A 65-year-old female with a history of diabetes, uncontrolled hypertension, and hypercholesterolemia presented due to new onset of chest discomfort during routine exertion. She had undergone nuclear stress testing, which revealed a small, reversible anteroseptal defect involving the apex to mid area. The patient’s initial troponins at the time of admission were negative; however, after the stress test, her troponins increased, peaking at 6.85. She was taken to the cardiac catheterization laboratory.
Right radial artery access was achieved with a 6 French Glidesheath (Terumo). After sheath placement, intraarterial vasodilators were administered, including verapamil 2.5 mg and nitroglycerin 200 mcg. A J guide wire could not be advanced into the mid radial artery because of resistance. An angiogram of the right radial artery showed a complex “radial loop” with a recurrent radial artery connecting to the brachial artery (Figure 1). Under fluoroscopy guidance, a 0.018” V-18 control wire was used to cross the loop, but a 6 Fr JR4 catheter could not be advanced. A 5 French hydrophilic Tiger 4.0 (Boston Scientific) catheter was successfully advanced and used to perform the coronary angiogram. The right coronary artery had a severe mid-vessel stenosis with a distal occlusion (Figure 2). The left coronary arteries had mild to moderate non-obstructive disease. Due to the distal right coronary artery occlusion, a 6 French guide was deemed necessary, as an aspiration thrombectomy catheter or simultaneous use of two balloons at the distal right coronary artery may be needed. The plan to use a 6 French MAC 3.0 guide (Medtronic) was challenged by spasm in the radial artery at the loop. Additional intra-arterial vasodilators did not help. The technique of balloon-assisted tracking was used to advance a 6 French guide (technique details are discussed below). The right coronary artery was engaged with the MAC 3.0 guide. A Kinetix wire (Boston Scientific) was used to cross the distal occlusion. After predilation with a 2.0 balloon, the distal right coronary artery bifurcation could be visualized. A Prowater wire (Abbott) was inserted in the posterolateral branch. A 3.5 x 32 mm Resolute drug-eluting stent (Medtronic) was deployed in the distal right coronary artery, just proximal to the bifurcation. The final angiogram showed a very good angiographic result (Figure 3).
A longer learning curve for transradial catheterization is largely due to a wide variation in the upper limb arterial anatomy. These variations are due to different origins of the radial artery and its connection with the radial recurrent branch or accessory radial artery. The radial artery can originate low in the forearm or high from the brachial or axillary artery (Figure 4). This, along with tortuosity, creates wide varieties of radial loops and bands (Figure 5). Embryologically, the radial artery is prone to spasm even if it is originating from the axillary artery (spasm would be higher up). For this reason, it is always prudent to avoid unnecessary catheter exchange during a transradial catheterization. Crossing the loops and tortuosity is at times challenging and requires torquable, hydrophilic wires. It is even more challenging to advance a catheter throughout these segments as it causes spasm, which can be severe at times. Using additional vasodilator medication, downsizing the catheter (5 French instead of 6 French), as well as a gentle clockwise and counter-clockwise rotation of the catheter while advancing it through the radial artery are some of the tips to successfully accomplish the intended procedure. When these suggestions fail, balloon-assisted tracking can be helpful.
Patel et al1 describe balloon-assisted tracking (BAT) of a guide catheter for effectively negotiating radial arteries with a smaller caliber, extreme tortuosity, spasm or atherosclerosis. It allows for an easy, atraumatic passage through these extremely difficult segments for the following reasons:
- The conical shape of an inflated balloon tip increases the flexibility of the assembly;
- It eliminates the obstruction of the edge of the guide by atheromatous plaque or tortuous vessels as it moves the biased wire off the vessel wall;
- It minimizes the razor effect, which in turn decreases the risk for perforation and dissection.1
The following steps describe the balloon-assisted tracking technique:
- Carefully cross a spastic tortuous radial artery segment or loop with a 0.014” standard angioplasty wire.
- Advance a 6 French guide catheter into the radial artery distal to the spasm segment. Advance a 2.0 mm x 15 to 20 mm rapid-exchange, compliant angioplasty balloon over the wire at the tip of the catheter. Keep the distal two-thirds of the balloon outside the guide and inflate just above nominal inflation pressure.
- Advance the entire assembly over the wire (Figure 6).
Disclosure: Dr. Shah and Dr. Sanghvi report no conflicts of interest regarding the content herein.
The authors can be contacted via Dr. Kintur Sanghvi at firstname.lastname@example.org.
1. Patel T, Shah S, Pancholy S. Balloon-assisted tracking of a guide catheter through difficult radial anatomy: a technical report. Catheter Cardiovasc Interv. 2012 May 28. doi: 10.1002/ccd.24504. [Epub ahead of print].