Effect of estrogen on coronary vasoconstriction in patients undergoing coronary angioplasty

Background: Estrogen has an antioxidant potential which may contribute to its cardioprotective effect. We sought to determine whether estrogen administration can affect coronary vasomotor tone in patients after angioplasty by reducing 8-iso-prostaglandin (PG) F_2α concentrations, a bioactive product of lipid peroxidation. Methods: The study was designed to prospectively investigate 30 consecutive patients scheduled for elective coronary angioplasty. Patients were randomized into two groups according to whether they did not (group 1, n=15) or did have (group 2, n=15) intracoronary (i.c.) treatment with estrogen prior to coronary angioplasty. Results: There were no significant differences of collateral circulation assessed by intracoronary Doppler flow velocity during balloon inflations between the study groups. The diameters of the coronary artery at the dilated and distal segments were significantly reduced 15 min after dilation compared with those immediately after dilation in group 1 (both P2α levels in plasma from the coronary sinus rose significantly from 194±45 to 390±97 pg/ml (P2α levels in group 1 (r=0.73, P=0.002). Conclusions: 8-iso-PGF_2α is released into the coronary circulation during angioplasty, and this vasoactive substance may contribute to the occurrence of vasoconstriction. Estrogen administration attenuated vasoconstriction by reducing the 8-iso-PGF_2α levels. This finding may provide a new strategy to treat coronary vasoconstriction after angioplasty.