This study sought to clarify the effectiveness of intracoronary administration of a
thromboxane (TX) A2 synthase inhibitor,
Ozagrel Na, to relieve coronary
spasms induced by intracoronary injection of
acetylcholine (ACh). An ACh
spasm provocation test was performed in 92 consecutive patients with coronary
spastic angina using incremental doses of 20, 50, and 80 microg into the right coronary artery, and 20, 50, and 100 microg into the left coronary artery within 20s. A coronary
spasm was defined as TIMI 0 or 1 flow and an intracoronary injection of 20 mg
Ozagrel Na was administered when it was provoked. Within 2 min of the administration of the TXA2 synthase inhibitor, ACh-induced coronary
spasms were relieved (TIMI 3 flow) in 88.1% of procedures without complications. In only 4 cases (4.3%), it took more than 3 min to relieve the coronary
spasms. Intracoronary administration of 20mg
Ozagrel Na when ACh-induced
spasms occurred, shortened the
spasm relief time in all 7 patients (200 +/- 59s vs 111 +/- 23s, p < 0.01), improved the maximal ST segment elevation in 5 of them (3.9 +/- 3.7 mm vs 0.7 +/- 1.5 mm, p < 0.05), and stopped
chest pain in 4 patients. In 4 patients who had ACh-induced coronary
spasm of the left anterior descending artery, the TXB2 concentration in the coronary sinus decreased after intracoronary administration of
Ozagrel Na into the left coronary artery (463 +/- 562 vs 96 +/- 45, p < 0.01). In conclusion, intracoronary administration of a TXA2 synthase inhibitor can relieve ACh-induced coronary
spasms by inhibiting TXA2 synthesis in the local coronary circulation.