Distal radial access (DRA) in the anatomical snuffbox (AS) is a relatively novel approach that can be considered an alternative to trans radial access (TRA) for coronary procedures. Several observational and randomized studies have established its feasibility and safety, with evidence of certain advantages over TRA, such as a reduction in hemostasis time, a lower incidence of complications at the puncture site, and a lower incidence of radial artery occlusion (RAO). Notwithstanding that a recent randomized study reported a similar RAO rate between DRA and TRA, several meta-analyzes confirm the advantages of DRA, despite a consistently higher crossover rate.

The objective of this observational study is to assess the performance of the procedure and to compare clinical characteristics in an all-comer population undergoing diagnostic or interventional coronary procedures.

The main questions it aims to answer are:

• Determine the success rate of DRA and measure the incidence of RAO in an all-comer population undergoing coronary procedures.
• Compare the clinical and anatomical characteristics of patients with DRA for coronary procedures and determine predictors of failure of access.

Introduction In recent decades, trans radial access (TRA) through the proximal radial artery has become the standard access site for performing diagnostic and therapeutic coronary procedures, its advantages over trans femoral access being demonstrated through multiple studies. such as reduction in access site complications and even reduction in mortality, especially in higher-risk patients.

There are circumstances in which anatomical variants can limit the clinical benefits of TRA, generating complications such as radial artery occlusion (RAO), which is by far the most frequent complication of this access, with a higher incidence at 24 h and recanalization after 30 days in 50% of patients. The presence of RAO limits access to future procedures, if necessary. The incidence of RAO reported in experienced centers remains high.

Distal Radial Access (DRA) through the anatomical snuffbox of the hand is a technique that has emerged in recent years and has been consolidated in multiple multicenter studies and meta-analyses to obtain arterial access in patients undergoing coronary angiography. and coronary intervention, which reduces the incidence of RAO, in addition to reducing hemostasis times, favoring patient and operator comfort compared to TRA.

DRA requires a slightly higher learning curve than TRA due to certain anatomical characteristics, such as the size of the distal radial artery, its depth, the presence of tortuosities, and the specific anatomical structures surrounding it. The DRA technique initially described was based on anatomical references (conventional puncture), however, the introduction of ultrasound as a puncture tool allows the operator to identify the size and course of the artery, in addition to a better assessment of the anatomy of the artery. area, thus avoiding injuries to them.

Most of the registries and clinical trials conducted to date are single centers, so the conduct of collaborative studies is of interest to determine the usefulness of different types of arterial access in coronary procedures.

OBJECTIVES Compare the clinical and procedural characteristics of patients undergoing diagnostic or therapeutic coronary procedures using DRA.

PRIMARY OBJECTIVE

1. Determine the success rate of DRA and measure the incidence of RAO.

SECONDARY OBJECTIVES

1. Compare the clinical (such as sex, age, weight, etc.) and anatomical characteristics (size of the proximal and distal radial artery size, depth of the distal radial artery) of patients with DRA.
2. Compare the time spent obtaining arterial access using DRA.
3. Assess the characteristics of the DRA procedure.
4. Assess the usefulness of ultrasound evaluation of the radial artery prior to DRA and US-guided DRA.
5. Investigate the predictors of failure for DRA.
6. Calculate the incidence of local complications related to DRA, radial spasm, puncture site hematoma, RAO, and presence of pseudoaneurysm of the radial artery.
7. Assess the operator's and patient comfort based on access.

STUDY DESIGN Prospective cohort of patients undergoing diagnostic or therapeutic coronary intervention, performed at the University Hospital Arnau de Vilanova in Lleida and open to other centers.

Inclusion criteria:

• Patients who have undergone diagnostic or therapeutic coronary procedures using DRA in any clinical setting.
• Patients over 18 years of age.
• Presence of distal radial pulse.
• The Barbeau test was recommended but not mandatory.

Exclusion criteria:

• Previously known allergy to iodinated contrast and inability to receive premedication.
• Absence of distal radial pulse and distal radial artery not feasible by ultrasound.
• Women with the possibility of being pregnant.
• Inclusion in other clinical trials or registries.

Cohort of patients who underwent diagnostic and therapeutic coronary procedures in an all-comer population using DRA between August 2020 and December 2025.

After anonymization, all data collected during the study could be shared. Data obtained through this study may be provided to qualified researchers with academic interest in cardiovascular diseases. The approval of the request and the execution of all applicable agreements are prerequisites for the sharing of data with the requesting party.

Data will be available from the publication of the study until 2 years later.

The data will be shared with people interested in distal radial access through the contact email.