Mesenchymal Stem Cell Administration in the Treatment of Coronary Graft Disease in Heart Transplant Patients

MES-HT is a phase 1-2 multicenter pilot prospective study conducted on 14 heart transplant patients who developed severe coronary vasculopathy, in the aim to assess the effect on myocardial perfusion of the intramyocardial administration by percutaneous way of autologous mesenchymal stem cells derived from the bone marrow.

The main objective is to show improvement in myocardial perfusion in a non-randomized and uncontrolled pilot study, before considering a randomized controlled study. The administration of intra myocardial cells using the NOGA system was carried out to date with more than 1,000 patients and is considered feasible and safe. However, the investigators will assess very carefully the feasibility and safety of this invasive approach.

The primary endpoint is the improvement of myocardial perfusion measured by MRI after endomyocardial injection of mesenchymal cells by percutaneous way, guided by the NOGA system.

The secondary endpoints are the feasibility and safety of this administration, changes in ejection fraction measured by contrast echocardiography, changes in other MRI cardiac parameters (left ventricular volumes , intramyocardial fibrosis), the oxygen consumption during exercise, myocardial perfusion measured by SPECT. Other secondary endpoints are the evolution of the immune status, and histological criteria of myocardial biopsy.

Once the mapping performed, preparation is injected through another catheter (MYOSTAR injection catheter) which will also be guided by the Noga® system. This catheter may be positioned on the regions of interest (viable ischemic areas) and allow the injection of the quantity of CSM (40 million / ml) in 10 to 12 different injection points and injection volumes 0.3 ml for a total dose of 120 to 144 million cells.

After each injection procedure, patients are monitored for 48 hours minimum clinically and under continuous ECG monitoring to detect possible arrhythmias. A troponin dosage is done after 6 H, and after 24 and 48 hours. An echocardiogram is performed immediately after the procedure and before the release to 48 H.

A clinical evaluation will be made after the patient is discharged at 1 month (clinical examination + Holter + echocardiography), 3 months (examination), 6 months (clinical examination, Holter, echocardiography, cardiac MRI, test of effort with measurement of VO2, effort myocardial tomoscintigraphy and for patients from Pitie-Salpetriere hospital, Rubidium 82 by positron emission tomography) and 12 months (examination). Myocardial biopsy and a control coronary angiography will be only performed within 12 months in accordance with the practice of the teams.

Patients will benefit from a biological monitoring which provides for the monitoring of immune response. This immuno-monitoring is to assess the possible influence of the injection of mesenchymal cells on immunological tolerance mechanisms. It will be implemented in the balance sheets of cardiac tissue at the waning annual biopsies and peripheral blood samples on inclusion, 48 hours after injection and at 1 month, 3 months and 6 months.

The limiting toxicity is defined as the occurrence at one month of a serious adverse effect related to the protocol , requiring an hospitalization or being able to be life-threatening , or like abundant pericardial effusion requiring pericardial drainage, bleeding complications requiring blood cell transfusion or surgery, stroke constituted, sepsis or septic shock, cardiogenic shock, severe ventricular rhythm refractory death.

All patients are followed for one year.