Plasma asymmetric dimethylarginine and L-arginine levels in patients with cardiac syndrome X.
BACKGROUND
Endothelial dysfunction and subsequently impaired microvascular circulation are the leading mechanisms in the development of cardiac syndrome X (CSX). The study evaluated the plasma asymmetric dimethylarginine (ADMA) and L-arginine levels of the patients with CSX and the control group and aimed to determine any relationship between these parameters and epicardial coronary blood flow and myocardial tissue perfusion.


METHODS
The study group consisted of 32 patients (mean age: 52.6+/-9.4 years, 14 men) with typical exertional angina, positive exercise test, and normal coronary arteries diagnosed as CSX. Plasma ADMA, L-arginine levels, and L-arginine/ADMA ratio were compared with the values of the control group, which consisted of 17 age-matched and sex-matched individuals. Concentrations of L-arginine and ADMA were measured by high-performance liquid chromatography. In all the coronary territories, epicardial coronary flow was assessed by thrombolysis in myocardial infarction (TIMI) frame count (TFC) method, and tissue level perfusion, by myocardial blush grade (MBG) method. A MBG score less than 3 was considered an impaired myocardial perfusion, and a MBG score of '3' in all the coronary territories, a normal myocardial perfusion.


RESULTS
The plasma ADMA levels of the study group were higher than those of the control group (0.83+/-0.38 vs. 0.55+/-0.44 micromol/l, P=0.03), whereas plasma L-arginine levels were similar in both groups (70.25+/-21.89 vs. 76.09+/-18.22 micromol/l, P=0.36), resulting in a diminished L-arginine/ADMA ratio in the patients with CSX [82.3 (60.2-128.8) vs. 242.2 (76.7-386.4), P=0.003]. In CSX group, the patients with abnormal myocardial tissue perfusion had increased plasma ADMA levels compared with those with normal tissue perfusion (0.99+/-0.37 vs. 0.69+/-0.34 micromol/l, P=0.02), whereas plasma L-arginine levels were similar in both groups. No correlations were observed between TFC values and plasma ADMA, L-arginine levels, and L-arginine/ADMA ratio. Plasma ADMA levels, however, were negatively correlated with MBG scores (r=-0.349, P=0.014).


CONCLUSIONS
We have shown for the first time that in the patients with CSX, increased plasma ADMA levels might be associated with impaired myocardial tissue perfusion when assessed by MBG.
Okyay
Kaan
K
Department of Cardiology, Division of Metabolism and Nutrition, Gazi University Medical School, Ankara, Turkey. drokyay@yahoo.com
Cengel
Atiye
A
Sahinarslan
Asife
A
Tavil
Yusuf
Y
Turkoglu
Sedat
S
Biberoglu
Gulser
G
Hasanoglu
Alev
A
D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood*; D017023:Coronary Angiography / Q000379:methods; D003326:Coronary Circulation; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000097:blood*; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D010477:Perfusion; D010496:Pericardium / Q000473:pathology
D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D001120:Arginine