Radial Access — Be Prepared!

ABSTRACT: We present the case of a 46-year-old female patient that experienced recurrent stent thrombosis and underwent attempted primary PCI via the radial artery. Although radial artery cannulation with a 6 Fr sheath and the diagnostic angiography were successfully performed, the PCI could not be achieved because of failure to advance the 6 Fr guide through the radial artery, due to severe angulation of a high take-off radial artery, combined with a proximal radial artery stenosis.

J INVASIVE CARDIOL 2008;20:549–550

Case Report. A 46 year-old female patient with a history of coronary artery disease (CAD) (balloon percutaneous transluminal coronary angioplasty [PTCA] at age 37), significant obesity, hypertension, hypercholesterolemia and smoking, and a positive family history for CAD and lupus anticoagulant-positive, presented electively for percutaneous coronary intervention (PCI) and underwent placement of drug-eluting stents in the proximal, mid and distal left anterior descending artery (LAD). Her course was complicated by a right retroperitoneal hematoma. Twelve days later, while on dual antiplatelet therapy, she experienced stent thrombosis of the distal LAD stent site. She was treated successfully with thrombectomy and balloon PTCA, but her course was further complicated by a left retroperitoneal hematoma and profound thrombocytopenia attributed to abciximab readministration and heparin-induced thrombocytopenia. While antiplatelet treatment was withheld, she experienced recurrent chest pain and new ST- elevation of the anterolateral leads. She was brought to the catheterization laboratory for emergent PCI and the decision was made to obtain vascular access via the right radial artery in order to minimize the risk of bleeding complications, given her propensity for retroperitoneal hematomas. Her radial pulse was good and her Allen’s test was normal.

Right radial artery vascular access was easily obtained with a 6 Fr sheath and diagnostic catheterization was performed without difficulty, using 5 Fr catheters with an outer diameter of 1.7 mm (Expo, Boston Scientific Corp., Natick, Massachusetts). Coronary angiography revealed mid-LAD stent thrombosis. The patient’s left ventricular systolic function was mildly reduced. Anticoagulation was started with bivalirudin. While the exchange-length 260 cm 0.035 inch J- tip fixed-core wire (Medtronic, Inc., Minneapolis, Minnesota) was left in place, the 5 Fr diagnostic catheter was removed and a 6 Fr JL 4 guide (Launcher, Medtronic), with an outer diameter of 2.08 mm, was inserted. At the mid-portion of the arm, the guide found resistance and could not be advanced.

A small amount of contrast media injected through the guide revealed a stenosis and angulation of the vessel distal to the guide tip. Despite changing to a different guide with a smaller outer diameter (Zuma, Medtronic, outer diameter 2.04 mm) and using a stiffer wire (Hi-Torque Supracore 35) to possibly straighten the vessel, the problem persisted, and in order to avoid further delay, right common femoral artery access was obtained. Balloon PTCA with thrombectomy was completed successfully. After completion of coronary PCI, angiography of the right upper extremity via the right common femoral artery revealed a high takeoff at almost 90 degrees’ origin of the radial artery from the brachial artery, with a proximal radial artery stenosis (Figure 1).

The following day, the patient was started on high-dose dual antiplatelet therapy and anticoagulation. The remainder of her hospital stay was uneventful and she was discharged home. The patient remains symptom-free.

Discussion. Evidence suggests that a transradial percutaneous approach for coronary angiography and angioplasty, including primary PCI, is feasible, clinically safe, has a high success rate, good outcomes and offers a low rate of vascular complications.1,2 Since the first radial approach in 1989, to cardiac catheterization using 5 Fr preshaped catheters3 and the first successful transradial PCI in 1993,4 the miniaturization of the equipment has allowed operators to perform complex cases via the radial artery. Even advanced devices such as suction thrombectomy catheters, rotational atherectomy, distal protection devices and intravascular ultrasound (IVUS) probes are now 6 Fr-compatible. However, technical failures are mainly due to anatomic variations of the radial artery, and it is essential that radial operators be prepared for such cases.

In the present case, although radial artery cannulation with a 6 Fr sheath and diagnostic angiography were successfully performed, the PCI could not be achieved because of failure to advance the 6 Fr guide through the radial artery due to severe angulation of a high takeoff radial artery, combined with a proximal radial artery stenosis. The diagnostic catheterization was performed with the use of 5 Fr catheters with an outer diameter of 1.7 mm (Expo, Boston Scientific). The 6 Fr stiffer guides with an outer diameter of 2.04–2.08 mm would not advance. Further attempts at crossing the angulated and stenotic vessel with the 6 Fr guides would have been hazardous as they may have resulted in dissections and perforations. Another possibility would have been to perform angioplasty of the stenotic vessel, but this would have delayed coronary PCI. Additionally, although the radial stenosis might have been easily treated with angioplasty, proximal to the stenosed vessel, angulation might have still prevented advancement of the larger and stiffer guide. Alternatively, a 5 Fr guide could have been attempted, but, although balloon angioplasty or stenting would have been possible, this would not have allowed the use of thrombectomy catheters.

Several radial artery variations have been described. Variations that involve the origin or course of the upper parts of the radial artery will not present a problem for initial vascular access. Furthermore, techniques to overcome the anatomic challenges of radial artery variations have also been described.5 In a recent study by Valchecchi et al in 2006,6 overall procedural success via the transradial approach using 6 Fr diagnostic catheters and 6, 7 or 8 Fr guiding catheters, was 97.8%. Transradial approach failure in patients with anatomic variations was 6.9%.6 It should also be mentioned that the presence of a high radial artery origin, which has been described in up to 14% of cases,7 may also complicate catheterization via brachial artery vascular access.8

In conclusion, while in the past variations of the radial artery have aroused the interest of only anatomists and radiologists, today, with the rapidly increasing numbers of radial procedures performed, interventional cardiologists are more likely to encounter these variations and need to be aware of and be prepared to develop strategies to overcome these “eventualities”.