Antiischemic effect of intracoronary diltiazem on myocardial ischemia during PTCA

To evaluate the effect of intracoronary diltiazem on myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA), 38 patients were randomly assigned to receive inactive placebo (n = 19; group C) or a low dose (1 mg, n = 10; group D1), or a high dose (2 or 3 mg, n = 9; group D2) of diltiazem in a double-blind manner. The agent was administered directly into the coronary artery via a balloon catheter following a control balloon inflation. Chest pain score (maximum, 10) and the magnitude of ischemic ST elevation on standard and intracoronary electrocardiograms (ECGs) during a balloon inflation were assessed in the control and posttreatment periods. After the administration of diltiazem, the chest pain score was significantly decreased in group D1 (control: 5.1 +/- 3.6, posttreatment: 3.8 +/- 3.1, P < 0.01) and group D2 (3.4 +/- 2.5 vs 2.5 +/- 2.0, P < 0.01), but not in group C (4.1 +/- 3.1 vs 3.7 +/- 3.3, difference not significant). The magnitude of ST elevation relative to the control on standard and intracoronary ECGs was significantly smaller in groups D1 and D2 than in group C (standard ECG; D1: 51.8 +/- 10.6% of control, D2: 41.6 +/- 28.7% vs C: 93.3 +/- 15.6% and intracoronary ECG; D1: 47.1 +/- 11.7% of control, D2: 27.5 +/- 26.9% vs C: 94.6 +/- 29.3%, all P < 0.01). Although systolic blood pressure decreased slightly in groups D1 and D2, there was no significant correlation between the change in ST elevation and the change in the rate-pressure product. Pretreatment with a small dose of intracoronary diltiazem attenuated myocardial ischemia during PTCA and this pretreatment may enable us to perform balloon inflation for a longer period.