Serpentine vs Traditional Hydrophilic Guidewire Tracking in Complex Radial Anatomy (S-TRACK)

July 15, 2026 updated by: Grigorios Tsigkas, University Hospital of Patras

Comparison of the "Serpentine" Technique Versus Hydrophilic Guidewire 0,035'' for Navigating Radial and Brachial Artery Loops, Tortuosity and Sharp Angulation During Transradial Access.

Coronary angiography and angioplasty are commonly performed through the radial artery. In some patients, anatomical variations of the radial and brachial arteries, such as loops, increased tortuosity or sharp angulations may pose challenges to equipment advancement.

Both the hydrophilic guidewire 0,035'' approach and the "Serpentine" technique have been described in the literature as techniques for overcoming radial anatomical challenges, with the hydrophilic guidewire approach being the more commonly used method.

In practical terms, both techniques involve the use of the same standard materials, with differences relating mainly to operator handling and technical manipulation. This study does not introduce any experimental device, material, or treatment; instead, it aims to compare the established approach using a 0.035'' hydrophilic guidewire with the emerging " Serpentine" technique with respect to effectiveness, procedural time, and safety.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Transradial access (TRA) has become the preferred approach for diagnostic coronary angiography and percutaneous coronary intervention (PCI), compared with transfemoral access (TFA). Contemporary guidelines on revascularization in both chronic and acute coronary syndromes (ACS) recommend TRA as the first-line strategy, primarily due to its reduced risk of complications.

Additional advantages of TRA include improved cost-effectiveness, shorter intensive care unit stay, shorter overall hospitalization, faster patient mobilization, and greater patient comfort. TRA has also been associated with reduced contrast use and a lower risk of contrast-induced acute kidney injury.

Despite its advantages, TRA has limitations. It is associated with a modest increase in radiation exposure. A key drawback is the need for crossover to another access site, which is relatively common; however, this can be mitigated by operator experience and ultrasound guidance.

Anatomical variants are a major cause of procedural failure and crossover, occurring in 9-23% of patients. The most frequent variants include high origin of the radial artery from the brachial artery, arterial loops, and tortuosity of the radial or subclavian artery. Radial artery loops and severe tortuosity, observed in 4.2-13,1% of cases, are strongly associated with procedural failure (3.8-50%) and increased crossover rates. These anatomical challenges prolong procedural time, increase radiation exposure, and raise the risk of vascular complication.

Several techniques have been proposed to overcome these challenges. The most commonly adopted is the use of hydrophilic guidewires. Other techniques include mechanical straightening of tortuous segments from the operator, the use of angioplasty guidewires, microcatheters, balloon-assisted tracking (BAT), pigtail-assisted tracking (PAT), or switching to ulnar, transfemoral, or contralateral radial access.

Preservation of the transradial approach is critical, as it reduces complications, facilitates faster mobilization, and shortens hospital stay. The most common cause of TRA failure is the presence of loops and tortuosity in the radial or brachial artery. To date, no randomized trials have directly compared different strategies for overcoming these challenges. The novel "Serpentine" technique, which will be compared against the widely used "0.035" hydrophilic guidewire, could become an additional tool for interventional cardiologists-providing a reliable method for crossing loops and tortuous segments, with reduced equipment use and comparable outcomes in terms of procedure time, radiation exposure, contrast use, and local complications.

The aim of this study is to compare the efficacy and safety of the novel "Serpentine" technique with that of hydrophilic guidewires in navigating radial and brachial artery loops and tortuosity during coronary angiography and PCI via TRA.

The S-TRACK Trial will be designed as a prospective, randomized, controlled, non-inferiority study. Consecutive eligible patients undergoing coronary angiography via transradial access, and not meeting any exclusion criteria, will be screened for enrollment. After successful radial artery cannulation, patients who demonstrate resistance to guidewire or catheter advancement will undergo radial and/or brachial angiography to identify the underlying anatomical cause. Participants with angiographically confirmed anatomical variants-specifically loops, pronounced tortuosity, or sharp angulations-will be considered eligible. Once the variant is confirmed, and oral consent provided, patients will be randomized in a 1:1 ratio to arterial navigation using either the standard hydrophilic 0.035'' guidewire-first technique or the Serpentine technique. At the end of the procedure informed consent will be signed. The study will involve operators-interventional cardiologists who will have been trained in the technique.

Baseline demographic, clinical, and laboratory parameters will be recorded, including age, sex, medical history, and indications for angiography. Additionally, the anatomical location of the loop or tortuosity will be recorded.

Study Type

Interventional

Enrollment (Estimated)

204

Phase

  • Not Applicable

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 Locations

  • Greece
      • Pátrai, Greece, 26504
        • Recruiting
        • University Hospital of Patras
        • 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

Description

Inclusion Criteria:

  • Age ≥18 years
  • Feasibility of TRA
  • Indication for coronary angiography
  • Angiographic documentation of radial or brachial artery loop/tortuosity
  • Written informed consent

Exclusion Criteria:

  • STEMI - high risk NSTEMI presentation
  • Hemodynamic instability
  • Anatomical contraindications (e.g., arteriovenous fistula)
  • Significant calcification of the radial or brachial artery on angiographic evaluation.

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Serpentine Technique
Participants will undergo transradial navigation of radial or brachial artery loops, tortuosity, or sharp angulation using the Serpentine catheter manipulation technique to facilitate coronary angiography or PCI.
Procedure: Serpentine Technique
Catheter-based navigation technique using controlled rotational catheter manipulation to cross radial or brachial artery loops, tortuosity, or sharp angulation during transradial coronary angiography or PCI.
Active Comparator: Hydrophilic Technique
Participants will undergo transradial navigation of radial or brachial artery loops, tortuosity, or sharp angulation using a standard 0.035-inch hydrophilic guidewire to facilitate coronary angiography or PCI.
Procedure: Hydrophilic Technique
Navigation of radial or brachial artery loops, tortuosity, or sharp angulation using a 0.035-inch hydrophilic guidewire during transradial coronary angiography or PCI.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Successful crossing of anatomical obstacles and procedure completion
Time Frame: During coronary angiography/PCI procedure, assessed up to 3 hours
Successful crossing of radial/brachial artery loops or tortuosity with completion of coronary angiography or PCI.
During coronary angiography/PCI procedure, assessed up to 3 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total procedure time
Time Frame: During index procedure, assessed up to 3 hours.
Total procedure time until completion of coronary angiography or PCI.
During index procedure, assessed up to 3 hours.
Fluoroscopy time
Time Frame: During index procedure, assessed up to 3 hours.
Total fluoroscopy time measured during coronary angiography or PCI.
During index procedure, assessed up to 3 hours.
Radiation exposure
Time Frame: During index procedure, assessed up to 3 hours.
Cumulative radiation dose assessed by Air Kerma and Dose Area Product (DAP) during the procedure.
During index procedure, assessed up to 3 hours.
Contrast volume used
Time Frame: During index procedure, assessed up to 3 hours.
Total contrast medium volume used during coronary angiography or PCI.
During index procedure, assessed up to 3 hours.
Success rate of loop access per technique
Time Frame: During index procedure, assessed up to 3 hours.
Successful navigation of radial or brachial artery loops or tortuosity using the assigned technique.
During index procedure, assessed up to 3 hours.
Number of guidewires used
Time Frame: During index procedure, assessed up to 3 hours.
Total number of guidewires used during the procedure.
During index procedure, assessed up to 3 hours.
Number of catheters used
Time Frame: During index procedure, assessed up to 3 hours.
Total number of catheters used during coronary angiography or PCI.
During index procedure, assessed up to 3 hours.
Radial artery spasm
Time Frame: During index procedure, assessed up to 3 hours.
Occurrence of radial artery spasm during the procedure.
During index procedure, assessed up to 3 hours.
Procedure-related symptoms
Time Frame: During index procedure, assessed up to 3 hours.
Pain (VAS 0-10), paresthesia, or paresis occurring during the procedure.
During index procedure, assessed up to 3 hours.
Access-site vascular complications
Time Frame: From procedure completion until discharge, assessed up to 7 days
Occurrence of post-procedural hematoma (EASY scale), pseudoaneurysm, arterial dissection, or compartment syndrome.
From procedure completion until discharge, assessed up to 7 days

Collaborators and Investigators

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

Sponsor

University Hospital of Patras

Investigators

  • Principal Investigator: Grigorios Tsigkas, MD, PhD, University Hospital of Patras

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)

May 14, 2026

Primary Completion (Estimated)

May 1, 2029

Study Completion (Estimated)

November 1, 2029

Study Registration Dates

First Submitted

July 6, 2026

First Submitted That Met QC Criteria

July 15, 2026

First Posted (Actual)

July 16, 2026

Study Record Updates

Last Update Posted (Actual)

July 16, 2026

Last Update Submitted That Met QC Criteria

July 15, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 397/7-10-2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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