Safety and efficacy of o-raffinose cross-linked human hemoglobin (Hemolink(TM)) in cardiac surgery

Purposes: There are currently two major classes of oxygen therapeutics: hem oglobin based oxygen carriers (HBOCs) and synthetic perfluorocarbons (PFCs) . This review focuses on the use of o-raffinose cross-linked human hemoglob in (Hb raffimer) in cardiac surgery. Source: The literature on HBOCs was reviewed and the development and clinic al trials on Hb raffimer were outlined. Principal findings: The benefits of HBOCs include avoidance of known viruse s. pathogens and cross-matching; increased stability and storage time; and efficient oxygen delivery to tissues. The limitations of HBOCs include bind ing the endogenous vasodilator, nitric oxide, thereby resulting in transien t hypertension, esophageal dysfunction and abdominal discomfort. The short hail-lives oi these products makes them best suited to situations of acute anemia. Hb raffimer is prepared from outdated red blood cells, cross-linked with o- raffinose, a polyaldehyde obtained through the oxidation of the trisacchari de raffinose. The Hb is covalently cross-linked (beta-beta) within the 2,3 DPG binding pocket to form a stable 64 kDa tetramer, At this time, a total of over 500 patients have been enrolled and more than 300 patients have bee n treated with Hb raffimer. Preliminary analysis of data from recent Phase II & III clinical trials of Hb raffimer in routine coronary artery bypass g rafting surgery suggest that the product is well tolerated and may facilita te avoidance of allogeneic blood product transfusion in this surgical setti ng. Conclusion: The converging evidence from clinical studies with HBOCs has de monstrated that these products have the potential to provide hemoglobin and oxygen carrying capacity to tissues in times of acute anemia during surger y. It is anticipated that Hb raffimer will be used to facilitate intraopera tive autologous donation and emerge as an important alternative to allogene ic blood transfusion during cardiac surgery.