An interventional study of Serpentine Technique and Hydrophilic Technique in Transradial Access(TRA), Coronary Angiography (CAG) and Percutaneous Coronary Intervention (PCI), sponsored by University Hospital of Patras. Recruiting at 1 site in Greece. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-16.
Sponsored by University Hospital of Patras · Not applicable, Interventional, and Treatment
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.
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.
University Hospital of Patras is the lead sponsor of 43 studies on the registry; 11 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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.
Navigation of radial or brachial artery loops, tortuosity, or sharp angulation using a 0.035-inch hydrophilic guidewire during transradial coronary angiography or PCI.
Successful crossing of anatomical obstacles and procedure completion
Successful crossing of radial/brachial artery loops or tortuosity with completion of coronary angiography or PCI.
Time frame: During coronary angiography/PCI procedure, assessed up to 3 hours
Total procedure time
Total procedure time until completion of coronary angiography or PCI.
Time frame: During index procedure, assessed up to 3 hours.
Fluoroscopy time
Total fluoroscopy time measured during coronary angiography or PCI.
Time frame: During index procedure, assessed up to 3 hours.
Radiation exposure
Cumulative radiation dose assessed by Air Kerma and Dose Area Product (DAP) during the procedure.
Time frame: During index procedure, assessed up to 3 hours.
Contrast volume used
Total contrast medium volume used during coronary angiography or PCI.
Time frame: During index procedure, assessed up to 3 hours.
Success rate of loop access per technique
Successful navigation of radial or brachial artery loops or tortuosity using the assigned technique.
Time frame: During index procedure, assessed up to 3 hours.
Number of guidewires used
Total number of guidewires used during the procedure.
Time frame: During index procedure, assessed up to 3 hours.
Number of catheters used
Total number of catheters used during coronary angiography or PCI.
Time frame: During index procedure, assessed up to 3 hours.
Radial artery spasm
Occurrence of radial artery spasm during the procedure.
Time frame: During index procedure, assessed up to 3 hours.
Procedure-related symptoms
Pain (VAS 0-10), paresthesia, or paresis occurring during the procedure.
Time frame: During index procedure, assessed up to 3 hours.
Access-site vascular complications
Occurrence of post-procedural hematoma (EASY scale), pseudoaneurysm, arterial dissection, or compartment syndrome.
Time frame: From procedure completion until discharge, assessed up to 7 days
Plan to share: No
Started May 2026 (actual). Primary completion is estimated for May 2029, 36 months after the start.
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University Hospital of Patras