Learning curves for transfemoral transcatheter aortic valve replacement in the PARTNER-I trial: Success and safety

Objectives To identify number of cases needed to maximize device success and minimize adverse events after transfemoral transcatheter aortic valve replacement (TF-TAVR), and determine if adverse events were linked to the technical performance learning curve. Background TF-TAVR is a complex procedure with an incompletely characterized learning curve for clinical outcomes. Methods From 4/2007-2/2012, 1521 patients underwent TF-TAVR in the PARTNER-I trial. Outcomes learning curves were defined as number of cases needed to reach a plateau for device success, adverse events, and post-procedure length of stay. Institutional variation was accounted for by mixed-model non-linear techniques, which were also used to identify contribution of the procedure time learning curve to 30-day major adverse events and length of stay. Results Eighty percent device success was achieved after 22 cases; major vascular complications fell below 5% after 70 cases and major bleeding below 10% after 25 cases. It took an average of 28 cases to achieve a consistent low risk of 30-day major adverse events, but institutions entering in the middle of the trial achieved it after about 26. The most significant correlate of 30-day major adverse events and post-procedure length of stay was procedure time (P < 0.0001). However, this association was related to patient and unmeasured variables, not the procedure time learning curve (P = 0.6). Conclusions By end of trial, a consistent low risk of adverse events was achieved after ∼26 cases. However, these improved results were due to change in patient risk profile; outcomes were not linked to the technical performance learning curve.