Starting a Transradial Vascular Access Program in the Cardiac Catheterization Laboratory

ABSTRACT: Over the past 20 years, since the first reports, trans-radial vascular access for coronary angiography and intervention has flourished in many countries while still accounting for less than 2% of all cases performed in the United States due, in part, to difficulties in introducing change to established practice patterns. The benefits of transradial access include decreased bleeding risk, increased patient comfort, lessened post-procedure nursing workload, and decreased hospital costs. A learning curve to gain the specific set of skills for transradial access has been well described. Although published data suggest that 100-200 cases are necessary to become proficient, the learning curve is likely highly individual, and some operators may become proficient sooner. The equipment to start a transradial program is minimal and includes modified sheaths and catheters. Patients with morbid obesity, peripheral vascular disease, and anticoagulation clearly benefit from this approach. To establish a transradial program and offer the benefits of this approach to most patients, a dedicated interventionalist must incorporate peers and hospital staff to create a multidisciplinary team. J INVASIVE CARDIOL 2009;21(Suppl a):11A–17A
In 1989, Lucien Campeau published his successful series of 100 coronary angiographies performed via the radial artery with minimal complications.¹ Subsequently in 1993, Kiemeneij described and published the use of transradial access for percutaneous coronary interventions using 6 French (Fr) guiding catheters in a time when most interventional procedures were performed with larger 8 Fr catheters.² Since then, transradial approach has continued to gain popularity in some regions of Europe, Canada, South America, Japan, and other sites outside the United States, where transradial access is used in more than 80% of the cases. Within the United States, however, the use of transradial vascular access is much less common. In the National Cardiovascular Data Registry (NCDR), transradial access accounted for 1.3% of all catheterization procedures with almost 90% of centers doing less than 2% of cases via the radial approach.³ The reasons transradial has not caught on in the US are unclear, but are probably related to physician and ancillary staff’s comfort with femoral access, and apprehension toward change. Additional deterrents for the use of transradial access include a higher operator radiation exposure,^4,5 and the well-described learning curve. However, once the procedure is mastered, the operator and staff become extremely comfortable with the technique and radiation exposure can be substantially reduced.^6,7 The purpose of our article is to provide a stepwise guide to starting a transradial vascular access program and to inform medical staff what to expect during the process. A determined operator who is familiar with the data and understands the compelling reasons for the use of transradial access can promote change and implement an institutional program. During the process, colleagues and staff members quickly realize the advantages of transradial access and the program gains widespread support within the catheterization laboratory. As an example, one operator of five performing procedures via transradial access at the University of North Carolina at Chapel Hill, increased the overall percentage of transradial cases from 2–3% per year to 11–13% per year over the course of 12 months (Figure 1). Understanding the Need for a Change A major step in the adoption of a new technique is understanding the limitations of local current practices. Cardiac catheterization via femoral access demands greater post-procedural nursing care, is limited by prolonged bed rest (usually about 4 hours), and delays discharge. In fact, when the procedure is performed late in the course of the day, patients are usually kept in hospital overnight for prevention of access-related bleeding. Femoral access is more frequently associated with increased back pain, urinary retention, delayed ambulation, and neuropathy.⁸ To overcome some of these limitations, many operators have adopted the use of vascular closure devices, but published data have consistently shown that these devices are associated with the same or increased hemorrhagic risks in comparison with manual compression.^9,10 In addition, rare complications such as infections, femoral artery stenosis, arterial laceration, uncontrolled bleeding, pseudoaneurysm, arteriovenous fistula, and device embolism and limb ischemia have all been reported with the use of vascular closure devices.¹¹ During recent years, it has become evident that bleeding complications and transfusions are associated with increased morbidity and mortality in patients undergoing percutaneous coronary interventions (PCI) and/or treated for acute coronary syndrome (ACS).^12-14 Of note, vascular access-related bleedings, including groin and retroperitoneal hematomas, account for more than 80% of all major and minor bleeds, according to a large cohort study of 10,974 patients undergoing PCI.¹⁵The Case for Transradial Vacular Access Transradial access poses significant benefits to patient comfort. There is no need for immobilization, back pain is substantially reduced, and the time to ambulation is decreased, letting the patient use the bathroom almost immediately after the procedure. In addition, decreased use of resources during the recovery time and early discharge results in significant cost savings.^8,16,17 However, the most compelling reason for adopting transradial access is the increased patient safety that results from the substantial reduction in bleeding and vascular access complications associated with this technique. Because transradial access virtually eliminates access-related bleeding, which accounts for more than 80% of major bleeding events in PCI, the interventional cardiologist can opt for more aggressive antithrombotic regimens during PCI, and at the end of the day, leave the hospital with peace of mind, knowing that the intervened patients have a low probability of severe bleeding. A recent meta-analysis including more than 2,400 patients enrolled in 23 trials demonstrated that transradial access was associated with a significant 73% reduction in major bleeding, and a 30% trend toward a reduction in the incidence of death, myocardial infarction, or stroke in comparison with femoral access.¹⁸ Indeed, the PCI operator would be hard-pressed to overlook radial access in light of these safety endpoints. In a large Canadian registry, the need for transfusing patients undergoing PCI was reduced by 50% with the use of transradial access and resulted in a significant mortality reduction at 30 days (OR: 0.71; 95% CI 0.61–0.82) and 1 year (OR: 0.83; 95% CI 0.71-0.98), in comparison with femoral access.¹⁹ From the technical standpoint, the superficial location of the radial artery makes it an ideal target for percutaneous arterial access (Table 1). The flat bony prominence of the radius facilitates compression and hemostasis after sheath removal. The collateralization of the radial artery decreases the risk of ischemia from prolonged occlusion, and there is no major adjacent nerve, minimizing the risk of neurologic sequelae. Steps Toward Becoming a Radial Operator Commitment Through the Learning Curve: Becoming a “radial operator” requires commitment and a mindset change. The first step in developing a practice is exposure to the technique that often starts during fellowship training, through courses offered by colleagues, or visits to catheterization labor-atories experienced in transradial access. In addition, didactic resources available on the Internet, such as tutorials and discussion forums, can be extremely helpful during the initial process. Examples of useful Web pages: • https://www.ptca.org/radial/slideshow.html • https://transradialworld.org/index.html • https://www.ptca.org/radial/index.html Understanding the existence and importance of the learning curve is key. Spaulding et al documented an initial access failure rate greater than 10% that decreased dramatically to about 2% after the first 80 cases. In addition, the time required for access and sheath insertion decreased from 10.2 ± 7.6 min to 2.8 ± 2.5 min and the procedure time also decreased from 25.7 ± 12.9 min to 17.4 ± 4.7 min.⁶Identifying a Target Population: The initial strategy involves identifying a target population and performing diagnostic angiography only. In the beginning, procedures take more time with higher contrast use and longer radiation exposure. Therefore, it is convenient to start the experience in young and large males, with normal renal function and low chance of needing PCI, as their radial arteries are likely to be larger and to have less vascular tortuosity. Logical initial targets also include morbidly obese patients²⁰ and patients with severe peripheral vascular disease (PAD),²¹ in which femoral access is associated with additional risks. On the other hand, elderly hypertensive females with small body surface area should be avoided during the initial learning curve because of a higher probability of finding smaller, tortuous vessels that pose more technical challenges.^22,23 Similarly, it may be less stressful to avoid high-risk cases, and instead get familiar with transradial access in elective stable patients. In the absence of anatomic anomalies, transradial access is successful in more than 95% of the cases. Throughout the learning process, the operator should not get discouraged by the presence of technical difficulties. It is important, though, that the operator recognizes his or her own limitations. Transradial catheterization should always be performed with finesse. Wires and catheters should advance without difficulty. If resistance is found, a limited angiography through an 18-gauge angiocath placed in the radial artery, or through the sheath or a catheter, will aid in defining the presence of anomalous anatomy or unusual tortuosity and will help in deciding the best technical options. Anatomic variations are associated with increased procedural failure and can be found in 14% to 23% of cases. Variations include tortuous radial configurations, stenoses, hypoplasia, radioulnar loops, aberrant right subclavian artery (arteria lusoria), and abnormal origin of radial artery.^23,24 The operator should be aware of the several techniques described to negotiate tortuous vessels and radioulnar loops with hydrophilic-coated guidewires and catheters.^22,25,26 Patients should not experience pain during the procedure. In the presence of forearm pain, the operator should suspect, recognize, and manage local complications such as refractory spasm, forearm hematoma, and vessel perforation.^27,28Expanding to Higher-Risk and Technically Challenging Cases: At the steep part of the learning curve, the operator is already familiar with the equipment and technique, is able to approach more technically demanding cases, use a single catheter to cannulate both coronary arteries, and perform interventional procedures in high-risk populations.^29-31 The operator’s mindset has already changed and every patient becomes a “transradial candidate” unless proven otherwise. Patients on oral anticoagulation who need a precise puncture become a target population. With use of transradial catheterization, anticoagulated patients with atrial fibrillation, mechanical valves or prothrombotic conditions do not need to be admitted beforehand and be bridged to heparin or receive fresh frozen plasma. The typical scenario is the anticoagulated patient presenting with an acute coronary syndrome needing urgent catheterization. Transradial access is extremely helpful in these cases as hemostasis can be easily achieved upon completion of the case.^32,33 Elderly patients also benefit from transradial access due to the lower incidence of vascular complications.³⁴ Transradial catheterization and PCI is also feasible in the setting of ST-elevation acute myocardial infarction without significant delays in door-to-balloon times and is associated with lower rates of bleeding and vascular complications.^30,31,35 The need for simultaneous right heart catheterization or the presence of aorto-coronary bypass-grafts should not be viewed as contraindications for transradial access. Right heart catheterization can be performed through one of the large veins located in the anticubital fossa. In our institution, a nurse usually obtains venous access with an 18-gauge catheter, which is subsequently exchanged for a 5 Fr sheath using a short 0.021-inch wire, and then a 5 Fr 120-cm balloon-tipped catheter is advanced into the superior vena cava with use of a 0.025-inch guidewire. Then, the wire is retrieved, the balloon inflated and the catheter advanced into the pulmonary artery.^36,37 In patients with prior coronary artery bypass grafting (CABG), radial access facilitates cannulation of the ipsilateral internal mammary artery (IMA) and allows selective engagement of aorto-coronary bypasses. Before the procedure, the patient’s type and number of grafts must be carefully evaluated in order to select the best access strategy (left versus right radial artery) and the appropriate catheter curves. A thorough review on transradial catheterization in patients with prior CABG is available in the literature.³⁸ As experience accumulates, the operator will face more challenging cases with tortuous anatomy, expand to non-coronary interventions,^39,40 and be exposed to unforeseen difficulties or complications, such as hematoma, vascular perforations, post-procedural loss of radial pulse, and abscess development at the puncture site.^41–45Changing the Institutional Culture — Implementing the Program When a motivated operator decides to setup a transradial program, a number of changes need to occur at the institutional level. It is important to realize that the program’s success will largely be dictated by how effectively the catheterization laboratory and staff members (nurses, technologists, administrators) become incorporated into the endeavor of creating a truly multidisciplinary program. The appropriate equipment needs to be readily available, and the staff must be trained in pre-procedure set-up and preparation, procedural expectations, and post-procedure patient care. Equipment: Even though there is relatively little additional or specialized equipment needed for transradial catheterization, there are products that greatly facilitate vascular access. With time, the operator will identify and stock the equipment that he or she feels most comfortable with. At our institution, we use short (10 cm) hydrophilic-coated sheaths compatible with a 0.021-inch wire. Hydrophilic sheaths have been shown to be associated with less patient discomfort, local pain, and easy removal.⁴⁶ Commercially available transradial access kits usually include a 25 mm 24-gauge micro-puncture needle, very useful to effectively stick the radial artery. In terms of catheters, a dual catheter technique using a Judkins catheter probably provides the easiest way to start the transradial learning curve and train fellows. For the left coronary it is recommended to downsize the curve of the JL catheter from 4.0 to 3.5 and for the right coronary to use either a JR4 or JR5. Catheters should always be exchanged over a long 260-cm 0.035-inch wire, especially in patients with tortuous radial or subclavian anatomy. At our institution, we use a hydrophilic-coated stiff-shaft wire with an angled tip, which lets us negotiate tortuosity and maintain stability during catheter exchanges. The more experienced operator can transition to a single-catheter technique to selectively engage both coronary arteries with a dedicated catheter shape, thus eliminating an exchange step and decreasing procedure and fluoroscopy time. Available shapes for the single-catheter approach include the multipurpose, Kimney, Tiger, and Jacky catheters, among others.²⁹ For coronary interventions, the 3.5 extra-backup curves (EBU, XP, Voda) usually work well and provide appropriate support. Recent studies examining the physics of catheter engagement and positioning in the ascending aorta indicate that the relatively new Ikari catheters (not available in the United States) provide better and more stable support for PCI than do Judkins catheters.⁴⁷Patient Preparation, Catheterization Laboratory Set-up, Arterial Access: It is important to develop a transradial access policy to provide guidance to the staff and maintain consistency across cases. This document should include clear instructions for pre-procedure patient preparation, a checklist of items that should be readily available in the catheterization laboratory, and post-procedural care and management of hemostasis. During patient preparation, the intravenous line is placed in the upper extremity contralateral to where transradial access is planned. If a line must be placed in the arm on the side of arterial access, it should be placed proximal to the wrist (preferably at the level of the elbow). To prevent ischemic hand complications, the collateral circulation of the hand needs to be evaluated. At our institution, the integrity of the arterial palmar arch is checked and documented with a modified Allen’s test using plethysmography and pulse oximetry, as described by Barbeau and colleagues.⁴⁸ Of note, there are no reports of ischemic hand complications secondary to transradial catheterization. Ischemic hand complications have been reported in association with intra-arterial lines placed in critical care units.⁴⁹ Advising the patient what to expect during and after the procedure is important. Patients receive explanation regarding the differences with the femoral approach, especially that the transradial catheterization is more involved, sometimes takes longer, and that in a minority of cases, significant forearm pain may develop as a consequence of radial spasm. In fact, much of the morbidity of the transradial procedure is related to vasospasm induced by the introduction of a sheath or catheter into the radial artery. Independent predictors of radial spasm include the presence of radial artery anomalies, multiple catheter exchanges, pain during radial cannulation, and radial diameter after administration of vasodilatory agents.⁵⁰ Vasospasm can be prevented with the use of a “spasmolytic cocktail” administered through the sidearm of the sheath immediately after obtaining radial access. We are presently using 3 mg of verapamil diluted in 10 ml of normal saline. Other agents used to prevent spasm include different combinations of lidocaine, nitroglycerin, nicardipine, papaverine, and diltiazem.⁵¹ In the catheterization laboratory, it is important that both patient and operator feel comfortable. As the patient is placed on the catheterization table, the arm is accommodated on an arm board, and the wrist is hyperextended and draped in sterile fashion (Figure 2). The femoral site should also be prepared in case it is needed, especially during the learning curve or in presence of a weak radial pulse. For the comfort of the operator, instead of a regular armboard, we recommend the use of an oversized Plexiglass rectangular board (3 feet by 4 feet) that provides support for the patient’s arm and the interventional equipment as depicted in Figure 3, so the operator does not feel like he/she is “working in the air.” For diagnostic catheterization, we usually administer intravenous heparin at a dose of 80 U/Kg to a maximum of 5,000 U to avoid radial artery occlusion. Additional doses of heparin or other anticoagulants can be administered if a subsequent interventional procedure is needed.⁵² Because of the possibility of vascular tortuosity at different levels in the upper extremity, we usually administer heparin after the guidewire has reached the ascending aorta and there is assurance that the procedure will be completed through the radial artery without crossover to femoral access. Post-procedure Care: Once the procedure is complete, the radial sheath is pulled in the catheterization laboratory regardless of the intensity of anticoagulation or antiplatelet therapy. Hemostasis can simply be achieved using a roll of gauze placed longitudinally on top of the arteriotomy site and wrapped with an elastic bandage around the wrist. Alternatively, dedicated devices, such as the RadiStop and the TR band, that apply pressure directly over the radial artery without compromising the venous circulation, may be more convenient (Figure 4). The transradial catheterization policy should be specific about the duration and intensity of compression. Prolonged occlusive compression increases the risk of radial artery occlusion, which, despite being clinically silent, limits the possibility of future transradial access. Pancholy et al have described a technique that allows “patent” hemostasis. Using pulse oximetry and plethysmography, compression over the radial artery is alleviated while applying manual pressure to the ulnar artery. Patent hemostasis is achieved when oximetry in the fingertip becomes positive and a waveform is visualized with plethysmography. With this technique, late occlusion rates are approximately 2%.⁴³ In our institution, hemostasis is achieved with an inflatable balloon device that applies selective pressure on the radial artery (TR Band). Two hours after placement of the device, 5 cc of air are released every 15 minutes, until the device is completely deflated and can be removed. Program Expectations Once the program is up and running, staff and physicians will comfortably offer this vascular access approach to all patients. The radial operator will increase his referral basis, initially at the expense of patients with no alternative vascular access, morbid obesity, or those on anticoagulation therapy. However, with time, colleagues will refer patients, staff will make patients aware that this approach is offered at the institution, and the community at large will recognize the benefits of transradial access and specifically request it. The ongoing RIVAL trial, a substudy of CURRENT-OASIS 7, will randomize a total of 2,000 patients with acute coronary syndromes to transradial versus transfemoral vascular access. Hopefully, this adequately-powered study will demonstrate the benefits of transradial access in terms of bleeding, vascular, and ischemic complications.⁵³ It is anticipated that transradial access will ultimately be recommended by clinical practice guidelines and become a benchmark for quality of care. References 1. Campeau L. Percutaneous radial artery approach for coronary angiography. Cathet Cardiovasc Diagn 1989;16(1):3–7. 2. Kiemeneij F, Laarman GJ. Percutaneous transradial artery approach for coronary stent implantation. Cathet Cardiovasc Diagn 1993;30(2):173–178. 3. 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;1(4):379–386. 4. Brasselet C, Blanpain T, Tassan-Mangina S, et al. Comparison of operator radiation exposure with optimized radiation protection devices during coronary angiograms and ad hoc percutaneous coronary interventions by radial and femoral routes. Eur Heart J 2008;29(1):63–70. 5. Lange HW, von Boetticher H. Randomized comparison of operator radiation exposure during coronary angiography and intervention by radial or femoral approach. Catheter Cardiovasc Interv 2006;67(1):12–16. 6. Spaulding C, Lefevre T, Funck F, et al. Left radial approach for coronary angiography: Results of a prospective study. Cathet Cardiovasc Diagn 1996;39(4):365–370. 7. Salgado Fernandez J, Calvino Santos R, Vazquez Rodriguez JM, et al. [Transradial approach to coronary angiography and angioplasty: Initial experience and learning curve]. Rev Esp Cardiol 2003;56(2):152–159. 8. 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(3 Pt 1):430–436. 9. Nikolsky E, Mehran R, Halkin A, et al. Vascular complications associated with arteriotomy closure devices in patients undergoing percutaneous coronary procedures: A meta-analysis. J Am Coll Cardiol 2004;44(6):1200–1209. 10. Koreny M, Riedmuller E, Nikfardjam M, et al. Arterial puncture closing devices compared with standard manual compression after cardiac catheterization: systematic review and meta-analysis. JAMA 2004;291(3):350–357. 11. Dauerman HL, Applegate RJ, Cohen DJ. Vascular closure devices: The second decade. J Am Coll Cardiol 2007;50(17):1617–1626. 12. Rao SV, O'Grady K, Pieper KS, et al. Impact of bleeding severity on clinical outcomes among patients with acute coronary syndromes. Am J Cardiol 2005;96(9):1200–1206. 13. Yang X, Alexander KP, Chen AY, et al. The implications of blood transfusions for patients with non-ST-segment elevation acute coronary syndromes: Results from the CRUSADE National Quality Improvement Initiative. J Am Coll Cardiol 2005;46(8):1490–1495. 14. Yatskar L, Selzer F, Feit F, et al. Access site hematoma requiring blood transfusion predicts mortality in patients undergoing percutaneous coronary intervention: Data from the National Heart, Lung, and Blood Institute Dynamic Registry. Catheter Cardiovasc Interv 2007;69(7):961–966. 15. Kinnaird TD, Stabile E, Mintz GS, et al. Incidence, predictors, and prognostic implications of bleeding and blood transfusion following percutaneous coronary interventions. Am J Cardiol 2003;92(8):930–935. 16. Roussanov O, Wilson SJ, Henley K, et al. Cost-effectiveness of the radial versus femoral artery approach to diagnostic cardiac catheterization. J Invasive Cardiol 2007;19(8):349–353. 17. Mann T, Cowper PA, Peterson ED, et al. Transradial coronary stenting: comparison with femoral access closed with an arterial suture device. Catheter Cardiovasc Interv 2000;49(2):150–156. 18. Jolly SS, Amlani S, Hamon M, et al. Radial versus femoral access for coronary angiography or intervention and the impact on major bleeding and ischemic events: A systematic review and meta-analysis of randomized trials. Am Heart J 2009;157(1):132–140. 19. Chase AJ, Fretz EB, Warburton WP, et al. Association of the arterial access site at angioplasty with transfusion and mortality: The M.O.R.T.A.L study (Mortality benefit Of Reduced Transfusion after percutaneous coronary intervention via the Arm or Leg). Heart 2008;94(8):1019–1025. 20. McNulty PH, Ettinger SM, Field JM, et al. Cardiac catheterization in morbidly obese patients. Catheter Cardiovasc Interv 2002;56(2):174–177. 21. Hildick-Smith DJ, Walsh JT, Lowe MD, et al. Coronary angiography in the presence of peripheral vascular disease: Femoral or brachial/radial approach? Catheter Cardiovasc Interv 2000;49(1):32–37. 22. Barbeau GR. Radial loop and extreme vessel tortuosity in the transradial approach: advantage of hydrophilic-coated guidewires and catheters. Catheter Cardiovasc Interv 2003;59(4):442–450. 23. Lo TS, Nolan J, Fountzopoulos E, et al. Radial artery anomaly and its influence on transradial coronary procedural outcome. Heart 2009;95(5):410–415. 24. Valsecchi O, Vassileva A, Musumeci G, et al. Failure of transradial approach during coronary interventions: anatomic considerations. Catheter Cardiovasc Interv 2006;67(6):870–878. 25. Wang HJ, Lee KW, Hsieh DJ. Brachial loop: transradial technique to overcome this rare anatomic variation. Catheter Cardiovasc Interv 2006;68(2):260–262. 26. Louvard Y, Lefevre T. Loops and transradial approach in coronary diagnosis and intervention. Catheter Cardiovasc Interv 2000;51:250–252. 27. Kiemeneij F. Prevention and management of radial artery spasm. J Invasive Cardiol 2006;18:159–160. 28. Tizon-Marcos H, Barbeau GR. Incidence of compartment syndrome of the arm in a large series of transradial approach for coronary procedures. J Interv Cardiol 2008;21:380–384. 29. Kim SM, Kim DK, Kim DI, et al. Novel diagnostic catheter specifically designed for both coronary arteries via the right transradial approach. A prospective, randomized trial of Tiger II vs. Judkins catheters. Int J Cardiovasc Imaging 2006;22:295–303. 30. Cantor WJ, Puley G, Natarajan MK, et al. Radial versus femoral access for emergent percutaneous coronary intervention with adjunct glycoprotein IIb/IIIa inhibition in acute myocardial infarction — the RADIAL-AMI pilot randomized trial. Am Heart J 2005;150:543–549. 31. Louvard Y, Ludwig J, Lefevre T, et al. Transradial approach for coronary angioplasty in the setting of acute myocardial infarction: a dual-center registry. Catheter Cardiovasc Interv 2002;55:206–211. 32. Helft G, Dambrin G, Zaman A, et al. Percutaneous coronary intervention in anticoagulated patients via radial artery access. Catheter Cardiovasc Interv 2009;73:44–47. 33. Hildick-Smith DJ, Walsh JT, Lowe MD, Petch MC. Coronary angiography in the fully anticoagulated patient: the transradial route is successful and safe. Catheter Cardiovasc Interv 2003;58:8–10. 34. Louvard Y, Benamer H, Garot P, et al. Comparison of transradial and transfemoral approaches for coronary angiography and angioplasty in octogenarians (the OCTOPLUS study). Am J Cardiol 2004;94:1177–1180. 35. Brasselet C, Tassan S, Nazeyrollas P, et al. Randomised comparison of femoral versus radial approach for percutaneous coronary intervention using abciximab in acute myocardial infarction: Results of the FARMI trial. Heart 2007;93:1556–1561. 36. Gilchrist IC, Kharabsheh S, Nickolaus MJ, Reddy R. Radial approach to right heart catheterization: early experience with a promising technique. Catheter Cardiovasc Interv 2002;55:20–22. 37. Lo TS, Buch AN, Hall IR, et al. Percutaneous left and right heart catheterization in fully anticoagulated patients utilizing the radial artery and forearm vein: A two-center experience. J Interv Cardiol 2006;19:258–263. 38. Burzotta F, Trani C, Hamon M, et al. Transradial approach for coronary angiography and interventions in patients with coronary bypass grafts: Tips and tricks. Catheter Cardiovasc Interv 2008;72:263–272. 39. Folmar J, Sachar R, Mann T. Transradial approach for carotid artery stenting: A feasibility study. Catheter Cardiovasc Interv 2007;69:355–361. 40. Sanghvi K, Kurian D, Coppola J. Transradial intervention of iliac and superficial femoral artery disease is feasible. J Interv Cardiol 2008;2:385–387. 41. Calvino-Santos RA, Vazquez-Rodriguez JM, Salgado-Fernandez J, et al. Management of iatrogenic radial artery perforation. Catheter Cardiovasc Interv 2004;61:74–78. 42. Stella PR, Kiemeneij F, Laarman GJ, Odekerken D, Slagboom T, van der Wieken R. Incidence and outcome of radial artery occlusion following transradial artery coronary angioplasty. Cathet Cardiovasc Diagn 1997;40(2):156-158. 43. Pancholy S, Coppola J, Patel T, et al. Prevention of radial artery occlusion-patent hemostasis evaluation trial (PROPHET study): A randomized comparison of traditional versus patency documented hemostasis after transradial catheterization. Catheter Cardiovasc Interv 2008;72:335–340. 44. Kozak M, Adams DR, Ioffreda MD, et al. Sterile inflammation associated with transradial catheterization and hydrophilic sheaths. Catheter Cardiovasc Interv 2003;59:207–213. 45. Subramanian R, White CJ, Sternbergh 3rd WC, et al. Nonhealing wound resulting from a foreign-body reaction to a radial arterial sheath. Catheter Cardiovasc Interv 2003;59:205–206. 46. Kiemeneij F, Fraser D, Slagboom T, et al. Hydrophilic coating aids radial sheath withdrawal and reduces patient discomfort following transradial coronary intervention: A randomized double-blind comparison of coated and uncoated sheaths. Catheter Cardiovasc Interv 2003;59:161–164. 47. Ikari Y, Nagaoka M, Kim JY, et al. The physics of guiding catheters for the left coronary artery in transfemoral and transradial interventions. J Invasive Cardiol 2005;17:636–641. 48. Barbeau GR, Arsenault F, Dugas L, et al. Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with the Allen's test in 1010 patients. Am Heart J 2004;147:489–493. 49. Wallach SG. Cannulation injury of the radial artery: diagnosis and treatment algorithm. Am J Crit Care 2004;13:315-319. 50. Ruiz-Salmeron RJ, Mora R, Masotti M, Betriu A. Assessment of the efficacy of phentolamine to prevent radial artery spasm during cardiac catheterization procedures: A randomized study comparing phentolamine vs. verapamil. Catheter Cardiovasc Interv 2005;66:192-198. 51. Kiemeneij F, Vajifdar BU, Eccleshall SC, et al. Evaluation of a spasmolytic cockt