Effect of L-arginine administration on myocardial thallium-201 perfusion during exercise in patients with angina pectoris and normal coronary angiograms.
OBJECTIVE
We tested the hypothesis that an exogenous supplement of L-arginine could alleviate coronary perfusion abnormality during exercise in patients with angina pectoris and normal coronary arteries.


RESULTS
Twelve patients underwent exercise thallium-201 scintigraphy without medication (control) and after intravenous administration of L-arginine. Exercise time was prolonged in the L-arginine study compared with the control (482 s vs 540 s, P < .05). TI-201 extent score was improved in the L-arginine study (0.33 vs 0.26, P < .05), and the severity score was also improved (23.7 vs 16.9, P < .05). In 7 of the 12 patients whose TI-201 redistribution disappeared in the L-arginine study, the percent increase in serum L-citrulline concentration during exercise was larger than that of the remaining 5 patients (18% vs 0.9%, P < .01). The percent reduction in epicardial coronary diameter in response to acetylcholine was also greater in the former group (28.3% vs 11.1%, P < .05).


CONCLUSIONS
Exogenous L-arginine improved myocardial perfusion during exercise in a subset of patients with angina pectoris and normal coronary arteries, probably by increasing production of nitric oxide.
Fujita
H
H
First Department of Internal Medicine, Kobe University School of Medicine, Japan. fujitaf@sannet.ne.jp
Yamabe
H
H
Yokoyama
M
M
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001120:Arginine / Q000097:blood / Q000494:pharmacology*; D002956:Citrulline / Q000097:blood; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects*; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes
D013794:Thallium Radioisotopes; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D000109:Acetylcholine