Individuals with heart disease or high blood pressure are often prescribed angiotensin converting enzyme (ACE) inhibitors to treat their disease. However, the use of ACE inhibitors can be associated with angioedema, a rare but life-threatening condition that causes swelling of the face and other body parts. This study will evaluate the effectiveness of the drug HOE-140 at decreasing symptoms of angioedema in people taking ACE inhibitors who develop the condition.