[Percutaneous transplantation of autologous myoblasts in ischemic cardiomyopathy]

Cell transplantation is emerging as a novel approach for the treatment of end-stage cardiac disease. In contrast to most human studies using intramyocardial injection of myoblasts during coronary artery bypass grafting (CABG) or left ventricular assist device implantation, the authors investigated both safety and feasibility of transcatheter transplantation of autologous skeletal myoblast as a standalone procedure in six patients with ischemic heart failure, and compared them to six control patients matched for demographic and clinical characteristics.

Skeletal myoblast transplantation by catheter-based injection was technically successful in all six patients with no complications; 19+/-10 injections were performed/patient corresponding to 210 x 10(6)+/-150 x 10(6) cells/patient. Postinterventional Holter monitoring and ICD memory check documented three episodes of ventricular tachycardia in two patients after myoblast implantation, one at 30 days in patient 1, and two at 27 and 41 days in patient 2. Patient 1, although asymptomatic, was subsequently subjected to oral amiodarone since he refused an ICD; in patient 2 each tachycardia was terminated by a previously implanted ICD. Both patients were followed for 6 months without any evidence of repeat ventricular arrhythmia. Matched control patients revealed one episode of ventricular tachycardia in three patients each of which was aborted by ICD discharge within 6 months of observation. None of the documented ventricular tachycardias in both groups occurred in relation to any new myocardial necrosis which was excluded by ECG and cardiac enzymes. Left ventricular ejection fraction (LVEF) rose from 24.3+/-6.7% at baseline to 33.2+/-10.2% 6 months after myoblast implantation (p=0.02 vs. baseline); in matched controls LVEF decreased from 24.7+/-4.6% to 22.2+/-6.2% (p<0.05 vs. myoblasttreated group at 6 months). Moreover, the 6-min walk test revealed an improvement from 371+/-49 m to 493+/-86 m 6 months after implantation (p=0.003 vs. baseline and p=0.015 vs. controls), whereas matched controls were unchanged at 360+/-24 m and 369+/-26 m, respectively. Accordingly, NYHA functional class improved from 3.17+/-0.41 to 1.67+/-0.82 within 6 months of myoblast implantation (p=0.001 vs. baseline and p=0.01 vs. controls), while NYHA class remained unchanged at 3+/-0 in matched controls.

Transcatheter transplantation of autologous skeletal myoblasts for severe left ventricular dysfunction in postinfarction patients is feasible, safe and promising and, thus, warrants the scrutiny of larger randomized double-blind multi-center trials with longer follow-up surveillance.