Lawrence Ang, MD, FSCAI; Debabrata Mukherjee, MD, MS, FSCAI; and Faisal Latif, MD, FSCAI

Introduction

Radial artery spasm is commonly encountered (4.3%–16%) during transradial diagnostic and interventional cardiology procedures.^{1, 2} While radial access is increasingly utilized over femoral access, due to lower rates of vascular complications, bleeding, and improved patient satisfaction, subsequent transradial procedures can be hindered and complicated by the occurrence of problematic spasm.^3–6 In this Tip of the Month, we present tips and tricks, including a simple catheter-in-guide technique, for operators to use for preventing and overcoming radial artery spasm and successfully completing transradial procedures.

Avoiding Radial Spasm

Approaches to avoid radial spasm generally aim to 1) maximize patient comfort and 2) avoid radial artery irritation (see Table 1). Overall, inadequate patient premedication, difficult arterial access, suboptimal sheath/catheter sizing, excessive catheter manipulation and exchanges, and smaller radial arteries contribute to radial artery irritation and the development of problematic spasm.

Table 1. Maximizing patient comfort while avoiding radial artery irritation.

Relieving Radial Spasm

Once radial spasm has begun to occur, as observed by catheter resistance during a manipulation or an exchange, it can be addressed by both pharmacologic and nonpharmacologic approaches (see Table 2).

Table 2. Pharmacologic and nonpharmacologic approaches for relief of radial spasm.

Catheter-in-Guide Technique

For transradial procedures that have been impacted by radial spasm (or other challenging anatomy) and still need to convert from a diagnostic coronary angiography to a coronary intervention, the catheter-in-guide technique may be a simple additional maneuver to safely and successfully advance the guide catheter through the radial artery and eliminate a traumatic “razor effect.”^{13, 14} Of note, balloon-assisted tracking has also been described to avoid the “razor effect” and facilitate guide catheter advancement for patients experiencing radial artery spasm.^15,

1. Maintaining 0.035” guidewire access—Following completion of a transradial coronary angiography, the diagnostic catheter is removed from the ascending aorta over an exchange-length 0.035-inch guidewire. Resistance to catheter removal and patient discomfort may signal the presence of radial spasm, thereby supporting the use of this catheter-in-guide technique.
2. Catheter-in-guide assembly—The 5F diagnostic catheter just used for a coronary angiography is an option to insert as a “dilator” within the guide catheter intended for a coronary intervention. The diagnostic catheter is completely advanced to ensure that its tip protrudes beyond the guide catheter tip, thus acting as a “dilator” for the guide. For many cases, a 5F TIG 4.0 or Jacky catheter (110 cm long) can be fully inserted into a 6F EBU 3.5 or JR 4.0 guide catheter (100 cm long) to facilitate the insertion of the guide catheter and the continuation of the transradial procedure. Other diagnostic and guide catheter length/diameter combinations can also be used (see Table 3).
3. Catheter assembly advancement—The 0.035” guidewire is loaded into the inner catheter, and both catheters are advanced together en bloc over the wire. Care is taken to ensure that the catheter assembly does not separate during advancement and that the inner catheter tip leads the guide catheter across the radial artery at all times, thus mitigating the “razor effect” (see Figure 1).
4. Inner catheter and wire removal—Once the catheter assembly is advanced over the guidewire into the ascending aorta, the inner catheter can be fixed in position while the advancement and adjustment of the final guide catheter are performed. The inner catheter also provides some helpful rigidity to the catheter assembly for guide catheter manipulation. Once the guiding catheter is in a reasonably desired position, the inner catheter and wire can be fully removed.

Table 3. Other diagnostic and guide catheter length/diameter combinations.

Ln = length, ID = inner diameter, OD = outer diameter.
5F TIG 4.0 and Jacky catheters (Terumo Medical Corp, Tokyo, Japan).
6F diagnostic catheter (Boston Scientific Corp, Marlborough, MA).
6F and 7F Launcher guide catheters (Medtronic, Dublin, Ireland).
Outer diameter measurements by digital caliper (Mitutoyo Corp, Kanagawa, Japan).

Figure 1. Catheter-in-guide assembly for a transradial coronary intervention.
The tip of a 5F TIG 4.0 diagnostic catheter (light blue) protrudes beyond the tip of a 6F EBU 3.5 guide catheter (white) and provides a gradual transition of the catheter assembly over a 0.035-inch guidewire (Panel A). In comparison, the tip of the guide catheter alone is abrupt and can cause a traumatic “razor effect” when advanced along the radial artery inner wall (Panel B). The TIG 4.0 diagnostic catheter (110 cm long) is completely hubbed within the guide catheter (100 cm long) and the catheter assembly advanced together in this fixed configuration across the radial artery (Panel C).

Conclusion

Transradial coronary angiographies and interventions can be hindered by radial spasm. Multiple approaches to prevent, treat, and sidestep the challenges of radial spasm, including a simple catheter-in-guide technique, can help operators successfully complete transradial procedures without changing the access site.

References

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