During a heart bypass procedure, a substance called "complement" is released by the body. This complement causes inflammation, which can lead to side effects such as chest pain, heart attacks, heart failure, or impairment of memory, language and motor skills. The purpose of this study is to find out if the study drug (pexelizumab), which blocks complement release, can reduce such side effects and be taken safely.

INCLUSION CRITERIA:

The study population will be drawn from patients undergoing CABG or CABG plus valve surgery using a bypass pump. In addition, they must meet all of the following criteria:

• be at least 18 years of age;
• have one or more of the following risk factors:
• diabetes mellitus;
• prior CABG;
• the need for urgent intervention, defined according to the American College of Cardiology/ American Heart Association (ACC/AHA) guidelines as being patients who are required to stay in the hospital, but may be scheduled and operated on within a normal scheduling routine, excluding patients who have had a MI within 48 hours of CABG;
• female;
• history of a neurologic event (cerebrovascular accident, transient ischemic attack or carotid endarterectomy);
• history of congestive heart failure (New York Heart Association [NYHA]Class III or IV);
• history of 2 myocardial infarctions, or a myocardial infarction that occurred greater than 48 hours but less than four (4) weeks prior to CABG;
• provide Informed Consent.

EXCLUSION CRITERIA:

A patient will be ineligible for study entry if he/she meets any of the following exclusion criteria:

• has planned aortic dissection repair and/or requires aortic root reconstruction;
• requires salvage intervention as defined by the ACC/AHA guidelines as being ongoing cardiopulmonary resuscitation on the way to the operating room;
• has current cardiogenic shock, acute left ventricular rupture, acute septal rupture or acute papillary muscle rupture;
• has uncontrolled diabetes, defined as a documented plasma blood glucose value > 400 mg/dl (22.2 mmol/L) within three (3) days before surgery;
• has a history of renal failure and a serum creatinine value greater than 3.0 mg/dl;
• has a history of chronic hepatic failure and/or hepatic cirrhosis;
• has a history of malignancy, excepting basal cell carcinoma and malignancies in remission (greater than 2 years);
• has any active bacterial or other infection which is clinically significant, in the opinion of the investigator (e.g. evaluate the evidence based on WBC, temperature, cultures, etc. as appropriate for the patient);
• has any serious medical condition which, in the opinion of the investigator is likely to alter the patient's course of recovery or the evaluation of the study medication's safety;
• has a history of alcohol or drug abuse within the past year;
• has a known or suspected hereditary complement deficiency;
• has participated in any other investigational drug study or was exposed to an investigational agent or device within 30 days of randomization;
• is receiving, or is planning to receive, any other investigational drug or device, or will participate in any other research study during the trial;
• is pregnant or breast-feeding.