Predicting blood transfusion factors in coronary artery bypass surgery.

OBJECTIVE

Blood conservation has become one of the most important issues in cardiac surgery. We clarified preoperative predictors of the need for blood transfusions during coronary artery bypass graft surgery.

METHODS

Subjects were 89 patients--66 men (74%) and 23 women (26%) 40 to 84 years old (mean: 66.2 +/- 8.3 years)--undergoing isolated coronary artery bypass surgery from September 1997 to December 1999. Of these, 66 patients (74%) received transfusion during hospitalization and 23 (26%) did not. Nine risk factors detected by univariate study were entered in a multivariate logistic regression model of the relationship between preoperative variables and blood transfusion.

RESULTS

Independent predictors were emergency surgery (P = .0023), lower hematocrit (P = .0027), older age (P = .0043), and the presence of peripheral vascular disease (P = .0070). Optimal cutoff of hematocrit for blood transfusion was 39% and age 64 years via receiver-operating characteristics curves based on the relation between sensitivity and specificity.

CONCLUSION

Patients older than 64 years with hematocrit less than 39% and/or peripheral vascular disease should be treated routinely using preoperative storage of autologous blood whenever the patient's condition permits. For patients undergoing emergency surgery, further studies are required, including lowering transfusion threshold and using determinants other than hematocrit.