Endothelium-Dependent and -Independent Perfusion Reserve and the Effect of <scp>l</scp> -arginine on Myocardial Perfusion in Patients With Syndrome X

Abstract

In patients with SX, the microcirculatory response to cold, reflecting the endothelium function, is normal and unaltered by intravenous L-arginine. This suggests preserved microcirculatory endothelial function. However, a markedly attenuated hyperemic flow and flow reserve after DIP suggest a dysfunction of the adenosine-mediated endothelium-independent vasodilatation at the microcirculatory level in these patients.