NCT06922695: RESPOND-AF

Responding to AF: Pill-in-Pocket Anticoagulation Guided by Automated Monitoring and Alerts

Recruiting now NA Last updated 23 April 2025

What this trial tests

NA trial testing Pill-in-pocket anticoagulation in Atrial Fibrillation (AF) in 50 participants. Currently enrolling.

Timeline

14 April 2025

Primary endpoint
15 April 2027

15 April 2027

Quick facts

Lead sponsor	Oxford University Hospitals NHS Trust
Phase	NA
Status	Recruiting now
Study type	INTERVENTIONAL
Allocation	na
Design	single group
Masking	none
Primary purpose	treatment
Enrollment	50
Start date	14 April 2025
Primary completion	15 April 2027
Estimated completion	15 April 2027
Sites	1 location across United Kingdom

Drugs / interventions tested

• Pill-in-pocket anticoagulation

Conditions studied

• Atrial Fibrillation (AF) — all drugs for Atrial Fibrillation (AF) →
• Atrial Fibrillation (Prevention of Stroke) — all drugs for Atrial Fibrillation (Prevention of Stroke) →

Sponsor

Oxford University Hospitals NHS Trust

Who can join

18 and older, any sex, with Atrial Fibrillation (AF) or Atrial Fibrillation (Prevention of Stroke). Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting 1-2 million people in the UK. AF is characterised by uncoordinated electrical activation and ineffective contraction of the upper cardiac chambers. AF can occur in temporary episodes, as in paroxysmal AF, or can be sustained continuously beyond 7 days' duration, as in persistent AF.

The most significant potential complication of AF is stroke caused by a blood clot (thromboembolic stroke). If untreated, the risk of stroke in AF can be increased as much as five-fold, depending on the presence of other risk factors.

The mechanism of thromboembolic stroke in AF patients is complicated and understanding of factors involved remains incomplete. AF has been shown to disrupt normal bodily mechanisms for controlling bleeding and clotting (haemostasis) and normal blood flow inside the cardiac chambers. In disrupting these mechanisms, AF can be said to create a 'prothrombotic' state or environment within the blood and heart (a tendency to form clots) which can lead to blood clot formation and subsequently to stroke.

There is research evidence that AF-related stroke risk is not fixed and changes over time. This dynamic risk may be related to the episodic nature of AF, with stroke risk changing during an episode of AF and for a period of weeks after the episode terminates.

Analytic studies have shown that the risk of stroke is highest in the days after an AF episode has occurred, peaking at 5 days and returning to baseline by 30 days. Other studies have shown that the duration of the AF episode can also influence the risk of stroke following each episode, with longer episodes being higher risk.

This dynamic risk likely relates to changes in the activation of the body's blood-clotting system and changes in blood flow within the heart.

Current clinical guidelines recommend that patients with AF and risk factors for stroke are treated with daily, uninterrupted anticoagulation (blood-thinning medication) to reduce the risk of stroke. These guidelines do not take into account the temporal pattern of AF or the frequency or duration of AF episodes.

An emerging approach to anticoagulation in AF is pill-in-pocket oral anticoagulation (PIPOAC). In this approach, AF patients only take their anticoagulation in response to episodes of AF, and for a period of time after normal heart rhythm is restored. This approach may suit AF patients who have lower risk, lower frequency AF and who wish to reduce their exposure to anticoagulation medication. It may also suit AF patients who have higher bleeding risk related to anticoagulation.

The RESPOND-AF study proposes a novel approach to delivering PIPOAC. It is a pilot study of this novel approach recruiting 50 participants. This includes participants having continuous heart rhythm monitoring using the Medtronic LINQ II implantable cardiac monitor. The LINQ II continuously monitors for evidence of AF. If AF is detected a transmission is uploaded to the Medtronic Carelink cloud portal.

Traditionally, healthcare professionals need to sign in to this portal to check for any transmissions. For the purposes of PIPOAC this traditional approach would be too slow and create a burdensome workload for clinicians. Due to the properties of blood clot formation in AF, it is important to initiate oral anticoagulation within 48 hours of AF episode onset to disrupt the clot-formation process.

For the purposes of this study, the investigators have developed a custom-designed software which continuously screens for transmissions of AF on the Carelink cloud portal. When an AF episode has been detected by the LINQ II monitor, the software will send an SMS smartphone alert to the patient informing them of the AF episode and instructing them to commence their oral anticoagulation as soon as possible. This approach, if shown to be safe and effective and acceptable to patients, could open the path to wider use of Pill-in-pocket oral anticoagulation.

This novel treatment can reduce the need for anticoagulation, meaning fewer bleeding complications. Pill-in-pocket oral anticoagulation empowers patients by offering a new treatment choice beyond current limited options.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. Discontinuation of Oral Anticoagulation After Successful Atrial Fibrillation Ablation - Are We Ready to Change Clinical Practice in 2026?
   Momot K, Surma S, Krauz K, Pruc M, et al · · 2026 · PMID 42098992 · DOI 10.12659/msm.952757