Transradial Percutaneous Coronary Interventions – Technique, Materials, Procedure, in the light of Anatomical- and Technical Considerations
Johannes B. Dahm, Frank van Buuren,
Department of Cardiology-Angiology, Heart-& Vascular Center Neu-Bethlehem, Göttingen, Germany

Department of Cardiology, Heart-& Diabetes Center NRW, Bad Oeynhausen, Germany

Overtime transradial artery has shown lower complication rates in diagnostic coronary angiography, hence is successfully introduced as a useful vascular access site for transradial percutaneous coronary interventions, since Kiemeneij et al (1995,1997). reported similar procedural and clinical outcomes as compared to transfemoral, and transbrachial access ( , ).  Moreover, recent data from prospective multicenter studies and large meta analysis revealed even significantly better immediate and long-term outcomes with radial access versus femoral access in contemporary, real-world clinical settings of percutaneous cardiovascular procedures (e.g. PREVAIL-, PRESTO-ACS-studies).  In this perspective, the lower rate of cardiovascular events after transradial percutaneous coronary interventions may be explained by the lower necessity of cessation of dual-antiplatelet therapy due to significant lower bleeding complications after radial access.  Radial access enhance patients’ comfort and reduces hospital staff workload and hospital ( , ).  Access failure has been reported to occur in less than 3-7% of cases (2).

Bleeding complications occur only rarely with this technique as compared to the transfemoral access, but the procedural success of the transradial access is occasionally limited by anatomical circumstances (e.g., anomalous radial branching patterns, tortuosity e.g. radial loops, and small radial artery diameters), which require enhanced capabilities of well trained interventionists in femoral approach.  Radial coronary angiography and angioplasty entail a secondary learning curve of at least 150 cases in order to become familiar and comfortable with this technique.  In the following, our radial catheterization procedure, as a result of more than 10 years of radial experience including constantly implementing new developing and materials is been described in detail.
Radial puncture procedure

Correspondence: Dr Johannes Bruno Dahm, Dept. of Cardiology-AngiologyHeart-& Vascular Center Neu-BethlehemHumboldtallee 6, D – 37073 Göttingen Germany
Email:dahm@herz-gefaesszentrum.org

comfortable supine position with his right arm laterally elevated only during the arterial puncture procedure (Fig. 1).  After successful placing the introducer sheath, the arm is positioned alongside the body with wrist next to the hip (right arm) (Fig. 2) respective on the patient (left arm).  This approach includes the benefit of standing on the normal interventionists position next to the right side of the patient, where majority of custom made coronary catheterization laboratories have preinstalled the radiation protection measures (e.g. shielding) to guarantee  maximum radiation protection.

Figure 1.  Radial puncture position (white arrow) proximal the base of Dig. I (still above   the bony part of the handroot).

Figure 2.Positioning of the punctured arm alongside the patients body with his wrist next to his hip.

often lead to extravascular wire exit just outside the artery, because parts of the longer needle-opening may remain outside the effectively punctured artery, while major parts of the longer opening are adequately positioned inside the artery and show a normal flush-back of blood. 
Right-arm access
After successfully introducing the vascular sheath, the right arm should be positioned alongside the patient’s body with the arm and forearm slightly rotated laterally, and the wrist supine and secured on a specially designed armplank next to the hip (Fig. 2).  In keeping the procedure as simple- and radiation exposure as low as possible, the right radial artery is the preferred approach.  Only in case of a pathological unilateral Allen test on the right or in patients after coronary bypass surgery with anastomized left mammarian arteries, the left approach should necessarily be chosen. 

Figure 3 a Puncture of the radial artery approximately 1-2 cm proximal the base of Dig. I using a 19 gauge needle.

Figure 3 b        Typical anatomical position of a 5F-introducer sheath

Left-arm access
After successful puncture with the arm elevated laterally, the arm is positioned and secured on foam pillows on a arm panel located on the left side with the lower arm slightly angulated so that the wrist can be positioned medially on the lower belly. 

Adjunct Pharmacological Therapy
In order to prevent radial spasm and posprocedural occlusion, 3 mg dinitrate (or molsidomin) and 3 mg verapamil should be administered through the sheath together with at least 3.000 IU of heparine.  All patients should be under aspirine and/or clopidogrel medication.  At least in patients predisposing for radial spasm and/or post-procedural occlusion (e.g. females, smokers, small radial diameter), antiphlogistic drugs should be described in order to prevent postprocedural radial arteritis (e.g. 400 mg ibuprofen twice daily for 3 days) predisposing for postprocedural radial occlusions.

Catheterization procedure
With respect to radial spasm and postprocedural occlusion, coronary angiograms with respect to angioplasty procedures (balloon angioplasty and stent implantation) should be performed with preferably 4-5F catheters (diagnostic catheters: Infinity or Super TorquePlus, Cordis Corp. Miami, FL; guiding catheter: Vista brite tip, Cordis Corp. Miami, FL, USA, Launcher, Medtronic Inc., Minneapolis, MN, USA), RunWay, Boston Scientific, Natick, MA, USA), and with application of standard balloon angioplasty and stenting techniques. 
In case of a right radial access, Amplatz II  should be the first choice for the left- and in more than 90% of the cases for the right  coronary ostium and saphenous bypass grafts.  Particularly in case of a left radial access, EBU (XB) or Judkins left respective Judkins right can be an alternative for engaging the left- respective right coronary ostium. 
In passing the arteries of the lower arm retrogradely, the use of a floppy PTFE-wire is strongly recommended, because the arteries are still small and J-shaped wires may easily cause dissections and spasm.  Due to economic reasons, we normally do not use any wire while passing the arteries of the lower arm retrogradely with a soft-tipped Cordis diagnostic catheter (5F or 4 F); a J-shaped 260cm wire is been introduced not earlier than in the axillian- or subclavian artery.

Figure 4 a        Amplatz II in a stable position in the ascending aorta.

Figure 4 b        LCA (RAO 30°): Catheter-tip in the left sinus valsalva, bend of Amplatz            catheter close to the aortic valve; catheter must be turned to the left in order to engage the LCA.

Passing the vertebralian artery and common brachio-cephalic trunk is the most critical part of the entire catheterization procedure (i.e. cerebral thromboembolic complications). Therefore and for easy passage into the ascending aorta, continous low-dose fluoroscopy (2-3 frames/sec) is strongly recommended, while asking the patient for a deep inspiration and/or dorsoflexion of the neck.  This maneuver gives rise to a caudal movement of the mediastinum and heart, initiating straightening of the great vessels, leading to a much easier and more successful passage of this potentially critical arteries.
After having placed the Amplatz II successfully in a stable position in the ascending aorta (Fig. 4 a), the catheter should be turned to the right to bring the tip into the left sinus valsalva (RAO 30°).  With the tip in the left sinus valsalva and the bend of the Amplatz-curve close to the aortic valve, the catheter must then been turned to the left in order to engage the LCA in RAO 30° (Fig. 4 b).
For cannulation of the RCA, the Amplatz-II should be placed into a central position of the ascending aorta close to the aortic valve, and then turned right into the right sinus valsalva while the patient inspirate deeply maintaining breathing (LAO 30°) (Fig. 4 c).
Because the Amplatz-II includes a ideal design for being placed safely into the left ventricle with its openings positioned freely in the LV-cavum, we use it also for handinjected LV-angiograms in patients without valvular disease or dilatative cardiomyopathies (Fig. 4 d).
Sheath Removal and Clamping
Because radial occlusions were associated with prolonged cannulation times ( , , ), the sheath should be removed immediately and hemostasis achieved by radial compression with an artery compression clamp (e.g. RadStat Radial comression system, MeritMedical Sastems Inc. South Jordan, Utah, USA) for 2-4 h.  Ideally, the radial clamp consists of easily adjustable foam liners and straps on a wrist support board with a  central strap-clamp for radial compression (Fig. 5).

Figure 4 c     RCA (LAO 30°): Amplatz II in a central position of ascending aorta with its   tip in the right sinus valsalva in deep inspiration, while turning right in order toengage the RCA.

Figure 4 d Amplatz II in left ventricle with its tip positioned freely in the LV-cavum.