Fully heparinize patient overnight Consider giving glucagon to stop bowel movement Get as selective as you can based on localizing study, that might be SMA or something more selective Give 200 mcg nitroglycerin and do an angiogram Wait 5 mins do another angiogram, maybe in a different obliquity Give up to 20 mg tPa and do an angiogram. 80% will be metabolized by the liver in the first pass so very little will make it to systemic circulation. Wait 5 mins do another angiogram, maybe in a different obliquity. Wait another 5 mins do another angiogram, maybe in a different obliquity