The MYocardial STem cell Administration after acute myocardial infaRction (MYSTAR) study is a multicenter, prospective, randomized, single-blind clinical trial designed to compare the early and late intracoronary or combined (percutaneous intramyocardial and intracoronary) administration of bone marrow-derived stem cells to patients after acute myocardial infarction with reopened infarct-related artery.

Previous data suggest that bone marrow-derived stem cells (BM-SCs) decrease the infarct size and beneficially affect the postinfarction remodeling.

The MYocardial STem cell Administration after acute myocardial infaRction (MYSTAR) study is a multicenter, prospective, randomized, single-blind clinical trial designed to compare the early and late intracoronary or combined (percutaneous intramyocardial and intracoronary) administration of BM-SCs to patients after acute myocardial infarction (AMI) with reopened infarct-related artery.

The primary endpoints are the changes in resting myocardial perfusion defect size and left ventricular ejection fraction (gated SPECT scintigraphy) 3 months after BM-SCs therapy.

The secondary endpoints relate to evaluation of 1) the safety and feasibility of the application modes, 2) the changes in left ventricular wall motion score index (transthoracic echocardiography), 3) myocardial voltage and segmental wall motion (NOGA mapping), 4) left ventricular end-diastolic and end-systolic volumes (contrast ventriculography), and 5) the clinical symptoms (CCS and NYHA) at follow-up.

Patients are randomly assigned into one of four groups, Group A: early treatment (21-42 days after AMI) with intracoronary injection; Group B: early treatment (21-42 days after AMI) with combined (intramyocardial and intracoronary) application; Group C: late treatment (3 months after AMI) with intracoronary delivery; and Group D: late treatment (3 months after AMI) with combined (intramyocardial and intracoronary) administration of BM-SCs. Besides the BM-SCs therapy, the standardized treatment of AMI is applied in all patients.

The MYSTAR trial is the first randomized trial to investigate the effects of the combined (intramyocardial and intracoronary) and the intracoronary mode of delivery of BM-SCs therapy in the early and late periods after AMI.

Inclusion Criteria:

• Patient with a definitive AMI not earlier than 21 days and not later than 42 days before randomization (day 0 is the day of infarction)
• Patients with open IRA without significant stenosis and TIMI flow 3, after successful percutaneous coronary intervention (PCI) of the IRA
• Patients with two- or three-vessel disease might be included after adequate PCI if no significant coronary lesion can be seen in the non-infarct-related major vessels at the time of BM-SCs therapy
• A persistent local new wall motion abnormality related to the recent infarct location.
• Preserved myocardial viability, at least in the part of the recent infarction should be demonstrated by a preserved wall thickness and/or hypokinesia determined by transthoracic echocardiography or contrast ventriculography, and preserved tracer uptake determined by early and late resting Thallium myocardial scintigraphy or FDG-PET.
• Global LVEF between 30 and 45%.
• Written informed consent.

Exclusion Criteria:

• Previous heart surgery
• Small posterior or inferior AMI
• Previous MI at the same location
• Regional wall motion abnormality outside the area involved in the index AMI
• Ventricular thrombus
• Severe valvular heart disease
• Severe renal, lung and liver disease
• Disease of the hematopoetic system
• Hemoglobin level below 9 mg%
• The patient cannot follow the study protocol
• NYHA functional class IV at baseline
• Postinfarct angina
• Significant coronary stenosis in the IRA requiring repeated PCI at the time of the planned BM-SCs therapy
• Significant coronary lesion in one or more major coronary vessels, requiring revascularization
• Age lower than 18 years