Timing of granulocyte-colony stimulating factor treatment after acute myocardial infarction and recovery of left ventricular function: results from the STEMMI trial.

BACKGROUND: Granulocyte-colony stimulating factor (G-CSF) therapy after ST-elevation myocardial infarction (STEMI) have not demonstrated impact on systolic recovery compared to placebo. However, recent studies suggest that timing of G-CSF therapy is crucial.

METHODS: Timing of G-CSF treatment was analyzed in the STEMMI MRI subpopulation including 54 patients with STEMI treated with primary percutaneous coronary intervention (PCI) <12 h after symptom onset. Patients were randomized to double blind treatment with G-CSF (10 microg/kg/day) or placebo. Treatment was initiated from 17 to 65 h (mean 30) after PCI. Left ventricular ejection fraction (LVEF) was evaluated with MRI.

RESULTS: Recovery of LVEF from baseline to 6 months was not associated with time from PCI to G-CSF. An identical improvement in LVEF was found in the placebo group and the G-CSF group (p=0.8). There was no correlation between time from PCI to G-CSF and maximum plasma concentration of CD34+ cells (r=-0.3, p=0.1). Similar results were found from data on recovery of the infarction size and change in the systolic wall thickening.

CONCLUSIONS: In the time window from 17 to 65 h after STEMI treated with PCI, the timing of G-CSF treatment does not seem to affect the recovery of LVEF. It remains to be determined if very early, or very late G-CSF treatment might be effective.