title: Propensity-matched analysis of minimally invasive mitral valve repair using a nationwide surgical database.
abstract: OBJECTIVE
  The aim of this study was to compare the cases of minimally invasive mitral valve surgery (MICS-mitral) performed using right mini-thoracotomy (RT) with those performed using median sternotomy (MS).
  
  
  METHODS
  Between 2008 and 2012, 6137 patients underwent isolated mitral valve repair at 210 institutions and were registered in the Japan Adult Cardiovascular Surgery Database. We compared 756 who underwent MICS-mitral via RT to 5381 MS patients and performed a one-to-one matched analysis based on the estimated propensity score.
  
  
  RESULTS
  The in-hospital mortality was similar between both groups (RT vs. MS: 0.5 vs. 1.1%). Although the incidence of postoperative stroke, renal failure, and prolonged ventilation was similar, the number of patients with mediastinitis was greater in the MS group (RT vs. MS: 0 vs. 0.7%, p < 0.01). Reexploration for bleeding was more frequent in the RT group (RT vs. MS: 2.9 vs. 1.4%, p < 0.01). Mortality and morbidity occurred at a higher rate in low-volume institutions. The propensity analysis showed that the operation-related times were significantly longer in the RT group, while the length of hospital stay was shorter. In a propensity analysis of patients <60 years of age, there was no in-hospital mortality.
  
  
  CONCLUSIONS
  MICS-mitral via RT was successful without compromising the clinical outcomes. Although the operation time and postoperative bleeding should be improved, an RT approach is safe in appropriately selected patients, especially those <60 years of age or treated in a high-volume center.
authors.affiliation: Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, 2-2, Yamada-Oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nishi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miyata
authors.forename: Noboru
authors.initials: N
authors.lastname: Motomura
authors.forename: Koichi
authors.initials: K
authors.lastname: Toda
authors.forename: Shigeru
authors.initials: S
authors.lastname: Miyagawa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takamoto
mesh_terms: D000368:Aged; D013504:Cardiovascular Surgical Procedures / Q000379:methods*; D016208:Databases, Factual; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007564:Japan; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods* / Q000401:mortality; D008943:Mitral Valve / Q000601:surgery*; D061646:Operative Time; D018579:Patient Selection; D019106:Postoperative Hemorrhage / Q000517:prevention & control; D057216:Propensity Score; D056346:Sternotomy / Q000379:methods* / Q000401:mortality; D015996:Survival Rate; D013908:Thoracotomy / Q000379:methods* / Q000401:mortality; D016896:Treatment Outcome