By: Kwan S. Lee, MD, FSCAI; Sandeep Nathan, MD, FSCAI; Huu Tam Truong, MD, FSCAI; Jayant Bagai, MD, FSCAI

Introduction

Transradial cardiac catheterization is usually performed via right radial access (RRA) due to the standard configuration of catheterization laboratories. Left radial access (LRA) is used less often, as it is not as ergonomic for the operator, especially for prolonged or complex percutaneous coronary intervention (PCI) and in obese patients. Given the benefits of the radial approach for PCI compared with the femoral approach, interventionalists must be familiar with unique advantages of LRA over RRA as well as with techniques that improve operator and patient comfort. Studies have shown significantly lower rates of subclavian tortuosity and slightly shorter fluoroscopy times with LRA compared to RRA.⁽¹⁾ Therefore, LRA should be considered in patients where tortuous vascular anatomy is expected (such as age > 75 years, height < 5’5’’).⁽²⁾ LRA should also be considered as the preferred approach in patients with a patent left internal mammary graft. Operator radiation exposure to the head and thyroid is also lower with LRA compared with RRA.⁽³⁾ Recently updated best practices recommend the choice between LRA versus RRA also be based on operator preference.⁽⁴⁾

In this Tip of the Month, we focus on setup, technical aspects of both proximal LRA (pLRA) and distal LRA (dLRA), and methods of hemostasis. In this article, which is not an endorsement of one approach over the other, pLRA refers to “conventional” LRA over the flexor aspect of the left wrist, while dLRA refers to the access in the anatomical “snuffbox.”

pLRA

Figure 1: pLRA setup

1. Setup for conventional LRA or pLRA is achieved with (Figure 1, A) or without (Figure 1, B) a flexible wrist support. The left wrist is propped on soft, supportive materials (Figure 1, C) with slight elbow flexion and partial hand pronation to ensure patient comfort and easy access from the right (Figure 1, D). The use of orthopedic finger traps or a hand strap, secured to the right side of the table, to leverage the arm toward the right and to avoid gradual slippage back has been described. Various devices have been used, such as the STARBoard radial arm board (Adept Medical Ltd. New Zealand).
2. Most operators obtain pLRA from the left side of the table with the wrist supinated using sheaths in a standard 10 cm length. The hand is repositioned as noted above, and the operators perform the procedure from the right side. A minority of operators work from the left side, but this requires significant room and table reconfiguration.
3. An alternative to the partial pronation technique is the use of a longer sheath (³ 16 cm) and a partial sheath insertion secured with clear adhesive. This increases exposure of the sheath access port and side arm for easier manipulation, allowing for more pronation and adduction to the right, reducing the reach required by the operator. One technique, described as “pseudoanatomical snuffbox access,” involves securing the sheath at the level of the snuffbox (Figure 2). Care must be taken to avoid kinking of the sheath. If this occurs, it can usually be corrected with a 0.035’’ wire and the insertion of a catheter.
4. Hemostasis is obtained with standard techniques and devices.

Figure 2: “Pseudoanatomical snuffbox access” using a partially inserted longer sheath

Distal Left Radial/Anatomical Snuffbox Access

Figure 3: dLRA

1. dLRA offers advantages of enhanced ergonomics and comfort for operator and patient. The hand may be prepped with full pronation, rested on the patient’s mid-to-low abdomen (Figure 3, A-D).
2. A roll of 4” x 4” gauze or small towel can be held to keep the dorsal area opened, separating the thumb and first finger. The hand is prepped in this position and anesthetized, and access is gained—preferably with ultrasound. Through-and-through puncture is not recommended since needle contact with the periosteum is painful.
3. Distal left radial hemostasis differs from proximal hemostasis. Common, rigid hemostasis bands depend on immobility of the wrist. The dorsal hand is more mobile, and these devices may be loosened by movement. One solution is to apply rolled gauze to the access site, secured by a tight elastic bandage for two hours. If a device is used, the dedicated distal radial PreludeSYNC DISTAL ^TM band (Merit Medical Systems, USA) has been suggested (Figure 4). Shorter hemostasis times may be observed.

Figure 4: PreludeSYNC DISTAL band dedicated distal radial hemostatic device (Merit Medical Systems, USA)

4. Possible benefits of dLRA over pLRA, beyond increased comfort, are reduction in the risk of forearm radial artery occlusion. This is because occlusion at the point of dLRA does not affect antegrade runoff through the superficial palmar arch, and this prevents proximal thrombus propagation. The risk of forearm compartment syndrome in the event of perforation is also lower. Other benefits include its ability to be used in patients with frozen shoulder who are unable to adduct their arm, as required for pLRA. Limitations include a smaller size of the vessel at this site, which makes access more difficult. The use of ultrasound is recommended in patients with a weak pulse.^(5-7)

Summary

LRA access, at the proximal or distal level, has several advantages over RRA. Interventionalists must be familiar with methods to improve operator and patient comfort with LRA. Knowledge of the techniques mentioned in this Tip of the Month will allow operators and cath lab staff to overcome barriers to LRA and prevent crossover to femoral access in patients where RRA is not possible or unsuccessful.

References

1. 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):260-4.
2. Rao SV, Tremmel JA, Gilchrist IC, Shah PB, Gulati R, Shroff AR, Crisco V, Woody W, Zoghbi G, Duffy PL, Sanghvi K, Krucoff MW, Pyne CT, Skelding KA, Patel T, Pancholy SB; Society for Cardiovascular Angiography and Intervention’s Transradial Working Group. Best practices for transradial angiography and intervention: a consensus statement from the society for cardiovascular angiography and intervention’s transradial working group. Catheter Cardiovasc Interv. 2014 Feb;83(2):228-36.
3. Kado H, Patel AM, Suryadevara S, Zenni MM, Box LC, Angiolillo DJ, Bass TA, Guzman LA. Operator radiation exposure and physical discomfort during a right versus left radial approach for coronary interventions: a randomized evaluation. JACC Cardiovasc Interv. 2014 Jul;7(7):810-16.
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