Reply: Radial versus femoral: Issues remain and questions need answers (Letter)

Abstract

Our viewpoint was a critical assessment of a trial and not intended to diminish the outstanding work done by physicians who have developed and promoted transradial access (TRA) for coronary intervention. That said, Dr. Rao and colleagues should not confuse 2 different factors that can independently influence an outcome in such a trial: 1) a center’s annual percutaneous coronary intervention (PCI) volume; and 2) a center’s proportion of radial PCI. In the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial (1), comparing TRA with transfemoral (TFA), the center’s annual PCI volume had the following impact on net adverse clinical events (NACE): low volume 10.8% versus 14.0% (p = 0.011), intermediate 9.4% versus 9.1% (p = 0.76), and high 9.0% versus 11.8% (p = 0.025); the p value for interaction was 0.89, indicating that the center’s volume did not differentially impact on the results. However, the p value for interaction of 0.0048 for a center’s proportion of radial PCI was so strong that to compare TRA and TFA without taking the center’s experience into consideration may not be appropriate. The benefit of TRA was entirely confined to the subset of patients randomized in centers where the proportion of radial PCI was very high (i.e., 80% to 98%). Moreover, the rates for NACE in the TFA group were quite excessive in the “high” TRA centers. In keeping with this, a high-volume academic radial PCI center recently reported that total vascular complications were higher in a contemporary cohort where both TRA and TFA were used as compared with a historical cohort where only TFA was used; the benefit associated with TRA was offset by a paradoxical increase in vascular complications among TFA patients (2). The report suggests that a center may become deskilled at performing TFA and that education and training are needed to ensure proficiency at TFA.