Tissue-Type Plasminogen Activator (t-PA) Release Predicts Major Adverse Cardiac Events (MACE) in Patients With Non-critical Coronary Artery Disease

Tissue-type Plasminogen Activator (tPA) is a protein in the blood which breaks down clots and plays an important role in preventing myocardial infarction. It is produced by the endothelial cell lining of the blood vessels. Previous studies demonstrate that t-PA is released in response to the hormones bradykinin and acetylcholine. Impaired t-PA release upon bradykinin stimulation may indicate endothelial dysfunction that leads to the development of acute coronary syndrome. In this project, we will determine whether impaired t-PA release can predict future occurrence of acute coronary syndrome. The study will involve individuals getting routine left heart cardiac catheterizations (indication for cardiac catheterization is solely based on clinical indication). Prior to the procedure, patient will have two blood samples (5 ml each) collected from their forearm before and after 2 minutes blood pressure cuff inflation on their arm. After routine diagnostic cardiac catheterization and there is no severe coronary artery stenosis (\<70% stenosis), research protocol will be initiated. Study includes infusion with increasing doses of bradykinin into their left main coronary artery, and sample small amounts of blood from their coronary sinus (15 ml total).