The Compleat Radialist

Izaak Walton’s “The Compleat Angler, or the Contemplative Man’s Recreation; Being a Discourse of Fish and Fishing, not unworthy the perusal of most Anglers” attempted to consolidate all practical knowledge of fishing as of 1653.¹ “Compleat” was the then-accepted spelling of the word we now know as “complete,” but it fell out of use in the eighteenth century. But Izaak Walton’s discourse on fishing remained so well known that “compleat” resurfaced in the twentieth century, used whimsically to mean the “embodiment of the perfect example of the practitioner of his or her craft.”² A report by Obaid et al in this issue of the Journal of Invasive Cardiology may encourage interventionalists to be a little more “compleat.”³ 

Obaid et al studied balloon-assisted tracking (BAT) to facilitate radial access. The technique involves inflating a 2 mm angioplasty balloon extending half-way out of the distal end of a guide catheter, and passing the balloon/catheter over an angioplasty wire through tortuous or spasmed radial and brachial arteries. Operators in Obaid’s study had experience of >10 years and >1000 percutaneous coronary interventions (PCIs), and used radial access for >80% of their PCIs. They surveyed their experience for the 12 months before and 14 months after implementing a strategy of attempting BAT before switching to femoral access when radial access seemed impossible. They used radial access as the default strategy for patients with stable angina, acute coronary syndromes, and ST-elevation myocardial infarction (STEMI). 

Before BAT, 2% of radial access attempts failed due to inability to access or cannulate the radial artery and 4% failed due to tortuosity or spasm. After routine use of BAT was implemented, 2% failed due to inability to access or cannulate the radial artery and 0.5% failed due to tortuosity or spasm. BAT was the difference between failure and success of radial access in 5% of cases. 

Difficult radial access requiring BAT requires more time than simple radial access not requiring BAT. The authors found that total procedural times with BAT (51 min) were insignificantly longer than when BAT was not used (47 min) and insignificantly shorter than when access was switched to the femoral route (61 min). Access times, measured as procedure start-to-first device (S2D) times, were provided for 818 STEMI patients. S2D times with BAT (23 min) were significantly longer than when BAT was not used (17 min; P<.001) and similar when access was switched to the femoral route (24 min). 

The authors conclude that use of BAT increased the success rate of radial access from 92.4% to 97.5% (P<.01), and BAT was successful in 91% of cases in which it was used. While difficult radial access increased S2D times, the delay was similar with either BAT or directly switching to femoral access. There was no learning curve, with BAT success rates and times similar for all operators, and stable over the entire period of the study.

The authors note several limitations to their study. They did not use ultrasound, which has been reported to facilitate radial access.⁴ Their back-up strategy for failed radial access did not include contralateral radial access, which is often successful.^5,6 They did not report on percentage of total cases using femoral access during the study period, and note only that femoral access was used as a primary strategy when radial pulses were absent or guide sheaths larger than 6 Fr were necessary. Use of the ulnar artery for access or sheathless 7 Fr guide catheters might have solved both of those problems.^7,8 Finally, it is a single-center observational study and the operators were experienced radialists; operators with less experience might have lower success rates.

Arguments against the use of BAT can be easily rebutted. The skills required are possessed by every interventionalist – passing .014˝ guidewires through small tortuous arteries under fluoroscopic guidance defines the profession. When radial access is difficult, BAT takes no longer than switching to femoral access. The cost of a balloon and guidewire is trivial when added to the costs of a PCI procedure, and often the guidewire and balloon can be re-used in the PCI. 

More comprehensive descriptions of optimal radial technique have been published,⁹ but it may be worthwhile here to point out a few tricks Obaid et al used in their successful radial access program, and a few they did not use. All of these are effective in the experience of this editorialist.

Ultrasound for radial puncture. Ultrasound has been documented to decrease the number of punctures and time needed to access the radial artery.⁴

Ulnar artery as an alternative access route. The ulnar artery is a reliable access route. When the radial artery proves impassable due to an extreme radial loop, the ulnar artery may provide a straight shot to the brachial artery.⁸

Contralateral radial access. On occasion, successful right radial access may be prevented by the anatomy of the right arm, innominate artery stenosis, or anatomy of the aortic arch. In these cases, the left radial may offer a straight route to the coronary arteries.^5,6

Imaging of the brachial bifurcation. Any time a wire or catheter fails to pass the elbow easily, image the brachial bifurcation area. Some operators advocate imaging the brachial bifurcation at the beginning of every case. As Obaid et al point out, imaging may show that the wire has passed up a small, recurrent radial artery that is too small to permit any catheter to pass. In other cases, imaging may show how a radial loop can be traversed. 

Angulated views of the brachial bifurcation. Sometimes the details of radial loops and the brachial bifurcation may be difficult to define. Angulated views (eg, 30° left or right anterior oblique) may clarify where to pass the wire.

Sheathless 7 Fr guides. The sheathless 6.5 Fr guide has the external diameter of a 5 Fr guide and the internal lumen of a 6.5 Fr guide.⁷ The larger sheathless guide has the external diameter of a 6 Fr guide and the internal lumen of a 7.5 Fr guide. These may be useful for complex PCI, 1.75 rotational atherectomy burrs, and chronic total occlusion PCI.

Tortuous or spasmodic arteries. While BAT is probably the most reliable solution, alternatives include a hydrophilic .035˝ wire, a 5 Fr catheter inside a 6 Fr catheter (as was used by Obaid et al in their pre-BAT cohort), or rotating the guide as it passes proximally to ease it around bends.

Antispasm cocktails. Vasodilators reduce the incidence of radial spasm and are used by most operators.^10,11

Innominate or subclavian challenges. Passage of the wire through serpentine subclavian vessels can be facilitated by oblique imaging (eg, 30° left anterior oblique for the right innominate). Tortuosity that makes torqueing of catheters in the aortic root difficult can be often overcome by using stiff wires, by cannulating coronary ostia before withdrawing the wire, or by using stiffer catheters (eg, guide catheters for diagnostic imaging).

Aberrant aortic arches. Origin of the right subclavian distal to the left subclavian (subclavian lusoria) can make manipulation of catheters in the aortic root impossible from the right radial, but will not impede a procedure using left radial access.¹²

In the United States, the use of radial access, as reported in the National Cardiovascular Data CathPCI Registry, has increased from 5% in 2010 to 35% in the fourth quarter of 2016, with a yearly increase of 3%-5%. Most early career interventionists are trained in and comfortable with radial access. These factors may help the United States catch up to Europe’s 80% use of radial access in the next decade. This is good: radial access decreases access-site complications and perhaps mortality, compared to femoral access.¹³ But for radial access to become the dominant access route, United States interventionalists will need to become “compleat radialists.” Fortunately, this requires only the skills possessed by all interventionalists. 

References

1.     Walton I. The Compleat Angler, or the Contemplative Man’s Recreation; Being a Discourse of Fish and Fishing, not unworthy the perusal of most Anglers. 1653. Re-published by Dent, London, 1953.

2.    https://boards.straightdope.com/sdmb/showthread.php?t=193859. Accessed May 30, 2017.

3.     Obaid D, Hailan A, Chase A, et al. Balloon-assisted tracking use reduces radial artery access failure in an experienced radial center and is feasible during primary PCI for STEMI. J Invasive Cardiol. 2017;29:219-224.

4.     Zaremski L, Quesada R, Kovacs M, Schernthaner M, Uthoff H. Prospective comparison of palpation versus ultrasound-guided radial access for cardiac catheterization. J Invasive Cardiol. 2013;25:538-542.

5.     Guo X, Ding J, Qi Y, et al. Left radial access is preferable to right radial access for the diagnostic or interventional coronary procedures: a meta-analysis involving 22 randomized clinical trials and 10287 patients. PloS one. 2013;8:e78499.

6.     Kedev S, Zafirovska B, Dharma S, Petkoska D. Safety and feasibility of transulnar catheterization when ipsilateral radial access is not available. Catheter Cardiovasc Interv. 2014;83:E51-E60.

7.     From AM, Bell MR, Rihal CS, Gulati R. Minimally invasive transradial intervention using sheathless standard guiding catheters. Catheter Cardiovasc Interv. 2011;78:866-871.

8.     de Andrade PB, Tebet MA, Nogueira EF, et al. Transulnar approach as an alternative access site for coronary invasive procedures after transradial approach failure. Am Heart J. 2012;164:462-467.

9.     Caputo RP, Tremmel JA, Rao S, et al. Transradial arterial access for coronary and peripheral procedures: executive summary by the Transradial Committee of the SCAI. Catheter Cardiovasc Interv. 2011;78:823-839.

10.     Ho HH, Jafary FH, Ong PJ. Radial artery spasm during transradial cardiac catheterization and percutaneous coronary intervention: incidence, predisposing factors, prevention, and management. Cardiovasc Revasc Med. 2012;13:193-195.

11.     Varenne O, Jégou A, Cohen R, et al. Prevention of arterial spasm during percutaneous coronary interventions through radial artery: the SPASM study. Catheter Cardiovasc Interv. 2006;68:231-235.

12.     Valsecchi O, Vassileva A, Musumeci G, et al. Failure of transradial approach during coronary interventions: anatomic considerations. Catheter Cardiovasc Interv. 2006;1;67:870-878.

13.     Karrowni W, Vyas A, Giacomino B, et al. Radial versus femoral access for primary percutaneous interventions in ST-segment elevation myocardial infarction patients: a meta-analysis of randomized controlled trials. JACC Cardiovasc Interv. 2013;6:814-823.

From the Geisinger Medical Center, Danville, Pennsylvania.

Disclosure: The author has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The author reports no conflicts of interest regarding the content herein.

Address for correspondence: James C. Blankenship, MD, MHCM, MACC, M-SCAI, Department of Cardiology 27-75, 100 N Academy Avenue, Geisinger Medical Center, Danville, PA 17822. Email: jblankenship@geisinger.edu