ABSTRACT: Objective. To study the suitability of the aberrant radial artery (ARA) as an access site for coronary angiography and angioplasty. Background. In certain situations, the radial artery operator finds that the right radial artery in its usual location is unsuitable for a transradial procedure (TRP). In such cases, the ARA should be considered as an alternate access site. Methods. Between January 2002 and December 2004, all patients considered suitable for a TRP with a clinically absent radial artery, or a small radial artery and a palpable ARA, underwent a TRP using this vessel as an access site. We describe the technical aspects and the differences that this approach entails, in comparison to the standard radial artery approach to TRPs. Results. Of the 3,610 patients considered suitable for a TRP, 22 patients underwent 29 procedures using the ARA as an access site [22 angiograms and 7 percutaneous transluminal coronary angioplasty procedures (PTCAs)]. The median age of the patients was 55 years, with 19 males and 3 females. All procedures using the aberrant radial artery were successful. None of the patients developed spasm or an access site complication. The mean fluoroscopy time for angiography in the right radial artery group was 4.6 minutes, and 4.8 minutes for the ARA group. The procedure timed were 24 minutes and 32 minutes, respectively. Conclusion. The aberrant radial artery can be used as a safe alternate access site for coronary angiography and angioplasty when the right radial artery at the usual site is not suitable.

       The percutaneous radial artery approach for coronary angiography (CAG) was first reported in 1989–1999¹ and subsequently transradial coronary angioplasty was reported in 1995 by Kiemeneij et al.² The advantages of the radial artery approach are numerous and include, a lower incidence of access site complications, earlier ambulation, decreased hospital stay and expenses.³ A larger number of patients prefer this approach.⁴ In patients with peripheral vascular disease it offers an excellent alternative to the femoral approach. Difficulties with this approach include, a deep and significant learning curve,⁵ increased fluoroscopy time,⁶ failure to adequately cannulate the coronary arteries,⁷ difficulties due to anatomical variations in the arterial tree of the upper limb, more pain during the procedure^7,8 and radial artery spasm.⁹ As of now this procedure continues to evolve and has generated considerable debate and comparison with the femoral approach.^10–12
       The radial artery operator occasionally faces a situation in which this access site cannot be used, as when the right radial artery at the wrist is small or is not palpable. In such situations, it is best to look for the presence of an aberrant radial artery (ARA) and consider using it as an alternate access site. The ARA is of specific importance when a radial artery forearm flap is used for surgical repair of soft tissue defects of the oral cavity,¹³ when it is inadvertently cannulated and drugs are administered intra-arterially instead of intravenously.^14,15 Thenar hypoplasia has been attributed to an ARA in the Klippel-Feil syndrome.¹⁶
       We present the incidence of this anomaly, the procedural details and the outcomes of angiography and angioplasty using the ARA approach.

Materials and Methods
       A total of 4,350 patients were assessed clinically as to their suitability for a transradial procedure

Figure 1

Angiogram of the right aberrant radial artery (lateral view). The arrows point to the right aberrant radial artery, which is larger, and the arrowheads point to the smaller, palpable radial artery at the usual site.

between January 2002 and December 2004. The right radial artery was assessed clinically in all patients, after which the Allen’s test was performed.

Figure 2

Angiogram of the right aberrant radial artery (PA view). The arrows point to the right aberrant radial artery, which is larger, and the arrowheads point to the smaller palpable radial artery at the usual site. The ulnar artery is visualized (thick arrow).

       Patients who had an adequate-sized right radial artery and a functional palmar arch underwent a transradial procedure. Of these 4,350 patients, 3,610 were considered suitable for the right radial approach; in the remaining patients, the left radial artery, right or left ulnar arteries, or the femoral artery was used as an access site. In the 3,610 patients considered suitable for a right radial approach, 22 had a clinical ARA. In 10 of these 22 patients, the right radial artery palpated at the usual site was clinically small, and in the remaining patients, the vessel was not palpable (Figures 1–5).

Figure 3

Angiogram of the right aberrant radial artery (PA view), in a patient with an impalpable radial artery at the classical site. The arrows point to the right aberrant radial artery, which is larger, and the arrowheads point to the extremely small radial artery at the usual site.

       The right upper limb was placed on the arm board in a semi-prone position, close to the torso. A few folded gauze pieces were secured on the arm board at the level of the wrist to elevate and expose the ARA (Figure 6). All patients except the first were given a roll of gauze to hold on to. This was prepared by using enough length of tightly-folded roller gauze to reach a diameter of about 1.5 inches and secured using a plaster. The patient was allowed to gently clutch the roll comfortably. This roll was not secured to the arm board in any manner, however, the hand was gently taped down with plaster (Figure 7).

Figure 4

Angiogram of the right aberrant radial artery (lateral view). The arrows point to the right aberrant radial artery, which is larger, and the arrowheads point to an extremely small, impalpable radial artery at the usual site.

       After painting the groin and the wrist in the position described, a standard bifemoral drape was used, exposing the right groin at the femoral artery and the ARA at the wrist.
       A large-bore 16 gauge needle was used to puncture the skin and create a subcutaneous track. Following this, a 20 gauge intravenous catheter (Jelco, Medex Medical Ltd, Rossendale, United Kingdom) was used to enter the ARA after attempts were made to fix the vessel by stretching the adjacent skin and tissue. An abrupt, brisk, forward movement of the Jelco into the vessel often obtained final ARA access. Over a 0.025 inch short wire, a 5 Fr (CAG) or 6 Fr [percutaneous transluminal coronary angioplasty (PTCA)], 70 mm

Figure 5

Right ulnar artery angiogram (thick arrow) following PTCA after a failed puncture of the aberrant radial artery (arrows) in a patient with a palpable radial artery (arrowheads) at the usual site.

Radiofocus Introducer II sheath (Terumo Corp., Japan) was inserted, and 10 mg of diltiazem and 100 µg of nitroglycerine were injected intra-arterially as a cocktail to prevent spasm.
       Subsequent catheterization was similar to standard transradial artery catheterization. In these 22 patients, 30 procedures were performed. Seven patients underwent subsequent PTCA using the same access site 2 days (4 patients) and, 3 days (3 patients) after the index angiography. One patient

Figure 6

The right upper limb positioned for the aberrant radial artery as an access site. A small wad of gauze (single thick arrow) adducts the wrist and exposes the aberrant radial artery, permitting easier puncture. The patient holds on to a 50 ml contrast bottle in the picture (two vertical arrows), however a roll of gauze is used for this purpose. A 5 Fr sheath is in situ (single arrowhead). The groin has been prepared for possible femoral access (arrowheads).

underwent transulnar PTCA 3 days following index angiography after several attempts to cannulate the right ARA failed. The hardware used for these procedures was in no way different from that used for standard transradial procedures. Following completion of the procedure, the sheaths were immediately pulled out, and a jet of blood was allowed to flush possible thrombi. An “X” band was then applied. Two strips of dynaplast, each about 3.5 inches in length, were diagonally applied so as to tamponade the puncture site (Figures 8 and 9). An additional 3 inches of dynaplast — “the crowning strip” — was applied horizontally to obtain further pressure at the compression site (Figures 10 and 11). These adhesive plasters were removed 4 hours after the procedure.

Figure 7

The wrist has been gently taped down with plaster (thin arrows) to immobilize it. A 5 Fr sheath is in situ (arrowhead), and a wad of gauze is below the wrist (thick arrow).

Observations
       Twenty-two patients underwent 30 procedures, including 7 patients who underwent subsequent angioplasty after angiography using the right ARA as an access site. In 1 patient, right ARA puncture failed, following which the ulnar artery was used as an access site for angioplasty. All of the procedures were successful. The median age was 55 years, with 19 men and 3 women. The baseline characteristics included: smokers 40.9% (n = 9), diabetes 27.27% (n = 6), hypertension 36.36% (n = 8) and hyperlipdemia 22.72% (n = 5). None of these patients developed spasm or vascular site complications.

Figure 8

Gauze piece is held firmly after sheath removal following the procedure.

       The procedure time, fluoroscopy time and details were noted (Tables 1 and 2). The procedure time for trans-ARA coronary angiography was significantly longer, with similar fluoroscopy times, suggesting that obtaining ARA access contributed to the longer procedure time in these patients.

Figure 9

The first limb of the “X” band has been applied.

Discussion
       The ARA is an additional vascular access site option for the transradial interventionist, along with the right and left ulnar and opposite radial arteries. In our experience, the incidence of this anomaly was 0.5%. The procedure was uneventful in all 22 patients. Significant differences in approach exist when this vessel is considered for use as an access site. It is essential to clinically look for this vessel in all cases, especially when the radial artery is not palpable at the usual site or is a small vessel.

Figure 10

The crowning strip being applied after both limbs of the “X” band are secured.

       When identified, the Allen’s test is modified to ensure occlusion of both the aberrant and the small radial arteries when looking for integrity of the palmar arch. When the wrist is draped in the conventional manner, it can be difficult to puncture the vessel. The semi-prone position permits easier access to the vessel and a small wad of gauze at the level of the wrist adducts the wrist and further exposes the vessel.

Figure 11

The final picture of the “X” band that secures hemostasis.

       The radial artery at the wrist lies in a bed between the flexor carpi radialis tendon medially, and the salient lower part of the anterior border of the radius laterally, and is a fairly straight segment. This anatomy allows for easy puncture. However, the ARA winds around the lateral aspect of the wrist where it runs in isolation, can be tortuous, extremely mobile and difficult to fix. To obtain access to this vessel, we used a 16 gauge needle to create a subcutaneous track and gained access through this track with an abrupt forward

Table 1

Fluoroscopy and procedure times for diagnostic angiography, comparing the right radial and aberrant radial artery approaches.

movement of a 20 gauge Jelco. Attempts to fix the vessel manually prior to puncture were unsuccessful.
       The first patient was uncomfortable during the procedure and had to be reminded to keep his wrist still, in spite of the fact that he was given adequate analgesia (4% local xylocaine) and sedation (1–1.25 µg/kg of intravenous fentanyl hydrochloride). In this patient, the forearm was semi-prone, the wrist slightly adducted and the hand taped down. For the subsequent cases we provided something to hold on to, consisting of a wad of rolled gauze sufficiently thick for the patients to clutch, after which the hand was taped down to the

Table 2

Details of angioplasty of the 8 patients with attempted aberrant radial artery as an access site.

underlying arm board. Following this modification, the patients kept the wrist still during the procedure and were comfortable.
       The procedure time for transaberrant radial artery coronary angiography was longer, with similar fluoroscopy times, suggesting that vessel puncture and obtaining access contributed to the longer procedure time.

Conclusion
       The ARA is an alternate access site for coronary angiography and angioplasty when the radial artery at the usual site is not suitable for the procedure. This can be easily accomplished with minor modifications to the technique. However, procedure time may be slightly prolonged, largely due to an increase in the time required to puncture the vessel. Most importantly, one must look for this vessel when the radial artery is small or is not palpable.

References
1. Campeau L. Percutaneous radial artery approach for coronary angiography. Cathet Cardiovasc Diagn 1989;16:3–7.
2. Kiemeneij F, Laarman GJ, de Melker E. Transradial artery coronary angioplasty. Am Heart J 1995;129:1–7.
3. Cooper CJ, El-Shiekh RA, Cohen DJ, et al. Effect of transradial access on quality of life and cost of cardiac catheterization: A randomized comparison. Am Heart J 1999;138:430–436.
4. Cooper CJ, El-Shiekh RA, Blaesing LD, et al. Patient preference for cardiac catheterization via the transfemoral approach. J Am Coll Cardiol 1997;29(Suppl A):310A.
5. Louvard Y, Krol M, Pezzano M, et al. Feasibility of routine transradial coronary angiography: A single operator's experience. J Invasive Cardiol 1999;11:543–548.
6. Hildick-Smith DJR, Lowe MD, Walsh JT, et al. Coronary angiography from the radial artery experience, complications and limitations. Int J Cardiol 1998;64:231–239.
7. Ludman PF, Stephens NG, Harcombe A, et al. Radial versus femoral approach for diagnostic coronary angiography in stable angina pectoris. Am J Cardiol 1997;79:1239–1241.
8. Stella PR, Kiemeneij F, Laarman GJ, et al. Incidence and outcome of radial artery occlusion following transradial artery coronary angioplasty. Cathet Cardiovasc Diagn 1997;40:156–158.
9. Goldberg SL, Rensio R, Sinow R, French WJ. Learning curve in the use of the radial artery as vascular access in the performance of percutaneous transluminal coronary angioplasty. Cathet Cardiovasc Diagn 1998;44:147–152.
10. Michael DE, Joseph AM. Transradial coronary stenting: Ready for prime time? (editorial). Cathet Cardiovasc Diagn 2000;49:157–159.
11. Rihal CS, Holmes DR. Transradial cardiac catheterization: Is femoral access obsolete? Am Heart J 1999;138:392–393.
12. Julius HG Jr. The radial artery approach: We have come such a long way for the long way (editorial). Cathet Cardiovasc Diagn 2000;49:257.
13. Martin-Granizo R, Gomex F, Sanchez-Cuellar A. An unusual anomaly of the radial artery with potential significance to the forearm free flap. Case report. J Craniomaxillofac Surg 2002;30:189–191.
14. Sivalingam P. Inadvertent cannulation of an aberrant radial artery and intra-arterial injection of midazolam. Anaesth Intens Care 1999;27:424–25.
15. Ang BL. Prolonged cutaneous sequelae after intra-arterial injection of propofol. Singapore Med J 1998;39:124–126.
16. WT Leo , PJ Wang , C Young, et al. Thenar hypoplasia in Klippel-Feil syndrome due to aberrant radial artery. Pediatr Neurol 1995;13:343–345.