title: Transcatheter aortic valve implantation: lessons from the learning curve of the first 270 high-risk patients.
abstract: BACKGROUND
  Transcatheter aortic valve implantation (TAVI) is a rapidly evolving strategy for therapy of aortic stenosis. We describe the effect of the learning curve from the first 270 high-risk patients in Vancouver, Canada.
  
  
  METHODS
  Patients underwent TAVI by transfemoral (63%) or transapical (37%) routes using balloon expandable valves. The experience was divided into the first half (FH, patients 1-135) and second half (SH, patients 136-270).
  
  
  RESULTS
  The mean age was 83.2 ± 8 years (FH 83 ± 12 vs. SH 81 ± 7 years, P = 0.12). The mean Society of Thoracic Surgeons Score (STS) was 9.5% ± 5.2%- FH 10.5 vs. SH 8.5% (P = 0.01). The overall procedural success rate in the FH was 92.6%, improving to 97.8% in the SH (P = 0.05). The transfemoral procedural success improved-FH 89.3% to SH 98.8% (P = 0.01). The transapical procedural success remained high-FH 98.0% to SH 96.1% (P = 0.53). The overall 30-day mortality was 9.6%, improving from FH 13.3% to SH 5.9% (P = 0.04). In the transfemoral cases, 30-day mortality decreased by 56% [10.7-4.7%, P = 0.14], and similarly in transapical cases [17.6-7.8%, P = 0.14]. In-hospital stroke occurred in 3.3% (FH 3.7% vs. SH 2.9%, P = 0.74). The overall need for a new permanent pacemaker was 5.9% (FH 5.9% vs. SH 5.9%, P = 1). The overall major vascular injury rate was 6.7% (FH 8.1% vs. SH 5.2%, P = 0.33). The overall incidence of coronary vessel occlusion was 1.1% (FH 1.5 % vs. SH 0.7%, P = 0.56). Device embolization or failure to cross the valve was rare and largely seen in the FH only. Procedural experience (>135 procedures) was an independent predictor of 30-day survival (HR: 6.7, 95% CI: 1.2-18.1, P = 0.03).
  
  
  CONCLUSIONS
  TAVI outcomes improve with experience and device development. While overall complication rates are low, scope remains to further reduce procedural adverse events.
authors.affiliation: Department of Cardiology and Cardiothoracic Surgery, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.
authors.forename: Ronen
authors.initials: R
authors.lastname: Gurvitch
authors.forename: Edgar L
authors.initials: EL
authors.lastname: Tay
authors.forename: Namal
authors.initials: N
authors.lastname: Wijesinghe
authors.forename: J
authors.initials: J
authors.lastname: Ye
authors.forename: Fabian
authors.initials: F
authors.lastname: Nietlispach
authors.forename: David A
authors.initials: DA
authors.lastname: Wood
authors.forename: Samuel
authors.initials: S
authors.lastname: Lichtenstein
authors.forename: Anson
authors.initials: A
authors.lastname: Cheung
authors.forename: John G
authors.initials: JG
authors.lastname: Webb
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000401:mortality / Q000628:therapy*; D001955:British Columbia; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation / Q000401:mortality; D002983:Clinical Competence; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods* / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D059032:Learning Curve; D008297:Male; D016016:Proportional Hazards Models; D012042:Registries; D012044:Regression Analysis; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome