Oestrogen attenuates coronary vasoconstriction after angioplasty: role of endothelin-I

Background and aims There were controversies as to whether endothelin-1 is released after coronary angioplasty. We sought to determine whether endothelin-1 is released after coronary angioplasty and whether oestrogen administration can affect coronary vasomotor tone by reducing endothelin-1 concentrations. Methods The study was designed to prospectively investigate 24 consecutive patients scheduled for elective coronary angioplasty. Patients were randomized into two groups according to whether they did not (group 1, n = 12) or did (group 2, n = 12) have intracoronary treatment with oestrogen. Quantitative coronary angiography was monitored at baseline, immediately after successful angioplasty, and 15 min after the last deflation. Blood samples for measuring the levels of endothelin-1 were drawn from the ascending aorta and the coronary sinus simultaneously before angioplasty and 15 min after balloon dilatation. Results The diameters of the coronary artery at the dilated segments were significantly reduced 15 min after dilation compared with those immediately after dilation in group 1 from 3.20 +/- 0.22 to 2.30 +/- 0.23 mm (P < 0.001), respectively. The vasoconstriction was significantly blunted in group 2. The endothelin-1 levels from the coronary sinus rose significantly, by 29%, 15 min after angioplasty in group 1, which was attenuated after administering oestrogen. Significant correlation was found between the changes of coronary vasomotion of the dilated segment and endothelin-1 levels (r = 0.70, P = 0.01). Conclusion Endothelin-1 is released into the coronary circulation after angioplasty, and this vasoactive substance may contribute to the occurrence of vasoconstriction. The vasoconstriction is attenuated by oestrogen by reducing the endothelin-1 levels. This finding provided a new strategy to treat coronary vasoconstriction after angioplasty.