title: Effect of negative pressure wound therapy followed by tissue flaps for deep sternal wound infection after cardiovascular surgery: propensity score matching analysis.
abstract: Deep sternal wound infection (DSWI) after cardiovascular surgery via median sternotomy remains a severe complication associated with a drastic decrease in the quality of life. We assessed the risk factors for in-hospital death caused by DSWI and the available treatments for DSWI.
  
  
  
  Between January 1991 and August 2015, we retrospectively reviewed 73 patients (51 males and 22 females, mean age 67.5 ± 10.3 years) who developed DSWI after cardiovascular surgery via median sternotomy. Pathogenic bacteria mainly comprised methicillin-resistant Staphylococcus aureus (MRSA) (49.3%). Fifteen patients (20.5%) died in hospital with DSWI. Treatment of DSWI consisted of open daily irrigation (up to 2006) or negative pressure wound therapy (NPWT) (2007 onwards), followed by primary closure or reconstruction of tissue flaps. We assessed the risk factors for in-hospital mortality from DSWI by comparing data from the 15 patients who died and the 58 survivors using propensity score matching analysis of the treatments used for DSWI.
  
  
  
  Univariate analysis identified age, use of intra-aortic balloon pumping, prolonged mechanical ventilation, tracheotomy, prolonged intensive care unit stay, postoperative low output syndrome, postoperative myocardial infarction, postoperative renal failure, postoperative use of haemodialysis, postoperative pneumonia, postoperative cerebral disorder, MRSA infection, NPWT and tissue flaps as being associated with in-hospital mortality (P < 0.05). Multivariate analysis identified NPWT (odds ratio, 0.062; 95% confidence interval, 0.004-0.897; P = 0.041) and tissue flaps (odds ratio, 0.022; 95% confidence interval, 0.000-0.960; P = 0.048) as independently associated with reduced in-hospital mortality after DSWI. On comparing 22 patients receiving NPWT with 22 not on NPWT using propensity score matching, patients on NPWT had significantly lower in-hospital mortality than those without NPWT (NPWT vs non-NPWT, 5 vs 36%, P = 0.021). In DSWI infected by MRSA, NPWT significantly reduced the in-hospital mortality caused by DSWI (NPWT vs non-NPWT, 0 vs 52%, P = 0.003).
  
  
  
  NPWT and tissue flaps may be favourable factors associated with reduced in-hospital mortality attributable to DSWI. NPWT as a bridge therapy to tissue flaps may play a major role in treating DSWI and improve the prognosis for patients with MRSA-infected DSWI.
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan m3_514@yahoo.co.jp.
authors.forename: Akimasa
authors.initials: A
authors.lastname: Morisaki
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Hosono
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Murakami
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Sakaguchi
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Suehiro
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nishimura
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Sakon
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yasumizu
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Kawase
authors.affiliation: Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shibata
mesh_terms: D000368:Aged; D013504:Cardiovascular Surgical Procedures / Q000009:adverse effects*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D015999:Multivariate Analysis; D054843:Negative-Pressure Wound Therapy; D016017:Odds Ratio; D011183:Postoperative Complications / Q000209:etiology / Q000628:therapy*; D057216:Propensity Score; D011788:Quality of Life; D012189:Retrospective Studies; D012307:Risk Factors; D056346:Sternotomy / Q000009:adverse effects*; D013524:Surgical Flaps; D013530:Surgical Wound Infection / Q000382:microbiology / Q000628:therapy*
keywords: Deep sternal wound infection; MRSA; Negative pressure wound therapy; Tissue flaps