Administering stem cells after STEMI did not improve left ventricular ejection fraction (LVEF) after one year, according to a research letter published in the Jan. 15 issue of JAMA.
In the Timing In Myocardial Infarction Evaluation (TIME) trial, investigators led by Jay H. Traverse, MD, of Minneapolis Heart Institute at Abbott Northwestern Hospital in Minneapolis, randomized 112 STEMI patients who had PCI and stenting and had LVEF of 45 percent or less to 150 million autologous bone marrow mononuclear cells (BMCs) or placebo with intracoronary delivery performed on day 3 or 7. At the end of one year, 95 participants remained.
The investigators primarily analyzed changes in LVEF and regional LV function between baseline and six months as indicated by magnetic resonance imaging.
LVEF increased from baseline to six months in both groups (46.2 percent to 50.1 percent in the BMC group and 46.3 percent to 51.5 percent in the placebo group), but did not improve after six months. Regional LV function increased in infarct and border zones up to six months, but not after.
LV volumes increased between baseline and one year in both the BMC and placebo groups, but the groups did not significantly differ from each other. Infarct size decreased in both groups between baseline and six months (44.7 g to 30.7 g in the BMC group and 46.3 g to 31.7 g in the placebo group). The size also decreased between six months and one year, but the decrease was smaller (30.7 g to 28.8 g in the BMC group and 31.7 g to 27.7 g in the placebo group).
Their one-year data, the authors wrote, do not support the use of BMCs after STEMI. “The administration of BMCs following moderate to large anterior STEMIs was not associated with improved recovery of global and regional LV function at one year, irrespective of cell delivery at 3 or 7 days.”