PLASMA ENDOTHELIN IN CORONARY SPASM

The role of endothelin, a powerful vasoconstrictor, was studied in cor onary spasm. A methylergonovine stress test was performed in patients with normal coronary angiography. Patients who developed spasm (Group I, n = 6) were compared with those who did not (Group II, n = 6). Plas ma endothelin was measured at 8, 11 a.m., 2 p.m., 4, 7, 9, 11 p.m. and 1 a.m. The stress test was carried out at 17 hours and an additional endothelin measurement was performed during spasm in positive cases. T he clinical characteristics of the two groups were comparable especial ly with regards to cardiovascular risk factors. Except for the value r ecorded during coronary spasm, the plasma endothelin levels were signi ficantly higher in the group with coronary spasm. A time-dependant var iation was observed in both groups with higher endothelin levels in th e morning. In group I the plasma endothelin levels were higher under b asal conditions and during spasm in patients with spastic angina.