Comparing standard and high doses of heparin to prevent radial artery occlusion

Standard vs High Dose of Unfractionated Heparin in the Incidence of Radial Artery Occlusion (DEFINITION) Trial.

Not applicable Interventional Instituto Nacional de Cardiologia Ignacio Chavez · NCT04561648

This study tests if using a higher dose of heparin can better prevent blockage of the radial artery during heart procedures compared to the standard dose.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment1988 (estimated)
Ages18 Years and up
SexAll
SponsorInstituto Nacional de Cardiologia Ignacio Chavez Academic / other
Locations1 site (Mexico City, Tlalpan)
Trial IDNCT04561648 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to compare the effectiveness of standard doses of Unfractionated Heparin (UFH) against high doses in preventing radial artery occlusion (RAO) during transradial access for coronary angiography. It is a double-blind, single-center study involving patients over 18 years who undergo elective diagnostic procedures. The trial will utilize Doppler ultrasound to assess the incidence of RAO within 24 hours post-procedure. The goal is to determine if higher doses of UFH can significantly reduce the occurrence of RAO compared to the standard dose.

Who should consider this trial

Good fit: Ideal candidates are adults over 18 years who are undergoing elective diagnostic coronary angiography via transradial access.

Not a fit: Patients with recent anticoagulant use, significant bleeding history, or anatomical issues at the radial access site may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved protocols for preventing radial artery occlusion, enhancing patient outcomes during coronary interventions.

How similar studies have performed: Previous studies have suggested that higher doses of UFH may reduce RAO incidence, but this is the first proper prospective clinical trial to investigate this hypothesis.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients over 18 years of age, both genders.
* Successful transradial acess for an elective diagnostic coronary angiography.

Exclusion Criteria:

* Weight \<50 Kg
* Puncture of the ipsilateral radial artery in the last month.
* Still ongoing effect of pre-procedural recently used oral anticoagulants.
* Use of enoxaparin in the past in the last 12 hours prior to the procedure.
* Use of unfractionated heparin in the last 6 hours prior the procedure
* Alterations in coagulation or platelets prone to bleeding or thrombotic complications.
* Anatomical alterations at the radial access site or radial artery.
* Arteriovenous fistula in the ipsilateral arm.
* History of major bleeding associated with the use of UFH.

Where this trial is running

Mexico City, Tlalpan

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Radial Artery OcclusionPercutaneous coronary interventionTransradial accessUnfractionated HeparinCoronary angiography
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.