Outcomes associated with mammalian target of rapamycin (mTOR) inhibitors in heart transplant recipients: A meta-analysis

BACKGROUND

Data evaluating mTOR inhibitor use heart transplant (HT) patients comes from relatively small studies and controversy exists regarding their specific role. We performed a meta-analysis of randomized trials to evaluate the efficacy and safety of mTOR inhibitors in HT patients.

METHODS

We performed a systematic literature search of Medline and Embase through July 2017 identifying studies evaluating mTOR inhibitors in HT patients reporting effects on coronary allograft vasculopathy (CAV), renal function, acute cellular rejection (ACR), cytomegalovirus (CMV) infection, and discontinuation due to adverse drug events (ADE). Data were pooled using a random-effects model producing a mean difference (MD; for continuous data) or odds ratio (OR; for dichotomous data) and 95% confidence interval (CI).

RESULTS

14 trials reported at least one outcome of interest. Change in mean maximal intimal thickness was significantly reduced with mTOR (-0.04 [-0.07 to -0.02]) compared to calcineurin inhibitor/mycophenolate mofetil (CNI/MMF). Rates of CMV infection were also significantly reduced (0.26; [0.2 to 0.32]) with mTOR regimens compared to CNI/MMF therapy. ACR was more frequent with CNI-sparing regimens 6.46 [1.55 to 26.95]). eGFR was significantly improved with CNI-sparing therapies (mean difference 12.09 mL/min [2.43 to 21.74]), but was similar between CNI/mTOR versus CNI/MMF regimens (p > 0.05). Rates of discontinuation due to ADE were higher in mTOR-containing regimens (OR 2.15 [1.28 to 3.60], p = 0.01), while mortality rates were similar (OR 0.91 [0.61 to 1.37], p = 0.62).

CONCLUSIONS

mTOR-containing regimens can attenuate CAV and CMV risk in HT recipients. A mTOR/MMF combination preserves renal function but increases the risk of ACR.

Socioeconomic Disparities in Adherence and Outcomes After Heart Transplant: A UNOS (United Network for Organ Sharing) Registry Analysis

BACKGROUND

There is mixed evidence of racial and socioeconomic disparities in heart transplant outcomes. Their underlying cause-and whether individual- or community-level traits are most influential-remains unclear. The current study aimed to characterize socioeconomic disparities in outcomes and identify time trends and mediators of these disparities.

METHODS AND RESULTS

We used United Network for Organ Sharing registry data and included 33 893 adult heart transplant recipients between 1994 and 2014. Socioeconomic status (SES) indicators included insurance, education, and neighborhood SES measured using a composite index. Black race and multiple indicators of low SES were associated with the primary outcome of death or retransplant, independent of baseline clinical characteristics. Blacks had lower HLA and race matching, but further adjustment for these and other graft characteristics only slightly attenuated the association with black race (HR, 1.25 after adjustment). This and the associations with neighborhood SES (HR, 1.19 for lowest versus highest decile), Medicare (HR, 1.17), Medicaid (HR, 1.29), and college education (HR, 0.90) remained significant after full adjustment. When comparing early (1994-2000) and late (2001-2014) cohorts, the disparities associated with the middle (second and third) quartiles significantly decreased over time, but those associated with lowest SES quartile and black race persisted. Low neighborhood SES was also associated with higher risks of noncompliance (HR, 1.76), rejection (HR, 1.28), hospitalization (HR, 1.13), and infection (HR, 1.10).

CONCLUSIONS

Racial and socioeconomic disparities exist in heart transplant outcomes, but the latter may be narrowing over time. These disparities are not explained by differences in clinical or graft characteristics.

Comparative Assessment of Anti-HLA Antibodies Using Two Commercially Available Luminex-Based Assays

BACKGROUND

Allospecific anti-HLA antibodies (Abs) are associated with rejection of solid organ grafts. The 2 main kits to detect anti-HLA Ab in patient serum are commercialized by Immucor and One Lambda/ThermoFisher. We sought to compare the performance of both platforms.

METHODS

Background-adjusted mean fluorescence intensity (MFI) values were used from both platforms to compare sera collected from 125 pretransplant and posttransplant heart and lung transplant recipients.

RESULTS

Most HLA class I (94.5%) and HLA class II (89%) Abs with moderate to high MFI titer (≥4000) were detected by both assays. A modest correlation was observed between MFI values obtained from the 2 assays for both class I (r = 0.3, r2 = 0.09, P < 0.0001) and class II Ab (r = 0.707, r2 = 0.5, P < 0.0001). Both assays detected anti-class I and II Ab that the other did not; however, no specific HLA allele was detected preferentially by either of the 2 assays. For a limited number of discrepant sera, dilution resulted in comparable reactivity profiles between the 2 platforms.

CONCLUSIONS

Immucor and One Lambda/ThermoFisher assays have a similar, albeit nonidentical, ability to detect anti-HLA Ab. Although the correlation between the assays was present, significant variances exist, some of which can be explained by a dilution-sensitive "prozone" effect.

Role of prophylactic coronary revascularisation in improving cardiovascular outcomes during non-cardiac surgery: A narrative review

Coronary revascularisation has been a topic of debate for over three decades in patients undergoing high-risk non-cardiac surgery. The paradigm shifted from routine coronary angiography toward stress test guided decision-making based on larger randomised trials. However, this paradigm is challenged by relatively newer data where routine coronary angiography and revascularisation is shown to improve perioperative cardiovascular outcomes. We review major studies performed over a long period including more contemporary data with regard to the 2014 American College of Cardiology/American Heart Association as well as 2014 European Society of Cardiology guideline on perioperative cardiovascular evaluation of patients undergoing non-cardiac surgery.

Genome-wide DNA methylation profiling of recurrent and non-recurrent chordomas

Chordomas are an aggressive rare type of malignant bone tumors arising from the remnant of the notochord. Chordomas occur mainly in vertebral bones and account for 1-4% of malignant bone tumors. Management and treatment of chordomas are difficult as they are resistant to conventional chemotherapy; therefore, they are mainly treated with surgery and radiation therapy. In this study, we performed DNA methylation profiling of 26 chordomas and normal nucleus pulposus samples plus UCH-1 chordoma cell line using the Illumina Infinium HumanMethylation450 BeadChips. Combined bisulfite restriction analysis and bisulfite sequencing was used to confirm the methylation data. Gene expression was analyzed using RT-PCR before and after 5-aza-2'-deoxycytidine (5-azaDC) treatment of chordoma cell lines. Analysis of the HumanMethylation450 BeadChip data led to the identification of 8,819 loci (2.9%) that were significantly differentially methylated (>0.2 average β-value difference) between chordomas and nucleus pulposus samples (adjusted P < 0.05). Among these, 5,868 probes (66.5%) were hypomethylated, compared to 2,951 (33.5%) loci that were hypermethylated in chordomas compared to controls. From the 2,951 differentially hypermethylated probes, 33.3% were localized in the promoter region (982 probes) and, among these, 104 probes showed cancer-specific hypermethylation. Ingenuity Pathway Analysis indicates that the cancer-specific differentially methylated loci are involved in various networks including cancer disease, nervous system development and function, cell death and survival, cellular growth, cellular development, and proliferation. Furthermore, we identified a subset of probes that were differentially methylated between recurrent and non-recurrent chordomas. BeadChip methylation data was confirmed for these genes and gene expression was shown to be upregulated in methylated chordoma cell lines after treatment with 5-azaDC. Understanding epigenetic changes in chordomas may provide insights into chordoma tumorigenesis and development of epigenetic biomarkers.

Infiltrative Cardiomyopathies

Infiltrative cardiomyopathies can result from a wide spectrum of both inherited and acquired conditions with varying systemic manifestations. They portend an adverse prognosis, with only a few exceptions (ie, glycogen storage disease), where early diagnosis can result in potentially curative treatment. The extent of cardiac abnormalities varies based on the degree of infiltration and results in increased ventricular wall thickness, chamber dilatation, and disruption of the conduction system. These changes often lead to the development of heart failure, atrioventricular (AV) block, and ventricular arrhythmia. Because these diseases are relatively rare, a high degree of clinical suspicion is important for diagnosis. Electrocardiography and echocardiography are helpful, but advanced techniques including cardiac magnetic resonance (CMR) and nuclear imaging are increasingly preferred. Treatment is dependent on the etiology and extent of the disease and involves medications, device therapy, and, in some cases, organ transplantation. Cardiac amyloid is the archetype of the infiltrative cardiomyopathies and is discussed in great detail in this review.

Ethnicity differences in breast cancer stage at the time of diagnosis in norway

Background and aims:

Several studies have demonstrated that breast cancer survival rates differ with ethnicity. Most of these studies analyzed discrepancies between African-American and Caucasian-American women and were performed in the United States. There are increasing concerns about differences in breast cancer survival among immigrants from Asia and Africa living in Europe, including those living in Scandinavian countries. There are few data on breast cancer survival in relation to race or ethnicity in Scandinavian countries, even though immigrants from Asia and Africa have lived in Scandinavian countries for decades. The aim of this study was to identify variations in breast cancer incidence, treatment modalities, relapse, and survival among women from Pakistan, Sri Lanka, and Somalia compared to ethnic Norwegian women.

Material and methods:

The incidence, treatment modalities, relapse, and survival of breast cancer were analyzed in women from Pakistan, Sri Lanka, and Somalia in a nation-based study over a period of 7 years. Results for women from Pakistan, Sri Lanka, and Somalia were compared with those from a group of ethnic Norwegian women during the same period. In our study, 63 patients from Pakistan, Sri Lanka, and Somalia were diagnosed with breast cancer during the period 2002–2009 in Norway.

Results and conclusion:

Comparison between women from Pakistan, Sri Lanka, and Somalia and ethnic women from Norway revealed significant differences in cancer stage at the time of diagnosis, age at diagnosis, type of surgical treatment, and relapse and breast cancer mortality rates. The findings of this study demonstrate that the outcome after a breast cancer diagnosis is significantly worse for women from Pakistan, Sri Lanka, and Somalia than for ethnic Norwegian women. In addition, the mean age at the breast cancer diagnosis was lower for women from Pakistan, Sri Lanka, and Somalia, especially those from Sri Lanka and Somalia, than for ethnic Norwegian women.

Preoperative assessment of high-risk candidates to predict survival after heart transplantation

BACKGROUND

Alternate waiting list strategies expand listing criteria for patients awaiting heart transplantation (HTx). We retrospectively analyzed clinical events and outcome of patients listed as high-risk recipients for HTx.

METHODS AND RESULTS

We analyzed 822 adult patients who underwent HTx of whom 111 patients met high-risk criteria. Clinical data were collected from medical records and outcome factors calculated for 61 characteristics. Significant factors were summarized in a prognostic score. Age >65 years (67%) and amyloidosis (19%) were the most common reasons for alternate listing. High-risk recipients were older (63.2±10.2 versus 51.4±11.8 years; P<0.001), had more renal dysfunction, prior cancer, and smoking. Survival analysis revealed lower post-HTx survival in high-risk recipients (82.2% versus 87.4% at 1-year; 59.8% versus 76.3% at 5-year post-HTx; P=0.0005). Prior cerebral vascular accident, albumin <3.5 mg/dL, re-HTx, renal dysfunction (glomerular filtration rate <40 mL/min), and >2 prior sternotomies were associated with poor survival after HTx. A prognostic risk score (CARRS [CVA, albumin, re-HTx, renal dysfunction, and sternotomies]) derived from these factors stratified survival post-HTx in high-risk (3+ points) versus low-risk (0-2 points) patients (87.9% versus 52.9% at 1-year; 65.9% versus 28.4% at 5-year post-HTx; P<0.001). Low-risk alternate patients had survival comparable with regular patients (87.9% versus 87.0% at 1-year and 65.9% versus 74.5% at 5-year post-HTx; P=0.46).

CONCLUSIONS

High-risk patients had reduced survival compared with regular patients post-HTx. Among patients previously accepted for alternate donor listing, application of the CARRS score identifies patients with unacceptably high mortality after HTx and those with a survival similar to regularly listed patients.

(99m)Tc-pyrophosphate scintigraphy for differentiating light-chain cardiac amyloidosis from the transthyretin-related familial and senile cardiac amyloidoses

BACKGROUND

Differentiating immunoglobulin light-chain (AL) from transthyretin-related cardiac amyloidoses (ATTR) is imperative given implications for prognosis, therapy, and genetic counseling. We validated the discriminatory ability of (99m)Tc-pyrophosphate ((99m)Tc-PYP) scintigraphy in AL versus ATTR.

METHODS AND RESULTS

Forty-five subjects (12 AL, 16 ATTR wild type, and 17 ATTR mutants) underwent (99m)Tc-PYP planar and single-photon positive emission computed tomography cardiac imaging. Scans were performed by experienced nuclear cardiologists blinded to the subjects' cohort assignment. Cardiac retention was assessed with both a semiquantitative visual score (range, 0; no uptake to 3, diffuse uptake) and by quantitative analysis by drawing a region of interest over the heart corrected for contralateral counts and calculating a heart-to-contralateral ratio. Subjects with ATTR cardiac amyloid had a significantly higher semiquantitative cardiac visual score than the AL cohort (2.9±0.06 versus 0.8±0.27; P<0.0001) as well as a higher quantitative score (1.80±0.04 versus 1.21±0.04; P<0.0001). Using a heart-to-contralateral ratio >1.5 consistent with intensely diffuse myocardial tracer retention had a 97% sensitivity and 100% specificity with area under the curve 0.992, P<0.0001 for identifying ATTR cardiac amyloidosis.

CONCLUSIONS

(99m)Tc-PYP cardiac imaging distinguishes AL from ATTR cardiac amyloidosis and may be a simple, widely available method for identifying subjects with ATTR cardiac amyloidosis, which should be studied in a larger prospective manner.

Development of a novel echocardiography ramp test for speed optimization and diagnosis of device thrombosis in continuous-flow left ventricular assist devices: the Columbia ramp study

OBJECTIVES

This study sought to develop a novel approach to optimizing continuous-flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions.

BACKGROUND

In CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp test.

METHODS

We devised a unique ramp test protocol to be routinely used at the time of discharge for speed optimization and/or if device malfunction was suspected. The patient's left ventricular end-diastolic dimension, frequency of aortic valve opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded in increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for left ventricular end-diastolic dimension, pulsatility index, and power were calculated.

RESULTS

Fifty-two ramp tests for 39 patients were prospectively collected and analyzed. Twenty-eight ramp tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424 ± 211 rpm. Seventeen patients had ramp tests performed for suspected device thrombosis, and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplantation. Device thrombosis was confirmed in 8 of 10 cases at the time of emergent device exchange or transplantation. All patients with device thrombosis, but none of the remaining patients had a left ventricular end-diastolic dimension slope >-0.16.

CONCLUSIONS

Ramp tests facilitate optimal speed changes and device malfunction detection and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients.

[Twenty-five statements on early initiation of fixed combination ICS/LABA treatment for asthma and COPD in primary and secondary care: consensus research by a modified Delphi process]

BACKGROUND

Guidelines recommend the addition of a long-acting β2-agonist (LABA) for patients whose asthma is uncontrolled on inhaled corticosteroid (ICS) monotherapy. For COPD patients the addition of an ICS to a long-acting bronchodilator is recommended for symptomatic patients at high risk of exacerbations. We examined whether in real-life practice guideline recommendations may delay optimal timing for initiation of combination treatment.

METHODS

A modified Delphi process was undertaken with a panel of physicians, including six GPs and four pulmonologists, in practice in Germany. The first round comprised a semi-structured questionnaire, the second stage was an online discussion to reach consensus on 25 statements concerning the use of ICS/LABA in patients with asthma or COPD.

RESULTS

Consensus was achieved on 24 of 25 prepared statements for early initiation of fixed ICS/LABA combination treatment. The panel agreed that a meaningful share of their asthma patients on ICS monotherapy experienced symptoms and exacerbations that should lead to addition of LABAs and that timely initiation of ICS/LABA therapy in asthma patients could improve asthma control, and prevent a significant number of emergency room visits, hospitalisations or additional specialist visits. The panel agreed that symptomatic patients with moderate to severe COPD, and frequent exacerbations should receive ICS without any delay in addition to their bronchodilator maintenance therapy. These patients could benefit from fewer exacerbations and a reduction in symptoms. The panel reached a consensus that fixed-dose ICS/LABA could have a positive effect on adherence, compared with separate inhalers for ICS and LABA, which may impact treatment outcomes.

CONCLUSION

A panel of ten physicians working in primary and secondary care agreed on 24 out of 25 statements that supported the early initiation of fixed combination treatment, if indicated in a meaningful number of their asthma and COPD patients.

Abstract P311: CAPTURE: Cardio-Pulmonary Tissue Repository

Background: Cardiothoracic tissue is highly sought by researchers, yet repositories for such tissue are conspicuously absent in the U.S.A. This limits the availability of research-quality tissue specimens. Columbia University is one of the nation's busiest heart and lung transplant centers and has excellent access to such tissue. Ca rdio p ulmonary T iss u e Re pository (CAPTURE) aims to fill this existing resource gap by creating a large-scale cardiothoracic tissue repository.

Methods: Since 1999 Columbia University has collected cardiothoracic tissue on an informal basis. This is now being transitioned into CAPTURE, a sophisticated tissue bank for the collection, preservation, and distribution of research-quality tissue specimens. A team is on call 24/7 to collect tissue samples and process them immediately by flash freezing, formalin or RNAlater. Samples are annotated with clinical data from the Patients' Advantage Cardiothoracic Surgery Clinical Research Project (PACTS-CR Project), labeled with bar codes, catalogued using PROGENY LIMS (a secure electronic tracking system), and stored in freezers protected by emergency back-up ( centralized storage and collection ). CAPTURE aims to expand into a strong network of regional hospitals that contribute and utilize tissues ( centralized storage and decentralized collection ), and then to transition into a specialized program of research excellence (SPORE), becoming an NIH/NHLBI partner and later a nationwide cardiopulmonary tissue repository ( decentralized storage and collection ).

Results: Tissue has been obtained from over 700 patients over the last decade. By obtaining up to 35 samples from each heart explanted during orthotopic heart transplant and up to 10 samples per myocardial core taken during ventricular assist device (VAD) implantation, over 12,000 tissue samples are currently stored. Intra- and multicenter collaborations have utilized these tissues to conduct several different studies.

Conclusion: Successful past experiences have shown the promise of maintaining even an informal bank of cardiothoracic tissue samples. By offering greatly expanded and sophisticated tissue banking facilities, we anticipate CAPTURE will accelerate basic science and translational research.

Drawing networks of rejection - a systems biological approach to the identification of candidate genes in heart transplantation

Technological development led to an increased interest in systems biological approaches to characterize disease mechanisms and candidate genes relevant to specific diseases. We suggested that the human peripheral blood mononuclear cells (PBMC) network can be delineated by cellular reconstruction to guide identification of candidate genes. Based on 285 microarrays (7370 genes) from 98 heart transplant patients enrolled in the Cardiac Allograft Rejection Gene Expression Observational study, we used an information-theoretic, reverse-engineering algorithm called ARACNe (algorithm for the reconstruction of accurate cellular networks) and chromatin immunoprecipitation assay to reconstruct and validate a putative gene PBMC interaction network. We focused our analysis on transcription factor (TF) genes and developed a priority score to incorporate aspects of network dynamics and information from published literature to supervise gene discovery. ARACNe generated a cellular network and predicted interactions for each TF during rejection and quiescence. Genes ranked highest by priority score included those related to apoptosis, humoural and cellular immune response such as GA binding protein transcription factor (GABP), nuclear factor of κ light polypeptide gene enhancer in B-cells (NFκB), Fas (TNFRSF6)-associated via death domain (FADD) and c-AMP response element binding protein. We used the TF CREB to validate our network. ARACNe predicted 29 putative first-neighbour genes of CREB. Eleven of these (37%) were previously reported. Out of the 18 unknown predicted interactions, 14 primers were identified and 11 could be immunoprecipitated (78.6%). Overall, 75% (n= 22) inferred CREB targets were validated, a significantly higher fraction than randomly expected (P < 0.001, Fisher’s exact test). Our results confirm the accuracy of ARACNe to reconstruct the PBMC transcriptional network and show the utility of systems biological approaches to identify possible molecular targets and biomarkers.

The neuronal repellent SLIT2 is a target for repression by EZH2 in prostate cancer

The neuronal repellent SLIT2 is repressed in a number of cancer types primarily through promoter hypermethylation. SLIT2, however, has not been studied in prostate cancer. Through genome-wide location analysis we identified SLIT2 as a target of Polycomb group (PcG) protein EZH2. The EZH2-containing Polycomb repressive complexes bound to the SLIT2 promoter inhibiting its expression. SLIT2 was down-regulated in a majority of metastatic prostate tumors exhibiting a negative correlation with EZH2. This repressed expression could be restored by methylation inhibitors or EZH2-suppressing compounds. In addition, a low level of SLIT2 expression was associated with aggressive prostate, breast and lung cancers. Functional assays showed that SLIT2 inhibited prostate cancer cell proliferation and invasion. Thus, this study demonstrated for the first time epigenetic silencing of SLIT2 in prostate tumors, and supported SLIT2 as a potential biomarker for aggressive solid tumors. Importantly, PcG-mediated repression may serve as a precursor for the silencing of SLIT2 by DNA methylation in cancer.

Novel thermodynamics of xylanase formation by a 2-deoxy-d-glucose resistant mutant of Thermomyces lanuginosus and its xylanase potential for biobleachability

Production of xylanases by Thermomyces lanuginosus wild type and its deoxyglucose resistant mutant M7 on different substrates was investigated. The mutation conferred catabolite repression resistance as M7 supported xylanase production on glucose-based medium that was 8.8-fold higher than that of wild type. Product formation parameters were highest in media containing a combination of corncob and corn steep liquor. Among the soluble substrates, xylose was the best inducer. In the presence of glucose, the wild type produced 26 IU of xylanase per g of glucose while the xylanase yield of the mutant was 224 IU per g of glucose. Thermodynamic studies showed that M7 required lower Gibbs free energy, enthalpy and entropy for product formation than the wild type. In biobleaching studies an 18.6% decrease in kappa number and 2.63% increase in brightness for enzyme-treated pulp was observed. Moreover prebleaching with M7-derived enzyme resulted in a 27.3% reduction in chlorine demand as compared with that of 18.5% decrease when wild organism-derived enzyme was employed. These improvements indicate that the mutant-derived enzymes possessed a useful prebleaching potential and could be exploited for large-scale application.

Peripheral blood mononuclear cell transcriptome profiles suggest T-cell immunosuppression after uncomplicated mechanical circulatory support device surgery

Mechanical circulatory support device (MCSD) surgery in patients with advanced heart failure patients is often complicated by infections that are linked to altered cell-mediated immunity. Using a transcriptome-wide peripheral blood mononuclear cell (PBMC) gene expression profiling approach, we analyzed expression patterns directly before and after MCSD implantation in 11 patients who had an uncomplicated course after MCSD implantation (Day 0-24 hours before, Day 1-24 hours after, and Day 7-1 week after implantation). Data were analyzed using Significance Analysis of Microarrays (SAM) and High-Throughput GoMiner on post-implantation profiles (Day 1, Day 7) in comparison with baseline (Day 0). Day1 profiles included differential expression of 821 genes (SAM, FDR <0.1, fold change >1.5), enriching >60 Gene Ontology (GO) categories. Grouping by component genes revealed GO clusters, which we term "interleukin related" (primarily upregulated), "T-cell related" (primarily downregulated), and "apoptosis related" (both up- and down-regulated genes). Day 7 profiles included GO categories related to repair processes. In conclusion, transcriptome-wide expression profiling of PBMCs suggests a response pattern to MCSD implantation of inflammatory activation and simultaneous T-cell suppression.

Relationship between a validated molecular cardiac transplant rejection classifier and routine organ function parameters

BACKGROUND

As acute cellular cardiac allograft rejection is a systemic process affecting the entire organism, we hypothesized that scores of a peripheral blood mononuclear cell gene expression profiling (GEP) test developed and validated to rule out International Society of Heart and Lung Transplantation (ISHLT) grade > or = 3A/2R acute cellular cardiac allograft rejection also reflects biologically plausible changes of the routinely assessed clinical parameters.

METHODS

We retrospectively analyzed 76 patients who underwent GEP testing, at the time of their routine clinical follow-up in our Institution between February 1, 2006 and January 31, 2007. Data were analyzed with t-test, nonparametric tests, bivariate Spearman's correlation, and multivariate linear regression modeling.

RESULTS

More activated GEP-score correlated with longer corrected QT (QTc)-interval (r = 0.377, p = 0.001, n = 63), longer QRS duration (r = 0.231, p = 0.03, n = 66), higher heart rate (r = 0.221, p = 0.037, n = 66), higher serum creatinine (r = 0.26, p = 0.01, n = 75), higher gamma-glutamyl transferase (GGT) GGT (r = 0.266, p = 0.037, n = 46), lower pulmonary artery oxygen saturation (r = -0.313, p = 0.003, n = 76), lower platelet count (r = -0.372, p = 0.001, n = 74), lower monocyte count (r = -0.208, p = 0.040, n = 72), and lower high-density lipoprotein (HDL) HDL level (r = -0.242, p = 0.041, n = 53). Multivariate analysis showed a significant amount of variance in the GEP score independently explained by the variability of QTc-interval (beta = 1.998, p = 0.001) and platelet count (beta = -1.540, p = 0.017). Post hoc analysis of the 11 individual GEP-classifier genes showed WDRA40 (p = 0.02) and ras homolog gene family, member U (RHOU) RHOU (p = 0.01) independently related to mixed venous O(2)Sat%.

CONCLUSION

A GEP test developed and validated to detect the absence of cardiac rejection correlates with electrocardiographic and hemodynamic cardiac parameters as well as renal, hepatic, bone marrow, and lipid metabolism parameters suggesting a complex relationship between rejection, leukocytes, and organ function within the continuum between alloimmunological quiescence and rejection.