Percutaneous versus surgical delivery of autologous myoblasts after chronic myocardial infarction: an in vivo cardiovascular magnetic resonance study.

Background: Stem cell transplantation for chronic myocardial infarction (MI) provides variable benefits. Most clinical trials have relied on surgical delivery, where results are biased by simultaneous coronary bypass. When bypass is not indicated, percutaneous delivery may provide comparable efficacy with reduced risk. We evaluated in vivo by cardiovascular magnetic resonance (CMR) the effects of autologous myoblast (AM) transplantation on myocardial morphology, function, perfusion and scar, and compared percutaneous versus surgical delivery.

Methods: Chronic MI was completed in 10 Yucatan mini-pigs. Three months later, AM were injected in half by percutaneous NOGA(R) system and in the other half by surgical mini-thoracotomy. CMR was performed at baseline and 6 months after transplantation.

Results: Six months after injection, AM transplantation led to a 26.3% decrease in indexed left ventricular end-diastolic volume (95% CI: 20.1-29.7%; P = 0.02), 25.5% thickening of the infarct-related segment (IRS) wall (95% CI: 19.6-33.2%; P = 0.03), and 20.9% increase in left ventricle (LV) ejection fraction (95% CI: 15.8-28.4%; P = 0.03). Scar tissue within IRS decreased by 29.4% (95% CI: 19.2-37.0%; P = 0.03), whereas the number of nonviable segments decreased by 25.0% (95% CI: 16.4-32.6%; P = 0.04). Myocardial perfusion of IRS improved by 29.1% (95% CI: 19.7-36.1%; P = 0.04). The arrhythmogenic peri-infarct zone increased by 33.2% (95% CI: 21.4-44.1%; P = 0.01) after AM transplantation. Benefits were similar by percutaneous or by surgical delivery.

Conclusions: Comprehensive in vivo CMR reveals reversed remodeling and improved systolic function, perfusion, and scar characteristics after AM transplantation. A relative increase in the arrhythmogenic peri-infarct border zone may explain previously reported arrhythmia. Percutaneous and surgical transplantation of AM both lead to comparable improvements in chronic MI.