Transulnar Access for Coronary Angiography and Percutaneous Coronary Intervention

Abstract: The use of transradial access for cardiac catheterization and percutaneous coronary intervention (PCI) has increased substantially in recent years. However, the transradial approach may not be feasible in certain patients. Although the transulnar approach can serve as an alternative approach in these subjects, it is infrequently used. We performed a detailed search of the current literature and identified 21 studies, including randomized controlled trials, case series, and abstract presentations at major conferences. The data reviewed is structured in an organized fashion to provide information on both feasibility and safety of this approach. Transulnar cardiac catheterization was reported in >2400 patients with a success rate exceeding 90% in most studies. The limited in-hospital and short-term clinical outcomes data demonstrate satisfactory safety of this approach in small-to-medium sized investigated cohorts. However, long-term safety and efficacy of this approach need to be further substantiated in large PCI cohorts before endorsing transulnar access as an alternative to transfemoral and transradial approaches in the majority of patients.

J INVASIVE CARDIOL 2014;26(8):404-408

Key words: ulnar artery, arterial access, radial artery, ulnar nerve, Guyton’s canal

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The use of transradial access (TRA) for diagnostic catheterization and percutaneous coronary intervention (PCI) has become popular over the last few years.^1,2 Increased use of TRA compared to transfemoral access is related to patient preference and comfort, low risk of vascular and bleeding complications and better clinical outcomes associated with TRA.^3-6 However, TRA may not be feasible in certain patients (Table 1) with radial artery loops and curvatures, hypoplastic or small diameter radial artery, radial artery spasm, failed radial artery puncture, repeated use of the radial artery, and those patients undergoing bypass surgery with use of radial artery grafts.^7,8 Prior literature suggests diagnostic catheterization and PCI via transulnar access (TUA) is safe and an excellent alternative to TRA.^9-14 In this review, we summarize the available literature and provide a concise and succinct update on the use of TUA for cardiac catheterization and PCI.

Terashima et al were the first to report the feasibility of TUA for diagnostic catheterization more than a decade ago.¹⁰ Shortly thereafter, Dashkoff et al reported the successful use of TUA for PCI in 2 patients.¹¹ Subsequently, several case series and 2 randomized controlled trials have evaluated TUA for diagnostic catheterization and PCI.^12-30 TUA is not routinely taught or practiced even by advanced radial operators. 

Search Strategy and Study Selection

The PUBMED, Cochrane, and EMBASE databases were searched for studies using the key words “ulnar artery catheterization,” “ulnar artery percutaneous coronary intervention,” and “ulnar artery approach.” The search was limited to adult patients and articles published in English. We also searched for references of review articles, editorials, and original studies identified by the original search to find other potentially eligible studies. Major United States, European, and Asian cardiology and interventional meeting publications were also reviewed and pertinent articles were included. The authors independently abstracted and reviewed data from the selected studies. 

We identified 21 studies that addressed TUA for cardiac catheterization and PCI (Table 2).^10-30 Current American College of Cardiology Fellowship/American Heart Association/Society for Cardiovascular Angiography and Interventions  guidelines (2011) do not even mention the potential use of the transulnar route for coronary angiography and intervention.

Technique

Patient preparation. The patient should be counseled about details of TUA and its related complications. The palm should be supported and fixed in a supinated hyperextended position similar to the TRA procedure. A modified Allen’s test using pulse oximetry should be performed to confirm dual arterial flow in the hand. Sedation may be beneficial to negate arterial spasm. 

Arterial access. The puncture is performed proximally to the pisiform bone, in the proximal wrists crease. The ulnar artery is punctured using a 22-gauge needle with either the Modified Seldinger’s technique or Seldinger’s technique. Unlike TRA guided cardiac catheterization, no clear evidence supportive of either of the two approaches exists. However, it is intuitive that with close anatomical relationship of the ulnar artery to ulnar nerve, an anterior wall approach would be preferable. After cannulation of the ulnar artery, a 0.018˝, soft-tip guidewire is introduced, over which a sheath with dilator is advanced. A 4 or 5 Fr sheath is suitable for diagnostic angiography and a 5 or 6 Fr sheath is preferred for PCI. Larger sheaths can also be used, but are rarely needed. Vasodilators like nitroglycerin (200-600 µg) in combination with verapamil (2.5-5 mg) or nicardipine (250-500 µg) are routinely administered intra-arterially to prevent vasospasm. The use of anticoagulation (40-70 U/kg unfractionated heparin) is also standard practice to prevent ulnar artery thrombosis. Right TUA is preferred over left TUA approach in the majority of cases, mainly due to operator familiarity and convenience. However, left TUA is preferred in patients with prior coronary artery bypass surgery. The left TUA is also used in PCI of heavily calcified and tortuous coronaries as it nearly simulates the femoral approach. In a similar manner to TRA, PCI to the RCA will receive more support using left TUA, while right TRA approach is preferred for PCI to the left coronary. 

Coronary angiography. Advancing the wire across the ulnar and brachial arteries could be done by conventional J-wire. In case of even mild resistance, angled-tip glidewire assisted by contrast injections under fluoroscopic guidance will result in safe navigation of the wire. Choice of catheter sizes is similar to TRA. Compared to left TUA, shorter-curve catheters are used to intubate the left coronary ostium using right TUA. Catheter exchanges should be done over a long (240 cm) J-wire. The ulnar sheath should be meticulously flushed with heparinized saline with every catheter exchange. Catheter and wire friction and reduced or absent backflow from the ulnar sheath side-port are clues for severe spasm or thrombosis and should be addressed immediately. Minimizing catheter exchanges and use of a single catheter for evaluating both right and left coronaries is recommended. 

Postprocedure care. Graded compression with light pressure with commercial hemostatic devices used for TRA is recommended after ulnar sheath removal. The compression should also be maintained for the shortest necessary time while allowing ulnar distal flow. In the AURA of ARTEMIS study, several different commercially available hemostatic devices were used.³⁰ In the PCVI-CUBA study, a hemostasis wrap over a gauze pad was used to achieve arterial compression.¹³ After sheath removal and at discharge, the patency of the ulnar artery is assessed by physical examination or pulse oxymetry while occluding the radial artery. Doppler ultrasound can be also used to assess patency; however, routine use of Doppler ultrasound is not current practice. 

Anatomy

The ulnar artery arises from the brachial artery and terminates in the superficial palmar arch. The ulnar artery is the larger of the two terminal branches of the brachial artery, typically originates distal to the bend of the elbow in the cubital fossa and courses obliquely and distally and reaches the medial (ulnar) aspect of the forearm (midway between the elbow and the wrist) and subsequently courses along the ulnar nerve toward the medial aspect of the forearm and crosses the transverse carpal ligament on the radial side of the pisiform bone, and immediately beyond this bone divides into two branches, which enter into the formation of the superficial and deep volar arches. It is best palpable on the anterior and medial aspect of the proximal wrist crease. The ulnar nerve runs medial and parallel to the ulnar artery in the distal forearm and both are encased by the restrictive Guyton’s canal in the wrist. The ulnar artery varies in its origin and course in a significant proportion of cases. Typically, it branches from the brachial artery about 5 to 7 cm distal to the elbow or medial epicondyle. Occasionally, it may emerge directly from the axillary artery proximal to the elbow. Most anatomy reports suggest that the ulnar artery is usually larger in size than the radial artery. Ultrasound-based studies observed no significant differences between the diameter of the two arteries: the radial artery was slightly larger than the ulnar artery in the PCVI-CUBA study¹³ (2.87 ± 0.6 mm vs 2.83 ± 0.9 mm, respectively; P=NS). Chugh et al³¹ reported considerably smaller diameters for both vessels (right ulnar artery size of 1.8 ± 0.3 mm and right radial artery size of 1.9 ± 1.1 mm; P=NS).

Ulnar artery anatomical variations are rare, but can occur and are similar to those seen with the radial artery. Ulnar artery loop and high take-off of the ulnar artery have been described.^2,11

Efficacy and Safety of Transulnar Approach

A current review of literature (Table 2)^10-30 shows limited albeit growing data regarding the efficacy and safety of TUA for cardiac catheterization and PCI. The published experience of TUA is limited to 2406 patients. The majority of these procedures were diagnostic coronary angiographies, while only a small proportion of these patients underwent PCI. Most TUA-guided PCIs were elective procedures, with a small proportion of patients undergoing PCI for acute coronary syndromes. The reported procedural success ranges from 67%-98% in studies that included >100 patients. The sheath sizes used ranged from 4-8 Fr. 

The possible complications related to TUA are summarized in Table 3. Most published studies reported only short-term complications related to TUA cardiac catheterization and PCI. However, the effects of TUA on the vessel itself and long-term complications related to TUA have not been thoroughly studied. Among all published cases, there were 20 large hematomas (0.8%) affecting a substantial part of the arm and 60 local hematomas (2.4%). The definitions of these hematomas were not uniform across all studies. Ulnar artery occlusion was reported in 46 patients (1.9%); however, this may be an underestimation since not all studies used clinical or ultrasound evaluation of ulnar artery patency at follow-up. The majority of these occlusions were asymptomatic. The ulnar artery pseudoaneurysm was reported in 2 patients (0.08%); transient ulnar nerve injury was reported in 4 patients (0.16%); ulnar artery perforation and ulnar artery venous fistula were reported in 1 patient each.

Ulnar artery spasm was also reported in several case series and randomized controlled trials. Reported incidence of ulnar artery spasm has been variable, with a broad range. In the PCVI-CUBA study (randomized controlled trial comparing TRA [215 patients] with TUA [216 patients]), ulnar artery spasm was reported in 8 patients (7.3%) in the TUA group vs 6 patients (5.7%) in the TRA group.¹³ Intraarterial verapamil (2.5 mg) was administered to prevent spasm. In contrast, in the AURA of ARTEMIS study (randomized controlled trial comparing TRA [455 patients] vs TUA [470 patients]), ulnar artery spasm was reported in 78 patients (16.9%) in the TUA group vs 56 patients (12.7%) in the TRA group. All patients in the AURA of ARTEMIS study received 200 µg intraarterial nitroglycerin to prevent spam.³⁰ 

Transradial Approach vs Transulnar Approach

Table 4 summarizes randomized controlled trials concerning TRA and TUA. Two randomized controlled trials have compared TRA and TUA in cardiac catheterization and PCI. The PCVI-CUBA study compared 215 patients randomized to TRA vs 216 patients to TUA. Access-site related events and PCI-related MACE were evaluated at 30 days. Secondary endpoints included procedure and fluoroscopy times. Follow-up ultrasound to evaluate the access site was performed. Successful arterial access was obtained in 93.1% of patients in the ulnar group, and in 95.5% of patients in the radial group (P=NS). There was no significant difference in both efficacy and safety 30-day outcomes.¹³ In the AURA of ARTEMIS study, 455 TRA patients were compared to 470 TUA patients. Vascular events related to access site and also efficacy outcomes at 60-day follow-up were compared. The TUA arm had lower success rates (with higher crossover to TRA) vs the TRA arm. The failure rate difference of 26.34% (95% confidence interval, 11.96%-40.69%; P<.01) in the first interim analysis of the primary outcome resulted in premature termination of the study.³⁰

Discussion

The available evidence suggests that ulnar artery access is feasible for both coronary angiography and intervention. Similar to TRA approach, routine use of vasodilators and anticoagulants to prevent spasm and thrombosis is mandatory in TUA-based diagnostic and interventional procedures. Since the ulnar artery is deeper and in close proximity to the ulnar nerve, ulnar artery puncture (although essentially resembles TRA) requires anterior wall puncture and additional learning curve even for advanced TRA operators. 

In the largest randomized controlled trial available to date (the AURA of ARTEMIS study), the TUA required more punctures and resulted in excessive time to obtain arterial access and increased contrast volume, procedural and fluoroscopy times, and higher crossover rates compared to the TRA. Additionally, in the intention to treat analysis, the composite primary endpoint (MACE and major access-site vascular event), the TUA was significantly inferior compared to the TRA before adjustment for operator clustering. However, after adjustment, the comparison results became inconclusive and non-inferior for the primary endpoint and showed significant inferiority of the TUA only for the higher crossover rates. In contrast, the majority of the other published data suggests that TUA has a high procedural success rate without significant vascular-site complications.

The use of TUA has been mainly studied in patients undergoing cardiac catheterization and in only a small proportion of patients undergoing PCI. Even though PCI was performed in patients with acute coronary syndromes in both randomized controlled trials, the suitability of TUA for complex PCI needs to be further evaluated. Recent data from the randomized controlled trials, comparing TRA to transfemoral approach, in ST-elevation myocardial infarction and acute coronary syndromes without ST elevation demonstrated significant clinical benefit favoring TRA (the RIVAL study showed significantly lower vascular complications favoring TRA vs transfemoral approach; the RIFLE-STEACS study showed significantly lower 30-day bleeding and mortality rates with TRA vs transfemoral approach).^32,33 Even though TUA-based cardiac catheterization and PCI is similar in equipment and approach to transradial route, extrapolation of benefits derived from TRA to TUA is not justifiable at this time.  

Future Research

Future research should focus on: (1) Enabling the operator to determine by ultrasound or other non-invasive tools the preferred arterial wrist access based on diameter, flow, and tortuosity. (2) Imaging or navigation tools to /files/small_8sattu3.pngfacilitate the puncture of the deeper ulnar artery without injury to the ulnar nerve and adjacent structures. (3) Specific devices for optimal hemostasis of ulnar access hemostasis. (4) Tools to indicate when an oversized ulnar sheath within the restrictive Guyton’s canal results in compression of the ulnar nerve. 

Conclusions

The ulnar artery is similar in diameter to the radial artery in most subjects; however, variation in size and dominance between the forearm arteries has important procedural implications. TUA for cardiac catheterization and PCI appears to be an adequate alternative to the TRA in selected cases, especially when transfemoral access is not an option. Although the efficacy and safety of TUA has not been subject to extensive investigation, it appears to be reasonably safe and effective.  

The astute and versatile interventionalist should familiarize himself with the TUA and master the methods to select the better forearm vessel and to conduct seamless access puncture at the optimal access site. 

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From the ¹Division of Interventional Cardiology, New York Methodist Hospital, Brooklyn, New York; ²Division of Cardiology, Robert Packer Hospital, Sayre, Pennsylvania; and ³Division of Cardiology, New Jersey Medical School, Newark, New Jersey.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Kaluski is a consultant for Inspire MD, and reports grants/honoraria from Astra Zenece; grants/speaker’s fees from Jannsen Pharmaceuticals; and travel expenses from Medtronic, unrelated to the content therein. Dr Singh reports a grant from the Guthrie Research Foundation.

Manuscript submitted October 18, 2013, provisional acceptance given November 27, 2013, final version accepted January 30, 2014.

Address for correspondence: Edo Kaluski, MD, FACC, FESC, Director of Cath Lab Robert Packer Hospital & Guthrie Health Systems, 1 Guthrie Square, Sayre PA 18840. Email: ekaluski@gmail.com