Response of conductance and resistance vessels of the coronary artery to intracoronary isosorbide dinitrate in patients with variant angina.

To elucidate the response of conductance and resistance vessels of the coronary artery after intracoronary isosorbide dinitrate (ISDN), we evaluated 11 patients with variant angina and 13 controls with a Doppler guidewire. Epicardial arterial diameter increased significantly after ISDN in patients with variant angina while it did not change significantly in the controls. Coronary diastolic flow velocity increased significantly in controls (p < 0.05), but was unchanged in patients with vasospastic angina. Coronary flow volume increased from 23.8 +/- 18.6 to 46.5 +/- 28.4 ml/min in patients with vasospastic angina as well as in the controls from 32.2 +/- 24.2 to 54.7 +/- 44.4 ml/min. Coronary resistance did not differ between the two groups before or after the injection of ISDN. Conductance vessels were dilated to a greater extent in the patients with variant angina. However, the response of resistance vessels did not differ significantly between the two groups.