title: Is transthoracic minimally invasive aortic valve replacement too time-consuming for the busy cardiac surgeon?
abstract: OBJECTIVE
  : Transthoracic minimally invasive aortic valve replacement (TMI-AVR) is gaining popularity despite criticism that time from incision to the initiation of cardiopulmonary bypass (exposure time, ET), cardiopulmonary bypass time (CPBT), and cross-clamp time (XCT) is excessive. Database analysis was used to characterize these parameters and their associated learning curves.
  
  
  METHODS
  : From 2004 to 2008, 101 patients underwent TMI-AVR at a single institution. Of them, 54 were men (53%) and 47 were women (47%). Mean age was 70 years (range, 24-90 years). ET includes 6-cm incision, second intercostals anterior thoracotomy, medial transection of the third rib, opening pericardial sac, retracing pericardium with stay sutures, placing aortic arterial, and right arterial venous bypass cannulae. ET, CPBT, XCT, and operating room times were calculated. Logarithmic trend analysis established associated learning curves.
  
  
  RESULTS
  : ET steadily improved over time. ET decreased from an average of 51 minutes for the first 25 patients to 39 minutes for the most recent 25 patients. When surgeon experience reached 10 procedures, the ET trend line began to decline steadily and plateaued by 55 cases. Cross-clamp (55 ± 21 minutes), cardiopulmonary bypass (77 ± 31 minutes), and operating room times (304 ± 67 minutes) all remained constant. There were no early deaths or conversions to sternotomy.
  
  
  CONCLUSIONS
  : ET learning curve for TMI-AVR was reflected after 10 procedures with continued gradual improvement. Reliability of TMI-AVR was observed in the absence of a learning curve for XCT, CPBT, and operating room times. A sternal-sparing transthoracic approach for AVR can be performed safely, with expected operative times equivalent to sternotomy.
authors.affiliation: From the Department of Cardiothoracic Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Cunningham
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Berberian
authors.forename: Vaughn A
authors.initials: VA
authors.lastname: Starnes