This study is designed to evaluate the safety and efficacy of a peripheral blood mononuclear cell gene expression profiling method (AlloMap) in monitoring asymptomatic heart transplant patients for acute rejection beginning 2-6 months(≥ 55-185 days) after transplantation.

Cardiac allograft rejection is experienced by 20-50% of patients at least once during the first year after cardiac transplantation under the present immunosuppression regimens. The standard for rejection surveillance has been the endomyocardial biopsy (EMB). However, EMB is invasive, causes morbidity, and is subject to sampling error and inter-observer variability.

Gene expression profiling (GEP), with its high negative predictive value (NPV) for acute cellular rejection (ACR), appears to be well suited to identify low-risk patients who can be safely managed without routine invasive endomyocardial biopsy (EMB).

The Invasive Monitoring Attenuation through Gene Expression (IMAGE) multicenter study was conducted between the years 2005-2009 and studied patients who were >6 months-5 years post transplant. The IMAGE study demonstrated that the clinical outcome of heart transplant patients managed with AlloMap® was noninferior to patients managed with EMB. The EIMAGE study expands the time window under study to include patients who are 2 months (≥ 55 days) post-transplant. This earlier time frame of study is the primary difference between the EIMAGE study and the IMAGE study.

Inclusion Criteria:

1. Heart transplant recipients who are 2-6 months (≥55 days -185 days) post-transplant at the time of the first study surveillance visit
2. Age ≥ 18 years
3. Left ventricular ejection fraction ≥ 50% by Echocardiography, Multiple Gated Acquisition (MUGA) scan, or ventriculography at study entry (baseline / enrollment study)

Exclusion Criteria:

1. Any clinical signs of declining graft function:

   • Symptoms of Congestive Heart Failure (CHF) at the first study surveillance visit
   • Signs of decompensated heart failure, including the development of a new S3 gallop at the enrollment visit
   • Elevated right heart pressures with diminished cardiac index < 2.2 L/min/m2 that is new compared to a previous measurement within 2 months
   • Decrease in LVEF as measured by echocardiography: ≥ 25% compared to prior measurement within 2 months

2. Rejection therapy for biopsy-proven ISHLT Grade 3A or higher during the preceding 2 months

3. Prior or current evidence of antibody-mediated rejection (AMR). AMR is defined according to the ISHLT 2004 Guidelines as positive histology and immunopathology (either immunofluorescence or immunoperoxidase) staining for AMR

4. Major changes in immunosuppression therapy within previous 30 days (e.g., discontinuation of calcineurin inhibitors, switch from mycophenolate mofetil to sirolimus or vice versa)

5. Unable to give written informed consent

6. Patient receiving hematopoietic growth factors (e.g., Neupogen, Epogen) currently or during the previous 30 days

7. Patients receiving ≥ 20 mg/day of prednisone equivalent corticosteroids at the time of first study surveillance visit

8. Patient enrolled in a trial requiring routine surveillance endomyocardial biopsies

9. Patient received transfusion within preceding 4 weeks

10. Patients with end-stage renal disease requiring some form of renal replacement therapy (hemodialysis or peritoneal dialysis)

11. Pregnancy at the time of first study surveillance visit