Transulnar Access in Patients With Ipsilateral Radial Artery Occlusion Undergoing Coronary Angiography or Angioplasty (ULNART)

January 28, 2026 updated by: Karelas Dimitrios, National and Kapodistrian University of Athens

Transulnar Access in Patients With Ipsilateral Radial Artery Occlusion Undergoing Coronary Angiography or Angioplasty: Safety and Effect on Hand Function (ULNART)

Coronary angiography and angioplasty are commonly performed through the radial artery at the wrist as this approach is associated with fewer bleeding complications and faster recovery. In some patients, the radial artery becomes occluded after prior procedures, requiring selection of an alternative access site for future coronary interventions.

The ulnar artery is a potential alternative wrist access. However, limited data are available on the safety of using the ulnar artery in the same arm as an occluded radial artery and on the possible effects on hand strength, sensation, and daily hand function.

The goal of this observational study is to evaluate the safety of transulnar access and its effect on hand function in adults with ipsilateral radial artery occlusion undergoing coronary angiography or angioplasty.

The main questions addressed by the study are:

  • How often do serious access-related vascular or nerve complications occur?
  • Does hand strength, sensation, or functional use of the hand change during follow-up?
  • Does the ulnar artery remain patent after the procedure? The choice of vascular access site is made by the treating physician based on clinical judgment. Participants who undergo transulnar access will undergo follow-up assessments, including ultrasound evaluation of arm arteries, standardized hand function testing, and short questionnaires assessing upper-limb function.

The findings of this study are expected to inform access-site selection, improve patient counseling, and support safer care for patients with radial artery occlusion undergoing coronary procedures.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Transradial access is the preferred approach for coronary angiography and angioplasty because it is associated with reduced bleeding complications and faster recovery compared with femoral access. Radial artery occlusion is a recognized complication of transradial procedures and may limit future use of this access site. In patients with radial artery occlusion, selection of an alternative vascular access is required, particularly when preservation of the contralateral radial artery is clinically important.

The ulnar artery represents an anatomically plausible alternative upper-limb access route, contributing substantially to hand perfusion through the palmar arterial network. However, concerns remain regarding the vascular and functional safety of transulnar access, especially when used ipsilateral to a pre-existing radial artery occlusion. Available evidence is limited and methodologically heterogeneous, with inconsistent assessment of vascular integrity and hand function.

ULNART is a prospective observational cohort designed to evaluate the safety and functional outcomes of transulnar arterial access in patients with ipsilateral radial artery occlusion undergoing coronary angiography or angioplasty. Vascular access selection is determined by the treating physician and is not assigned by the study protocol. The study observes outcomes following transulnar access without influencing procedural decision-making.

Participants undergo standardized baseline and follow-up assessments integrating vascular imaging, objective neuromuscular testing, and patient-reported outcome measures. Color duplex ultrasonography is used to assess upper-limb arterial anatomy and ulnar artery patency, while hand function is evaluated using quantitative strength testing, sensory assessment, and validated questionnaires addressing upper-limb function and cold sensitivity. Assessments are repeated shortly after the procedure and at predefined later time points to evaluate recovery and detect early or delayed access-related effects.

The primary objective is to estimate the incidence of serious access-related vascular and clinical neuromuscular complications. Secondary objectives include characterization of ulnar artery patency, changes in hand strength and sensory function over time, patient-reported functional outcomes, and identification of factors associated with adverse events. Data are collected prospectively using standardized protocols and analyzed according to a prespecified statistical analysis plan appropriate for an observational cohort.

The results of ULNART are expected to provide systematic evidence on the vascular safety and functional impact of transulnar access in patients with radial artery occlusion, supporting informed access-site selection and patient counseling when transradial access is unavailable or clinically undesirable.

Study Type

Observational

Enrollment (Estimated)

127

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Konstantinos Aznaouridis, Ass. Professor of Cardiology
  • Phone Number: +30 697 2024534
  • Email: conazna@yahoo.com

Study Locations

  • Greece
      • Athens, Greece
        • Recruiting
        • Hellenic Red Cross Hospital
        • Contact:
      • Athens, Greece
        • Recruiting
        • Hippokratio General Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Participants are recruited from cardiac catheterization laboratories and cardiology services of two tertiary-care public hospitals in Greece, including high-volume referral centers performing invasive coronary procedures. The study population represents adults undergoing routine elective coronary angiography or angioplasty in these hospital settings, where vascular access decisions are made as part of standard clinical practice.

Description

Inclusion Criteria

Participants must meet all of the following criteria to be eligible:

  • Adults aged 18 years or older
  • Documented radial artery occlusion in the upper limb intended for vascular access, confirmed by ultrasound or angiography
  • Scheduled to undergo elective coronary angiography and/or angioplasty
  • Transulnar arterial access on the same side as the occluded radial artery is selected by the treating physician
  • Contralateral radial artery access is not feasible or is clinically undesirable, including for reasons such as:
  • documented occlusion or severe disease of the contralateral radial artery
  • unfavorable anatomy or prior failed access
  • strategic preservation of the contralateral radial artery for future surgical or dialysis needs
  • Adequate ulnar artery flow and anatomy for access, as assessed by pre-procedural ultrasound
  • Able and willing to provide written informed consent

Exclusion Criteria

Participants meeting any of the following criteria will be excluded:

  • Inadequate or absent ulnar artery flow at the intended access site on ultrasound
  • Known ulnar nerve injury or neuropathy affecting the access-side upper limb
  • Severe pre-existing motor or sensory dysfunction of the access-side hand that would interfere with functional assessment
  • Emergency coronary procedures that preclude baseline vascular or functional assessment
  • Participation in another interventional clinical study involving vascular access or intervention in the same upper limb
  • Local conditions at the intended access site, such as active infection, burn, or extensive scarring
  • Pregnancy or breastfeeding
  • Life expectancy less than 6 months

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
ULNART Cohort
Adults with documented radial artery occlusion undergoing elective coronary angiography or angioplasty, in whom transulnar arterial access ipsilateral to the occluded radial artery is selected by the treating physician. Participants are followed prospectively to assess vascular safety and hand function outcomes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Serious Access-Related Vascular and Clinical Neuromuscular Complications
Time Frame: 30 days
Composite incidence of serious vascular and clinical neuromuscular complications attributable to transulnar arterial access ipsilateral to radial artery occlusion. Serious vascular events include acute hand ischemia, symptomatic ulnar artery occlusion, flow-limiting dissection requiring treatment, pseudoaneurysm or arteriovenous fistula requiring intervention, major access-site hematoma, or major bleeding. Clinical neuromuscular events include new, clinically evident motor or sensory deficits in the ulnar nerve distribution that persist or require targeted therapy.
30 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Access Attempts
Time Frame: During the index procedure
Number of puncture attempts required to obtain successful vascular access
During the index procedure
Technical Success Without Access-Site Crossover
Time Frame: During the index procedure
Successful completion of coronary angiography or angioplasty via intended transulnar access without conversion to an alternative vascular access site.
During the index procedure
Procedure Duration
Time Frame: During the index procedure
Total procedural time from vascular access to sheath removal
During the index procedure
Ulnar Artery Patency
Time Frame: Within 24 hours, 30 days, and 180 days
Assessment of ulnar artery patency and flow characteristics using color duplex ultrasonography, including presence of antegrade flow and absence of occlusion or flow-limiting abnormalities.
Within 24 hours, 30 days, and 180 days
Early Access-Related Vascular and Neuromuscular Complications
Time Frame: Within 24 hours after band removal
Incidence of access-related vascular and neurologic complications occurring within 24 hours after removal of the hemostatic device, including minor bleeding, hematoma, reversible neurologic symptoms, and access-site findings not meeting criteria for the primary endpoint.
Within 24 hours after band removal
Change in Handgrip Strength
Time Frame: Within 24 hours, 30 days, and 180 days
Change from baseline in handgrip strength of the access-side hand measured with a calibrated dynamometer.
Within 24 hours, 30 days, and 180 days
Change in Key Pinch Strength
Time Frame: Within 24 hours, 30 days, and 180 days
Change from baseline in key (lateral) pinch strength of the access-side hand measured with a calibrated pinch gauge.
Within 24 hours, 30 days, and 180 days
Change in Sensory Function
Time Frame: Within 24 hours, 30 days, and 180 days
Change from baseline in tactile sensation of the ulnar nerve distribution assessed using standardized light-touch threshold testing.
Within 24 hours, 30 days, and 180 days
Change in Patient-Reported Upper-Limb Function
Time Frame: 10 days, 30 days and 180 days
Change from baseline in patient-reported upper-limb function assessed using validated questionnaires evaluating disability and cold sensitivity.
10 days, 30 days and 180 days
Late Vascular or Neuromuscular Complications
Time Frame: 6 months
Incidence of vascular or neurologic complications occurring beyond 30 days that do not meet primary endpoint criteria.
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National and Kapodistrian University of Athens

Investigators

  • Principal Investigator: Konstantinos Aznaouridis, Ass. Professor of Cardiology, 1st Department of Cardiology, Hippokration Hospital, National and Kapodistrian University of Athens
  • Principal Investigator: Dimitrios Karelas, MD, National and Kapodistrian University of Athens
  • Principal Investigator: Ioannis Tsiafoutis, MD, PhD, 2nd Department of Cardiology, Hellenic Red Cross Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 1, 2025

Primary Completion (Estimated)

January 1, 2030

Study Completion (Estimated)

January 1, 2032

Study Registration Dates

First Submitted

January 21, 2026

First Submitted That Met QC Criteria

January 28, 2026

First Posted (Actual)

February 2, 2026

Study Record Updates

Last Update Posted (Actual)

February 2, 2026

Last Update Submitted That Met QC Criteria

January 28, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 21171-01/12/2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data that underlie the results reported in publications arising from this study will be made available, including demographic variables, procedural characteristics, vascular imaging findings, functional test results, and patient-reported outcome measures. A corresponding data dictionary and study protocol will be provided. Data will be shared after publication of the primary results, upon reasonable request, subject to approval by the study investigators and completion of a data-use agreement, in accordance with applicable ethical approvals and data protection regulations.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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