This study was planned, but recruitment and enrollment never began.

This is a single-center double blind, placebo controlled study of patients undergoing a cardiac catheterization where the need for a percutaneous coronary intervention (PCI) is anticipated or will be determined during the early diagnostic phase. The study will assess the use of intracoronary nicardipine vs. sterile saline injection in reducing the index measurement of microcirculatory resistance (IMR). Fifty consecutive patients presenting to the Thomas Jefferson University (TJUH) Cardiac Catheterization lab will be randomized in a 1:1 fashion to receive either intracoronary nicardipine or sterile saline injection prior to PCI. IMR values will be assessed pre and post procedure. Data on clinical outcomes and adverse events will be collected by phone at 30 days and 1 year following the procedure.

Inclusion Criteria:

• Consenting adults age > 18 years
• Patients with stable coronary disease, stable angina, and/or objective evidence of myocardial ischemia OR
• Target vessel lesion with > 50% stenosis treated by PCI

Exclusion Criteria:

• Patients presenting with ST elevation myocardial infarction
• Complete total occlusion of the vessel
• Unprotected left main disease
• Presentation with acute coronary syndrome and actively rising troponin
• Contraindication to adenosine (advanced heart blocks, bronchospasm, HSN to the drug)
• Known hypersensitivity to nicardipine
• Severe aortic stenosis
• Left Ventricular dysfunction with ejection fraction less than 30%
• Hemodynamically unstable defined as systolic blood pressure < 90 mmHg and not responding to IV fluids
• Significant chronic renal insufficiency (Glomerular filtration rate [GFR] <30)
• Unwilling or unable to provide informed consent