Objectives: A prospective randomized multicentre trial was performed to analyse the efficacy of a vest (Posthorax support vest®) to prevent sternal wound infection after cardiac surgery, and to identify risk factors.
Methods: From September 2007 to March 2010, 2539 patients undergoing cardiac surgery via median sternotomy were prospectively randomized into those who received a Posthorax® vest and those who did not. Patients were instructed to wear the vest postoperatively for 24 h a day for at least 6 weeks; the duration of follow-up was 90 days. Patients who did not use the vest within a period of 72 h postoperatively were regarded as study dropouts. Statistical calculations were based on an intention-to-treat (ITT) analysis. Further evaluations comprised all subgroups of patients.
Results: Complete data were available for 2539 patients (age 67 ± 11years, 45% female). Of these, 1351 were randomized to receive a vest, while 1188 received no vest. No significant differences were observed between groups regarding age, gender, diabetes, body mass index, chronic obstructive pulmonary disease (COPD), renal failure, the logistic EuroSCORE and the indication for surgery. The frequency of deep wound complications (dWC: mediastinitis and sternal dehiscence) was significantly lower in vest (n = 14; 1.04%) vs non-vest (n = 27; 2.27%) patients (ITT, P < 0.01), but superficial complications did not differ between groups. Subanalysis of vest patients revealed that only 933 (Group A) wore the vest according to the protocol, while 202 (Group BR) refused to wear the vest (non-compliance) and 216 (Group BN) did not use the vest for other reasons. All dWC occurred in Groups BR (n = 7) and BN (n = 7), although these groups had the same preoperative risk profile as Group A. Postoperatively, Group BN had a prolonged intubation time, a longer stay in the intensive care unit, greater use of intra-aortic balloon pump, higher frequency of COPD and a larger percentage of patients who required prolonged surgery.
Conclusions: Consistent use of the Posthorax® vest prevented deep sternal wounds. The anticipated risk factors for wound complications did not prove to be relevant, whereas intra- and postoperative complications appear to be very significant.
Keywords: Prevention; Site infection; Sternum.