Local vessel injury following percutaneous coronary intervention does not promote early mobilisation of endothelial progenitor cells in the absence of myocardial necrosis.

BACKGROUND/OBJECTIVES: Endothelial progenitor cells (EPCs) are circulating mononuclear cells that are released from the bone marrow in response to injury and participate in vascular repair. Some previous studies have suggested an early mobilisation of EPCs following percutaneous coronary intervention (PCI) that could modulate the subsequent risk of restenosis or stent thrombosis. However, those studies did not discriminate between vascular injury caused by PCI and any associated myocardial injury. Myocardial injury alone can influence EPC mobilisation in a non-specific manner, and could therefore confound any association with risk. We investigated the effect of local endothelial trauma following PCI on EPC mobilisation in the absence of myocyte necrosis.

DESIGN

We quantified circulating EPCs from 20 patients immediately before, 6 hours and 24 hours following elective PCI in patients without a 24-hour troponin rise. Absolute counts of EPCs expressing combinations of CD45, CD34, CD133 and kinase domain receptor (KDR) were recorded using flow cytometry.

RESULTS

There was a fall of 7-15% in EPC numbers between baseline and 6 hours post procedure and a subsequent rise (5-18%) from 6 hours to 24 hours. At 24 hours EPC levels were similar to baseline.

CONCLUSIONS

The specific localised vascular injury induced by PCI did not lead to early mobilisation of EPCs. However, the fall in EPCs 6 hours after PCI was significant and its relation to early post-PCI complications such as stent thrombosis requires further exploration.