989-57 Increased Plasma Soluble Intercellular Adhesion Molecule-1 (sICAM-1) Levels in Coronary Circulation in Patients with Unstable Angina

To determine whether plasma sICAM-1 levels increase in the coronary circulation in patients (pts) with unstable angina, we measured plasma sICAM-1 levels in the coronary sinus (CS) and aortic root (Ao) simultaneously in 18 unstable angina pts (UA), 18 stable exertional angina pts (SEA) and 14 control pts (Cont). Unstable angina was defined as worsening effort or rest angina, or both within 1 month of catherization. The three groups were matched for age and gender. The levels of sICAM-1 were measured by enzyme-linked immunosorbent assay. Data are shown below as means ± SE (ng/ml) UA SEA Cont CS 201 ± 16 * # 124 ± 8 119 ± 11 Ao 187 ± 15 * 123 ± 9 118 ± 11 * p l 0.01 vs SEA and Cont # p l 0.01 vs Ao The mean values of CS and Ao were significantly higher in UA than in SEA and in Cont. Furthermore, in UA the mean value was higher in CS than in Ao. There were no significant differences of the mean values of CS and Ao between SEA and Cont. We conclude that sICAM-1 release is increased especially in coronary circulation in UA. ICAM-1 is known to be a major ligand on endothelial cells for adherence of activated leukocyles. These results suggest that activation of leukocytes take place within coronary circulation, further may activate platelet and induce coronary thrombosis in UA