Deep sternal wound infection requiring revision surgery: impact on mid-term survival following cardiac surgery.

Objective: To assess the impact of deep sternal wound infection on in-hospital mortality and mid-term survival following adult cardiac surgery.

Methods: Prospectively collected data on 4586 consecutive patients who underwent a cardiac surgical procedure via a median sternotomy from 1st January 2001 to 31st December 2005 were analysed. Patients with a deep sternal wound infection (DSWI) were identified in accordance with the Centres for Disease Control and Prevention guidelines. Nineteen variables (patient-related, operative and postoperative) were analysed. Logistic regression analysis was used to calculate a propensity score for each patient. Late survival data were obtained from the UK Central Cardiac Audit Database. Mean follow-up of DSWI patients was 2.28 years.

Results: DSWI requiring revision surgery developed in 1.65% (76/4586) patients. Stepwise multivariable logistic regression analysis identified age, diabetes, a smoking history and ventilation time as independent predictors of a DSWI. DSWI patients were more likely to develop renal failure, require reventilation and a tracheostomy postoperatively. Treatment included vacuum assisted closure therapy in 81.5% (62/76) patients and sternectomy with musculocutaneous flap reconstruction in 35.5% (27/76) patients. In-hospital mortality was 9.2% (7/76) in DSWI patients and 3.7% (167/4510) in non-DSWI patients (OR 1.300 (0.434-3.894) p=0.639). Survival with Cox regression analysis with mean propensity score (co-variate) showed freedom from all-cause mortality in DSWI at 1, 2, 3 and 4 years was 91%, 89%, 84% and 79%, respectively compared with 95%, 93%, 90% and 86%, respectively for patients without DSWI ((p=0.082) HR 1.59 95% CI (0.94-2.68)).

Conclusion: DSWI is not an independent predictor of a higher in-hospital mortality or reduced mid-term survival following cardiac surgery in this population.