CLINICAL EFFECTS AND UTILITY OF INTRACORONARY DILTIAZEM

Coronary artery spasm is a known complication of coronary intervention s, for which intracoronary nitroglycerin (ICN) is the treatment of cho ice, Some forms of intense spasm are resistant to ICN. Calcium channel antagonists are also known to be effective for coronary artery spasm, including nitroglycerin-resistant spasm. Here we describe a protocol for the clinical use of intracoronary diltiazem (ICD), By this protoco l, ICD can be safely given without disturbing the clinical status of p atients. ICD (2.5 mg) given slowly over 1 minute produced no vasodilit ation of normal vessel segments but did produce significant dilatation of stenotic segments above and beyond the effects of nitrates, Mean m inimum lumen diameter increased 18%, from 0.89 +/- 0.06 mm to 1.06 +/- 0.07 mm (mean +/- SEM, P < 0.001), ICD produced clinically insignific ant changes in systolic blood pressure, diastolic blood pressure, hear t rate, and PR, QRS, and QT intervals, This protocol has been employed to safely use ICD to relieve both nitroglycerin-resistant epicardial artery spasm and nitroglycerin-resistant distal microvascular spasm (t he no reflow phenomenon). (C) 1995 Wiley-Liss, Inc.