The following case is part of a series of transradial-focused reports directed by section editor Dr. Samir Pancholy. This case series is supported by an educational grant from Medtronic.

Disclosure: The authors report no conflicts of interest regarding the content herein.

Dr. Giselle Baquero can be contacted at gbaquero@hmc.psu.edu.

Dr. Ian Gilchrist can be contacted at icg1@psu.edu.

Introduction

During the past decade, the transradial approach (TRA) has been increasingly adopted by interventionists and requested by patients as the preferred access route for percutaneous coronary procedures. Its rising popularity derives from its recognized benefits over the transfemoral approach, including improved clinical outcomes by the reduction of vascular and bleeding complications, early patient ambulation, shorter hospital stay, and lower hospital costs.¹ Despite all the demonstrated advantages, radial access feasibility may be compromised in 5-15% of patients.² The failure in TRA can be attributed to the operator learning curve, inability to successfully puncture the radial artery, failure to obtain adequate guide catheter support or advance the catheter to the ascending aorta due to vasospasm, dissection, or anatomic variation of radial and brachial arteries.³ In these circumstances, most operators will commonly attempt a contralateral radial artery or transfemoral approach; however, there might be instances in which a transulnar approach (TUA) may represent a reasonable alternative for the performance of coronary procedures. We present the case of an elderly woman in whom transulnar artery cannulation deemed the only feasible access approach. We describe the technique and rational for implementing TUA as an alternative access site for percutaneous coronary studies.

Case description

A 70-year-old woman with symptomatic severe mitral regurgitation was referred for coronary angiography prior to mitral valve surgery. The patient had history of hypertension, dyslipidemia, severe peripheral vascular disease including a 6.1cm abdominal aortic aneurysm with mural thrombus restricting flow below the aortic bifurcation, recent bilateral critical lower extremities limb ischemia for which she underwent urgent right axillobifemoral bypass graft two months prior to her presentation, and left mastectomy for breast cancer 5 years ago. Pre-surgical cardiothoracic and vascular evaluation included a chest computed tomography (CT) scan angiography that showed pre-occlusive left subclavian stenosis, bovine arch with type II degree of angulation, and a right-sided subclavian conduit intended to the abdomen. Upon arrival to the catheterization laboratory, vascular assessment of the patient revealed absent right radial pulse, palpable right ulnar and brachial pulses, and weak left radial and brachial pulses with an absent left ulnar pulse. Bilateral femoral access was deemed unfeasible (Figure 1). Because noted left subclavian stenosis and the left radial and brachial pulses were not easily palpable, we decided to pursue cannulation of the right ulnar artery (UA). 

Ulnar access technique

Right ulnar pulse was palpable at the level of the pisiform bone. The wrist was hyperextended and the skin was prepared with local anesthesia (1 ml lidocaine 2%) around 1-2cm proximal to the flexor crease skin fold along the path with the most bounding pulsation of the UA. Right ulnar access was obtained using anterior puncture technique with a 20mm bare needle. Access entry site was distal, about 0.5cm proximal to the pisiform bone with the needle angled laterally (Figure 2). After entering the ulnar artery, we placed a 4 French (Fr) sheath. After confirming pulsatile return of blood, we injected nicardipine 250µgm into the sheath to reduce ulnar artery spasm. Immediately thereafter, UA angiography revealed a patent, minimally tortuous UA and an atretic right radial artery. The distal brachial artery appeared intact (Figure 3). Following right ulnar angiography, 4Fr left and right Judkins catheters were advanced under fluoroscopic guidance over a 0.035-inch J-tip wire. Upon entry of the initial catheter into central circulation, intravenous unfractionated heparin (UH) was administered (50-70units/kg, up to 5,000 units). Diagnostic coronary angiography was completed uneventfully. At the conclusion of the procedure, we injected additional nicardipine 250µgm. The sheath was removed and hemostasis was achieved by placing a radial balloon compression device, aligning the balloon 1cm proximal to the access entry in the UA. No neurologic or access site complications were encountered.

Discussion

The transradial approach (TRA) has progressively become the preferred access site for percutaneous coronary procedures worldwide. Regardless of its wide-reaching acceptance, this popular approach confronts a higher failure rate compared to transfemoral approach. Even among exceptionally trained radial operators, crossover rates have been reported to reach up to 2%.⁴ Furthermore, TRA may be limited in a number of conditions, including radial artery occlusion or barely palpable radial pulses as result of repeated TRA procedures⁵ or severe peripheral vascular disease/calcified vessels, as was seen with our patient. 

In our case, the only feasible access options were either a brachial or transulnar approach (TUA). Another challenge was our patient’s history of left mastectomy. Even though we had already decided to respect the left-sided vessels for access as a result of known severe peripheral vascular disease, this is worth mentioning as it is a commonly encountered apprehension in breast cancer survivors, given the historical fear of lymphedema perceived by the patient and the medical staff. To this regard, our group recently demonstrated in a multicenter retrospective cohort that ipsilateral transradial cardiac catheterization can be safely performed in breast cancer survivors without increasing the risk of lymphedema or other vascular arm complications.⁶ 

We debated the options further to determine the more convenient and safest access route as the debate narrowed between right brachial vs ulnar approach. A percutaneous brachial approach to coronary angiography, although perceived as the easiest of the arm approaches, is considered obsolete and only used occasionally when other well-established approaches (e.g. radial, femoral) are not feasible. Hildick-Smith et al demonstrated in their retrospective cohort that percutaneous brachial coronary angiography is a hazardous procedure when undertaken by occasional brachial operators⁷, with an unacceptable high rate (36%) of complications, making it a less desirable alternative in our case. Given that the patient had a strong palpable right ulnar pulse, this appeared to be the safest bailout to cardiac catheterization.

Beyond the rationale of sharing the same efficacy and safety as TRA, TUA has many other anatomical advantages that make it a reasonable wrist access alternative in the lack of available radial access. The UA is a larger caliber vessel with straighter course compared to the radial artery.⁸ This structural feature allows it to be less prone to catheter-induced vasospasm and provides it with the ability to accommodate larger devices for coronary interventions. Despite its lack of tortuosity, from its origin out of the brachial artery (slightly below the bend of the elbow), the UA runs deep in the forearm along the ulnar border until it crosses the anterior and medial aspect of the wrist, where it becomes palpable at the level of the pisiform bone. Because of its deeper course, this vessel is generally less compressible and more difficult to palpate than the radial artery. 

Hyperextending the wrist may facilitate ulnar pulse perception and arterial puncture. As described in our TUA technique, access to the UA should be acquired at its most superficial point (by puncturing the vessel 1-3cm proximal to the pisiform bone) to allow for obtaining appropriate manual or mechanical hemostasis. Another important aspect to highlight when puncturing the UA is the likelihood of producing neural trauma to the ulnar nerve, which runs just lateral (ulnar side of the arm) to the ulnar artery. This access complication can be avoided by entering the vessel laterally. 

A major concern with the TUA approach is achieving appropriate hemostasis and preventing ischemic complications. Hemostasis to the ulnar artery may be safely accomplished by manual compression. In our catheterization laboratory, we use a radial balloon compression device, off label, by aligning the balloon with the ulnar artery. We have not encountered any bleeding or vascular access site complications until this date. TUA has also been reported successful during ipsilateral crossover after a failed TR approach. For these cases, Singh et al reported achieving successful simultaneous hemostasis in both the radial and UA by using a balloon compression device designed with two balloons that align with each wrist artery.⁹ Ischemic injuries have been reported as uncommon to TUA.^2,10 This could be attributed to the reported larger caliber of the ulnar artery^2,9 and dual blood supply to the hand by the radial artery which gives way to the deep palmar arch and the ulnar artery which then branches out into the superficial palmar arch. The palmar arches are functionally valuable arterial connections between their major sources that protect the hand against ischemia if one of the source arteries is occluded. While the deep palmar arch is found to be angiographically complete in 95% of subjects, a complete superficial palmar arch is only seen in 40-80% of people¹¹, suggesting that radial collateral support is more consistently present, making TUA a relatively safe access route. 

Single case reports and a small case series have endorsed the UA access feasibility and safety for coronary procedures.¹⁰ Some authors have even demonstrated that it could be used routinely for percutaneous coronary procedures when performed by dedicated transradial operators.^2,12 However, due to the above-described ulnar structural characteristics, access to this vessel can be difficult for the inexperienced operator. This may explain the findings by Hahais et al, who compared TUA with TRA as a default strategy for coronary procedures and found TUA to be inferior to TRA as a result of the need for cross-over.¹³ Thus the importance of being familiarized with the ulnar artery’s course and appropriate access technique.

In summary, TUA may be considered a safe bailout route to coronary procedures when other well-established access approaches are not feasible. Successful cannulation of the ulnar vessel rests on entering the vessel distally, proximal to the pisiform bone to provide hemostasis support, and laterally to respect its anatomic relation with the ulnar nerve. 

References

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