A Paradigm Shift Toward Forearm Arterial Access Requires Establishing Preprocedure Adequacy of Hand Collateralization or Patency of Collateralizing Forearm Arteries

Dear Editors,

We read Gokhroo et al’s¹ original article, “Ulnar Artery Interventions Non-Inferior to Radial Approach: Ajmer Ulnar ARtery (AJULAR) Intervention Working Group Study Results” with interest. We would like to congratulate the authors for a well-designed and insightful study. 

As indicated in the editorial comments accompanying this study,² through this single-center randomized trial, not only have the authors established the safety of transulnar interventions in the hands of experienced operators,¹ but by using a protocol of converting to left ulnar access if access through right ulnar failed, they may also have helped reinforce minimizing crossover to femoral access by shifting the current paradigm toward interventions through forearm arteries.^3,4  

In this context, since postprocedure occlusion occurs more often in smaller access arteries, it would be logical to go for an access artery in the forearm with the largest diameter based upon preprocedure ultrasound assessment of the four forearm arteries, since contrary to the claim in the discussion of the subject by the authors, the ulnar artery is not always bigger than the radial and equally, one, or both radial arteries could be larger than the ulnar in a patient.^3,4 

Also, there are a few other limitations of this work that we would like to highlight.

Using the non-inferiority margin of 1.93 in the analysis, the study confirmed non-inferiority for all components of composite primary endpoints except large hematoma, for which the analysis was inconclusive. The ulnar (which is anatomically deeper) is often harder to compress and the use of compression bandages, as in this study, can often lead to large hematomas. Use of manual compression following sheath removal when activated clotting time is <160 seconds for transulnar procedures⁴ may conversely have led to a lower incidence of hematomas in their study and may have helped conclusively establish its non-inferiority to transradial access in this regard too.  

Again, although a 5-hour compression of the radial access site using a bandage could have contributed to a high radial artery occlusion rate as well, it would be hard to conclude the precise rate of access artery occlusion in the absence of Doppler use. Arterial patency testing by palpation alone has inherent limitations; ulnar arteries can be difficult to palpate because of their deeper course compared with the radials. Furthermore, if the clinician palpating the access artery simultaneously does not also occlude the collateralizing forearm artery (radial for ulnar and vice versa) to prevent its filling through the palmar arch (as is done for reverse Allen’s test), the findings can be misinterpreted.

Preprocedure Allen’s and Barbeau’s tests (or testing of dual circulation of the hand) seem to have gone out of vogue recently⁵ for good reasons and it is understandable therefore that the authors did not perform them in their patient cohorts. 

However, in situations with an asymptomatic occlusion of the ulnar artery from a prior translunar procedure, the ipsilateral radial artery pulse is usually well felt (due to an adequate pulse volume from collateral filling through the palmar arch),⁶ which may lead an unsuspecting radial operator to intervene through it, potentially putting the patient’s hand at risk for vascular compromise if the hand lacks adequate collateralization. 

Since Allen’s and/or Barbeau’s and reverse Allen’s and/or reverse Barbeau’s testing have limitations,⁵ in the absence of a better test to assess adequacy of hand collateralizations, a preprocedure ultrasound assessment of forearm arteries^3,4 would not only  help identify the largest forearm  artery for access, it would also establish patency of its corresponding collateralizing artery to avoid inadvertent transradial procedures in patients with occluded ulnar arteries, or vice versa. Even though data are available for interventions in such situations,^7,8 they are scant and lack validation in randomized multicenter trials; hence, current recommendations advocate avoiding these cases in the interest of patient safety.

Therefore, a paradigm shift to “forearm access” with the equivalent use of radial or ulnar access, and priority of crossing over first to an alternate forearm access site, should mandate the need for an accurate test of patency of the collateralizing artery. 

References 

1.    Gokhroo R, Kishor K, Bhanwar R, Bisht D, Gupta S, Avinash A. Ulnar artery interventions non inferior to radial approach: Ajmer Ulnar Artery (AJULAR) intervention working group study results. J Invasive Cardiol. 2016;28:1-8. 

2.    Sawlani N, Rao SV, Bhatt DL. A call for comprehensive forearm access? J Invasive Cardiol. 2016;28:8-9.

3.    Chugh SK, Chugh Y, Chugh S. Overcoming the challenge of transradial interventions in women: insights from a color Doppler study. J Am Coll Cardiol. 2014;64:B240.

4.    Chugh SK, Chugh S, Chugh Y, Rao SV. Feasibility and utility of pre-procedural ultrasound imaging of the arm to facilitate transradial coronary diagnostic and interventional procedures (PRIMAFACIE-TRI). Catheter Cardiovasc Interv. 2013;82:64-73.

5.    Gilchrist IC. Is the Allen’s test accurate for patients considered for transradial coronary angiography? J Am Coll Cardiol. 2006;48:1283-1288.

6.    Shroff A, Siddiqui S, Burg A, Single I. Identification and management of complications of transradial procedures. Curr Cardiol Rep. 2013;15:350.

7.    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. 

8.    Kwan TW, Ratcliffe JA, Chaudhry M, et al. Transulnar catheterization in patients with ipsilateral radial artery occlusion. Catheter Cardiovasc Interv. 2013;82:E849-E855.  

Authors’ Response

Dr Chugh and colleagues speculated that ultrasound imaging enables reliable evaluation of the diameter of forearm arteries and may guide the operator to cannulate larger arteries; however, this modality was not used in the current study so as to mimic a real-word scenario where it would increase the cost and time of the procedure. Also, despite the disparity in size of forearm arteries that may exist in an individual patient, either artery can accommodate the 6 Fr catheter and sheath easily. 

Although data regarding ulnar artery occlusion (UAO) are scarce, only a few cases of severe hand ischemia after radial occlusion have been reported. In the majority of patients, the radial and ulnar arteries are connected at the wrist by the deep and superficial palmar arches. Interosseous collaterals also provide additional communications.

Since the incidence of radial artery occlusion is proportionate to postprocedure compression time and the presence of anterograde flow in the artery during hemostasis, we insist upon the immediate removal of sheath after procedure. However, the concept of using an activated clotting time of <160 seconds to minimize the large hematoma and at the same time minimize postprocedure compression time is a welcome step.

Fear of hand ischemia while cannulating the radial artery in patients with prior occluded ulnar artery cannulation can be addressed by the routine palpation of both arteries just before radial artery cannulation.

Sincerely,

Rajendra Gokhroo, DM;  Kamal Kishor, MD, DM;  Bhanwar Ranwa, DM;  Devendra Bisht, DM;  Sajal Gupta, DM;  Deepak Padmanabhan, DM;  A. Avinash, DM