Abstract 2714: Myocardial Assistance by Grafting a New Bioartificial Upgraded Myocardium (MAGNUM Trial): Clinical Feasibility Study
In ischemic heart disease the contracting cells and the extracellular myocardial matrix are replaced by fibrotic tissue, collagen type I (responsible of structural support) decreases from 80 to 40%. The purpose of this study was to evaluate in ischemic patients the potential use of a biodegradable collagen type I matrix seeded with cells and grafted onto the ventricular epicardium, associated with intrainfarct stem cell implantation.
Methods In 30 consecutive patients (aged 56.3±5.1 years) presenting LV postischemic myocardial scars and with indication for a single OP-CABG for revascularization of remote areas, autologous mononuclear bone marrow cells (BMC) were implanted during surgery in the scar (300±28 million cells, CD34+ 8%). In the last 15 pts a 3D collagen type I matrix (size: 7 x 5 x 0.6 cm) seeded with the same number of BMC was added on top of the scarred area. It was fixed onto the epicardium by 4 single sutures and covered by a second non-cellularized matrix.
Results At follow-up of 12±3.9 months, significant improvements were observed in NYHA functional class in both groups, from 3.2 to 1.4 (matrix) and from 3.1 to 1.3 (no-matrix). SPECT Tc99m-sestamibi studies showed a significant reduction of the infarct scar areas in both groups, the reduction in the matrix-goup (−32±4.3%) was most important than in the no-matrix group (−19±6.2%) (p=0.03). Significant differences were observed in the matrix-group concerning diastolic function and postischemic remodelling: LV filling deceleration time (DT) in the matrix group improved from 160±6ms to 198±7ms (p=0.01), but not in the no-matrix group (from 158±5ms to 165±7ms, NS). LVEDD evolved from 59±1.8 to 52±1.5 mm (matrix, p=0.04) vs 57±3.3 to 58±2.7mm (no-matrix, NS). The scar area thickness progress from 6±1.7 to 11±2.6mm (matrix, p=0.001) vs 5±1.7 to 6±2.3mm (no-matrix, NS). EF improved significantly in both groups: from 17±5 to 32±5% (matrix) vs 18±3 to 33±5% (no matrix).
Conclusions The association of a cell seeded collagen type I matrix appears to improve diastolic function, to reduce the size and reinforce the infarct scar area with viable bioartificial tissues thus limiting ventricular remodeling. This tissue engineered approach seems to be safe and to improve the efficiency of cellular cardiomyoplasty.