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), and it has been suggested that these individuals have generalized disorder of small vessels not confined to the intramyocardial vasculature, 2. Small arteries were therefore obtained from biopsies of skin and subcutaneous fat from nine normotensive patients with Syndrome X and nine matched control subjects, Vessels were dissected and mounted as ring preparations in a myograph for morphological and functional assessment. 3. Morphological measurements revealed a significant increase in media thickness/lumen diameter ratio in arteries from patients with Syndrome X, Contractile responses to U46619 were similar in arteries from patients and control subjects, Endothelium-dependent relaxation induced with acetylcholine and bradykinin was greater in arteries from patients although differences were not statistically significant, Endothelium-independent relaxation induced by forskolin and sodium nitroprusside was not different, 4. In conclusion, these data demonstrate that subcutaneous small arteries from patients with Syndrome X are characterized by increased media thickness/lumen diameter ratios, although contractile responses were normal, Additionally, endothelium-dependent relaxation was not impaired in arteries from these patients, Thus, no significant functional abnormalities were associated with the observed structural differences.