Diagnosis Of Heart Transplant Rejection Research Articles

Emerging role of circulating piRNAs in the diagnosis of heart transplant rejection.

Liquid biopsy offers a potential alternative to decrease or eliminate endomyocardial biopsy (EMB) for diagnosing allograft rejection. piRNAs are novel and promising disease biomarkers for their intrinsic characteristics such as stability in body fluids; however, their role in allograft rejection remains unexplored. A training set based on small RNA sequencing technology was performed to identify piRNAs in endomyocardial tissue (n=8) and serum samples (n=40) from patients following heart transplantation. A validation set of the potential piRNAs identified in the training study was conducted in an independent larger cohort for the detection of acute cellular rejection (ACR, n=105) and antibody-mediated rejection (AMR, n=61). We identified 20292 piRNAs in endomyocardial tissue and 24602 piRNAs in serum samples from patients following heart transplantation. We identified seven piRNAs with a coincident expression profile in both types of samples and potential capacity for the non-invasive detection of cardiac rejection. Validation in a large independent cohort demonstrated that a panel of these piRNAs showed excellent performance for detecting grade ≥2R ACR (AUC=0.819; p<0.0001) and grade 1R ACR (AUC=0.721; p=0.001). Furthermore, our piRNA panel showed a potential discrimination ability of pAMR2 (AUC=0.967; p<0.0001). To the best of knowledge, this study is the first to report the presence of piRNAs in both endomyocardial tissue and serum samples of patients after heart transplant, including their association with allograft rejection events. We propose a novel piRNA panel for the detection of cardiac allograft rejection.

A gentler approach to monitor for heart transplant rejection.

Despite developments in circulating biomarker and imaging technology in the assessment of cardiovascular disease, the surveillance and diagnosis of heart transplant rejection has continued to rely on histopathologic interpretation of the endomyocardial biopsy. Increasing evidence shows the utility of molecular evaluations, such as donor-specific antibodies and donor-derived cell-free DNA, as well as advanced imaging techniques, such as cardiac magnetic resonance imaging, in the assessment of rejection, resulting in the elimination of many surveillance endomyocardial biopsies. As non-invasive technologies in heart transplant rejection continue to evolve and are incorporated into practice, they may supplant endomyocardial biopsy even when rejection is suspected, allowing for more precise and expeditious rejection therapy. This review describes the current and near-future states for the evaluation of heart transplant rejection, both in the settings of rejection surveillance and rejection diagnosis. As biomarkers of rejection continue to evolve, rejection risk prediction may allow for a more personalized approach to immunosuppression.

Gene Expression Profiling for the Identification and Classification of Antibody-Mediated Heart Rejection.

Antibody-mediated rejection (AMR) contributes to heart allograft loss. However, an important knowledge gap remains in terms of the pathophysiology of AMR and how detection of immune activity, injury degree, and stage could be improved by intragraft gene expression profiling. We prospectively monitored 617 heart transplant recipients referred from 4 French transplant centers (January 1, 2006-January 1, 2011) for AMR. We compared patients with AMR (n=55) with a matched control group of 55 patients without AMR. We characterized all patients using histopathology (ISHLT [International Society for Heart and Lung Transplantation] 2013 grades), immunostaining, and circulating anti-HLA donor-specific antibodies at the time of biopsy, together with systematic gene expression assessments of the allograft tissue, using microarrays. Effector cells were evaluated with in vitro human cell cultures. We studied a validation cohort of 98 heart recipients transplanted in Edmonton, AB, Canada, including 27 cases of AMR and 71 controls. A total of 240 heart transplant endomyocardial biopsies were assessed. AMR showed a distinct pattern of injury characterized by endothelial activation with microcirculatory inflammation by monocytes/macrophages and natural killer (NK) cells. We also observed selective changes in endothelial/angiogenesis and NK cell transcripts, including CD16A signaling and interferon-γ-inducible genes. The AMR-selective gene sets accurately discriminated patients with AMR from those without and included NK transcripts (area under the curve=0.87), endothelial activation transcripts (area under the curve=0.80), macrophage transcripts (area under the curve=0.86), and interferon-γ transcripts (area under the curve=0.84; P<0.0001 for all comparisons). These 4 gene sets showed increased expression with increasing pathological AMR (pAMR) International Society for Heart and Lung Transplantation grade (P<0.001) and association with donor-specific antibody levels. The unsupervised principal components analysis demonstrated a high proportion of molecularly inactive pAMR1(I+), and there was significant molecular overlap between pAMR1(H+) and full-blown pAMR2/3 cases. Endothelial activation transcripts, interferon-γ, and NK transcripts showed association with chronic allograft vasculopathy. The molecular architecture and selective AMR transcripts, together with gene set discrimination capacity for AMR identified in the discovery set, were reproduced in the validation cohort. Tissue-based measurements of specific pathogenesis-based transcripts reflecting NK burden, endothelial activation, macrophage burden, and interferon-γ effects accurately classify AMR and correlate with degree of injury and disease activity. This study illustrates the clinical potential of a tissue-based analysis of gene transcripts to refine diagnosis of heart transplant rejection.

Cardiac magnetic resonance T1 mapping pre and post contrast characterizes the myocardium in orthotopic heart transplantation recipients without active rejection

Background: Transplant rejection is characterized by interstitial inflammatory infiltrate. This inflammatory reaction is followed by both replacement fibrosis and interstitial fibrosis which in the long term can impair diastolic and systolic ventricular (LV) function.Cardiac magnetic resonance (CMR) with gadolinium quantifies replacement fibrosis and compares well with biopsy in the diagnosis of heart transplant rejection. New T1 mapping sequences are proposed for the quantification of interstitial fibrosis. Methods: We studied 33 heart transplant patients (Tx) (7 Females), mean time from Tx 112±56 mo (range 2–1288) and 12 normals (N), age 48±13 and 40±11 p=0.04. Absence of active rejection was confirmed by EMB. CMR was performed on a 1.5 Tesla scanner (Siemens). Short axis SSFP cine images covering the LV were acquired; image position was used for T1-mapping and late gadolinium enhancement (LGE). MOLLI T1 maps were generated from 5-7 SSFP images with variable inversion preparation time as described by Messroghli (2007) before and after gadobutrol i.v. (0.15 mmol/kg). Region of interest were drawn on 3 short axis (base,mid,apex) average T1 values pre and post contrast administration (msec) were fitted by a non-linear curve. Data are mean±SD Results: Systolic function was similar in both groups Tx 65±10 vs N 67±5 p=0.69, LV Mass Index was slightly higher in Tx 76±17 vs 66±8 N p=0.16. In Tx pre -contrast T1 was longer 1020±93 vs 957±45 msec p<0.001, whereas post contrast was shorter 406±46 msec vs 455±35 msec p<0.001. In Tx with cytomegalovirus infection (n=17) T1 mean pre-contrast was significantly higher 1043±15 vs 981±46 p=0.018. T1 post-contrast but not pre-contrast was inversely correlated to time interval from Tx y=4925-0.327x; p<0.05. Patients with LVH (n=7) had a significantly higher T1 both pre (p=0.007) and post contrast (p=0.04). LV mass index was directly correlated to T1 pre P=0.05 and inversely correlated to T1 post (p=0.002). Twentythree out of 33 Tx had patchy LGE distribution mainly in the inferior RV insertion, 2 had a previous myocardial infarction and 8 did not show LGE. Conclusions: Patient transplanted with no active rejection show a significant increase of interstitial fibrosis which builds up over time. CMR beside anatomo-functional parameters combining LGE and T1 mapping can provide a useful non invasive characterization of the collagen deposition in transplanted hearts and allow a better insight into the progression of restrictive physiology

Endomyocardial biopsy: Yesterday, today and tomorrow

The major goals of this presentation are to give the updated knowledge of primary heart muscle disease, cardiomyopathies (CMP), their classification, the diagnostic possibilities using endomyocardial biopsy (EMB) and to estimate the value of EMB in the choice of the right therapeutic approach. Despite many controversies, EMB is today a widely accepted method, with low percentage of complications for analysing CMPs, and is considered to be a routine procedure in many cardiological centers. Inspite the fact that we started with the use of EMB in 80's, it is not performed often today in Belgrade, like many years ago (2). It's difficult to say why ? The CMPs may be subdivided, according to the functional and structural features, into two groups: idiopathic and specific, or primary and secundary. Idipathic group is consisted of 5 subgroups: hypertrophic, dilated, restrictive, arrithmogenic right ventricular CMP and unclassified. Specific CMPs may be subdivided into 8 groups mainly based on etiopathogenetic characteristics: infective, with viral myocarditis as the most common entity, metabolic, including endocrine disorders and infiltration and storage diseases. Deficiency disorders and heart involvement in connective tissue disorders are also included. Granulomas, neoplasms and neuromuscular disorders are also very often presented with cardiac dysfunction and structural abnormalities. Sensitivity and toxic reactions with long list of substances which may affect the heart are probably the most present today. Finally, the last group represent miscellaneous systemic syndromes with heart affection. EMB has been increasingly used in the diagnosis of CMPs, with special influence on diagnosis of heart transplant rejection, myocarditis, treatment modalities of different types of myocarditis, with low complication rate, considered effective, useful and safe procedure.

Echo rejection score: new echocardiographic approach to diagnosis of heart transplant rejection☆

The gold standard test in the diagnosis of heart transplant rejection is right ventricular (RV) myocardial biopsy, which is an invasive, time-consuming, expensive method. In an effort to find a reliable method to minimise the sequential use of myocardial biopsy, we assessed the main echocardiographic indices for the detection of allograft rejection. Fifty myocardial specimens were examined in this prospective study, which assessed the prominent echocardiographic parameters propounded by previous studies as indicators of rejection. Prior to biopsy, all the patients underwent preoperative transthoracic echocardiography. The accuracy of the echocardiographic indices was compared with that of myocardial biopsy indices as the gold standard. At three myocardial segments, namely, RV base, interventricular septal (Sep) base and lateral left ventricular (Lat) base, peak systolic strain (RV-S, Lat-S and Sep-S) was measured. In addition, time to systole (TS) was measured at the same three segments, yielding the three variables of RV-TS, Sep-TS and Lat-TS. Our logistic regression model revealed that the four factors of Lat-S (%), Sep-TS (ms), posterior wall thickness (PWT; mm) and left ventricular mass index (LVMI; g m(-2)) could denote heart transplant rejection. We devised a new index, the echo rejection score, using the following formula: [(PWT+LVMI)-(Lat-S+Sep-TS)]. This new formula has an area under a curve of 0.932 and a cut-off point of 0; it yields a sensitivity of 100.0%, specificity of 71.0%, positive predictive value of 67.9% and a negative predictive value of 100.0%. If the echo rejection score is >0, there is a 67.9% possibility that a cardiac transplant patient is presenting with allograft rejection, while a score < or =0 denotes a 100% improbability of rejection. Our proposed method for screening patients at risk of acute cardiac rejection with echo rejection score showed a good sensitivity in detection of graft rejection. However, further study is required to determine if it can be used as an adjunct to the myocardial biopsy.

Evaluation of myocardial performance index to predict mild rejection in cardiac transplantation.

Early diagnosis of heart transplant rejection is mandatory, since even mild rejection can rapidly progress to more severe rejection. Noninvasive diagnosis of heart transplant rejection still remains a challenge. The purpose of the study was to determine a possible association between myocardial performance index (MPI) and biopsy score of the heart transplant. This is a retrospective cohort analysis of 99 complete Doppler echocardiographic studies from 24 consecutive patients (23 men) performed within 24 h of endomyocardial biopsy. Mean age of the cohort was 50 +/- 9 years and mean time from transplantation was 19 +/- 21 months (1-81). All patients were in sinus rhythm. Myocardial performance index was calculated as the ratio of isovolumic contraction time plus isovolumic relaxation time divided by ejection time. Left ventricular dimensions, left ventricular mass, ejection fraction, and a number of Doppler indices (E-point velocity, A-point velocity, deceleration time, and deceleration slope) were also measured. The International Society for Heart and Lung Transplantation (ISHLT) grading system was used for the classification of endomyocardial biopsies. Myocardial performance index was significantly prolonged (0.60 +/- 0.13, 0.68 +/- 0.08, 0.75 +/- 0.20, in biopsy scores 0, IA, and IB, respectively; p<0.001). Isovolumic contraction time was significantly prolonged; isovolumic relaxation time was not significantly changed. Ejection time and deceleration time were significantly shortened. Multivariate stepwise regression analysis revealed that MPI and deceleration time were the only independent predictors of biopsy score (r=0.48, F=10.53, p<0.0001). Myocardial performance index seems to be a useful adjunct in the follow-up of cardiac transplant patients. These preliminary data suggest that a larger study may be indicated to clarify the relevance of myocardial performance index.

Utility of cardiac magnetic resonance imaging for the diagnosis of heart transplant rejection

Objectives To assess the value of the use of cardiac MRI to detect rejection (necrosis) and its ability to discriminate it from other pathologic alterations (edema and fibrosis). Materials and methods A prospective and consecutive study was designed in which cardiac MRI was performed at the same time as the scheduled endomyocardial biopsy. The study period was from 31-10-01 to 01-05-02. Ten patients with claustrophobia were excluded. Sixty-four examinations were performed in the remaining 40 patients. MRI assessment was blinded to the biopsy result. The 17 biopsies performed were insufficient (too small sample). Rejection was defined as the presence of at least 1 focus of myocyte necrosis. Technique. A high-field (1.5 T) GE CV/i magnetic resonance imaging system was used to obtain pre- and postcontrast white and black blood anatomic sequences (breathhold fast spin-echo T1-weighted images), as well as myocardial cine, perfusion and viability sequences. Variables analyzed. Ejection fraction, ventricular volumes, pericardial effusion, hypertrophy, absolute and relative myocardial intensity and uptake. Statistics. Variables were normally distributed. Student's t test was used for quantitative variables and the χ 2 test for proportions. Results Mean age, 51 ± 13 years. Women 5, men 35. Time since HT, 13 to 3725 days. No significant differences were found between rejection and ventricular volumes or the presence of effusion and hypertrophy. Visual estimation of myocardial perfusion and viability sequences did not detect any significant changes. Uptake showed a clear trend to increase in patients with necrosis: 34 ± 21 versus 23 ± 17 for relative uptake, P < .05. There were also differences in uptake when fibrosis was present: 68 ± 47 versus 102 ± 48 in the group without fibrosis, P < .05; but not in the presence of edema: 93 ± 55 versus 94 ± 45 for absolute uptake. Conclusions (1) Cardiac MRI is a promising technique for diagnosis of rejection. (2) Patients with myocyte necrosis show a clear trend toward increased myocardial uptake. (3) Interstitial fibrosis is associated with decreased levels of uptake.

Sensitivity and specificity of clinical variables in the diagnosis of heart transplant rejection

Sensitivity and specificity of clinical variables in the diagnosis of heart transplant rejection