Early diastolic left ventricular function as a marker of acute cardiac rejection: a prospective serial echocardiographic study

The evolution of patient-specific precision biomarkers to guide personalized heart-transplant care

Introduction

In parallel to the clinical maturation of heart transplantation over the last 50 years, rejection testing has been revolutionized within the systems biology paradigm triggered by the Human Genome Project.

Areas Covered

We have co-developed the first FDA-cleared diagnostic and prognostic leukocyte gene expression profiling biomarker test in transplantation medicine that gained international evidence-based medicine guideline acceptance to rule out moderate/severe acute cellular cardiac allograft rejection without invasive endomyocardial biopsies. This work prompted molecular re-classification of intragraft biology, culminating in the identification of a pattern of intragraft myocyte injury, in addition to acute cellular rejection and antibody-mediated rejection. This insight stimulated research into non-invasive detection of myocardial allograft injury. The addition of a donor-organ specific myocardial injury marker based on donor-derived cell-free DNA further strengthens the non-invasive monitoring concept, combining the clinical use of two complementary non-invasive blood-based measures, host immune activity-related risk of acute rejection as well as cardiac allograft injury.

Expert Opinion

This novel complementary non-invasive heart transplant monitoring strategy based on leukocyte gene expression profiling and donor-derived cell-free DNA that incorporates longitudinal variability measures provides an exciting novel algorithm of heart transplant allograft monitoring. This algorithm's clinical utility will need to be tested in an appropriately designed randomized clinical trial which is in preparation.

Functional tricuspid valve insufficiency after cardiac transplantation: Which factor is the most important?

Objectives

Tricuspid insufficiency (TI) is the most common valvular complication following orthotopic heart transplantation (HTx) and in serious cases is associated with increased mortality. In this study, we analyze the possible variables influencing TI following HTx and aim to identify the most important risk factors and mechanisms responsible for functional TI development and progression.

Methods

We identified the incidence of TI within our institute in 857 of 1515 patients who underwent HTx using the biatrial anastomosis technique in the years between 1986 and 2010. The risk factors that could influence TI were retrospectively analyzed in detail in a representative group of 152 patients with identical TI distribution as found in the entire program. Patients of the group were subdivided into 2 groups according to the severity of TI: patients with TI grade ≤2 and those with TI grade >2. Impact on long-term survival (>15 years) was assessed.

Results

In univariable analysis, study variables such as age of recipient (P = .027), donor to recipient right atrium anterior wall ratio (P < .001), tricuspid annulus anterior to septal leaflet excursion ratio (P = .001), dialysis (P = .026), and total biopsy number (P = .003) showed significant differences. The variables, height of recipient (P = .080), body mass index donor to body mass index recipient ratio (P = .080), and number of biopsies with more than moderate grade (P = .067) showed a trend toward significance in the development of severe TI after HTx. In multivariable analysis, we found an independent significant association between TI after HTx and donor to recipient right atrium anterior wall ratio, number of biopsies, and dialysis.

Conclusions

Changes in tricuspid annulus geometry, number of biopsies, and dialysis are the most important risk factors for the development and progression of TI following cardiac transplantation. It could be prevented using modified operative techniques, noninvasive diagnostic modalities, and intensified ultrafiltration. In patients with biatrial anastomosis technique with generous atrial cuff, the presence of TI greater than grade 2 did not impact long-term survival.

Diagnostic performance of echocardiography for the detection of acute cardiac allograft rejection: a systematic review and meta-analysis

Objective

Many studies have addressed the diagnostic performance of echocardiography to evaluate acute cardiac allograft rejection compared with endomyocardial biopsy. But the existence of heterogeneity limited its clinical application. Thus, we conducted a comprehensive, systematic literature review and meta-analysis for the purpose.

Methods

Studies prior to September 1, 2014 identified by Medline/PubMed, EMBASE and Cochrance were examined by two independent reviews. We conducted meta-analysis by using Meta-DiSc 1.4 software. An assessment tool of QUADAS-2 was applied to evaluate the risk of bias and applicability of the studies.

Results

Thirty studies met the inclusion criteria of meta-analysis. The four parameters of pressure half time, isovolumic relaxation time, index of myocardial performance and late diastolic mitral annular motion velocity were included in the meta-analysis, with a pooled diagnostic odds ratio of 10.43, 6.89, 15.95 and 5.68 respectively, and the area under the summary receiver operating characteristic curves value of 0.829, 0.599, 0.871 and 0.685 respectively.

Conclusion

The meta-analysis and systematic review demonstrate that no single parameter of echocardiography showed a reliable diagnostic performance for acute cardiac allograft rejection. A result of echocardiography for ACAR should be comprehensively considered by physicians in the context of clinical presentations and imaging feature.

Utility of left ventricular systolic torsion derived from 2-dimensional speckle-tracking echocardiography in monitoring acute cellular rejection in heart transplant recipients

BACKGROUND

Reduced left ventricular torsion (LV-tor) has been reported to be associated with acute rejection in heart transplant (HTx) recipients. We investigated the utility of LV-tor analysis derived from 2-dimensional speckle-tracking echocardiography (2D-STE) for detecting allograft rejection.

METHODS

A total of 301 endomyocardial biopsies (EMBs), right heart catheterizations and echocardiograms were performed in 32 HTx recipients. Echocardiography was done within 3 hours from EMB or simultaneously with the procedures. The LV-tor was defined as the difference between apical and basal end-systolic rotations. The LV-tor values with and without cellular rejection were compared. In addition, we investigated whether the change in LV-tor values predicts the change in rejection grade in each patient. The baseline LV-tor value in each patient was defined as a mean value of the first 3 LV-tor measurements obtained when the patient was free from rejection.

RESULTS

According to the conventional International Society for Heart and Lung Transplantation criteria, 274 biopsies showed a rejection Grade of 0, 1a or 1b (Group AR(-)), whereas 27 biopsies were Grade 2 or higher (Group AR(+)). LV-tor decreased more in Group AR(+) than in Group AR(-) (9.3 ± 0.7 vs 12.2 ± 0.2 degrees, p < 0.0001). In the LV-tor measurement for each patient, the 25% reduction in LV-tor value from baseline predicted Grade 2 or higher rejection with a predictive accuracy of 92.9%.

CONCLUSION

LV-tor derived from 2D-STE could be of clinical value for non-invasive monitoring of acute rejection in HTx recipients.

Echocardiography in the cardiac transplant recipient

Despite the widespread use of echocardiography in the cardiac allograft recipient, the clinical usefulness of this practice is not well defined. In this article, the authors review the spectrum of echocardiographic findings in the adult heart transplant patient. Appreciation of typical alterations from "normal" allows the transplant physician to identify clinically significant changes and to avoid unnecessary invasive procedures based on misinterpretation of these differences. Though abnormalities of systolic and diastolic function correlate with episodes of acute rejection, the primary diagnostic usefulness of echocardiography in acute rejection is guiding the endomyocardial biopsy. Additionally, echocardiography has found a role as a supplement to invasive angiography in the diagnosis of cardiac allograft vasculopathy.

Noninvasive discrimination of rejection in cardiac allograft recipients using gene expression profiling

Rejection diagnosis by endomyocardial biopsy (EMB) is invasive, expensive and variable. We investigated gene expression profiling of peripheral blood mononuclear cells (PBMC) to discriminate ISHLT grade 0 rejection (quiescence) from moderate/severe rejection (ISHLT > or = 3A). Patients were followed prospectively with blood sampling at post-transplant visits. Biopsies were graded by ISHLT criteria locally and by three independent pathologists blinded to clinical data. Known alloimmune pathways and leukocyte microarrays identified 252 candidate genes for which real-time PCR assays were developed. An 11 gene real-time PCR test was derived from a training set (n = 145 samples, 107 patients) using linear discriminant analysis (LDA), converted into a score (0-40), and validated prospectively in an independent set (n = 63 samples, 63 patients). The test distinguished biopsy-defined moderate/severe rejection from quiescence (p = 0.0018) in the validation set, and had agreement of 84% (95% CI 66% C94%) with grade ISHLT > or = 3A rejection. Patients >1 year post-transplant with scores below 30 (approximately 68% of the study population) are very unlikely to have grade > or = 3A rejection (NPV = 99.6%). Gene expression testing can detect absence of moderate/severe rejection, thus avoiding biopsy in certain clinical settings. Additional clinical experience is needed to establish the role of molecular testing for clinical event prediction and immunosuppression management.

Plasmapheresis and cyclophosphamide in the treatment of humoral rejection after heart transplantation

BACKGROUND

Clinical reports on humoral rejection after heart transplantation showed that these episodes were often more severe than those mediated through T lymphocytes and that the patient's prognosis was significantly worsened.

METHODS

To evaluate the impact of plasmapheresis on the course of humoral rejection with hemodynamic compromise (HRHC) episodes, we retrospectively investigated the records of 1,108 heart transplant patients. All patients received triple-drug immunosuppression (cyclosporine a, azathioprine, prednisone) and cytolytic antibodies for induction. Between April 1986 and December 1990, HRHC episodes were treated with cortisone boli and cytolytic antibodies for at least 3 days (Group A). Between January 1991 and April 1999, HRHC episodes were treated with cortisone boli, cytolytic antibodies, and plasmapheresis for at least 3 days (Group B). All patients who survived their first HRHC episode received cyclophosphamide instead of azathioprine as maintenance immunosuppression.

RESULTS

Altogether we observed 29 HRHC episodes. In 11 cases, no therapy could be administered or the therapy regimen did not correspond to either Protocol A or B. In the remaining 18 HRHC episodes, 7 episodes in 7 patients were treated without plasmapheresis (Group A), but only 2 patients survived, whereas in 11 HRHC episodes in 6 patients, therapy included plasmapheresis (Group B) and all patients survived (p = 0.002). Four of 6 patients who received cyclophosphamide after their first HRHC episode experienced at least 1 further HRHC episode.

CONCLUSIONS

Plasmapheresis seems to improve outcomes in HRHC. However, cyclophosphamide as a maintenance immunosuppressive drug failed to prevent further humoral rejection episodes.

Daily noninvasive rejection monitoring improves long-term survival in pediatric heart transplantation

BACKGROUND

Acute rejection episodes and transplant vasculopathy (TVP) account for most of the late deaths after heart transplantation in both adults and children. Accumulating evidence indicates that fatal acute rejection and TVP are related to unrecognized and untreated early and ongoing acute rejection. Day-by-day surveillance of the heart and prompt treatment of any rejection may yield improved long-term survival.

METHODS

In almost all patients having transplantation at our institution (978 patients since 1986), the intramyocardial electrogram (IMEG) was recorded routinely every day through a telemetry pacemaker and transmitted to our center by telephone modem. Earlier studies showed a substantial voltage drop in the IMEG QRS complex is highly indicative of acute rejection, including humoral rejection. In this study, we reviewed the data from 69 pediatric patients up to 16 years old for the incidence of acute rejection, TVP, and long-term outcome. Diagnostic endomyocardial biopsies were performed in only 10 patients, and recent coronary angiograms from 29 children were reviewed.

RESULTS

In 50 children discharged after heart transplantation, IMEG surveillance data for a mean of 2.9 years indicated 72 acute rejection episodes. During follow-up of 1 month to 10.5 years (mean follow-up, 4.4 years), 2 patients died late of causes unrelated to either rejection or TVP. Another patient died of rejection during unrecognized underimmunosuppression nearly 8 years after transplantation and nearly 31/2 years after discontinuing IMEG recordings. Two patients without IMEG recording died of acute rejection or late TVP. In 1 patient, moderate TVP was seen on an angiogram after 41/2 years (incidence, 2.0%; 5-year incidence, 5.6%).

CONCLUSIONS

Daily recording of the IMEG can reliably detect early stages of acute rejection episodes, and immediate rejection treatment seems to keep the incidence of TVP low. The IMEG appears better than all the other rejection monitoring protocols currently in use.

T-cell and monocyte subsets, inflammatory molecules, rejection, and hemodynamics early after cardiac transplantation

BACKGROUND

In the early period after cardiac transplantation, differential diagnosis of graft failure due to rejection, infection, and other causes is important but difficult.

METHODS

In 22 consecutive patients undergoing heart transplantation, we prospectively determined levels of interleukin-6 as well as T-cell and monocyte subsets at eight points in time during biopsy and right heart catheterization and within 12 hr of echocardiography during the first 3 months after transplantation.

RESULTS

Worse hemodynamic parameters, as characterized by dichotomization according to median values (pulmonary capillary wedge pressure >10 mmHg, mean pulmonary arterial pressure > 18 mmHg, pulmonary vascular resistance > 115 dyn x sec x cm(-5), right atrial pressure > 5 mmHg, cardiac index <3 L/min/m2, early mitral deceleration time < 135 msec, and isovolumic relaxation time <80 msec), were associated with higher levels of interleukin-6, C-reactive protein, polymorphonuclear cells, CD71+/CD14+ monocytes, and IgM levels and, in contrast, with lower levels of immunocompetence markers such as CD3+ T cells, CD4+ T cells, CD8+ T cells, CD3+/CD25+ T cells, CD4+/ CD45RO+ T cells, NK cells, and lower biopsy scores.

CONCLUSION

Early after cardiac transplantation, elevated levels of inflammatory cells and soluble inflammatory molecules and lower levels of immunocompetence markers are associated with impaired allograft function in the absence of cellular rejection.

Possible relationship between heat shock protein 70, cardiac hemodynamics, and survival in the early period after heart transplantation

BACKGROUND

Heat shock proteins (HSPs) are produced by cells in response to a wide variety of stresses. To determine a possible relationship between hemodynamic parameters and HSP 70 in the early postoperative period after heart transplantation, we examined immunohistochemically the inducible HSP 70 (anti-HSP 72) response in human heart biopsies, as well as the effect of myocardial rejection on HSP.

METHODS

A total of 105 routinely processed endomyocardial biopsies from 15 consecutive patients who underwent heart transplantation were examined. Analysis of hemodynamic and echocardiographic parameters were performed within 30 min and 12 hr after the biopsies.

RESULTS

Immunohistochemically detected inducible HSP 70 was mainly located in the cytoplasm and nucleus/nucleolus of cardiomyocytes. Two specimens additionally showed HSP 70-positive interstitial cells and smooth muscle cells of arteries, whereas lymphocytes were consistently negative. There was a significant relation between the echocardiographically determined increased relaxation time and positive HSP 70 staining (P < 0.011). Patients with elevated right atrial pressure (P < 0.098), as well as those with increased left ventricular end systolic diameter (P < 0.06), showed a trend to higher HSP expression. Three patients who died of sepsis or multiorgan failure showed significantly higher cytoplasmic HSP 70 expression compared with 12 patients with stable clinical course. In case of rejection, significantly more patients showed no HSP expression.

CONCLUSION

Although only five patients showed organ rejection, our results suggest an inverse relationship between HSP expression and rejection with the possibility of a role for HSP 70 as a graft marker to assess graft function.