Response to letter regarding article, 'The learning curve for transradial percutaneous coronary intervention among operators in the United States: a study from the National Cardiovascular Data Registry'

We thank Drs Azzalini and Ly for their interest in our work and for their comments.1 Access site crossover is certainly an important indicator of transradial percutaneous coronary intervention (TRI; PCI) success and operator proficiency. As acknowledged in our limitations, we could not account for this confounder, because it is not captured in the CathPCI Registry. The authors state in their letter that we “excluded cases where PCI was unlikely to be completed transradially and/or the postprocedural angiographic result was judged a priori to be potentially suboptimal,” resulting in a “low” threshold for overcoming the TRI learning curve. To support their hypothesis, they cite the 89.7% of TRIs that were ad hoc. Several points merit discussion. First, we agree that operators may stage complex PCIs through the femoral approach, especially early in their radial learning curve. We intentionally excluded femoral cases, as they …