Flow Dynamics During Simulated Hemostasis at the Proximal and Distal Radial Arteries (FLOW-PRADA)

Flow Dynamics During Simulated Hemostasis at the Proximal and Distal Radial Arteries: The FLOW-PRADA Study

Transradial access (TRA) has been widely adopted for coronary angiography and percutaneous coronary intervention, as it has been shown to significantly reduce bleeding complications, vascular complications, and mortality compared with transfemoral access (TFA). Based on this evidence, recent international guidelines recommend TRA as the preferred access strategy.

Radial artery occlusion (RAO), a potential complication following TRA, is often clinically silent and therefore underestimated. However, RAO has important clinical implications, particularly in patients who may require repeated coronary procedures, those in whom the radial artery may be used as a conduit for coronary artery bypass grafting, or patients with chronic kidney disease requiring arteriovenous fistula formation. Therefore, maintaining radial artery patency after the procedure is of considerable clinical importance.

Distal radial access (DRA), which utilizes the radial artery at the anatomical snuffbox, is a relatively recent approach. Multiple studies and meta-analyses have demonstrated that DRA provides comparable procedural success rates to TRA while significantly reducing bleeding complications and the incidence of RAO. Notably, despite the generally accepted association between smaller vessel diameter and higher risk of occlusion, DRA paradoxically shows a lower incidence of RAO. The underlying mechanism for this observation remains incompletely understood.

Sgueglia et al. evaluated peak systolic velocity using Doppler ultrasonography under conditions of arterial compression and reported that antegrade blood flow was better preserved during distal radial artery compression compared with proximal radial artery compression. This finding suggests a potential mechanistic explanation for the lower incidence of RAO observed with DRA.

However, there is a paucity of studies that systematically evaluate hemodynamic changes under simulated real-world hemostatic conditions at both proximal and distal radial arteries.

Therefore, the aim of this study is to quantitatively assess hemodynamic changes induced by simulated occlusive hemostasis at the proximal and distal radial arteries using Doppler ultrasonography, and to elucidate the mechanisms underlying the lower incidence of RAO observed with DRA.

Study Overview

• Status: Not yet recruiting
• Conditions: Hemostasis of Arterial Punctures
• Intervention / Treatment: Device: Air-filled hemostatic band

• Study Type: Observational
• Enrollment (Estimated): 220

Contacts and Locations

• Study Contact: Name: Jun-Won Lee, MD, PhD; Email: ljwcardio@yonsei.ac.kr
• Study Contact Backup: Name: Jung-Woo Son; Phone Number: +82-33-741-0910; Email: soneycar@gmail.com

Study Locations

• South Korea
  • Gangwon-do
    • Wŏnju, Gangwon-do, South Korea, 26426
      • WonJu Severance Christian Hospital
      • Contact: Jung-Woo Son, MD; Phone Number: +82-33-741-0920; Email: soneycar@gmail.com
      • Contact: Jun-Won Lee, MD, PhD; Phone Number: +82-33-741-0920; Email: ljwcardio@yonsei.ac.kr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults (≥19 years) scheduled for coronary angiography for atypical chest pain, stable angina, or acute coronary syndrome, undergoing pre-procedural transthoracic echocardiography, with palpable proximal and distal radial arteries; excluding those with cardiogenic shock, prior distal radial coronary angiography before echocardiography, inability/refusal to consent, ipsilateral arteriovenous fistula, or pregnancy/breastfeeding.

Description

Inclusion Criteria:

A. Adults aged ≥19 years B. Patients scheduled for coronary angiography due to atypical chest pain, stable angina, or acute coronary syndrome C. Patients undergoing transthoracic echocardiography for assessment of cardiac function prior to coronary angiography D. Palpable proximal and distal radial arteries

Exclusion Criteria:

A. Cardiogenic shock B. Patients who have undergone coronary angiography via distal radial access prior to echocardiographic evaluation C. Refusal or inability to provide informed consent D. Presence of an ipsilateral arteriovenous fistula E. Pregnant or breastfeeding women

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patent hemostasis of distal radial artery; Patent hemostasis of distal radial artery using TR band	Device: Air-filled hemostatic band; Simulated patent hemostasis using air-filled TR band
Patent hemostasis of proximal radial artery; Patent hemostasis of proximal radial artery using TR band	Device: Air-filled hemostatic band; Simulated patent hemostasis using air-filled TR band

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in end-diastolic velocity	Difference in end-diastolic velocity between proximal and distal radial arteries during patent hemostasis by Doppler ultrasound	Periprocedural

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Flow preservation ratio	Flow preservation ratio in proximal and distal radial arteries	Periprocedural
Blood flow volume	Blood flow volume in proximal and distal radial arteries	Periprocedural
Flow volume per beat	Flow volume per beat in proximal and distal radial arteries	Periprocedural
Pulsatility index	Pulsatility index in proximal and distal radial arteries	Periprocedural
Resistance index	Resistance index in proximal and distal radial arteries	Periprocedural
Peak systolic velocity	Peak systolic velocity in proximal and distal radial arteries	Periprocedural
Velocity time integral	Velocity time integral in proximal and distal radial arteries	Periprocedural
Radial artery occlusion	Radial artery occlusion	up to 1 month

Collaborators and Investigators

• Sponsor: Wonju Severance Christian Hospital
• Collaborators: Whanin Pharmaceutical Company
• Investigators: Principal Investigator: Jung-Woo Son, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: June 24, 2026
• First Submitted That Met QC Criteria: July 1, 2026
• First Posted (Actual): July 6, 2026

Study Record Updates

• Last Update Posted (Actual): July 6, 2026
• Last Update Submitted That Met QC Criteria: July 1, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Hemostasis; Distal radial access
• Other Study ID Numbers: CR326050

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No