Almost a quarter-century has passed since the seminal works describing the feasibility of transradial percutaneous coronary intervention (TRI). The message has always been the same… TRI, though technically more challenging, leads to decreased access site complications and improved patient comfort compared to the traditional transfemoral approach (TFI). Despite this, a steady push toward widespread, routine TRI utilization is only evident over the past few years.

While numerous factors account for relatively slow uptake over the past few decades, a number of large registries and randomized trials have confirmed reduced access site complications and, more importantly, a potential mortality benefit in certain patient subgroups . What was formerly considered observational data touted by a “cult” of TRI enthusiasts is now a reasonably large evidence base, and TRI has garnered significant physician, industry, societal and public support. Indeed, dedicated scientific sessions, didactic courses, practical workshops and proctorships exist in support of a growing interest in TRI worldwide.

Not surprisingly, innumerable small registries have emerged describing favorable outcomes of TRI in a variety of complex lesion subsets. The report by Tomassini et al. in the current issue of CRM is another example . In this non-randomized, single-center, single-operator analysis of 49 unprotected left main PCI procedures, the authors report similar success, procedural complications and major adverse cardiovascular events between TRI and TFI. The authors recognize the possibility of selection bias within their series, and their results are largely similar to other registries of unprotected left main TRI . The nuance here is that the operator was relatively new on the TRI learning curve compared to other studies in complex lesion/patient subsets. It is therefore postulated that TRI is feasible for unprotected left main PCI regardless of TRI expertise.

Whether or not complex PCI can be accomplished via the radial artery is not really the question. More appropriately, we should focus on how to best approach a particular patient or lesion. Based on the preponderance of evidence, there is little question that, at least with regard to access site complications, TRI is safer. Whether the patient is better treated by TRI remains somewhat debatable. As a result, the fundamental issues relate to the patient on the table and the operator performing the procedure.

It has been argued by many (including myself) that any lesion, regardless of location or complexity, can be approached by TRI provided guide catheter alignment/support can be safely achieved, and the procedure can be effectively performed. The classic teaching is that the majority of patients have radial artery diameters sufficient for 6 F access (approximately 2.6 mm), but larger access is not feasible for many patients . Given the available equipment in the United States, most advocate no more than a 6 F system for TRI, especially during the “earlier” portions of the learning curve, and techniques based on 6 F systems should form the essential base of TRI strategy. Outside the United States, other options exist including sheathless guide catheters up to 7.5 F (with outer diameters similar to 6 F sheaths), and this was used for 3 cases in the current series.

It is important to recognize that appropriate treatment of the coronary lesion takes precedence over the chosen access site. With regard to the unprotected left main, many lesions can be safely and effectively approached with a 6 F system, and are thus amenable to TRI. Ostial and mid-shaft left main lesions are relatively straightforward, and TRI is certainly feasible and potentially preferable, given decreased access site complications. Distal, bifurcation lesions may also be approached via TRI provided the treatment plan (one vs. two stent strategies, adjunctive equipment or rescue techniques) supports TRI access. This is a moving target based on operator comfort or experience, and some variation is reasonable given that the primary goal is treating the coronary lesion.

Ultimately, the access site chosen for complex coronary intervention is at the discretion of the operator. Based on reduced access site complications, one could argue TRI is preferred for any case (including unprotected left main) in which the procedure can be effectively performed. However, as demonstrated in the The RadIal Vs femorAL access for coronary intervention (RIVAL) trial, the primary endpoint of death, myocardial infarction and stroke was not significantly different between the two groups . This suggests that, in terms of hard clinical endpoints, TFI is still a reasonable option in cases where increased options for guide catheter size and adjunct equipment are desirable.

Ultimately, a balance between can and should is important. Just because we can treat via TRI, doesn’t mean it is always best. The patient, lesion and treating physician’s comfort levels are all important factors. Dedicated training and technologic evolution will continue to increase our capacity for complex TRI, and although unprotected left main PCI is certainly feasible via TRI, it must be remembered that access is only a part of the case. In the end, it comes down to the patient and the physician.