Bypass Graft Angiography From a Transradial Approach

Transradial access (TRA) has emerged as an alternative approach to cardiac catheterization and has been associated with less bleeding and vascular complications, earlier ambulation, and greater patient acceptability.^1,2 For bypass graft angiography, left radial artery (LRA) access has been recommended as a default access site, as the majority of these patients have an in situ left internal mammary artery (IMA) bypass graft. Right radial artery access may be used in patients who have an unsuitable or absent LRA. 

As the trajectory of the catheters entering the ascending aorta from the LRA is similar to femoral access, the majority of the catheter choices to engage sapheneous vein graft (SVG) ostia from the LRA are similar to catheter choices for transfemoral access. The Judkins right shape, as well as dedicated left and right coronary bypass catheters, may be used with reasonable success from the LRA. Experienced operators can use a Tiger catheter (Terumo) interchangeably with these catheters in an effort to limit catheter exchanges (Figure 1). These catheters tend to succeed in patients with normal diameter or narrow aortas. In patients with a larger aortic diameter due to unfolding, a catheter with a longer tip is needed, and an Amplatz left catheter frequently succeeds (Figure 2). Catheters with similar shape, including Jacky and Sarah catheters (Terumo), may succeed. For a right coronary SVG with an inferior takeoff, a multi-purpose catheter provides coaxial engagement, especially in patients without significant aortic dilatation. In those with a dilated aorta, an Amplatz left shape can be manipulated into an inferior takeoff right coronary artery (RCA) graft with better success (Figure 3). There are important technical differences in SVG cannulation using right vs left radial approaches. The right radial approach may be associated with some additional technical complexities.³ The efficacy and the backup provided by these curves are lesser for the right radial approach compared to the left radial approach.3 Amplatz left is the preferred catheter shape for a SVG arising anteriorly or laterally from the aorta. Occasionally, for a SVG located on the left side of the ascending aorta and when using the left radial approach, the Judkins left may be successfully used and can provide adequate backup support for SVG interventions. When facing an unusual SVG graft origin from the aorta, especially by the right radial, unusual guiding catheter curve selections such as Extra Backup Left 3 (Medtronic) or hockey stick guiding catheter, and manipulations with the stiff end of the J wire inside the guiding catheter during cannulation to modulate the geometry of the distal curve, may be useful. Additional techniques include the use of guide catheter extensions such as the GuideLiner (Vascular Solutions) or Guidezilla (Boston Scientific) for deep intubation, and the use of a second guide wire. A “buddy wire” may be advisable for delivery of hardware through difficult geometry, as backup support from the contralateral aortic wall is frequently not available in these instances.

Ipsilateral transradial access better facilitates the catheterization of an IMA graft compared to the transfemoral approach.⁴ The time for IMA cannulation and the time for IMA assessment (time interval between start of the IMA cannulation attempt and last IMA projection) were found to be 39% and 46% lower, respectively, in patients studied via TRA vs transfemoral access. In addition, the use of an ipsilateral radial approach minimizes the catheter manipulation in the aortic arch and proximal subclavian artery, thus reducing the likelihood of embolization. Left internal mammary graft (LIMA) to anterior coronary circulation cannulation from the radial route may be considered from either left or right radial artery access. Ipsilateral radial access is preferred in view of obvious ease. Although a standard LIMA catheter (designed for femoral access) may suffice, other options include the Judkins right (JR) and VB-1 (Cordis) catheters. The choice of catheter is based on subclavian artery diameter and the angle of origin of the LIMA from the left subclavian artery. For a “shallow” or obtuse angle takeoff of the LIMA, a JR catheter provides adequate coaxiality. For a “perpendicular” takeoff, a LIMA catheter or JR shape should succeed. For an acute angle takeoff, the VB-1 catheter provides coaxial engagement. Care should be exercised with any of these catheters to avoid deep intubation, maintain coaxiality, and avoid forceful contrast injection to prevent ostial trauma. Successful use of the Tiger catheter from the left radial artery has been described in a few series.⁵    

LIMA cannulation from the right radial is technically challenging and has a learning curve. It is considered in circumstances when the left radial artery has been explanted as a bypass graft or the right internal mammary artery (RIMA) has been used for bypass. The major challenges are to navigate through the (right) subclavian and aortic tortuosity, cannulate the left subclavian artery, and park the guide wire into the left arm, as the wire has a tendency to prolapse into the ascending aorta. Standard 5 French catheters, including a Judkins left or Tiger catheter, may be used to cannulate the left subclavian artery by advancing the catheter into the descending thoracic aorta, facing the superior wall of the arch with the “open” portion of the curve, and engaging the left subclavian artery (Figures 4-5). A .035-inch guide wire, usually a soft-bodied, hydrophilic wire, is carefully advanced deep into the subclavian artery and into the brachial sector (Figure 6). The catheter is then advanced into the subclavian or a different catheter could then be exchanged over the wire. If guiding catheter advancement into the subclavian artery is difficult, stabilization of the wire in the contralateral arm may be obtained by external compression, either manually or by using an inflated blood pressure (BP) cuff to trap the exchange-length wire in the brachial artery. This maneuver usually increases wire support and allows catheter advancement over the exchange wire into the subclavian artery. Patel et al have shown that the elbow flexion technique seems to provide similar support for trapping a hydrophilic guide wire⁶ (Figure 7).

Once the catheter has entered the subclavian artery, careful pullback (with counter-clockwise torque) of the catheter will usually engage the LIMA ostium (Figure 8). In diagnostic angiographic procedures with difficult LIMA cannulation, non-selective subclavian angiograms with an inflated BP cuff on the left arm may yield diagnostic information about the graft status. 

Transradial access makes an excellent access site choice for patients referred for bypass graft angiography and intervention. Using catheter and aortic geometry, as in any other instance, provides adequate support. Using newer adjunctive devices such as mother-daughter catheters and other technical tricks may further improve procedural success. 

References

1. Rao SV, Ou FS, Wang TY, et al. Trends in the prevalence and outcomes of radial and femoral approaches to percutaneous coronary intervention: a report from the National Cardiovascular Data Registry. JACC Cardiovasc Interv. 2008 Aug; 1(4): 379-386. doi: 10.1016/j.jcin.2008.05.007.
2. Hamon M, Mehta S, Steg PG, et al. Impact of transradial and transfemoral coronary interventions on bleeding and net adverse clinical events in acute coronary syndromes. EuroIntervention. 2011 May; 7(1): 91-97. doi: 10.4244/EIJV7I1A16.
3. Burzotta F, Trani C, Hamon M, Amoroso G, Kiemeneij F. Transradial approach for coronary angiography and interventions in patients with coronary bypass grafts: tips and tricks. Catheter Cardiovasc Interv. 2008 Aug 1; 72(2): 263-272.
4. Burzotta F, Trani C, Todaro D, Romagnoli E, Niccoli G, Giannico F, et al. Comparison of the transradial and transfemoral approaches for coronary angiographic evaluation in patients with internal mammary artery grafts. J Cardiovasc Med (Hagerstown). 2008 Mar; 9(3): 263-266.
5. Kadhim H, Radomski A. Coronary and bypass graft angiography using a single catheter via the left trans-radial artery. Br J Cardiol. 2015; 22: (2). doi:10.5837/bjc.2015.017.
6. Patel T, Shah S, Patel T. Cannulating LIMA graft using right transradial approach: two simple and innovative techniques. Catheter Cardiovasc Interv. 2012; 80(2): 316-320.  
7. Rathore S, Roberts E, Hakeem AR, Pauriah M, Beaumont A, Morris JL. The feasibility of percutaneous transradial coronary intervention for saphenous vein graft lesions and comparison with transfemoral route. J Interv Cardiol. 2009 Aug; 22(4): 336-340.

Disclosure: Dr. Samir Pancholy reports he is a technical consultant for the transradial product line for Terumo and a speaker for Pfizer. Dr. Biswas and Dr. Vayada report no conflicts of interest regarding the content herein.

Dr. Pancholy can be contacted at pancholy8@gmail.com