Endothelial Progenitor Cell Biology and Vascular Recovery Following Transradial Cardiac Catheterization

Background-Transradial catheterization is associated with radial artery injury and vasomotor dysfunction and represents an accessible model of acute vascular injury in humans. We characterized vascular injury and functional recovery to understand the role of circulating endothelial progenitor cells in vascular repair. Methods and Results-In 50 patients (aged 64 +/- 10 years, 70% male) undergoing transradial cardiac catheterization, radial artery injury was assessed by optical coherence tomography and examination of explanted vascular sheaths. Flow-and nitrate-mediated dilatation of the radial artery was assessed in both arms at baseline, at 24 hours, and at 1, 4, and 12 weeks. Circulating endothelial progenitor cell populations were quantified using flow cytometry. Late endothelial outgrowth colonies were isolated and examined in vitro. Optical coherence tomography identified macroscopic injury in 12 of 50 patients (24%), but endothelial cells (1.9 +/- 1.29104 cells) were isolated from all arterial sheaths examined. Compared with the noncatheterized radial artery, flowmediated vasodilatation was impaired in the catheterized artery at 24 hours (9.9 +/- 4.6% versus 4.1 +/- 3.1%, P<0.0001) and recovered by 12 weeks (8.1 +/- 4.9% versus 10.1 +/- 4.9%, P=0.09). Although the number of CD133(+) cells increased 24 hours after catheterization (P=0.02), the numbers of CD34(+) cells and endothelial outgrowth colonies were unchanged. Migration of endothelial cells derived from endothelial outgrowth colonies correlated with arterial function before catheterization but was not related to recovery of function following injury. Conclusions-Transradial cardiac catheterization causes endothelial denudation, vascular injury, and vasomotor dysfunction that recover over 12 weeks. Recovery of vascular function does not appear to be dependent on the mobilization or function of endothelial progenitor cells.