Letter to the Editor

Suggesting a New Primary Access Site for Treating Chronic Total Occlusions: Bilateral Distal Transradial Intervention (bdTRI)

Irzal Had≈æibegović, MD, PhD and Boris Starčević, MD, PhD 

Irzal Had≈æibegović, MD, PhD and Boris Starčević, MD, PhD 

Dear Editor,

We have read with interest the article from the latest issue of the Journal of Invasive Cardiology by Basavarajaiah et al on possible technical and anatomical difficulties in the process of adoption of transradial approach as a standard access site for coronary angiography and intervention.1 During the last several years, transradial approach has been recognized as a first-choice access site all over the world, and the recently published European Society of Cardiology (ESC) guidelines for myocardial revascularization finally endorsed it as a primary access site for coronary angiography and intervention with the strongest level of recommendation.2 However, there are some fields of complex coronary interventions that have been perceived as a “non-preferred radial access zone.” Chronic total occlusion (CTO) interventions are certainly one of them, where the issues raised by Basavarajaiah et al might be important. Although transradial access for CTO was fully shown to be feasible and effective in most complex CTO interventions,3 some issues on patient and operator comfort during left radial access, need for larger guiding catheters, and radial artery occlusion with larger sheaths have been raised in everyday practice.

When performing a CTO intervention using double injection by standard bilateral transradial access, the position of the patient’s left hand is difficult to maintain, while the operator must lean forward in order to easily operate with different materials. Sometimes, if the patient is obese, it can make the procedure rather uncomfortable for both the patient (unnatural and painful left hand position) and the operator (increased x-ray exposure because of x-ray tube proximity). Also, radial artery occlusion could potentially be an important issue because of a more frequent need for redo procedures and routine coronary angiographies in CTO patients.

After looking into all issues on routine implementation of transradial approach to CTO interventions, we found that bilateral distal transradial intervention (bdTRI – “snuffbox” radial artery access site)4 with dedicated hydrophilic 7 Fr sheaths provided a simple but effective complete solution. Although it has been demonstrated that radial artery diameter in the snuffbox position is typically 0.3 mm smaller than the radial artery diameter in the standard puncture site, with the development of new dedicated radial artery hydrophilic 7 Fr and even 8 Fr sheaths that have outer diameters comparable to standard 6 Fr and 7 Fr sheaths, almost all patients with favorable radial/brachial artery anatomy are good candidates for wrist approach to most complex coronary artery interventions. The advantages of bdTRI in this setting are clear: natural left hand position with more distal access allowing a more comfortable procedure for both patient and operator, and almost no radial artery occlusion. Figure 1 shows a female patient at our center who underwent CTO intervention of the right coronary artery that utilized 7 Fr hydrophilic sheaths in both radial arteries. Left radial artery puncture was performed in the distal/dorsal site (snuffbox), allowing a natural left hand position. The right radial artery was punctured in a classic fashion, with both sheaths almost aligned and a comfortable left hand position, not so distant from the operator standing on the right patient side (Figure 1). If the left radial artery is used for injection into the collaterals in an anterograde strategy, it can be easily converted into a retrograde procedure, without patient and operator discomfort.

The first positive bdTRI experiences have been published very recently,5,6 and have demonstrated that >90% of patients were good candidates for bdTRI. Larger-scale trials on snuffbox puncture using 7 Fr and even 8 Fr dedicated slender sheaths are warranted in order to prove the feasibility of snuffbox puncture in everyday CTO practice. However, based on our recent experiences with snuffbox access, comparative advantages of routine bdTRI were most evident in CTO interventions. Therefore, we suggest bdTRI as a new primary access strategy for CTO interventions and call for more involvement worldwide in order to collect valuable data.


1.    Basavarajaiah S, Brown A, Naganuma T, Gajendragadkar P, McCormick L, West N. Should technical and anatomical difficulties discourage operators from embarking on transradial access for percutaneous coronary intervention? J Invasive Cardiol. 2018;30:341-347.

2.    Neumann FJ, Sousa-Uva M, Ahlsson A, et al; ESC Scientific Document Group. 2018 ESC/EACTS guidelines on myocardial revascularization. Eur Heart J. 2018 Aug 25. (Epub ahead of print).

3.    Bakker EJ, Maeremans J, Zivelonghi C, et al. Fully transradial versus transfemoral approach for percutaneous intervention of coronary chronic total occlusions applying the hybrid algorithm: insights from RECHARGE registry. Circ Cardiovasc Interv. 2017;10(9).

4.    Kiemeneij F. Left distal transradial access in the anatomical snuffbox for coronary angiography (ldTRA) and interventions (ldTRI). EuroIntervention. 2017;13:851-857.

5.    Lee JW, Park SW, Son JW, Ahn SG, Lee SH. Real world experience of the left distal transradial approach for coronary angiography and percutaneous coronary intervention: a prospective observational study (LeDRA). EuroIntervention. 2018;14:e995-e1003. 

6.    Valsecchi O, Vassileva A, Cereda AF, et al. Early clinical experience with right and left distal transradial access in the anatomical snuffbox in 52 consecutive patients. J Invasive Cardiol. 2018;30:218-223.