Unique US trial shows bone-marrow stem cells to be safe for AMI

The first randomized, double-blind, placebo-controlled US trial of bone-marrow stem cells in patients with ST-elevation MI (STEMI) has shown the therapy to be safe and to improve left ventricular volume compared with placebo.

Dr Jay H Traverse (Minneapolis Heart Institute, MN) and colleagues report the findings in the September 2010 issue of the American Heart Journal. Traverse told that this small, phase 1 trial differs in some ways from the European trials that have been performed with bone-marrow-derived stem cells in MI, which he admits are "considerably larger."

This is the first time all patients have received the same number of cells—100 million—whereas in European studies, for example REPAIR-AMI, some patients got three times as many cells as others. "Meta-analyses suggest there is a dose-response effect, so if you're giving people different numbers of cells, this introduces another variable that may affect the results," Traverse observes.

And this US study took "all-comers, including those with cardiac arrest, cardiogenic shock, or [who underwent therapeutic] hypothermia," he notes, adding that "most of the other trials have excluded this type of patient." And this trial is the first to have delivered stem cells by intracoronary infusion—using a small hollow catheter advanced to where the stent is placed—in an attempt to eliminate the potential confounding effects of repeated episodes of ischemia and reperfusion induced by the stop-flow technique used in Europe, he says.