Abstract 19898: Systemic Nitroglycerin Administration Mitigates the Protective Effects of Inhaled Nitric Oxide During Cardiac Ischemia-Reperfusion

Introduction: Inhaled nitric oxide (iNO) reduces infarct size during experimental myocardial ischemia-reperfusion (I/R). Concomitant intra-arterial administration of nitroglycerin (NTG) during percutaneous coronary intervention offsets the benefit of iNO in STEMI patients. In the absence of specific STEMI guidelines on pharmacological NO-donor use, we studied the interaction between NTG and iNO in porcine myocardial I/R. Methods: Myocardial ischemia was induced by 50 min balloon occlusion of the mid LAD followed by 4 h R. Pigs were randomized to receive iNO (80 ppm for 4 h) mixed in 50% O2 10 min before balloon deflation with or without intra-arterial bolus of 0.5 mg NTG and 2.5 mg verapamil (iNONTG n=8 and iNO n=9) or NTG alone (0.5mg bolus, n=6) 5 min before R. Control pigs (CON, n=8) received 50% O2. Oxidative NO-species, NOx, were measured in arterial and coronary sinus plasma at baseline, after 40 min LAD occlusion, and at 5 and 240 min R. Infarct size (IS, % LV mass) and extent of microvascular obst...