Transcatheter aortic valve implantation: assessing the learning curve

The aim of this study was to assess the learning curve for the implantation of the percutaneous aortic valve via the transfemoral route.

Transcutaneous aortic valve insertion is a fundamentally new procedure for the treatment of aortic valve stenosis. The number of cases needed to gain proficiency with concomitant ease and familiarity (i.e., the "learning curve") with the procedure is unknown.

We performed a retrospective analysis of the first 44 consecutive patients who underwent transcatheter aortic valve implantation as part of the PARTNER (Placement of Aortic Transcatheter Valves) trial at our institution between November 2008 and May 2011.

The median age of the patients was 83 years (interquartile range: 77 to 87 years) and a median Society of Thoracic Surgery risk score of 9.6. Pre-procedural assessment of the aortic valve revealed a mean gradient of 53.5 mm Hg, mean aortic valve area of 0.7 mm(2), and a median ejection fraction of 59.5%. Patients were divided into tertiles based on sequence. Significant decreases in median contrast volume (180 to 160 to 130 ml, p = 0.003), valvuloplasty to valve deployment time (12.0 to 11.6 to 7.0 min, p < 0.001) and fluoroscopy times, from 26.1 to 17.2 and 14.3 min occurred from tertiles 1 to 3, p < 0.001. Significant decreases in radiation doses were also seen across the 3 tertiles, p < 0.001. The 30-day mortality for the entire cohort was 11%.

Experience accumulated over 44 transfemoral aortic valve implantations led to significant decreases in procedural times, radiation, and contrast volumes. Our data show increasing proficiency with evidence of plateau after the first 30 cases. More studies are needed to confirm these findings.