Abstract 555: Safety and Feasibility of Percutaneous Autologous Skeletal Myoblast Transplantation for Ischemic Cardiomyopathy: Six-Month Interim Analysis
Introduction: Our initial investigations of autologous skeletal myoblast (ASM) transplantation as a possible therapy for chronic MI have demonstrated safety, feasibility and proof of concept that ASM engraft and survive within a chronic infarct. Previous delivery techniques included epicardial injections concomitant with CABG or LVAD. A less invasive method of ASM transplantation via a percutaneous approach may be more advantageous.
Methods: A phase I, single site, randomized, controlled, open-label study was initiated to evaluate endomyocardial delivery of ASM in 24 subjects with CHF due to previous MI, EF less than 40% and NYHA class II-IV. Subjects who were ineligible for revascularization were prospectively randomized 1:1 to maximum medical therapy (MMT) plus ASM transplantation or MMT only. Pre and post clinical exam, ECG, heart catheterization, echocardiogram, SPECT imaging and electromechanical mapping (EMM) were performed. Implantable loop recorder or cardioverter-defibrillator interrogation was used for arrhythmia monitoring. ASM derived from the recipient’s own skeletal muscle were isolated and expanded in culture over 4 weeks and subjects were divided into 4 dose groups (3 subjects per group) of 30, 100, 300 and 600 X 106 cells. A biological delivery system using EMM was used to identify the infarcted myocardium for ASM transplantation.
Results: To date, 16 of the planned 24 subjects were enrolled. ASM transplant procedures were successfully performed with no injection-related complications. Six months follow-up of echocardiography for 6 subjects, 3 ASM (30 X 106) treated and 3 MMT showed no difference in EF, end-diastolic or end-systolic volumes. The ASM group improved by 1 NYHA class, while the MMT group was unchanged. Baseline unipolar voltage measured by EMM was 3.46 mV and 4.75 mV at 3 months follow-up. Of significant note, no arrhythmias were observed during follow-up in either group.
Conclusion: These findings indicate that endomyocardial delivery of ASM is safe and feasible. Improvement in viability was seen in the infarct area (ASM injected segments) reflecting increased viability. No changes in heart function were seen in 3 subjects who received a low dose of 30 X 106 cells. Complete follow-up data for 24 subjects will be presented.