Evolution of Coronary Vascular Tone in Vasospastic Angina

In general, anginal symptoms diminish with time in patients with vasospastic angina. We assessed changes in coronary vascular tone (CVT) in patients with vasospastic angina over a 4-year period to evaluate the time course of spastic activity. Vasospastic angina was evaluated in 39 patients in whom occlusive spasm was evoked by selective intracoronary injection of ergonovine maleate (ERG-S) 48 h after stopping all coronary vasodilator drugs. These patients had no organic coronary stenosis and developed no stenosis during follow-up. ERG-S was repeated 3 times at 2-year intervals. CVT was determined at each ERG-S study using the equation: CVT=1-(coronary artery diameter before ERG-S/coronary artery diameter after intracoronary injection of isosorbide dinitrate). Thirty-four patients (87%) had no angina pectoris at the second ERG-S study and 28 (72%) had none at the third. Coronary spasm was induced in 25 patients at the second ERG-S study and in 20 at the third. The overall CVT was shown to decrease at each successive ERG-S study (p<0.01). There was no correlation between changes in CVT and anginal symptoms or the coronary spasm induction rate. These results demonstrate that CVT decreases over time in patients with vasospastic angina, suggesting that myocardial ischemia may improve spontaneously. (Jpn Circ J 1997; 61: 211 - 217)