Acute cellular rejection the first year after heart transplantation and its impact on survival: a single-centre retrospective study at Skåne University Hospital in Lund 1988-2010

Pre-transplant immune cell function assay as a predictor of early cardiac allograft rejection

INTRODUCTION

ImmuKnow, an immune cell function assay that quantifies overall immune system activity can assist in post-transplant immunosuppression adjustment. However, the utility of pre-transplant ImmuKnow results representing a patient's baseline immune system activity is unknown. This study sought to assess if pre-transplant ImmuKnow results are predictive of rejection at the time of first biopsy in our cardiac transplant population.

METHODS

This is a single center, retrospective observational study of consecutive patients from January 1, 2018 to October 1, 2020 who underwent orthotopic cardiac transplantation at NYU Langone Health. Patients were excluded if a pre-transplant ImmuKnow assay was not performed. ImmuKnow results were categorized according to clinical interpretation ranges (low, moderate, and high activity), and patients were divided into two groups: a low activity group versus a combined moderate-high activity group. Pre-transplant clinical characteristics, induction immunosuppression use, early postoperative tacrolimus levels, and first endomyocardial biopsy results were collected for all patients. Rates of clinically significant early rejection (defined as rejection ≥ 1R/1B) were compared between pre-transplant ImmuKnow groups.

RESULTS

Of 110 patients who underwent cardiac transplant, 81 had pre-transplant ImmuKnow results. The low ImmuKnow activity group was comprised of 15 patients, and 66 patients were in the combined moderate-high group. Baseline characteristics were similar between groups. Early rejection occurred in 0 (0%) patients with low pre-transplant ImmuKnow levels. Among the moderate- high pre-transplant ImmuKnow group, 16 (24.2%) patients experienced early rejection (P = .033). The mean ImmuKnow level in the non-rejection group was the 364.9 ng/ml of ATP compared to 499.3 ng/ml of ATP for those with rejection (P = .020).

CONCLUSION

Patients with low pre-transplant ImmuKnow levels had lower risk of early rejection when compared with patients with moderate or high levels. Our study suggests a possible utility in performing pre-transplant ImmuKnow to identify patients at-risk for early rejection who may benefit from intensified upfront immunosuppression as well as to recognize those where slower calcineurin inhibitor initiation may be appropriate.

Bone mineral density in pediatric heart transplanted patients: A retrospective single-center study at Skåne University Hospital in Lund 1988-2016

BACKGROUND

Impaired bone mineral density (BMD) and osteoporosis are commonly found in patients who have undergone heart transplantation (HT), which increases the risk for bone fractures which is associated with increased morbidity and mortality in adults. However, the long-term evolution of BMD after HT in pediatric patients has not been thoroughly investigated.

METHOD

Bone mineral density up to 10 years after HT was investigated in 30 patients who underwent HT at an age <20 years at Skåne University Hospital in Lund 1988-2016.

RESULTS

The total observed time was 235 person-years. Before HT, 86% had low BMD for chronologic age in the lumbar spine. In lumbar spine, BMD was significantly lower than normal for chronological age before HT (p = .034), but recovered at the 4th year (p = .009). In whole body, BMD was normal at the 4th annual check-up (p = .030) and remained so throughout the follow-up period. The median T score in the lumbar spine and femoral neck 10 years after HT did not differ between the two groups based on age at HT (<20 years vs 20 years or older; p = .779 in the lumbar spine and p = .388 in the femoral neck).

CONCLUSIONS

Patients who undergo HT at an age of <20 years have low BMD for chronological age already before HT, but BMD may recover completely within the first 4 years after HT. The results indicate no difference in BMD at 10 years after HT between pediatric and adult patients.

Microcirculatory Resistance Predicts Allograft Rejection and Cardiac Events After Heart Transplantation

BACKGROUND

Single-center data suggest that the index of microcirculatory resistance (IMR) measured early after heart transplantation predicts subsequent acute rejection.

OBJECTIVES

The goal of this study was to validate whether IMR measured early after transplantation can predict subsequent acute rejection and long-term outcome in a large multicenter cohort.

METHODS

From 5 international cohorts, 237 patients who underwent IMR measurement early after transplantation were enrolled. The primary outcome was acute allograft rejection (AAR) within 1 year after transplantation. A key secondary outcome was major adverse cardiac events (MACE) (the composite of death, re-transplantation, myocardial infarction, stroke, graft dysfunction, and readmission) at 10 years.

RESULTS

IMR was measured at a median of 7 weeks (interquartile range: 3-10 weeks) post-transplantation. At 1 year, the incidence of AAR was 14.4%. IMR was associated proportionally with the risk of AAR (per increase of 1-U IMR; adjusted hazard ratio [aHR]: 1.04; 95% confidence interval [CI]: 1.02-1.06; p < 0.001). The incidence of AAR in patients with an IMR ≥18 was 23.8%, whereas the incidence of AAR in those with an IMR <18 was 6.3% (aHR: 3.93; 95% CI: 1.77-8.73; P = 0.001). At 10 years, MACE occurred in 86 (36.3%) patients. IMR was significantly associated with the risk of MACE (per increase of 1-U IMR; aHR: 1.02; 95% CI: 1.01-1.04; P = 0.005).

CONCLUSIONS

IMR measured early after heart transplantation is associated with subsequent AAR at 1 year and clinical events at 10 years. Early IMR measurement after transplantation identifies patients at higher risk and may guide personalized posttransplantation management.

Single-cell transcriptomic identified HIF1A as a target for attenuating acute rejection after heart transplantation

Acute rejection (AR) is an important contributor to graft failure, which remains a leading cause of death after heart transplantation (HTX). The regulation of immune metabolism has become a new hotspot in the development of immunosuppressive drugs. In this study, Increased glucose metabolism of cardiac macrophages was found in patients with AR. To find new therapeutic targets of immune metabolism regulation for AR, CD45⁺ immune cells extracted from murine isografts, allografts, and untransplanted donor hearts were explored by single-cell RNA sequencing. Total 20 immune cell subtypes were identified among 46,040 cells. The function of immune cells in AR were illustrated simultaneously. Cardiac resident macrophages were substantially replaced by monocytes and proinflammatory macrophages during AR. Monocytes/macrophages in AR allograft were more active in antigen presentation and inflammatory recruitment ability, and glycolysis. Based on transcription factor regulation analysis, we found that the increase of glycolysis in monocytes/macrophages was mainly regulated by HIF1A. Inhibition of HIF1A could alleviate inflammatory cells infiltration in AR. To find out the effect of HIF1A on AR, CD45⁺ immune cells extracted from allografts after HIF1A inhibitor treatment were explored by single-cell RNA sequencing. HIF1A inhibitor could reduce the antigen presenting ability and pro-inflammatory ability of macrophages, and reduce the infiltration of Cd4+ and Cd8a+ T cells in AR. The expression of Hif1α in AR monocytes/macrophages was regulated by pyruvate kinase 2. Higher expression of HIF1A in macrophages was also detected in human hearts with AR. These indicated HIF1A may serve as a potential target for attenuating AR.

The impact of donor sex on heart transplantation outcomes-a study of over 60,000 patients in the United States

BACKGROUND

The impact of donor sex on heart transplantation outcomes irrespective of recipient sex remains unclear. The objective of this study was to evaluate the impact of donor sex on heart transplantation outcomes in the United States.

METHODS

From 1987 to March 2019, 63,775 adult patients who underwent heart transplantation were matched to 27,509 male and 11,474 female donors in the United States. Data were prospectively collected by the United Network for Organ Sharing (UNOS). Patients without missing data were stratified by donor sex and donor menopause status. The groups were matched 1:1 using the propensity score of each patient. Kaplan-Meier survival and cox proportional hazards regression analyses were performed. The primary endpoint was all-cause mortality. Secondary endpoints were postoperative complications.

RESULTS

Propensity matching generated 15,506 and 1,094 patients based on donor sex and menopause status, respectively. Recipients who received female donor allografts were more likely to have acute rejection episodes requiring anti-rejection medical treatment (11.9% vs 10.1%, p = .007) and require post-transplant dialysis (10.9% vs 9.3%, p = .001) than those who received male donor allografts. Overall survival using female vs male donor allografts was similar (p = .34). Recipients who received pre- vs post-menopausal female donor hearts had similar postoperative outcomes and overall survival (p = .23).

CONCLUSIONS

Analysis of the UNOS database showed similar median survival using female vs male donor hearts in adult heart transplantation, irrespective of donor menopause status. Female donor allografts are used far less frequently, thus these results represent an opportunity to maximize usage by better utilization of suitable female donor organs.

The XVth Banff Conference on Allograft Pathology the Banff Workshop Heart Report: Improving the diagnostic yield from endomyocardial biopsies and Quilty effect revisited

The XVth Banff Conference on Allograft Pathology meeting was held on September 23-27, 2019, in Pittsburgh, Pennsylvania, USA. During this meeting, two main topics in cardiac transplant pathology were addressed: (a) Improvement of endomyocardial biopsy (EMB) accuracy for the diagnosis of rejection and other significant injury patterns, and (b) the orphaned lesion known as Quilty effect or nodular endocardial infiltrates. Molecular technologies have evolved in recent years, deciphering pathophysiology of cardiac rejection. Diagnostically, it is time to integrate the histopathology of EMBs and molecular data. The goal is to incorporate molecular pathology, performed on the same paraffin block as a companion test for histopathology, to yield more accurate and objective EMB interpretation. Application of digital image analysis from hematoxylin and eosin (H&E) stain to multiplex labeling is another means of extracting additional information from EMBs. New concepts have emerged exploring the multifaceted significance of myocardial injury, minimal rejection patterns supported by molecular profiles, and lesions of arteriolitis/vasculitis in the setting of T cell-mediated rejection (TCMR) and antibody-mediated rejection (AMR). The orphaned lesion known as Quilty effect or nodular endocardial infiltrates. A state-of-the-art session with historical aspects and current dilemmas was reviewed, and possible pathogenesis proposed, based on advances in immunology to explain conflicting data. The Quilty effect will be the subject of a multicenter project to explore whether it functions as a tertiary lymphoid organ.

Dominant regulation of long-term allograft survival is mediated by microRNA-142

Organ transplantation is often lifesaving, but the long-term deleterious effects of combinatorial immunosuppression regimens and allograft failure cause significant morbidity and mortality. Long-term graft survival in the absence of continuing immunosuppression, defined as operational tolerance, has never been described in the context of multiple major histocompatibility complex (MHC) mismatches. Here, we show that miR-142 deficiency leads to indefinite allograft survival in a fully MHC mismatched murine cardiac transplant model in the absence of exogenous immunosuppression. We demonstrate that the cause of indefinite allograft survival in the absence of miR-142 maps specifically to the T cell compartment. Of therapeutic relevance, temporal deletion of miR-142 in adult mice prior to transplantation of a fully MHC mismatched skin allograft resulted in prolonged allograft survival. Mechanistically, miR-142 directly targets Tgfbr1 for repression in regulatory T cells (TREG ). This leads to increased TREG sensitivity to transforming growth factor - beta and promotes transplant tolerance via an augmented peripheral TREG response in the absence of miR-142. These data identify manipulation of miR-142 as a promising approach for the induction of tolerance in human transplantation.

Surgical considerations for cardiac allograft rejection

This article reviews the surgical considerations of cardiac allograft rejection after heart transplantation and describes current treatment modalities for the failing graft. Cardiac allograft rejection can be a moribund diagnosis, especially when it is acute and high grade. It is broadly categorized into hyperacute, acute cellular, and antibody-mediated rejection. Treatment includes a multitude of medical and immunomodulation therapies for graft recovery. Severe rejection requires mechanical circulatory support for hemodynamic stability to maintain end-organ function. Retransplantation for graft loss is the ultimate therapy; however, it portends poor outcomes.

Impact of gender on echocardiographic characteristics in heart transplant recipients

AIMS

Assessment following heart transplantation (HTx) is routinely performed using transthoracic echocardiography. Differences in long-term mortality following HTx related to donor-recipient matching have been reported, but effects of gender on cardiac size and function are not well studied. The aims of this study were to evaluate differences in echocardiographic characteristics of HTx recipients defined by gender.

METHODS AND RESULTS

The study prospectively enrolled 123 (n = 34 female) HTx recipients of which 23 recipients was donor-recipient gender mismatched. Patients were examined with 2-dimensional echocardiography using Philips iE33 ultrasound system. Data were analysed across strata based on recipient gender and gender mismatch. Male recipients had larger left ventricular (LV) mass, thicker septal wall (P<0·001) and larger absolute LV volumes (P<0·001). Mean LV ejection fraction (EF) was higher in females (P<0·05), but no differences in conventional parameters of right ventricular (RV) function were found. Ventricular strain was higher in females than in males: LV global longitudinal strain (P<0·01), RV global longitudinal strain (P<0·05) and RV lateral free wall (P<0·05). The male group receiving a female donor heart had comparable EF and strain parameters to the female group receiving a gender-matched heart.

CONCLUSION

We found that female recipient gender was associated with smaller chamber size, higher LV EF and better LV and RV longitudinal strain. Gender-mismatched male recipients appeared to exhibit function parameters similar to gender-matched female recipients. Our results indicate that the gender aspect, analogous to current reference guidelines in general population, should be taken into consideration when examining patients post-HTx.

Factors Related to the Acute Cellular Rejection During the First Year After Heart Transplant

INTRODUCTION

The acute cellular rejection is recognized as a factor related to the long-term viability of the heart graft. We intend to establish which factors are associated with the acute cellular rejection during the first year post heart transplant using a longitudinal model with repeated measures.

METHODS

A retrospective cohort study was performed with all the patients who underwent heart transplant between 2005-2018 at the Hospital Universitario San Ignacio in Bogota, Colombia. In order to determine the factors associated with the development of acute cellular rejection, a generalized estimating equation approach was used, with an interchangeable correlation structure. The lowest value of quasi-likelihood information criterion and P < .05 was considered significant.

RESULTS

Fifty-five patients (49.3 ± 11.1 years old) were included. The mortality during the first month was 16.3% and the accumulated mortality during the first year was 23.6%. The incidence of the acute cellular rejection was higher during the third month after the transplant (79.9%); most of them were acute cellular rejection grade 1. The factors associated with the development of the rejection were the cyclosporine levels out of the therapeutic range in several periods of evaluation (P < .03) and the age of the receptor (P = .049).

CONCLUSIONS

Using advanced modeling methodologies of longitudinal data we identified that the factors associated with acute cellular rejection during the first year after the transplant are related to the therapeutic levels of the calcineurin inhibitor (cyclosporin) during the first 6 months of follow-up and the age of the receptor.

The clinical impact of donor-specific antibodies in heart transplantation

Donor-specific antibodies (DSA) are integral to the development of antibody-mediated rejection (AMR). Chronic AMR is associated with high mortality and an increased risk for cardiac allograft vasculopathy (CAV). Anti-donor HLA antibodies are present in 3-11% of patients at the time of heart transplantation (HTx), with de novo DSA (predominantly anti-HLA class II) developing post-transplant in 10-30% of patients. DSA are associated with lower graft and patient survival after HTx, with one study suggesting a three-fold increase in mortality in patients who develop de novo DSA (dnDSA). DSA against anti-HLA class II, notably DQ, are at particularly high risk for graft loss. Although detection of DSA is not a criterion for pathologic diagnosis of AMR, circulating DSA are found in almost all cases of AMR. MFI thresholds of ~5000 for DSA against class I antibodies, 2000 against class II antibodies, or an overall cut-off of 5-6000 for any DSA, have been suggested as being predictive for AMR. There is no firm consensus on pre-transplant strategies to treat HLA antibodies, or for the elimination of antibodies after diagnosis of AMR. Minimizing the risk of dnDSA is rational but data on risk factors in HTx are limited. The effect of different immunosuppressive regimens is largely unexplored in HTx, but studies in kidney transplantation emphasize the importance of adherence and maintaining adequate immunosuppression. One study has suggested a reduced risk for dnDSA with rabbit antithymocyte globulin induction. Management of DSA pre- and post-HTx varies but typically most centers rely on a plasmapheresis or immunoadsorption, with or without rituximab and/or intravenous immunoglobulin. Based on the literature and a multi-center survey, an algorithm for a suggested surveillance and therapeutic strategy is provided.

Posttransplant Pulmonary Hypertension Is Correlated With Acute Rejection and Death Among Cardiac Transplant Recipients: A Single Center Study

OBJECTIVES

Endomyocardial biopsy sampling is used to check acute rejection after cardiac transplant. However, it may lead to tricuspid valve injury and cardiac perforation; therefore, less invasive tools may be useful. Right heart catheterization provides valuable information about cardiac hemodynamics. Herein, we aimed to determine the correlation of right heart catheterization parameters with acute rejection and death during cardiac transplant follow-up.

MATERIALS AND METHODS

We retrospectively evaluated follow-up right heart catheterization and endomyocardial biopsy results from 47 adult patients who underwent cardiac transplant at Başkent University Faculty of Medicine between 2004 and 2016. Right heart catheterization parameters were compared between deceased and surviving patients and were correlated with acute cellular and humoral rejection. Averaged right heart catheterization parameters were correlated with death. We used Cox regression analysis to determine risk of death and acute cellular rejection and Kaplan-Meier survival analysis to determine any survival differences associated with pulmonary hypertension.

RESULTS

There were 47 patients (38 males, 9 females) with a mean age of 44 ± 10 years at transplant. In our patient group, 18 patients (38.3%) died at a median time of 11.2 months. Ninety endomyocardial biopsy samples (22.1%) showed cellular rejection, and 61 samples (4.5%) showed humoral rejection. The deceased patients had significantly greater mean and systolic pulmonary artery pressures, which were significantly correlated with acute cellular rejection. Death was significantly correlated with averaged values of mean and systolic pulmonary artery pressures. Our Cox regression analysis revealed that pulmonary hypertension was significantly associated with risk of death and acute cellular rejection. A Kaplan-Meier survival analysis revealed that pulmonary hypertension was associated with a significantly lower median survival.

CONCLUSIONS

Pulmonary artery pressures are significantly correlated with acute cellular rejection and death after cardiac transplant. Pulmonary hypertension significantly increases the risk of death and shortens survival after cardiac transplant.

Normal Reference Ranges for Transthoracic Echocardiography Following Heart Transplantation

BACKGROUND

Heart function following heart transplantation (HTx) is influenced by numerous factors. It is typically evaluated using transthoracic echocardiography, but reference values are currently unavailable for this context. The primary aim of the present study was to derive echocardiographic reference values for chamber size and function, including cardiac mechanics, in clinically stable HTx patients.

METHODS

The study enrolled 124 healthy HTx patients examined prospectively. Patients underwent comprehensive two-dimensional echocardiographic examinations according to contemporary guidelines. Results were compared with recognized reference values for healthy subjects.

RESULTS

Compared with guidelines, larger atrial dimensions were seen in HTx patients. Left ventricular (LV) diastolic volume was smaller, and LV wall thickness was increased. With respect to LV function, both ejection fraction (62 ± 7%, P < .01) and global longitudinal strain (-16.5 ± 3.3%, P < .0001) were lower. All measures of right ventricular (RV) size were greater than reference values (P < .0001), and all measures of RV function were reduced (tricuspid annular plane systolic excursion 15 ± 4 mm [P < .0001], RV systolic tissue Doppler velocity 10 ± 6 cm/sec [P < .0001], fractional area change 40 ± 8% [P < .0001], and RV free wall strain -16.9 ± 4.2% [P < .0001]). Ejection fraction and LV global longitudinal strain were significantly lower in patients with previous rejection.

CONCLUSION

The findings of this study indicate that the distribution of routinely used echocardiographic measures differs between stable HTx patients and healthy subjects. In particular, markedly larger RV and atrial volumes and mild reductions in both LV and RV longitudinal strain were evident. The observed differences could be clinically relevant in the assessment of HTx patients, and specific reference values should be applied in this context.

Osteoporosis following heart transplantation and immunosuppressive therapy

Heart transplantation (HT) remains the ultimate final therapy for patients with end-stage heart failure, who despite optimal medical and surgical treatments exhibit severe symptoms. To prevent rejection of the transplanted organ, HT patients require life-long immunosuppressive therapy. The goal of the immunosuppression is to minimise the risk of immune-mediated graft rejection, while avoiding clinical side-effects. Current immunosuppressive agents have yielded good survival outcome, however, complications of the immunosuppressive therapy, such as impaired bone strength and increased fracture risk, are common among HT patients rendering increased morbidity and mortality rates. The main aim of the present review was to summarise current knowledge on bone strength impairment after HT and concomitant immunosuppressive therapy.

Postoperative management of heart transplantation patients

Heart transplant recipients are at risk for a number of post-transplantation complications such as graft dysfunction, rejection, and infection. The rates of many complications are decreasing over time, and prognosis is improving. However, these patients continue to experience significant morbidity and mortality. This review focuses on the optimal management of heart transplant recipients in the postoperative period, based on current knowledge. More information is needed about the best ways to predict, prevent, and treat primary graft dysfunction, right ventricular failure, and cellular and antibody-mediated rejection.

Acute cellular rejection later than one year after heart transplantation: A single-center retrospective study at Skåne University Hospital in Lund 1988-2010

Routine endomyocardial biopsy (EMB) to detect acute cellular rejection (ACR) late (>1 year) after heart transplantation (HT) remains debated. To gain knowledge on late ACR and thereby approach this issue, we studied the incidence, predictors, and outcome of late ACR. 815 late EMBs from 183 patients transplanted 1988-2010 were retrospectively reviewed until June 30, 2012. Only 4.4% of the routine and 17.6% of the additional clinically indicated late EMBs showed ACR ≥ grade 2. With time post-HT, there was a clear trend toward fewer ACRs, a lower incidence of ACR per patient per year, and a deceleration in the decrease in the proportion of patients free from ACR. Sex-mismatching and first-year ACR were associated with an increased risk of late ACR, which also was associated with worse outcome. Although rare, when compared to our previous study on first-year EMBs, it appears as if late more often than early ACR remains undetected and that also late and not only early ACR influences outcome. Extended EMB surveillance >1 year post-HT therefore still seems reasonable in "high-risk" patients, as also suggested in the International Society for Heart and Lung Transplantation guidelines. These should include, but not be limited to, the two risk groups above.

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

BACKGROUND

T₂ mapping is a magnetic resonance imaging technique measuring T₂ relaxation time, which increases with the myocardial tissue water content. Myocardial edema is a component of acute cellular rejection (ACR) after heart transplantation. This pilot study compares in heart transplantation recipients a novel high resolution 3-dimensional (3D) T₂-mapping technique with standard 2-dimensional (2D) T₂-mapping for ACR detection.

METHODS

Consecutive asymptomatic patients (n = 26) underwent both 3D T₂ mapping and reference 2D T₂ mapping magnetic resonance imaging on the day of endomyocardial biopsy (EMB). 3D T₂ maps were obtained at an isotropic spatial resolution of 1.72 mm (voxel volume 5.1 mm³). 2D and 3D maps were matched anatomically, and maximum segmental T₂ values were compared blinded to EMB results. In addition, all 3D T₂ maps were rendered as 3D images and inspected for foci of T₂ elevation.

RESULTS

T₂ values of segments from 2D and reformatted 3D T₂ maps agreed (p > 0.5). The highest 2D segmental T₂ values were 49.9 ± 4.0 ms (no ACR = 0R, n = 18), 48.9 ± 0.8 ms (mild ACR = 1R, n = 3), and 65.0 ms (moderate ACR = 2R). Rendered 3D T₂ maps of cases with 1R showed foci with significantly elevated T₂ signal (T₂ = 58.2 ± 3.6 ms); 5 cases (28%) in the 0R group showed foci with increased T₂ values (>2 SD above adjacent tissue) that were not visible on the 2D T₂ maps.

CONCLUSIONS

This pilot study in a small cohort suggests equivalency of standard segmental analysis between 3D and 2D T₂-mapping. 3D T₂ mapping provides a spatial resolution that permits detection of foci with elevated T₂ in patients with mild ACR.

Impact of postoperative pulmonary hypertension on outcome after heart transplantation

OBJECTIVES

We wanted to investigate the effects of postoperative pulmonary hypertension (PH_postop: mean pulmonary artery pressure [MPAP] ≥ 25 mmHg), diastolic pressure gradient (DPG), pulmonary vascular resistance (PVR), and repeated hemodynamic measurements on long-term survival after heart transplantation (HT).

DESIGN

Eighty-nine patients who underwent HT at Skåne University Hospital in Lund in the period 1988-2010 and who were evaluated with right-heart-catheterization at rest, prior to HT and repeatedly during the first postoperative year, were grouped based on their MPAP, DPG, and PVR.

RESULTS

One year after HT, survival was lower in patients with PH_postop than in those without, in patients with DPG ≥7 mmHg than in those with DPG <7 mmHg, and in patients with PVR >3 WU than in those with PVR ≤3 WU. Moreover, compared to patients with no PH_postop or with PH_postop at one evaluation during the first year after HT, PH_postop at repeated evaluations was associated with higher mortality (hazard ratio 3.4, 95% CI 1.4-8.0). There was no significant difference in acute cellular rejection between patients with and without PH_postop, but postoperative kidney function was worse in patients with repeated PH_postop.

CONCLUSIONS

When defined according to present guidelines, PH one year after HT may emerge as a prognostic marker for long-term outcome after HT. Moreover, PH_postop at repeated evaluations during the first year after HT had stronger prognostic value than PH_postop at a single examination, illustrating a means of identifying a high-risk population. However, confirmation in larger multi-center studies is warranted.

Immunobiology in VCA

Transplantation of vascularized composite tissue is a relatively new field that is an amalgamation of experience in solid organ transplantation and reconstructive plastic and orthopedic surgery. What is novel about the immunobiology of VCA is the addition of tissues with unique immunologic characteristics such as skin and vascularized bone, and the nature of VCA grafts, with direct exposure to the environment, and external forces of trauma. VCAs are distinguished from solid organ transplants by the requirement of rigorous physical therapy for optimal outcomes and the fact that these procedures are not lifesaving in most cases. In this review, we will discuss the immunobiology of these systems and how the interplay can result in pathology unique to VCA as well as provide potential targets for therapy.

Safety and efficacy of the switch to generic mycophenolate mofetil and tacrolimus in heart transplant patients

BACKGROUND

Generic immunosuppressants may offer economic advantages, but their use is still controversial. At our center, 55 heart transplant patients were switched from CellCept(®) to Myfenax Teva(®) (MT) (n = 51, 18% female, 8.1 ± 6.6 yr post-transplantation) and/or Prograf(®) to Tacrolimus Sandoz(®) (TS) (n = 17, 41% female, 6.6 ± 5.8 yr post-transplantation).

METHODS

We conducted an acute monitoring and a retrospective follow-up with regard to safety and efficacy. Acute cellular rejections (ACRs) on endomyocardial biopsies (EMBs) four wk after the MT switch were specifically compared to a matched retrospective control group.

RESULTS

Tacrolimus C0 levels (TS switch) as well as hemoglobin, leukocytes, and thrombocytes (MT switch) did not change (p = NS) during the three wk after each respective switch (8.7 ± 2.9 vs. 8.4 ± 1.9 μg/L, 129.1 ± 12.6 vs. 130.1 ± 12.8 g/L, 6.3 vs. 6.2 × 10(9) /L, and 217.4 ± 56.6 vs. 219.3 ± 61.8 × 10(9) /L, respectively). 0% of the EMBs in the MT switch vs. 3% of the EMBs in the control group showed ACR>grade 1R (p = NS). After six months, survival was 96% (MT switch) and 100% (TS switch), and the frequency of severe ACR was low. Safety parameters measured at the next annual follow-up were also stable following each switch.

CONCLUSION

Switching to MT and/or TS several years after heart transplantation appeared safe in the short-term perspective, showing no detectable changes in tacrolimus C0 levels, safety or efficacy, during an average follow-up of six months.

A single-center retrospective clinicopathologic study of endomyocardial biopsies after heart transplant at Baskent University Hospital in Ankara, 1993-2014

OBJECTIVES

The purpose of this study was to investigate the frequency and prognostic importance of acute cellular rejection after heart transplant.

MATERIALS AND METHODS

All 84 heart transplant patients at our center from January 1993 to January 2014, including all 576 endomyocardial biopsies, were evaluated with retrospective review of clinical records and endomyocardial biopsies. Routine and clinically indicated endomyocardial biopsies after heart transplant were graded for acute cellular rejection (2005 International Society for Heart and Lung Transplantation Working Formulation). Survival analysis was performed using Kaplan-Meier method.

RESULTS

There were 61 male (73%) and 23 female recipients. Median age at heart transplant was 29 years (range, 1-62 y). Posttransplant early mortality rate was 17.9% (15 patients). In the other 69 patients, 23 patients died and 46 patients (66.7%) were alive at mean 69.3 ± 7.2 months after heart transplant. Mean follow-up was 35.4 ± 29.8 months (range, 0.07-117.5 mo). Mean 8.4 ± 4.2 endomyocardial biopsies (range, 1-19 biopsies) were performed per patient. Median first biopsy time was 7 days (range, 1-78 d). The frequency of posttransplant acute cellular rejection was 63.8% (44 of 69 patients) by histopathology; 86% patients experienced the first episode of acute cellular rejection within 6 months after transplant. There were 18 patients with acute cellular rejection ≥ grade 2R on ≥ 1 endomyocardial biopsy in 44 patients with acute cellular rejection. No significant difference was observed between survival rates of patients with grade 1R or ≥ grade 2R acute cellular rejection, or between survival rates of patients with or without diagnosis of any grade of acute cellular rejection. Acute cellular rejection was not related to any prognostic risk factor.

CONCLUSIONS

Acute cellular rejection had no negative effect on heart recipient long-term survival, but it was a frequent complication after heart transplant, especially within the first 6 months.

Late rejection occurred in recipients who experienced acute cellular rejection within the first year after heart transplantation

Serial endomyocardial biopsies (EMBs) are scheduled even several years after heart transplantation (HTx) to monitor for late rejection (LR). However, repeated EMBs are associated with an increased risk for fatal complications and decrease the quality of life of the recipient. We retrospectively analyzed clinical data from 42 adult recipients who had received HTx and were followed > 1 year at the University of Tokyo Hospital. Five recipients experienced LR at 1130 ± 157 days after HTx, and all 5 had experienced acute cellular rejection (ACR) with ISHLT grade ≥ 2R within the first year, which was treated with methylprednisolone pulse therapy (sensitivity, 1.000; specificity, 0.7027). Logistic regression analyses demonstrated that positive panel reactive antibody (PRA) was the only significant predictor for LR among all parameters at 1 year after HTx (P = 0.020, odds ratio 24.00). Among the 5 recipients with LR, LR occurred earlier in the two PRA positive recipients than in those with a negative PRA (981 ± 12 versus 1230 ± 110 days, P = 0.042). Among the perioperative parameters, gender mismatch [n = 13 (31%)] was the only significant predictor for ACR within the first year in logistic regression analyses (P = 0.042, odds ratio 4.200). In conclusion, the current schedule of serial EMBs should perhaps be reconsidered for recipients without any history of ACR within the first year due to their lower risk of LR.