UK Cardiology Trials Face Recruitment Challenges, Seek Diversity

Two significant cardiology trials in the United Kingdom, the BRITISH study and CRAAFT-HF, are reportedly struggling to meet their patient recruitment targets, as highlighted during the British Cardiovascular Society (BCS) Annual Conference held in Manchester. The BRITISH study, which aims to enroll 2,504 patients over a span of three years, has managed to recruit fewer than one-third of its target within the first two years. Meanwhile, the CRAAFT-HF trial, launched in December 2024, has recruited only 22 out of its goal of 1,200 participants.

According to Andrew Flett, a consultant cardiologist at University Hospital Southampton NHS Trust and principal investigator for the BRITISH study, "We are running behind schedule. We're running at about 50% of where we should be, and we're putting in every effort to try and improve that." Flett’s concerns are echoed by Pier Lambiase, professor of cardiology at University College London and chief investigator for the CRAAFT-HF trial, who noted that the trial's eligibility criteria are being adjusted to enhance recruitment rates.

The CRAAFT-HF trial focuses on comparing surgical versus medical ablation of atrial fibrillation (AF) in patients with heart failure and reduced ejection fraction. Lambiase indicated that, despite a substantial pool of potential candidates, only about 5% of patients with heart failure and AF are referred for ablation procedures. To improve recruitment, the trial is considering broadening the definition of AF to include paroxysmal and persistent types, relaxing inclusion thresholds for New York Heart Association (NYHA) class and left ventricular ejection fraction (LVEF), and removing certain medication optimization criteria.

"We've learned very quickly that this is threatening the trial," Lambiase remarked. He estimates that the revised criteria could potentially add 62 patients, effectively tripling current enrollment. The CRAAFT-HF trial is currently operational at 14 sites, each having been active for an average of 4.5 months. Lambiase remains optimistic about recruitment improvements through remote follow-up protocols and international collaborations with centers in Canada, Australia, Sweden, and Spain.

In contrast, the BRITISH study, which has been active since 2023, is currently running at 46 of its planned 50 sites across the UK and aims to determine whether scarring detected via cardiovascular magnetic resonance is associated with reduced mortality in patients with nonischaemic cardiomyopathy who receive implantable cardioverter defibrillators. As of now, 390 patients have been enrolled, with nearly half being recruited within one year of diagnosis and almost 20% within six months. However, the demographics raise concerns about gender diversity, as only 20% of participants are female. Flett emphasized the importance of addressing this imbalance, stating, "The underrepresentation of women is a major source of concern."

The British Cardiovascular Society and the British Heart Foundation Clinical Research Collaborative have previously underscored the necessity for greater female representation in clinical trials. While Flett acknowledged the disparity, he noted that nonischaemic cardiomyopathy is more prevalent in men, complicating recruitment efforts. In an effort to address these issues, both studies are considering opening additional sites internationally and increasing the number of female principal investigators, as currently only six out of 46 PIs are women.

With recruitment proceeding at the current pace, it is estimated that completion of the trials could take an additional two to three years. The BRITISH and CRAAFT-HF studies are funded by the British Heart Foundation, and both Flett and Lambiase disclosed no conflicts of interest.

The implications of these recruitment challenges extend beyond the immediate need for patient involvement; they raise crucial questions about inclusivity in clinical research and the need for trials that better reflect the populations affected by cardiovascular diseases. As researchers continue to adapt their strategies and methodologies, the focus remains on achieving diversity and enhancing the overall quality of clinical outcomes for future patients.