Diagnosis Of Cardiac Allograft Rejection Research Articles

Noninvasive quantification of granzyme B in cardiac allograft rejection using targeted ultrasound imaging.

Endomyocardial biopsy is the gold standard method for the diagnosis of cardiac allograft rejection. However, it causes damage to the heart. In this study, we developed a noninvasive method for quantification of granzyme B (GzB) in vivo by targeted ultrasound imaging, which detects and provides quantitative information for specific molecules, for acute rejection assessment in a murine cardiac transplantation model. Microbubbles bearing anti-GzB antibodies (MBGzb) or isotype antibodies (MBcon) were prepared. Hearts were transplanted from C57BL/6J (allogeneic) or C3H (syngeneic) donors to C3H recipients. Target ultrasound imaging was performed on Days 2 and 5 post-transplantations. A pathologic assessment was performed. The expression of granzyme B and IL-6 in the heart was detected by Western blotting. After MB injection, we observed and collected data at 3 and 6min before and after the flash pulse. Quantitative analysis revealed that the reduction in peak intensity was significantly higher in the allogeneic MBGzb group than in the allogeneic MBcon group and the isogeneic MBcon group at PODs 2 and 5. In the allogeneic groups, granzyme B and IL-6 expression levels were higher than those in the isogeneic group. In addition, more CD8 T cells and neutrophils were observed in the allogeneic groups. Ultrasound molecular imaging of granzyme B can be used as a noninvasive method for acute rejection detection after cardiac transplantation.

A Review of Biomarkers of Cardiac Allograft Rejection: Toward an Integrated Diagnosis of Rejection.

Despite major advances in immunosuppression, allograft rejection remains an important complication after heart transplantation, and it is associated with increased morbidity and mortality. The gold standard invasive strategy to monitor and diagnose cardiac allograft rejection, based on the pathologic evaluation of endomyocardial biopsies, suffers from many limitations including the low prevalence of rejection, sample bias, high inter-observer variability, and international working formulations based on arbitrary cut-offs that simplify the landscape of rejection. The development of innovative diagnostic and prognostic strategies—integrating conventional histology, molecular profiling of allograft biopsy, and the discovery of new tissue or circulating biomarkers—is one of the major challenges of translational medicine in solid organ transplantation, and particularly in heart transplantation. Major advances in the field of biomarkers of rejection have paved the way for a paradigm shift in the monitoring and diagnosis of cardiac allograft rejection. We review the recent developments in the field, including non-invasive biomarkers to minimize the number of protocol endomyocardial biopsies and tissue biomarkers as companion tools of pathology to refine the diagnosis of cardiac rejection. Finally, we discuss the potential role of these biomarkers to provide an integrated bio-histomolecular diagnosis of cardiac allograft rejection.

Sarcomere ACTC1 and MYO18A serum expression levels detect acute cellular rejection in cardiac transplant patients

Abstract Introduction and purpose The development of non-invasive approaches for the early diagnosis of cardiac allograft rejection is necessary. Given the central role of sarcomeric dysfunction in cardiomyocyte biology and sarcomere alterations, described in endomyocardial biopsies of transplant patients with rejection, we hypothesized that the serum expression levels of genes encoding sarcomeric proteins were altered in acute cellular rejection (ACR). Methods Forty consecutive serum samples from transplant recipients undergoing routine endomyocardial biopsies were included in an RNA sequencing analysis. Results We identified 61 sarcomeric genes, 19 of which were differentially expressed in patients with clinically relevant rejection (ACR grade ≥2R). A receiver operating characteristic curve was done to assess their accuracy for ACR detection, and found that 8 relevant actins, myosins, and other sarcomere-related genes showed great diagnostic capacity (AUC≥0.800); ACTC1 (AUC=1.000, p<0.0001) and MYO18A (AUC=1.000, p<0.0001) showed the best results. MYO18A had a good ability to detect mild rejection (AUC=0.789, p<0.05). We found a relationship between MYO18A and the left ventricular end-systolic (p<0.01) and end-diastolic (p<0.05) diameters. Conclusions ACTC1 and MYO18A also showed a significant correlation with the NT-proBNP levels (p<0.05). Because of their precision to detect ACR, we propose sarcomere ACTC1 and MYO18A serum expression levels as potential candidates for non-invasive ACR detection. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Carlos IIIEuropean Regional Development Fund (ERDF)

CS as a Novel Biomarker for Diagnosis of Cardiac Allograft Rejection

Purpose Cardiac bridging integrator 1 (cBIN1) is a cardiomyocyte protein which regulates excitation-contraction coupling and is downregulated with adverse myocardial remodeling. The natural log of the inverse of cBIN1 plasma concentration known as CS, has been shown to be a diagnostic and prognostic marker for ambulatory heart failure patients. In this pilot study, we examined the performance of CS as a diagnostic marker of cardiac allograft rejection. Methods Out of 708 heart transplant (HT) recipients consented for the study from 2014 to 2018, 12 patients experienced advanced rejection (AMR/ACR grade ≥2) with CS level drawn at the time. Convalescent sera were drawn at least 6 months post therapy. A control group of 11 patients was matched by age, sex and time since HT. CS was measured in plasma samples by Sarcotein, Inc. Pair-wise comparison of CS among the 2 groups was performed using the Wilcoxon signed rank test. Major adverse outcomes (MACE), defined as ventricular tachycardia, cardiac allograft vasculopathy, recurrent rejection, cardiac hospitalization, and death were determined by chart review at most recent clinic visit. Results Rejection occurred at 211 (IQR 127-303) days post-HT. Patients with rejection had significantly lower CS levels compared to controls (1.92[IQR 1.57-2.33] vs 2.36[IQR 1.86-3.71] p=0.03). Following anti-rejection therapy, CS values were determined at 189 (IQR 126.8-303) days after the episode and did not differ significantly from the time of rejection. Notably, post rejection patients experienced a high rate of MACE (7/12) at 4 years of follow-up. Those who experienced MACE had a numerically higher median increase in CS values on follow-up compared to those who did not (1.04 vs 0.50). Conclusion In this pilot study, CS shows promise as a marker of cardiac allograft rejection. CS was significantly decreased by 20% in the setting of rejection compared to matched control samples. Larger studies are needed to validate our findings and determine the prognostic value of CS level changes post-therapy.

Incidence and risk factors for biopsy-proven heart allograft rejection during the first-year post heart transplantation

The diagnosis of cardiac allograft rejection is based on the histological analysis of a myocardial tissue sample obtained by endomyocardial biopsy (EMB), an invasive procedure at risk of complications. Our aim is to enable the shift from a protocol biopsy approach, to a precision medicine approach, in which the need for EMB is tailored to each patient's individual risk. To analyze the incidence and the risk factors for biopsy-proven rejections following heart transplantation in a large cohort of highly phenotyped heart-transplant recipients. We performed a multicenter, retrospective, observational study (Pitié-Salpêtrière, HEGP, 2004–2016). We included all patients with ≥ 1 EMB during the first year ( n = 1050 patients, 13677 EMB). All EMB performed before 2012 were retrospectively reviewed and graded according to ISHLT guidelines. Rejections were defined as acute cellular rejection (ACR) ≥ 1R1B and/or antibody-mediated rejections (AMR) ≥ pAMR1. Pre-formed DSA were evaluated using Luminex Single Antigen Assay (MFI ≥ 500). Risk factors for rejection were identified using Cox proportional hazard model. Biopsy-proven rejections were diagnosed in 489 patients (46.4%) representing 1009 EMB (7.3%, mostly low-grade rejections: ACR 1R1B or 1R2: n = 724, see Fig. 1 ). Risk factors for rejection included recipient's age (HR = 0.988 per 1-year increment, P = 0.002), type of transplantation (combined heart-kidney and heart-liver compared to isolated heart: HR = 0.336 and 0.204 respectively, P < 0.001), pre-formed DSA (HR = 1.422, P < 0.001), HLA A-B-DR mismatches (HR = 1.129 per 1-mismatch increment, P = 0.02) and the type of induction (basiliximab compared to anti-thymocyte globulins: HR = 1.725, P = 0.008). We identified five independent risk factors for biopsy-proven rejection during the first-year post-heart transplantation. Our findings might help clinicians to customize post-transplant endomyocardial biopsies monitoring.

Native T1 Mapping in the Diagnosis of Cardiac Allograft Rejection: A Prospective Histologically Validated Study

ObjectivesThis study aimed to determine the role of T1 mapping in identifying cardiac allograft rejection. BackgroundEndomyocardial biopsy (EMBx), the current gold standard to diagnose cardiac allograft rejection, is associated with potentially serious complications. Cardiac magnetic resonance (CMR)–based T1 mapping detects interstitial edema and fibrosis, which are important markers of acute and chronic rejection. Therefore, T1 mapping can potentially diagnose cardiac allograft rejection noninvasively. MethodsPatients underwent CMR within 24 h of EMBx. T1 maps were acquired at 1.5-T. EMBx-determined rejection was graded according to International Society of Heart and Lung Transplant (ISHLT) criteria. ResultsOf 112 biopsies with simultaneous CMR, 60 were classified as group 0 (ISHLT grade 0), 35 as group 1 (ISHLT grade 1R), and 17 as group 2 (2R, 3R, clinically diagnosed rejection, antibody-mediated rejection). Native T1 values in patients with grade 0 biopsies and left ventricular ejection fraction >60% (983 ± 42 ms; 95% confidence interval: 972 to 994 ms) were comparable to values in nontransplant healthy control subjects (974 ± 45 ms; 95% confidence interval: 962 to 987 ms). T1 values were significantly higher in group 2 (1,066 ± 78 ms) versus group 0 (984 ± 42 ms; p = 0.0001) and versus group 1 (1,001 ± 54 ms; p = 0.001). After excluding patients with an estimated glomerular filtration rate <50 ml/min/m2, there was a moderate correlation of log-transformed native T1 with high-sensitivity troponin T (r = 0.54, p < 0.0001) and pro–B-type natriuretic peptide (r = 0.67, p < 0.0001). Using a T1 cutoff value of 1,029 ms, the sensitivity, specificity, and negative predictive value were 93%, 79%, and 99%, respectively. ConclusionsMyocardial tissue characterization with T1 mapping displays excellent negative predictive capacity for the noninvasive detection of cardiac allograft rejection and holds promise to reduce substantially the EMBx requirement in cardiac transplant rejection surveillance.

Noninvasive Diagnosis of Cardiac Allograft Rejection Using Echocardiography Indices of Systolic and Diastolic Function

Background Limited and conflicting data exist on the diagnosis of cardiac allograft rejection with the use of echocardiography. The purpose of our study was to evaluate various systolic and diastolic indices, including newer tissue Doppler imaging techniques, in diagnosing cardiac allograft rejection. Methods We prospectively performed 426 echocardiography studies at the time of endomyocardial biopsy in 54 cardiac transplant patients. We measured left ventricular (LV) systolic and diastolic dimensions, mitral inflow pattern and annular velocities, and the myocardial performance index. Biopsies were assessed for cellular rejection and antibody-mediated rejection (AMR). Results Mild cellular rejection was diagnosed in 74 biopsy specimens and significant cellular rejection in 10 biopsy specimens. AMR was diagnosed in 30 biopsy specimens. In patients with mild or significant cellular rejection, no significant differences in echocardiographic parameters were observed. In patients with AMR, LV fractional shortening was significantly reduced compared with those with no AMR (mean ± SD 31.8 ± 8.9% vs 36.0 ± 7.1%; P = .02). Conclusions Although 1 echocardiographic parameter was statistically different in the setting of rejection, lack of consistency and overlap between nonrejection and rejection groups does not permit definitive noninvasive diagnosis of cardiac allograft rejection using this imaging modality.

A web-based pilot study of inter-pathologist reproducibility using the ISHLT 2004 working formulation for biopsy diagnosis of cardiac allograft rejection: The European experience

The aim of this study was to assess, at the European level and using digital technology, the inter-pathologist reproducibility of the ISHLT 2004 system and to compare it with the 1990 system We also assessed the reproducibility of the morphologic criteria for diagnosis of antibody-mediated rejection detailed in the 2004 grading system. The hematoxylin-eosin-stained sections of 20 sets of endomyocardial biopsies were pre-selected and graded by two pathologists (A.A. and M.B.) and digitized using a telepathology digital pathology system (Aperio ImageScope System; for details refer to http://aperio.com/). Their diagnoses were considered the index diagnoses, which covered all grades of acute cellular rejection (ACR), early ischemic lesions, Quilty lesions, late ischemic lesions and (in the 2005 system) antibody-mediated rejection (AMR). Eighteen pathologists from 16 heart transplant centers in 7 European countries participated in the study. Inter-observer reproducibility was assessed using Fleiss's kappa and Krippendorff's alpha statistics. The combined kappa value of all grades diagnosed by all 18 pathologists was 0.31 for the 1990 grading system and 0.39 for the 2005 grading system, with alpha statistics at 0.57 and 0.55, respectively. Kappa values by grade for 1990/2005, respectively, were: 0 = 0.52/0.51; 1A/1R = 0.24/0.36; 1B = 0.15; 2 = 0.13; 3A/2R = 0.29/0.29; 3B/3R = 0.13/0.23; and 4 = 0.18. For the 2 cases of AMR, 6 of 18 pathologists correctly suspected AMR on the hematoxylin-eosin slides, whereas, in each of 17 of the 18 AMR-negative cases a small percentage of pathologists (range 5% to 33%) overinterpreted the findings as suggestive for AMR. Reproducibility studies of cardiac biopsies by pathologists in different centers at the international level were feasible using digitized slides rather than conventional histology glass slides. There was a small improvement in interobserver agreement between pathologists of different European centers when moving from the 1990 ISHLT classification to the "new" 2005 ISHLT classification. Morphologic suspicion of AMR in the 2004 system on hematoxylin-eosin-stained slides only was poor, highlighting the need for better standardization of morphologic criteria for AMR. Ongoing educational programs are needed to ensure standardization of diagnosis of both acute cellular and antibody-mediated rejection.

Functional genomics applied to cardiovascular medicine.

Since completion of the draft sequence of the human genome in 2000, the landscape of biomedical research has undergone a rapid transformation. Growing knowledge of genome structure and variation has spawned the development of technologies that allow researchers to study thousands of genes, transcripts, and proteins simultaneously. This has expanded biomedical science beyond reductionist approaches that test the function of individual genes to less biased approaches that study the behavior of many or all genes in homeostasis and disease. Such studies have been grouped under the broad label of functional genomics, which can be defined as the branch of biology that seeks to uncover the properties and function of the entirety of the genes and gene products of an organism.1 Functional genomics is fueling an explosion of new insights in biology and medicine, and many of these insights were completely unanticipated. Because these advances have begun to influence clinical practice,2,3 physicians will be expected to understand the potential uses and limitations of functional genomics in clinical settings. The purpose of this review is to provide a conceptual overview of functional genomics applied to the practice of cardiovascular medicine. We begin with a review of commonly used terms and approaches and then describe examples of their use for screening, diagnosis, and treatment selection in clinical cardiology. We also highlight emerging trends and speculate about where the field is headed in the near term. Although some predictions will be overly optimistic and some major advances unanticipated, we hope this review will help prepare cardiologists for their role in the application of genome science to the diagnosis and treatment of disease. This review is part of a series that introduces several related areas of cardiovascular genetics and genomics.4 We refer to these other contributions to guide further reading …

Quantitative Short-Tandem Repeat Analysis of Recipient-Derived Cells as an Additional Tool for Diagnosing Cardiac Allograft Rejection

Diagnosis of cardiac allograft rejection is currently based on histologic exploration of endomyocardial biopsies. Moderate interobserver reproducibility in the estimation of number and distribution of inflammatory cells leads to disagreements in the assignment of rejection grades. Short-tandem repeat (STR) analysis is routinely used after hematopoietic stem-cell transplantation to determine the proportions of donor cells. We compared the amount of recipient-derived cells with the histopathologic grade of rejection in cardiac allografts to determine whether this method might be useful for the assessment of rejection episodes. One hundred forty-three endomyocardial biopsies from 18 patients were investigated for the percentage of recipient-derived cell content by polymerase chain reaction-based STR analysis and correlated with rejection grades determined according to the International Society for Heart and Lung Transplantation grading system. Y-chromosome chromogene in situ hybridization was performed in gender-mismatched (female-to-male) heart transplants to explore the influence of cardiomyocyte cell chimerism. The mean percentages of recipient-derived cells associated with various degrees of rejection were 13% in grade 0, 24% in grade 1A, 29% in grade 1B, 35% in grade 2, and 50% in grade > or =3A. Samples lacking signs of rejection (grade 0) had a significantly lower (P<0.001) amount of recipient-derived cells than higher degrees of rejections. Chromogene in situ hybridization analysis revealed that the recipient-derived cells were mainly inflammatory. The results of STR-analysis indicate that rejection is correlated with a higher proportion of recipient-derived cells. This assessment is observer independent and may thus represent an additional diagnostic tool for the assessment of rejection and management of immunosuppressive treatment.

512: Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Allograft Rejection

512: Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Allograft Rejection

The utility of pacemaker evoked T wave amplitude for the noninvasive diagnosis of cardiac allograft rejection.

Previous work suggested that pacemaker evoked T wave amplitude (ETWA) may be a sensitive noninvasive marker of cardiac allograft rejection. A Topaz QT sensing rate responsive pacemaker (Vitatron Medical) was implanted at transplantation using epicardial ventricular leads in 45 recipients (35 males; median age 51 years, range 20-63). The median duration of follow-up was 129 days (range 4-327). The ETWA at a paced rate of 100 beats/min was measured daily during hospitalization and at each outpatient attendance (900 readings). Endomyocardial biopsies were at routine intervals or when otherwise clinically indicated (257 biopsies with concurrent ETWA data). There were 58 episodes of rejection > or = grade 3a in 28 patients. The biopsies were classed as either no rejection (grade < 3a) or rejection requiring treatment (grade > or = 3a). The median normalized ETWA was 100.8% (range 24.6-239.7) without rejection and 89.9% (17.0-189.7) with rejection (Mann-Whitney U Test: P = 0.028). The performance of ETWA monitoring as a diagnostic test for the individual recipient was evaluated with exponentially weighted moving average quality control charts. For the diagnosis of all rejection episodes, ETWA monitoring had a sensitivity of 55%, a specificity of 62%, a positive predictive value of 30%, and negative predictive value of 83%. It is concluded that although analysis of pooled data showed a significant reduction in normalized ETWA with biopsy proven rejection, ETWA monitoring requires further refinement to improve sensitivity before it can be considered a clinically useful technique for the non-invasive diagnosis of cardiac allograft rejection in individual recipients.

Sensitive diagnosis of cardiac allograft rejection by detection of cytokine transcription in situ.

In situ transcription of cytokines which are important in the development of cardiac rejection has not been evaluated for diagnosing rejection. The objective was to evaluate the usefulness of in situ reverse transcriptase polymerase chain reaction (RT-PCR) for sensitive detection of acute cardiac rejection. We studied interferon (IFN)-gamma and interleukin (IL)-2 expression using immunohistochemistry and in situ RT-PCR in murine cardiac transplant models. Hearts were heterotopically transplanted (BALB/c to C3H/He) and some mice were not treated (n = 23); others were treated with anti-intercellular adhesion molecule (ICAM)-1 and anti-lymphocyte function associated antigen (LFA)-1 monoclonal antibodies (mAbs) (n = 23). Allografts were removed at days 1 to 7. For control, isografts were harvested at day 7 (n = 2). Mice without treatment rejected allografts within 7 days, while all mAb-treated recipients accepted allografts for the same period. At day 1, allografts of both groups showed scattered myocardial cell infiltration which increased in non-treated allografts, but remained stable in mAb-treated grafts thereafter. In situ RT-PCR showed that IL-2 and IFN-gamma mRNA positive cells were present in non-treated allografts, while few mRNA positive cells were expressed in infiltrating cells in the mAb-treated allografts (IL-2, day 3: 88.8 +/- 28.3 vs. 7.2 +/- 6.4, p < 0.05, positive cells within 10 fields per section). However, immunohistochemistry could not reveal the difference at day 3. In situ RT-PCR is a sensitive method for diagnosing acute rejection, and it reveals the characteristics of myocardial infiltrate cells to determine their role in the process of rejection.

Noninvasive diagnosis of cardiac allograft rejection: the effect of procainamide.

The surface electrocardiogram (ECG) has been used as a noninvasive technique for the diagnosis of cardiac allograft rejection. Alteration in conduction, R-wave amplitude, and rhythm have been associated with rejection. These ECG findings are modulated by the myocyte sodium channel, but are inconsistent and occur only during severe rejection episodes. The purpose of this study was to (1) characterize changes in cardiac electrophysiology during allograft rejection using the highly sensitive intramyocardial electrocardiogram and (2) determine whether pharmacological sodium channel blockade with procainamide enhances subtle ECG changes. Nine mongrel dogs underwent heterotopic heart transplantation in which four intramyocardial leads (one anteriorly and posteriorly on each ventricle) were attached. Leads exited to a subcutaneously placed ECG block which was transcutaneously accessed posttransplant to record direct intramyocardial electrocardiograms. Six animals were treated with procainamide, while three were not and served as controls. Daily measurements included the QRS, QT, and QTc intervals and the R-wave amplitude. Endomyocardial biopsies were performed weekly and also when significant decline in ECG amplitude occurred. Detailed ECG interval analysis failed to establish any correlation between conduction and rejection, even in the procainamide-treated group. Intramyocardial amplitude analysis, however, had a sensitivity of 100% and a specificity of 86% for the diagnosis of rejection. The results indicate that intramyocardial ECG interval analysis is not predictive of rejection even when prolonging conduction with procainamide. Amplitude analysis, however, remains an accurate noninvasive means for the early detection of cardiac allograft rejection and should allow more selective use of endomyocardial biopsy.

Closure of a coronary cameral fistula following endomyocardial biopsies in a cardiac transplant patient with a detachable balloon

Endomyocardial biopsy is the reference standard for the diagnosis of cardiac allograft rejection and is performed frequently in cardiac transplant patients. Biopsies are taken percutaneously via the right internal jugular or femoral vein. Fistulas from coronary arteries into the right ventricle following endomyocardial biopsies are a relatively frequent finding. Most of these fistulas are small angiographically, haemodynamically insignificant, and tend to disappear. We report a case of a haemodynamic significant coronary fistula, closed by a percutaneously introduced detachable balloon.

Prognostic indicators for endomyocardial biopsies: intragraft IL-2 and IFN-gamma are associated with poor longterm survival of cardiac allografts

Currently the diagnosis of cardiac allograft rejection depends on morphologic analysis of paraffin sections of endomyocardial biopsies. The clinical decision of when lo treat rejection, especially if the patient is well, remains a difficult decision. We questioned if expression of cytokines and other activation molecules was predictive of a given rejection episode leading to fata! rejection vs. longterm survival. Hence, a rat model of cardiac allograft rejection was established whereby a clinically relevant protocol of peri-transplant injection of donor spleen cells, plus a single injection of cyclosporin 2 days post-transplant, induced longterm allograft survival (>90 d). whereas unirealed controls rejected by day 7. We undertook immunoperoxidase localization of various leucocyte populations, cytokines and markers of cytokine-induced immune activation. Whilst H&E staining of paraffin sections at day 7 post-Tx showed grade Illb rejection for both groups, the results of immunoperoxidase staining were markedly different: Group No Rx Spleen Cells plus CsA (day 7) (day 7) (day 93) IL-2R (CD25) 21 ± 3 1 ± 1 ** 0 MHC Class 11+ cells 57 ± 11 21 ± 14 * 30 ± 8 PCNA 26 ± 4 5 ± 1 ** not done IL-2 10 ± 5 0 ** 0 IFN-gamma 7 ± 5 1 ± 1 ** 0 * p ** p Moreover, uprcgulation of endothelial ICAM-1 expression and downregulation of thrombomodulin were seen in untreated but not treated groups. Thus, despite identical grading of cardiac rejection using standard criteria applied to H&E-slained paraffin sections, immunohistologic demonstration of key pro-inflammatory cytokines IL-2 and IFN-gamma, as well as the activalion molecules IL-2R and PCNA (proliferating cell nuclear antigen), allowed clearcut prediction of those cardiac allografts which would result in acute rejection versus those likely lo achieve longterm survival. This approach may (a) improve the accuracy of diagnosis of clinical cardiac allograft rejection. (b) predict Ihe outcome of a rejection episode, and (c) increase overall survival rales and decrease mortality from infection, by decreasing immunosuppressive requirements in allografts found lo show prognostic indicators of longterm survival.

Noninvasive diagnosis of cardiac allograft rejection. Another of many searches for the grail.

Noninvasive diagnosis of cardiac allograft rejection. Another of many searches for the grail.

Noninvasive diagnosis of cardiac allograft rejection by means of pulsed Doppler and M-mode ultrasound.

The changes of left ventricular (LV) diastolic function associated with cardiac rejection were evaluated. Twenty-one cardiac allograft recipients aged 41 +/- 9 years, 11 with moderate to severe and 10 allograft rejection without rejection at myocardial biopsy underwent serial echo examination, including peak velocity (PEV), pressure half-time (PHT), velocity-time integral (VTI-E) of early mitral flow, and isovolumetric relaxation period (IVRP). In transplant recipients, significantly higher values than in 22 age-matched healthy controls were found for PEV (71 versus 56 cm/s; P less than 0.01), PHT (51 versus 43 ms; P less than 0.001), VTI-E (72 versus 57 mm; P less than 0.001), and IVRP (90 versus 73 ms; P less than 0.001). During rejection, heart rate increased significantly from 78 to 91 beats per minute (P less than 0.01). Furthermore, a significant decrease was found for PEV from 73 to 63 cm/s (P less than 0.01), for PHT from 52 to 40 ms (P less than 0.001), for VTI-E from 75 to 61 mm (P less than 0.001), and for IVRP from 90 to 74 ms (P less than 0.001) during cardiac rejection. Thus, sonographic evaluation of LV diastolic function helps to early detect cardiac rejection and to decrease the frequency of myocardial biopsy.

Diagnosis of Early Cardiac Transplant Rejection by Fall in Evoked T Wave Amplitude Measured Using an Externalized QT Driven Rate Responsive Pacemaker

Reliable diagnosis of cardiac allograft rejection is at present only possible using endomyocardial biopsy. We have serially measured epicardial evoked T wave amplitude during ventricular pacing with an externalized QT driven rate responsive pacemaker telemetered to a TP2 analyzer in 13 patients (12 males) followed for 19 (14-26) days after transplantation. A total of 228 records were analyzed. Rejection was defined on endomyocardial biopsy. On 17 of the 31 occasions on which biopsy was performed during the study, specimens showed significant (moderate) rejection. In 11 patients the initial biopsy proven rejection episode was associated with a significant fall in the evoked T wave amplitude from 1.3 (0.7-2.3) mV to 0.6 (0.5-1.8) mV (P less than 0.005), which began 2 (1-4) days earlier. One patient with uncontrolled diabetes mellitus had no change in evoked T wave amplitude during rejection. The evoked T wave amplitude did not fall in the absence of histologic rejection. These results suggest a noninvasive method for detecting cardiac rejection, which appears both sensitive (92%) and specific (100%) in the first rejection episodes.

Human Cardiac Allograft Rejection: Correlation of Grading with Expression of Different Monocyte/Macrophage Markers

Endomyocardial biopsies from human cardiac allografts were investigated with the use of immunohistochemical methods. A correlation between the different degrees of rejection reaction and subtypes of monocyte/macrophage infiltrates was established. Early and mild rejection is characterized by recently immigrated monocytes/macrophages positive for the monoclonal antibody Ki-M1. In contrast, the cellular infiltrates in severe and resolving rejection show strong expression of antigens recognized by Ki-M6 and Ki-M8, indicating increased phagocytotic function of monocytes/macrophages. The immunohistochemical assessment of monocytes/macrophages can thus be used, in addition to conventional histology, in the diagnosis of cardiac allograft rejection.