Navigating a Radial Loop

Orlando Marrero, RCIS, MBA, can be contacted at orlm8597@icloud.com. 

Dr. Zaheed Tai can be contacted at zaheedtai@gmail.com.

Disclosures: Orlando Marrero reports he works for Mercator MedSystems and is a consultant for Boston Scientific. Dr. Zaheed Tai reports the following: Terumo (proctor for transradial course), Spectranetics (proctor for laser course, speaker, advisory board member), AstraZeneca (speakers bureau).

Case report

A 56-year-old female with hypertension and hyperlipidemia presented with chest discomfort. She underwent a stress test that was positive for ischemia in the anterior region. She was referred for diagnostic catheterization.

In the cath lab, the right radial was prepped and draped in sterile fashion. The right radial was accessed with a Glidesheath Slender sheath (Terumo). Initial catheter advancement was without resistance, and with resistance encountered between the antecubital and subclavian region. The initial approach was to downsize to a 5 French (Fr) catheter, as it was thought that the larger catheter may have induced spasm in this patient. Again resistance was encountered; therefore, the catheter was removed and an angiogram was performed to define the anatomy.  As can be seen in Figure 1, there is a radial loop, as well as the remnant radial artery (where the wire initially went). We had to navigate a radial loop (Figure 1), initially attempted with a Terumo Glide wire, and then with an 0.014-inch Runthrough wire (Terumo) that was easier to shape and torque through the loop. A 0.035-inch, 60cm Quick-Cross catheter (Spectranetics) was then advanced, but would not easily advance over the Runthrough. Therefore, a second Runthrough was advanced as a “buddy wire”. The Quick-Cross was able to navigate the loop and advance over the two wires. We removed the wire, exchanged it for a 0.035-inch J-wire, and advanced the J-wire into the ascending aorta. At this point, retraction on the system resulted in straightening of the loop and allowed us to complete the procedure. A Tiger catheter (Terumo) was used to engage the left coronary system and a 4Fr Amplatz right (AR) mod catheter was used to engage the right coronary system. By angiography, the left main was patent, and the left circumflex and obtuse marginal arteries were patent, as well as the right coronary artery, which was the dominant vessel. The patient had non-obstructive coronary disease.

Discussion

Since the first reports of transradial approach for angiography and intervention in 1989 and 1992 by Campeau and Kiemeneij, respectively, the transradial approach has continued to become more prevalent. More recently, with the advent of specific radial equipment, training courses, abundant literature, and patient preference and satisfaction have grown, as well as economic benefits. Once the catheter engages the coronary ostium, there is very little difference between transradial angioplasty and transfemoral, save some  catheter support issues and perhaps guide size. It is the route to the coronary that can often be more difficult via the transradial approach and requires a learning curve to feel comfortable with the different situations that one may encounter. Patel el al¹ have divided this into 3 sections: 1) radial artery spasm; 2) variant anatomy of the radial/brachial arteries such as tortuosity, loops, and anomalies; and 3) acquired abnormalities such as perforation, athereosclerosis, and calcification. Radial artery spasm is an access issue. Once access is obtained, then it is either an anatomic issue or an acquired variant that may prohibit completion of the procedure. Radial loops may occur more frequently on the right side and therefore, an obvious alternative solution to potentially avoid crossover to a femoral approach may be to switch to the left radial.² 

A few tips to overcome the radial loop:

1. Take a picture. Have a low threshold to perform radial angiography and visualize the anatomy.  
2. Change the wire. Use of an 0.014-inch or 0.025-inch wire +/- a buddy wire may facilitate crossing of the loop. Hydrophilic wires may be easier to use, but caution must be used to avoid dissection. Additionally, repeated attempts to cross with a 0.035-inch wire or stiffer, small wire could potentially result in spasm, perforation, or patient pain.³ 
3. Straighten the loop. This can usually be achieved by advancing the wire as far toward the ascending aorta as possible and then retracting the system. Apply pressure to the arm above the antecubital space with the hand and then simultaneously pull caudal on the wire and squeeze and push cranial with the other hand.
4. Adjunctive techniques. Consider use of BAT (balloon-assisted tracking) to facilitate crossing.⁴ During BAT, a partially inflated balloon protrudes through the catheter tip to minimize trauma in crossing. In addition, use of a low-profile crossing catheter may be easier than using a coronary catheter to cross. The Quick-Cross (Spectranetics) and CXI (Cook) are used in our lab to cross the loop over two 0.014-inch wires and then exchanged for the 0.035-inch wire.

Once the loop is straightened, additional sedation, readministration of a cocktail (without heparin) and use of  single catheter (Terumo’s Jacky Radial, Tiger, etc.) may facilitate completion of the procedure. Use of longer sheath will allow catheter exchange without aggravating the area, although there is the potential for spasm upon sheath removal.

References

1. Patel T, Shah S, Pancholy S, Radadiya R, Deora S, Vyas C, Hamon M, Gilchrist IC. Working through complexities of radial and brachial vasculature during transradial approach. Catheter Cardiovasc Interv. 2014 Jun 1; 83(7): 1074-1088. doi: 10.1002/ccd.25210. 
2. Norgaz T, Gorgulu S, Dagdelen S. A randomized study comparing the effectiveness of right and left radial approach for coronary angiography. Catheter Cardiovasc Interv. 2012 Aug 1; 80(2): 260-264. doi: 10.1002/ccd.23463. 
3. Louvard Y, Lefèvre T.  Loops and transradial approach in coronary diagnosis and intervention.  Catheter Cardiovasc Interv. 2000 Oct; 51(2): 250-252.
4. Patel T, Shah S, Pancholy S, Rao S, Bertrand OF, Kwan T. Balloon-assisted tracking: a must-know technique to overcome difficult anatomy during transradial approach. Catheter Cardiovasc Interv. 2014 Feb; 83(2): 211-220. doi: 10.1002/ccd.24959.