CardioSource WorldNews Interventions | In the catheterization world of arterial access, revolution is in the air. Transradial (TRA) catheterization and TRA PCI are now widely used throughout the world, and fellows-in-training are keen to list experience with the radial approach in their personal summaries. There seems to be a sense that the “new” site is a hot topic, and interventionalists wear their TRA credentials like Top Gun insignias. Reports summarizing the virtues of TRA are in the literature,^1,2 and, indeed, there are many features that make TRA a good choice for many patients. If nothing else, patient demand for, and satisfaction with TRA, may lead the list. To the lay public, there is something slightly magical about doing a diagnostic cath or a PCI from the wrist. In response, cardiologists are indicating that they plan to increase the number of times they will perform TRA in the future² and there are webinars and mini-courses on how best to do TRA for initiates.

But TRA is not without its critics. I confess to being wary about abandoning the transfemoral (TF) approach. Much of that wariness comes from the fact that a long list of reports (both observational and randomized) of TRA versus TF approaches has produced mixed messages. Some recent randomized trials have not been able to demonstrate superiority for TRA over TF,^3,4 making any wholesale conversion to TRA less than data-driven. There may be any number of reasons that this is the cased—small numbers, patient selection bias, restrictive definitions, etc., but the fact is that there is no large randomized trial that has shown unequivocal TRA superiority. In addition, TRA is not without its own difficulties: the small radial artery that is difficult to access; arterial spasm in the brachio-radial tree, radial anomalies (radial loop, accessory radial artery), intrathoracic anomalies (bovine arch), need for smaller catheters, greater difficulty in engaging the coronaries and graft vessels, familiarity with specialized TRA catheter shapes, and importantly, longer fluoroscopy time and greater radiation dose to both patient and operator (though experienced operators seem able to overcome this),⁵ etc. Dangerous bleeding complications are not in the purview of TF alone and can occur with TRA (e.g. anterior compartment syndrome from mid-radial perforation) and the possibility of stroke from traversing the commonly found plaque at the innominate bifurcation or from embolic intima carried from the radial artery is always present.6 Thrombotic hand ischemia can occur⁷ as can wrist/hand dysfunction from compression nerve injury.⁸ FA naysayers are able to list an equally discomfiting list of TF difficulties, and observational studies have even suggested a mortality benefit for TRA over TF.⁹

Now in the July issue of JACC: Cardiovascular Interventions, there is a meta-analysis that sheds further light on this controversy.¹⁰ The meta-analysis supports TRA as the “default” strategy but cites multiple important limitations of which the authors state: “Although this meta-analysis provides evidence supporting the superiority of radial approach as compared to femoral approach, […] differences in absolute event rates between groups were small for several endpoints leading to a number needed to treat to benefit or harm above 100.” Despite the “strong” and “moderately strong” conclusions listed in the report, this meta-analysis carries with it the inherent difficulties of any meta-analysis. To allay these, the authors have used some unique statistical methods to help their cause. But in addition to the “usual suspects” of meta-analysis bashing, there are additional potential problems. The studies that were chosen for the meta-analysis are largely from centers interested in TRA, with expertise that is not universal. Some of the randomized trials included were done more than 10 years ago. Techniques, even for TF approaches, have changed. A majority of the trials that were included in the analysis used manual compression for TF hemostasis. That too has changed in centers in which TF expertise with closure devices has evolved. It is not my purpose to editorialize the report, but meta-analyses are fraught with potential bias, and cannot take the place of well-designed randomized trials.¹¹ For those looking for TRA support in this controversy, John A. Bittl, MD, FACC, in an accompanying, even-handed editorial has approached that.¹²

In my view, the problem is complex and this recent meta-analysis does not solve the controversy. If we abandon TF for TRA, will we be throwing the baby out with the bathwater? Not everyone is a candidate for TRA. Patients with small radial arteries or abnormal Allen or oximetry tests or upper-extremity hemodialysis shunts are not candidates. Use of large interventional devices > 7Fr or hemodynamic support devices are unsuitable for TRA, and bail-out situations for a complication of TRA almost always mean an urgent TF approach. One can argue that such patients are a small minority of those having cardiac catheterization or PCI, but they exist in any center. Furthermore, with expansion of transcatheter techniques for structural heart disease, TF access expertise remains mandatory, and with it complete understanding of femoral closure. Just like TRA, TF access and the understanding of TF catheterization and interventions require expertise and experience to maximize safety.

The question is how do we manage to be experts at both? It is easy to say that all catheterizers/interventionalists simply will have to be competent doing both TRA and TF, but it is likely that maintenance of competence for both will require more cases per year than many centers can provide. Choosing specific physicians to do “only” TF or TRA is an unlikely scenario, and what happens if a complication requires a urgent change from TRA to TF? In the movie The Usual Suspects, Verbal Kint (a.k.a. Keyser Soze) asks the provocative questions: “How do you shoot the Devil in the back?... What if you miss?” Mr. Soze was referring to a fallback position, which is exactly what every TRA operator needs to have in mind in case something goes terribly wrong. That is a situation where lack of TF expertise might add injury to injury.

At this point, the rush to TRA is simply not supported by the data available. What is needed is a well-conceived randomized trial that compares TRA with TF. Exactly how that design might evolve is debatable, but the inclusion of an arm that mandates an TF closure device might help us understand what role (if any) such devices have in helping choose patients for TF versus TRA. Will such a trial happen? Perhaps, but funding for such a venture (that will require enrollment of thousands of patients) is a real deterrent.

References

1. Rao SV, Cohen MG, Kandzari DE, et al. J Am Coll Cardiol. 2010;55:2187-95.
2. Bertrand OF, Rao SV, Pancholy S, et al. J Am Coll Cardiol. 2010;55:2187-95.
3. Jolly SS, Yusuf S, Cairns J, et al. Lancet. 2011;377:1409-20.
4. Rao SV, Hess CN, Barham B, et al. JACC Int. 2014;7:857-67.
5. Jolly SJ, MD, Cairns J, Niemela K, et al. JACC Int. 2013;6(3):258-66.
6. Jaworski C, Brown AJ, Hoole SP, et al. JACC Int. 2015;8(11):177-8.
7. Rademakers LM and Laarman GJ. Neth Heart J. 2012;20(9):372-75.
8. Gilchrist IC. Cardiac Interventions Today. Jan/Feb 2008.
9. Vorobcsuk A., Konyi A., Aradi D. Am Heart J. 2009;158:814-21.
10. Ferrante G, Rao SV, MD, Jüni P, et al. JACC Int. 2016;doi. 10.1016/j.jcin.2016.04.014
11. LeLorier J, Grégoire G, Benhaddad A, et al. N Engl J Med. 1997;337(8):536-42.
12. Bittl JA. JACC Int. 2016;doi:10.1016jcin.2016.05.026

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Peter C. Block, MD, is a professor of medicine and cardiology at Emory University Hospital and School of Medicine in Atlanta, GA.

Read the full July/August issue of CardioSource WorldNews Interventions at ACC.org/CSWNI

Keywords: CardioSource WorldNews Interventions, Arteries, Neuroaxonal Dystrophies, Personal Satisfaction, Virtues, Catheterization

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