The patients in CSD group had significantly more blood loss (mean Hb drop - 33g/L) as compared to the “No-Drain used” group (mean Hb drop - 27g/L) (P =0.039). There was a non-significant trend toward a lower complication rate (return to theatre and postoperative infection) in the no-drain group (p=0.84) (Table 3). This evidence concerns the gene GSTM1 and infection.