Introduction:

CIRCULATE-AMI (NCT03404063), a cardiac magnetic resonance imaging (cMRI) infarct size-reduction-powered double-blind randomized controlled trial (RCT) of standardized Wharton jelly multipotent stem cells (WJMSCs, CardioCell Investigational Medical Product) vs. placebo (2 : 1) transcoronary transfer on acute myocardial infarction (AMI) day ~5–7, is preceded by safety and feasibility evaluation in a pilot study cohort (CIRCULATE-AMI PSC). Aim: To evaluate WJMSC transplantation safety and evolution of left ventricular (LV) remodeling in CIRCULATE-AMI PSC.

Material and methods:

In 10 consecutive patients (32–65 years, peak CK-MB 533 ±89 U/l, cMRI-LVEF 40.3 ±2.7%, cMRI-infarct size 20.1 ±2.8%), 30 × 10⁶ WJMSCs were administered using a novel cell delivery-dedicated, coronary-non-occlusive method (CIRCULATE catheter). Other treatment was guideline-based.

Results:

WJMSC transfer was safe and occurred in the absence of coronary (TIMI-3 in all) or myocardial (corrected TIMI frame count (cTFC) 45 ±8 vs. 44 ±9, p = 0.51) flow deterioration or troponin elevation. By 3 years, one patient died from a new, non-index territory AMI; there were no other major adverse cardiovascular and cerebrovascular events (MACCE) and no adverse events that might be related to WJMSCs. cMRI infarct size was reduced from 33.2 ±7.6 g to 25.5 ±6.4 g at 1 year and 23.1 ±5.6 g at 3 years (p = 0.03 vs. baseline). cMRI, SPECT, and echo showed a consistent, statistically significant increase in LVEF at 6–12 months (41.9 ±2.6% vs. 51.0 ±3.3%, 36.0 ±3.9% vs. 44.9 ±5.0%, and 38.4 ±2.5% vs. 48.0 ±2.1% respectively, p < 0.01 for all); the effect was sustained at 3 years.

Conclusions:

CIRCULATE-AMI PSC data suggest that WJMSC transcoronary application ~5–7 days after large AMI in humans is feasible and safe and it may be associated with a durable LVEF improvement. CIRCULATE-AMI RCT will quantify the magnitude of LV adverse remodeling attenuation with CardioCell/placebo administration.