Author + information
- Stéphane Rinfret, MD, SM∗ ( and )
- Rustem Dautov, MD, PhD
- ↵∗Address for correspondence:
Dr. Stéphane Rinfret, McGill University Health Centre, 1001 Boulevard Décarie, Montreal, QC, Canada, H4A 3J1.
Since its description by Campeau (1), interventional cardiology has witnessed an exponential use of transradial techniques in percutaneous coronary interventions (PCI), now used in complex procedures, such as chronic total occlusion (CTO) PCI (2,3). Although the pivotal RIVAL trial failed to demonstrate a reduction in mortality, it still showed less bleeding and vascular complications with the transradial compared with the traditional transfemoral approach (4).
In this issue of JACC: Cardiovascular Interventions, Tanaka et al. (5) bring the radial versus femoral debate into the CTO PCI arena. In their 10-year series, 280 and 305 CTO PCI procedures were performed from the transradial or transfemoral access, respectively. Technical success rates did not differ by access site, and were relatively low (≤75%). In the small proportion of very difficult cases, success from the radial was lower (35.7% vs. 58.2%; p = 0.04). Catheter size <7-F, calcifications, and lesions longer than 20 mm predicted higher transradial CTO PCI failure. The authors conclude that albeit transradial CTO PCI may be feasible in simpler cases, complex CTOs are better managed from the femoral approach.
Unfortunately, Tanaka et al. (5) did not report the proportion of patients who underwent dual catheter PCI. Patients post-coronary artery bypass graft and use of the retrograde approach were more common in the transfemoral group, highlighting obvious selection bias. Also, when the radial was selected, smaller catheters were used in 91% of cases. Less than 10% underwent their PCI from the radial with 7-F to 7.5-F guiding catheters, none with 8-F catheter, whereas ≥7-F guiding catheters were used in ≥95% of transfemoral patients. In summary, there was a clear bias toward smaller catheters in the radial group. Therefore, this study should not be considered as a clean comparison of access sites for CTO PCI as did RIVAL for non-CTO PCI, where 6-F guiding catheters were used (4): it is also a comparison of success and complications using smaller versus larger catheters for CTO PCI. Nevertheless, the authors found some excess of access-site complications with the transfemoral approach. Although the absolute number of events was very low, with only 9 patients who had such complications, not a single access-site event was observed in the radial arm, confirming the safety of the radial for CTO PCI. However, given the nonrandomized selection, difference in catheter size and in the risk profile between groups, the authors’ conclusions about the limitations of the transradial approach for CTO PCI need to be put in perspective for the benefit of the readers.
When we started our CTO PCI program in 2010, we already had years of experience with the transradial approach. For practical issues, and to reduce peer pressure in a center that pioneered the transradial approach, we elected to perform as many cases as possible from the radial, and therefore mainly used 6-F guiding catheters. Our initial experience in complex cases was favorable, with low access site complications, in an era when such outcomes deserved poor interest in CTO PCI (3). We could also demonstrate that it was feasible, which encouraged some hybrid operators to decrease from 8-F to 6-F catheter, especially on the retrograde side, and use of more radial access (2).
However, it became clear with experience and collegial exchange that our default selection of transradial and small 6-F catheters involved many trade-offs. The 8-F guiding catheters offer additional support that is 3-fold greater compared with equivalent curves in 6-F guides. Larger guides also allow for the use of simultaneous catheters, facilitating complex antegrade maneuvers. Also, with the advent of CrossBoss and Stingray (Boston Scientific, Natick, Massachusetts), catheters for antegrade dissection and re-entry, it became evident that 8F catheters would ease the procedure. Therefore, from March 2013, we decided to use 8-F catheters antegrade as our default. To maintain a high bilateral radial use, we developed an 8-F sheathless transradial technique to overcome limitations of smaller guides (6). This novel sheathless transradial technique could be used in one-half of patients. The outer diameter of 8-F catheters and 6-F sheaths is the same. Interestingly, in a subgroup that came for radial Doppler assessment 3 to 6 months later, the radial occlusion rate was low. CTO PCI success rates higher than 90% could be achieved with the full spectrum of hybrid techniques. Otherwise, a combination of an 8-F catheter from the femoral and a radial to the donor artery was used, with low vascular complications (6). Alternatively, new thin-walled sheaths, called “slender sheaths” (Terumo, Tokyo, Japan), allow for the use of a 7-F guiding catheters into a sheath that has the outer diameter of a 6-F sheath. Nowadays, the trapping technique can be done with the Stingray (Boston Scientific, Natick, Massachusetts), LP within a 7-F guiding catheter without friction.
Therefore, the experience reported by Tanaka et al. (5) may not represent what can be achieved from a transradial approach with currently available equipment and techniques. But most importantly, the debate of comparing radial with femoral for CTO PCI is somewhat passé, because both approaches offer advantages and limitations that need to be understood. Ironically, this study is one good example because operators selected radial and femoral approaches prospectively in different circumstances. Trying to discriminate criteria that favored radial or femoral is difficult, and use of a propensity-score unsatisfactorily accounts for such factors. Dual radial approach permits early sitting and ambulation, which can be a huge advantage in some patients. Although larger-bore catheters for CTO PCI are useful, they are not invariably necessary. Antegrade-only operators using wire escalation, for low J-CTO score lesions, derive minimal benefit from larger catheters. This is consistent with the conclusions of Tanaka et al. (5). When operators understand that dual catheters are mandatory in almost all CTO PCI (7,8), use of at least 1 radial logically halves the risk of access site complication. With 6-F guiding catheter, trapping balloon and mother-and-child techniques can be used with most microcatheters. To improve success rates, training with the full spectrum of hybrid techniques and using dual access will have more impact on outcomes than the selection of a radial or a femoral approach.
The transradial approach may also be inappropriate in some cases. Females with smaller radials offer challenges; however, females represent <20% of CTO PCI candidates. Selective use of femoral approach in females is necessary to improve success. Patients with occluded carotid or vertebral arteries, depending on collateral flow to the brain, may not be ideal candidate for CTO PCI with a catheter standing in front of the carotid or vertebral ostium for hours. Finally, ostial CTOs are very difficult to treat from the radial. The guide needs a good landing zone and stable position in the coronary ostium for the transradial approach to be effective, because the tip of the catheter tends to disengage with breathing and lowering of the diaphragm with inspiration, which does not occur from the femoral. Therefore, we advocate for the use of a transfemoral approach and a large 8-F catheter for ostial right coronary artery CTOs, and use of side-holes. However, the transradial remains unavoidable in many cases, as in post-coronary artery bypass graft cases with multiple sources of collateral channels that require 2 retrograde catheters, in cases when left ventricular hemodynamic support is required, in very obese patients, or when severe peripheral disease limits femoral access.
In conclusion, antegrade-only operators can use their preferred approach when simpler cases are performed. The data from Tanaka et al. (5) support that statement. Antegrade-only operators not using dissection re-entry techniques can perform most techniques with 6-F guiding catheters. However, hybrid operators tackling complex cases need to master both approaches, and maximize the use of 8-F catheters on the antegrade side, although 7-F guiding catheters delivered through slender sheaths can be satisfactory in most situations. Therefore, with the 8F sheathless transradial technique, new slender sheaths, and safer approaches to femoral puncture, such as with micropuncture kits or echo-Doppler guidance, both radial and femoral approaches need to be frequently used and tailored to maximize guide size and success rate while avoiding bleeding and vascular complications, which remain low in most series. Simply put, there is no need to be dogmatic: CTO PCI operators need to master both approaches.
↵∗ Editorials published in JACC: Cardiovascular Interventions reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Interventions or the American College of Cardiology.
Dr. Rinfret has received speaker and proctorship honoraria from Boston Scientific, Abbott Vascular Canada, Medtronic Canada, InCathlab, and Terumo U.S.; holds research support for Medtronic and Abbott Vascular; and is a consultant for Soundbite Medical and Vascular Solutions. Dr. Dautov has reported that he has no relationships relevant to the contents of this paper to disclose.
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