Is allogeneic blood transfusion a risk factor for sternal dehiscence following cardiac surgery? A prospective observational study.

Sternal dehiscence following cardiac surgery has a multifactorial etiology. Significant risk factors contributing to sternal dehiscence include chronic obstructive pulmonary disease (COPD), obesity, or re-exploration due to bleeding or pericardial tamponade. We have focused on the role of allogeneic blood transfusion as a factor leading to the poor healing of surgical wounds. A prospective observational study of 1553 elective and emergency cardiac surgery patients was performed between January 2003 and June 2007. All of the patients enrolled in this study underwent median sternotomy. We studied the relationship between sternal dehiscence following cardiac surgery and the total number of packed red blood cells transfused. The incidence of sternal dehiscence in the study group was 3.4%. Diabetic patients did not have a higher incidence of wound dehiscence. Although COPD, obesity, and re-exploration contributed to sternal dehiscence, the number of allogeneic blood transfusions during the perioperative period was an important independent risk factor for sternal dehiscence. Patients with sternal dehiscence received an average of 7.6 transfusion units (TU) of allogeneic blood versus 1.6 TU of allogeneic blood in the group without sternal dehiscence (P < 0.00005). The dehiscence affected patients without any other significant risk factor who received 6 or more TU, or patients with at least one significant risk factor who received 4 or more TU of allogeneic blood. According to our results, the total amount of allogeneic blood transfused is an important risk factor contributing to sternal dehiscence. Regardless of other risk preconditions, the transfusion of 6 or more TU could result in sternal dehiscence following cardiac surgery.