[Intracoronary nifedipine--separation of drug specific and vehicle-induced effects].

: In 22 patients we studied the effects of 0.2 mg nifedipine given intracoronary during the course of routine PTCA. In 9 patients the effect of the nifedipine-free solvent was additionally tested. Injections were made through the guiding catheters or balloon catheters as pre- and poststenotic injections. We monitored frequency and character of pain, ECG changes (continuous recording of full 12-lead ECG) and pressure recordings from the left ventricle and pre- and poststenotic coronary artery. Short-lasting "stinging" pain sensations were described by 41% of the patients after nifedipine and 33% after solvent injection (n.s.). Patients described the pain as different from their usual angina pectoris. Pain was more frequent after poststenotic injections (through the balloon catheter) than after pre-stenotic injections (59% vs. 19%, p less than 0.01). ECG changes were peaking T waves, ST elevation and ST depression. They were recorded after pre-stenotic injections in 21 of 22 cases for nifedipine and 6 of 9 for solvent and after poststenotic injections in 22 of 22 cases for nifedipine and 8 of 9 cases for solvent. After nifedipine 0.2 mg i.c. the pressures decreased by 3.5% pre-stenotic and 9.7% post-stenotic. LVEDP increased by 10.7%. Our results show that pain sensations and electrocardiographic changes occur with similar character and frequency after i.c. injections of nifedipine or nifedipine-free solvent. Thus these effects do not seem to be caused by nifedipine. Hemodynamic effects were small and there was no disproportionate decrease of poststenotic pressure.