RESUMO
The study was designed to compare the response pattern of plasma l-arginine and methylarginines to stent placement in patients with or without ST segment elevation myocardial infarction (STEMI). Two groups of patients with obstructive coronary artery disease (OCAD) undergoing percutaneous coronary intervention (PCI) with stenting were enrolled in the study. Group I consisted of 16 patients with STEMI, whereas group II included 24 patients without STEMI (controls). Before PCI and at <1 h, 5 and 30 days after reperfusion, blood samples were taken for measurement of l-arginine and methylarginines. L-arginine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), N-monomethylarginine (MMA) and l-ornithine plasma levels were measured by LC-MS-MS. Arginine methylation index (Arg-MI) was calculated according to the formula, Arg-MI = (ADMA+SDMA)/MMA. In patients without STEMI, stenting induced a prompt and sustained depression of ADMA (p<0.000), and l-ornithine (p<0.000) with simultaneous increase of l-arginine (p<0.001), l-arginine/ADMA ratio (p<0.000) and an inconsistent change in MMA. Arg-MI remained at the baseline value. By contrast, STEMI patients responded to stent placement with a variable increase in l-arginine (p<0.01), ADMA (p<0.069), SDMA, MMA (p<0.01) and l-ornithine (p<0.000), whereas there was an early fall of Arg-MI after stenting, followed by a steady increase approaching the initial values. The differences in the time-course for ADMA (p<0.000), MMA (p<0.007), Arg-MI (p<0.01) and l-ornithine (p<0.003) proved to be significant between the STEMI and control group. It can be concluded therefore, that stent placement improves endothelial dysfunction in patients with OCAD when it is not complicated by STEMI.
