During a heart bypass procedure, a substance called "complement" is activated by the body. This "complement activation" causes an inflammatory response that can lead to side affects such as chest pain, heart attacks, stroke, heart failure, or death. The purpose of this study is to find out if the study drug (pexelizumab), that blocks "complement activation," can reduce such side effects and be given safely to patients requiring the bypass procedure with the use of the heart-lung machine.

Inclusion Criteria:

• be at least 18 years of age;

• have 2 or more of the following risk factors:

  • diabetes mellitus; • repeat CABG; • the need for urgent intervention, defined according to the ACC/AHA guidelines as being patients who are required to stay in the hospital due to medical factors, but may be scheduled and operated on within a normal scheduling routine, excluding patients who have had an 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 (NYHA CHF Class III or IV); • history of 2 MIs, or an MI that occurred greater than 48 hours but less than 4 weeks prior to CABG;

• provide Informed Consent.

Exclusion Criteria:

• requires salvage intervention as defined by the ACC/AHA guidelines 10 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 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 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 within 30 days of randomization;
• is pregnant or breast-feeding.