SMALL ARTERY STRUCTURAL ALTERATIONS OF PATIENTS WITH MICROVASCULAR ANGINA (SYNDROME-X)

1. There is increasing evidence that a substantial number of patients who suffer from angina have normal epicardial arteries (Syndrome X), a nd it has been suggested that these individuals have generalized disor der of small vessels not confined to the intramyocardial vasculature, 2. Small arteries were therefore obtained from biopsies of skin and su bcutaneous fat from nine normotensive patients with Syndrome X and nin e matched control subjects, Vessels were dissected and mounted as ring preparations in a myograph for morphological and functional assessmen t. 3. Morphological measurements revealed a significant increase in me dia thickness/lumen diameter ratio in arteries from patients with Synd rome X, Contractile responses to U46619 were similar in arteries from patients and control subjects, Endothelium-dependent relaxation induce d with acetylcholine and bradykinin was greater in arteries from patie nts although differences were not statistically significant, Endotheli um-independent relaxation induced by forskolin and sodium nitroprussid e was not different, 4. In conclusion, these data demonstrate that sub cutaneous small arteries from patients with Syndrome X are characteriz ed by increased media thickness/lumen diameter ratios, although contra ctile responses were normal, Additionally, endothelium-dependent relax ation was not impaired in arteries from these patients, Thus, no signi ficant functional abnormalities were associated with the observed stru ctural differences.