Effect of experience on results of transcatheter aortic valve implantation using a Medtronic CoreValve System

Outcome after transcatheter aortic valve implantation (TAVI) depends on the patient risk profile, operator experience, progress in technology, and technique. We sought to compare the results of TAVI during the initiation phase and after certification to perform TAVI with the Medtronic CoreValve System without proctoring. A total of 165 consecutive patients was categorized into a first cohort of 33 patients treated before certification (November 2005 to December 2007) and a second cohort of 132 patients treated after certification (January 2008 to October 2010). The study end points were selected and defined according to the Valve Academic Research Consortium recommendations. Compared to cohort 2, the patients in cohort 1 more frequently had New York Heart Association class III-IV (100% vs 71%, p <0.001), hypertension (67% vs 39%, p = 0.004), and aortic regurgitation grade III-IV (46% vs 22%, p = 0.006) before TAVI. Over time, the patients in cohort 2 more frequently underwent a truly percutaneous approach (98% vs 82%, p = 0.002) without circulatory support (96% vs 67%, p <0.001) but with more concomitant percutaneous coronary intervention (11% vs 0%, p = 0.042) than the patients in cohort 1. They also more often received a 29-mm prosthesis (72% vs 24%, p <0.001), required less postimplantation balloon dilation (10% vs 27%, p = 0.008), and had less aortic regurgitation grade III-IV after TAVI (12% vs 30%, p = 0.010). The clinical outcome showed a nonsignificant reduction in the combined safety end point (30% to 17%) but a significant reduction in cerebrovascular events (21% to 7%, p = 0.020) and life-threatening bleeding (15% to 5%, p = 0.044) in cohort 2. However, the reduction in overall bleeding and vascular complications (25% and 14%, respectively) was not significant. In conclusion, TAVI became significantly less complex and was associated with better results over time but remained associated with a high frequency of periprocedural major cardiovascular complications.