odds of experiencing CMV infection compared with AZA (P < 0.001). In study A2403, CMV infection was low in both everolimus arms, irrespective of CsA dosing, and in study A2411, patients allocated to everolimus experienced an 80% reduction in odds of experiencing CMV infection, compared with MMF (P < 0.001). CMV syndrome/disease was rare and less frequent in everolimus-treated patients. Subgroup analyses showed that the benefit everolimus provides, in terms of CMV events, is retained in CMV-naïve recipients and is independent of anti-CMV prophylaxis or preemptive approaches. CONCLUSIONS: Everolimus is associated with a lower incidence of CMV infection compared with AZA and MMF, which combined with its immunosuppressive efficacy and antiproliferative effects may positively impact long-term outcomes.

Proliferation signal inhibitors and post-transplant malignancies in heart transplantation: practical clinical management questions.

Although malignancy is a major threat to long-term survival of heart transplant (HT) recipients, clear strategies to manage immunosuppression in these patients are lacking. Several lines of evidences support the hypothesis of an anticancer effect of proliferation signal inhibitors (PSIs: mammalian target of rapamycin [mTOR] inhibitors) in HT recipients. This property may arise from PSI's ability to replace immunosuppressive therapies that promote cancer progression, such as calcineurin inhibitors or azathioprine, and/or through their direct biological actions in preventing tumor development and progression. Given the lack of randomized studies specifically exploring these issues in the transplant setting, a collaborative group reviewed current literature and personal clinical experience to reach a consensus aimed to provide practical guidance for the clinical conduct in HT recipients with malignancy, or at high risk of malignancy, with a special focus on advice relevant to potential role of PSIs.

Changes in exercise capacity induced by heart transplantation: prognostic and therapeutic implications.

Survival and exercise performance are key targets of heart transplantation (HT). We designed this study to help in identifying (1) patients with chronic heart failure (CHF) at risk of poor exercise capacity after HT and (2) HT recipients presenting risk factors modifiable with exercise showing a potential impact on outcome. We enrolled 49 HT recipients (age 52 ± 12 years, 84% males) who underwent a cardiopulmonary exercise test before (9 ± 6 months) and after (20 ± 14 months) HT. In the CHF phase, lower peak oxygen consumption (VO(2) ) (odds ratio 0.69, P=0.017) independently predicted peak VO(2) improvement after HT. In the post-HT phase, body mass index (BMI) [adjusted hazard ratio (HR) 1.16, P=0.034] and VE (ventilation)/VCO(2) (carbon dioxide production) slope (adjusted HR 1.07, P=0.031) independently predicted mortality. In conclusion, CHF patients with only a moderate impairment of peak VO(2) are at a risk of failing to achieve a significant improvement of exercise performance after HT. In the post-HT phase, a BMI≥28 and/or a VE/VCO(2) slope ≥47 represent risk factors for death, which are potentially modifiable with exercise. Prospective randomized studies are needed to analyze the effects of training on functional capacity and outcome in the different subsets of HT recipients.

Prevalence of substance-related disorders in heart transplantation candidates.

Substance abuse cessation is one of the leading factors in determining the eligibility for the heart transplantation waiting list, as noncompliance with this issue may seriously endanger posttransplantation outcomes. Yet, the prevalence of substance-related disorders among candidates for heart transplantation has not been evaluated enough. Eighty three heart transplantation candidates were assessed for prior or current substance-related disorders through the Structured Clinical Interview for mental disorders according to DSM-IV. A prior history of at least one substance-related disorder was found in 64% of patients, with nicotine dependence as the most prevalent diagnosis (61.4% of the sample). Ten subjects were currently smokers, despite heart failure. A prior history of alcohol abuse and caffeine intoxication was found in 9.6% and 2.4% of patients, respectively. Substance abuse or dependence behaviors should be monitored during all the phases of heart transplantation program. Early identification of current substance-related disorders may allow better allocation of organ resources and proper lifestyle modification programs provision. A prior history of substance-related disorders should alert physicians to assess patients for possible relapse, especially after transplantation. The inclusion of a specialist in the assessment and treatment of substance-related disorders in the heart transplantation unit may reduce the risk of unsuccessful outcomes due to noncompliance with an adequate lifestyle.

Long-term safety and effectiveness of statins for heart transplant recipients in routine clinical practice.

BACKGROUND: Whereas the efficacy of statins after heart transplantation (HT) in controlled study settings has been clearly demonstrated, more extensive data are required on the safety and effectiveness of long-term treatment in routine clinical practice. METHODS: We analyzed the risks and benefits in clinical practice of treatment with statins in all patients who survived HT for at least a month from December 1985 through 2001. RESULTS: During a mean follow-up of 4.8+/-3.8 years, 186 patients were treated with statins (for a median duration [25th to 75th percentile] of 29 [12 to 54] months), while 48 received dietary therapy alone. Patients treated with statins (pravastatin, 48%; atorvastatin, 37%; simvastatin, 14%) presented linearized rates of rhabdomyolisis, myositis, and significant transaminase elevation of 0.37%, 0.74%, and 0.37% per year of treatment, respectively (no fatal event occurred). Low-density lipoprotein decreased after statins by 19% (P<.001). At multivariate analysis, treatment with statins was independently associated with reduced risk of cardiac allograft vasculopathy and overall mortality (P<.001). CONCLUSIONS: Our data provide necessary confirmation of the safety and effectiveness in routine clinical practice of appropriately monitored long-term administration of statins (particularly atorvastatin, pravastatin, and simvastatin) in the chronic post-HT phase. Strict follow-up is needed for HT recipients receiving high doses of statins with/without other medications potentially exacerbating the risk of adverse effects.

Folate supplementation after heart transplantation: effects on homocysteine plasma levels and allograft vascular disease.

BACKGROUND AND AIMS: After heart transplantation, the effects of folate supplementation on total homocysteine plasma levels (THcy) and heart allograft vascular disease (AVD) remain unclear. METHODS: Accordingly, we prospectively analyzed 48 heart transplant receipients referred for routine follow-up from July to September 1998 (age 54+/-11 years, 75% male, 35+/-27 months from transplant). Among these patients, 17 were treated with folate supplementation for 12 months (Group F), while 31 cross-matched for age, gender, serum creatinine and time from transplant (P>0.3 vs Group F for all) did not assume folate supplementation (Group NF). Routine coronary angiography for AVD detection was routinely obtained in every patient. RESULTS: THcy overall increased during the study period (from 16.6+/-6.5 to 19.4+/-7.6 micromol/l, P<0.001), and a strong trend toward higher THcy was observed in patients presenting AVD (22.4+/-8.7 vs 17.6+/-6.8 micromol/l, P=0.051). After 12 months THcy was lower in Group F as compared to Group NF (16.2+/-5.6 vs 21.1+/-8.1 micromol/l, respectively, P=0.033). CONCLUSIONS: Our results demonstrate that THcy increases over time in heart transplant recipients, and a strong trend toward higher THcy is observed in the presence of AVD. Since folate supplementation appears to positively influence THcy, a favorable effect of folate on AVD can be hypothesized.

Interplay between methylenetetrahydrofolate reductase gene polymorphism 677C-->T and serum folate levels in determining hyperhomocysteinemia in heart transplant recipients.

BACKGROUND: Homocysteine metabolism is often impaired in heart transplant recipients, and increased total homocysteine plasma levels may constitute a risk factor for the development of heart allograft vascular disease. Although 677C-->T transition in methylenetetrahydrofolate reductase (MTHFR) is associated with increased homocysteine levels in the general population, it is unclear whether MTHFR polymorphism influences homocysteine metabolism after heart transplant. METHODS: Homocysteine, serum folate, renal function, concentrations of cyclosporine and its metabolites, and MTHFR genotype were determined in 57 heart transplant recipients (age, 55 +/- 11 yr; 21% women; time from transplant, 48 +/- 42 months). RESULTS: Forty nine percent of the study population presented with hyperhomocysteinemia. Homocysteine was 17.1 +/- 5.9 micromol/liter, 19.4 +/- 4.9 micromol/liter, and 26.3 +/- 14.2 micromol/liter for genotypes CC, CT, and TT, respectively (p = 0.028, Kruskal-Wallis test). At multivariate analysis, MTHFR genotype was independently associated with homocysteine (p = 0.005). When the study population was divided into 2 groups accordingly to serum folate levels (above/below the median value of 6.1 ng/ml), MTHFR genotype remained a significant predictor of homocysteine only in patients with low serum folate (p = 0.048). CONCLUSIONS: This study demonstrates that hyperhomocysteinemia is frequent in heart transplant recipients and that the 677C-->T transition in the MTHFR gene independently and unfavorably influences homocysteine metabolism in this group of patients. Adequate folate intake may overcome genetic predisposition to hyperhomocysteinemia.

[Familial predisposition to ischemic cardiopathy: role of homocysteine and genetic polymorphism of methylenetetrahydrofolate reductase]. / La predisposizione familiare alla cardiopatia ischemica: ruolo dell'omocisteina e del polimorfismo genetico della metilenetetraidrofolato reduttasi.

Homocysteine represents a risk factor for coronary artery disease determined not only by nutritional habits, but also by the genetic polymorphism of the enzymes involved in its metabolism (i.e. methylenetetrahydrofolate reductase - MTHFR). However, recent prospective studies questioned the initial evidence of a clear epidemiological and pathogenetic link between homocysteine levels and coronary artery disease. Moreover, the relationships between MTHFR polymorphism and coronary artery disease remain unclear. In this paper, the recent literature analyzing the role of homocysteine and MTHFR polymorphism as a risk factor for coronary artery disease has been reviewed.

Role of statins in the management of dyslipidemia after cardiac transplant: randomized controlled trial comparing the efficacy and the safety of atorvastatin with pravastatin.

BACKGROUND: Cardiac transplant patients are at increased risk of dyslipidemia, a known pathogenetic factor in chronic rejection. The aim of this study was to compare the efficacy and the safety of treatment with atorvastatin (AT) and treatment with pravastatin (PV) in a population of dyslipidemic transplant patients. METHODS: Thirty-nine transplant patients were randomized to receive a 4-month cycle of therapy with AT or PV, in a cross-over sequence. We analyzed the effects on their lipid profiles using Student t-test for paired data. RESULTS AND CONCLUSION: Atorvastatin was significantly more effective than PV in reducing total cholesterol (33% vs 21%, p < 0.001), LDL cholesterol (45% vs 30%, p = 0.001), and triglycerides (24% vs 7.7%, p < 0.001), at lower doses and with comparable tolerability and safety.

Increasing plasma homocysteine during follow-up in heart transplant recipients: effects of folate and renal function.

BACKGROUND: Hyperhomocysteinemia is a common finding in heart transplant recipients and may represent a risk factor for graft failure. However, the time-course, determinants and effects of medical therapy on total homocysteine plasma levels after heart transplantation remain undetermined. The aim of this study was to prospectively analyze 1) the time-course of total homocysteine in heart transplant recipients; 2) the effects of folate supplements and cyclosporine A on total homocysteine; 3) the relation among renal function, serum vitamin levels, and total homocysteine. METHODS: Fifty-two heart transplant recipients consecutively evaluated for routine follow-up during 1998 were included in the study (mean age 54 +/- 12 years; 28% female). Among the 52 patients, 10 patients were treated with folate for the entire period of the study (Group F), while 26 patients never received folate (Group NF). The remaining 16 patients who did not take folate on a regular basis were excluded from subgroup analysis. Total homocysteine and creatinine plasma levels were assayed at entry into the study (time 0) and at the end of the study, 12 months later (time 12). RESULTS: Homocysteinemia increased significantly from time 0 to time 12 (p < 0.001), regardless of creatinine plasma levels (p = 0.03) and folate intake (p < 0.01). However, total homocysteine levels were lower in Group F compared to Group NF at time 0 and time 12 (p < 0.02). On multivariate analysis, time of follow-up, serum creatinine and lack of folate intake were positive independent predictors of total homocysteine. CONCLUSIONS: Homocysteinemia increased over time in heart transplant recipients, regardless of renal function and folate administration. Lower total homocysteine levels were associated with folate intake, suggesting that folate supplements may play a role in the prevention of vascular allograft disease.

Delayed acquisition of high-avidity anti-cytomegalovirus antibody is correlated with prolonged antigenemia in solid organ transplant recipients.

Previous studies have demonstrated that maturation of cytomegalovirus (CMV)-specific antibodies in solid organ transplant recipients is delayed after primary CMV infection. To investigate the clinical significance of this finding, the avidity indices of anti-CMV antibody were determined in parallel with other serologic and virologic parameters in serial serum samples from 24 solid organ transplant recipients who had primary CMV infection that began during the first 3 months after transplantation. The data obtained show that a delay in antibody maturation is significantly correlated with a long persistence of positive antigenemia.