title: The association of transcatheter aortic valve replacement availability and hospital aortic valve replacement volume and mortality in the United States.
abstract: BACKGROUND
  Whether the introduction of transcatheter aortic valve replacement (TAVR) has affected hospitals' surgical aortic valve replacement (SAVR) and overall aortic valve replacement (AVR) case volumes and outcomes in the United States is unknown.
  
  
  METHODS
  We utilized data from The Society of Thoracic Surgeons (STS) adult cardiac surgery database and the STS/American College of Cardiology (ACC) transcatheter valve therapies registry to examine SAVR and TAVR procedures. Temporal trends in total case volume (SAVR plus TAVR), and observed and risk-adjusted in-hospital mortality rates were assessed among low-risk cases (STS predicted risk of operative mortality < 4%), intermediate-risk cases (4% to 8%), and high-risk cases (> 8%). A contemporary control was provided by non-TAVR centers.
  
  
  RESULTS
  From 2008 to 2013, the total annual volume of AVR among 246 TAVR-performing hospitals increased from 19,578 to 33,004, with a 22% growth in SAVR volumes; non-TAVR hospital (n = 555) increases were more modest (16,563 to 19,134; 16% growth). Expanded volumes at TAVR hospitals included increased SAVR use in low- and intermediate-risk cases, and TAVR use in high-risk cases. In parallel, in-hospital mortality for all AVR procedures at TAVR sites declined from 3.4% to 2.9% (observed to expected [O:E] ratio 0.75 to 0.58, p < 0.001); the greatest declines were among intermediate- and high-risk SAVR patients. Owing to reduced SAVR mortality, TAVR centers experienced a significantly greater decline in O:E ratio for high-risk patient in-hospital mortality than non-TAVR centers (TAVR center O:E ratio, 0.81 to 0.61; non-TAVR center O:E ratio, 0.85 to 0.76; p < 0.001). After approval of TAVR for clinical use, a trend toward higher in-hospital mortality rates and O:E ratios for TAVR procedures was observed at new (but not at established) TAVR centers (O:E ratio, 0.41 to 0.67; p = 0.08).
  
  
  CONCLUSIONS
  Since the introduction of TAVR, the total volume of AVR procedures, including higher overall use of SAVR, at TAVR sites has significantly increased in the United States. Overall, in-hospital survival of patients undergoing treatment for aortic valve stenosis continues to improve.
authors.affiliation: Duke University Medical Center, Duke Clinical Research Institute, Durham, North Carolina. Electronic address: j.matthew.brennan@dm.duke.edu.
authors.forename: J Matthew
authors.initials: JM
authors.lastname: Brennan
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.affiliation: Duke University Medical Center, Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Sherwood
authors.affiliation: University of Florida, Jacksonville, Florida.
authors.forename: Fred H
authors.initials: FH
authors.lastname: Edwards
authors.affiliation: Denver VA Medical Center, Denver, Colorado.
authors.forename: John D
authors.initials: JD
authors.lastname: Carroll
authors.affiliation: Denver VA Medical Center, Denver, Colorado.
authors.forename: Fred L
authors.initials: FL
authors.lastname: Grover
authors.affiliation: Cleveland Clinic, Cleveland, Ohio.
authors.forename: E Murat
authors.initials: EM
authors.lastname: Tuzcu
authors.affiliation: Emory University, Atlanta, Georgia.
authors.forename: Vinod
authors.initials: V
authors.lastname: Thourani
authors.affiliation: University of California, San Francisco, California.
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Brindis
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: David M
authors.initials: DM
authors.lastname: Shahian
authors.affiliation: Cleveland Clinic, Cleveland, Ohio.
authors.forename: Lars G
authors.initials: LG
authors.lastname: Svensson
authors.affiliation: Duke University Medical Center, Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: Sean M
authors.initials: SM
authors.lastname: O'Brien
authors.affiliation: The Society of Thoracic Surgeons, Chicago, Illinois.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Shewan
authors.affiliation: American College of Cardiology, Washington, DC.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hewitt
authors.affiliation: University of Maryland, Baltimore, Maryland.
authors.forename: James S
authors.initials: JS
authors.lastname: Gammie
authors.affiliation: Denver VA Medical Center, Denver, Colorado.
authors.forename: John S
authors.initials: JS
authors.lastname: Rumsfeld
authors.affiliation: Duke University Medical Center, Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Peterson
authors.affiliation: Heart Hospital Baylor Plano, Baylor Healthcare System, Plano, Texas.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mack
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000401:mortality / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D065467:Transcatheter Aortic Valve Replacement / Q000401:mortality*; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology