International Journal of Cardiology 173 (2014) 347–348

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International Journal of Cardiology

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Editorial

Think left and think right and think low and think high. Oh, the thinksyou can think up if only you try! (Theodore Seuss Geisel, a.k.a. Dr. Seuss)

Christian Pristipino ⁎Interventional Cardiology Unit, San Filippo Neri Hospital, Via A. Poerio, 140-00152 Roma, Italy

⁎ Tel.: +39 0633062481; fax: +39 0633062516.E-mail address: pristipino.c@gmail.com.

http://dx.doi.org/10.1016/j.ijcard.2014.03.0940167-5273/© 2014 Elsevier Ireland Ltd. All rights reserved

a r t i c l e i n f o

Article history:

Received 20 January 2014Accepted 14 March 2014Available online 20 March 2014

Keywords:Radial approachLeft radial approachRight radial approachMeta-analysis

already published in the International Journal of Cardiology [5], addingmore recent randomized studies, as well as non-randomized studiesinto their analysis. They show that, in spite of similar procedural successrate and total procedural time, the left radial approach is associatedwitha statistically-significant reduction in radiation exposure and adminis-tered contrast media than the right radial approach in 7603 procedures.This is of unclear clinical importance.

Indeed, the average 43 s difference in the patient's radiation expo-sure and the 4 ml reduction in contrast media are not likely to impactoutcomes. In observational trials, these differences are more marked

Compared to a femoral approach, radial access significantly reducesvascular access-related haemorrhages and, in STEMI patients, it general-ly yields better outcomes [1]. However, the feasibility, associated radia-tion exposure, and duration of radial approach procedures are subject toconsiderable variability across studies, relative to femoral access [2].This variability has been attributed to differences in operator expertise,because proficiently accessing the radial artery requires both an ade-quate learning curve and a consistent ongoing procedural volume of in-terventions [3]. However, following Dr. Seuss' suggestion, if you lookclosely enough, considering the “radial approach” as a single entity ismisguided. Instead, left and right radial approaches should be consid-ered separately, because they are so different.

For example, the right radial approach is often considered morechallenging. This is because there are more arterial tortuosities in thedominant arm, more tortuosities in the anonymous trunk versus theleft subclavian artery, and a different pathway for catheters to reachthe aortic root relative to left-sided routes [4]. Despite these difficulties,a number of operators still prefer it. One main reason relates to thephysician's comfort, since they need not bend over the patient eitherduring arterial puncture or during the subsequent procedure, a factthat may become critical in case of obesity of the patient. In addition,using the right side may expose the operator to a lower radiationdose. Thepreference for right versus left access is supported by evidenceindicating that left and right radial approaches exhibit similar feasibilityand success rates during interventional procedures. This being said,some of these studies suggest that theremay be a difference in radiationexposure and in procedure duration between the two techniques.

.

In this issue, De Rosa et al. greatly expand a previous meta-analysis

than in randomized trials, but still insufficient to render them clinicallysignificant. Nonetheless, the main message of this meta-analysis is thatthe right radial approach is, on average, technically more demandingthan achieving access via the left, apparently in an independent wayfrom operator's proficiency. The small observed difference may also beconsidered a statistical anomaly secondary to inhomogeneous popula-tions, different procedures and different operators. Likely, there are sit-uations that may magnify the clinical significance of the differences inradiation exposure and contrast use between right and left radial ap-proaches. Consequently, future research should be directed towardsclarifying which patients benefit most from a left versus right radial ap-proach, and vice versa. This implies that the disadvantages of a right ra-dial approach, despite being clinically negligible on average, mightbecome critical in particular conditions; for example, when operatorsare insufficiently trained or still on their learning curve. This point alsohighlights that, in research on non-pharmacological interventions inwhich outcomes are operator-dependent, special caution must betaken, both when interpreting results and earlier when designing thestudy, taking into account a number of neglected variables like individ-ual operator and centre proficiency. Unfortunately, the majority ofstudies on which De Rosa et al.'s meta-analysis is based lack any quan-tification of operator or team proficiency in either left or right radial ap-proach. This should be a requirement of all contemporary radialapproach studies, so that their internal validity can be determined.

Another point that needs to be addressed in future studies is thesafety of left versus right radial access in terms of cerebral embolization[6], which has been insufficiently studied in the available researches.

Finally, an overall higher degree of patient exposure during a proce-dure does not necessarily translate into greater exposure for the opera-tor. Indeed, if the operator can be more easily shielded with a rightradial approach because of his or her position relative to the patient,the final result could render the higher radiation dose irrelevant [7].

Fig. 1. Proposed framework for learning steps and competency levels for TRI.(Reprinted from EuroIntervention Vol 8 / number 11, Hamon M, Pristipino C, Di Mario C,et al, Consensus document on the radial approach in percutaneous cardiovascular inter-ventions: position paper by the European Association of Percutaneous CardiovascularInterventions andWorkingGroupsonAcute Cardiac Care andThrombosis of theEuropeanSociety of Cardiology. Page 1447, Copyright (2013), with permission from Europa Digital& Publishing.)

348 Editorial

Again, specific studies must be directed towards clarifying such aquestion.

Taking all these data and considerations together, it is possibleto corroborate the recently-issued ESC EAPCI consensus documenton radial approaches [1], suggesting no preference for one accessroute over the other at this stage; though more attention to

radiation is suggested in the learning phase with the right radialapproach. As such, a radial approach should be considered primaryroutine access when indications are present and operators havesufficient training, paying particular attention to achieving optimalproficiency in both left and right access approaches, possiblyfollowing EAPCI/ESC recommendations for the learning curve foreach side of access (Fig. 1), so as to overcome any differences inher-ent between the two sides.

References

[1] Hamon M, Pristipino C, Di Mario C, et al. Consensus document on the radial approachin percutaneous cardiovascular interventions: position paper by the European Associ-ation of Percutaneous Cardiovascular Interventions and Working Groups on AcuteCardiac Care and Thrombosis of the European Society of Cardiology. EuroIntervention2013;8:1242–51.

[2] Agostoni P, Biondi-Zoccai GG, de Benedictis ML, et al. Radial versus femoral ap-proach for percutaneous coronary diagnostic and interventional procedures; sys-tematic overview and meta-analysis of randomized trials. J Am Coll Cardiol2004;44:349–56.

[3] Pristipino C, Roncella A, Trani C, et al. Prospective Registry of Vascular Access in Interven-tions in Lazio region (PREVAIL) study group. Identifying factors that predict the choiceand success rate of radial artery catheterisation in contemporary real world cardiologypractice: a sub-analysis of the PREVAIL study data. EuroIntervention 2010;6:240–6.

[4] Norgaz T, Gorgulu S, Dagdelen S. A randomized study comparing the effectiveness ofright and left radial approach for coronary angiography. Catheter Cardiovasc Interv2012;80:260–4.

[5] Biondi-Zoccai G, Sciahbasi A, Bodí V, et al. Right versus left radial artery accessfor coronary procedures: an international collaborative systematic review andmeta-analysis including 5 randomized trials and 3210 patients. Int J Cardiol2013;166:621–6.

[6] Pristipino C, Hamon M. Letter by Pristipino and Hamon regarding article, “cerebralmicroembolism during coronary angiography: a randomized comparison betweenfemoral and radial arterial access”. Stroke 2011;42:e418.

[7] Pristipino C. Radial artery catheterization and radiological exposure. Eur Heart J2008;29:2316–7.