Rationale and design of the PREGnancy, HEART Health and Cardiovascular Disease (PREG-HEART) Cohort Study

This paper outlines the rationale, design, and protocol for the PREG-HEART study, a patient-driven digital cohort initiative aimed at establishing a large-scale platform to investigate the epidemiology, natural history, and optimal management of cardiovascular disease in pregnancy through direct-to-patient recruitment, national health record linkage, and future clinical trials.

The Gist

Imagine the human body as a complex, high-performance car. Now, imagine that car has to carry a heavy, fragile passenger (a developing baby) while driving through a storm (pregnancy). If the car's engine (the heart) has a pre-existing issue, or if the storm makes the engine struggle, things can go wrong very quickly.

For a long time, doctors have been trying to figure out exactly how to keep these "cars" safe, but they've been driving blind. They only had a few test drives from a handful of specific garages (hospitals), and those test drives didn't represent the millions of different cars on the road.

This paper introduces PREG-HEART, a new, massive project designed to fix that blind spot. Here is the breakdown in simple terms:

1. The Problem: The "Small Sample" Trap

Currently, research on heart problems during pregnancy is like trying to understand how all cars behave by only looking at three red sports cars in one city.

• Why? Heart issues in pregnancy are rare individually, so single hospitals don't see enough patients to learn from them.
• The Result: Doctors don't have enough data to know the best way to treat these women, leading to worse outcomes for mothers and babies. Also, women from poorer areas or different ethnic backgrounds are often left out of these small studies, meaning the advice given doesn't work for everyone.

2. The Solution: The "Digital Highway"

Instead of waiting for doctors to find patients and drag them into a study, PREG-HEART is building a digital highway that goes directly to the people.

• How it works: Think of it as a specialized app or website. If a woman is pregnant and has a heart condition (or even if she's just a healthy pregnant woman for comparison), she can sign up herself.
• The Analogy: It's like a "Waze" for pregnancy heart health. Instead of waiting for a traffic cop (the doctor) to tell you to report a pothole, the app lets you report it instantly from your phone. This removes the barriers of geography and busy hospital schedules.

3. What They Are Collecting: The "Digital Twin"

Once women sign up, they aren't just filling out a boring form. They are building a "Digital Twin" of their health journey.

• The Data: They share details about their life, their heart condition, and their pregnancy.
• The "Leftovers": When a woman goes to the hospital for a blood test, usually the extra blood is thrown away. PREG-HEART asks, "Can we keep a little bit of that extra blood?" This creates a giant library of biological samples (a Bio-bank) that scientists can study later to find new medicines or markers.
• The Long Game: With permission, they link this data to national health records. This means they can follow these women for years, like watching a movie in fast-forward, to see how pregnancy affects their heart health decades later.

4. The Pilot Phase: The "Test Drive"

The paper describes the first 6 months of this project as a "pilot" or a test drive.

• The Goal: They aren't trying to solve all the mysteries yet. They just want to see: Can we get enough people to sign up? Are we getting a mix of people from different backgrounds, or just the same group as usual?
• The Checkpoint: If the test drive goes well, they will use the money and data to launch the full-scale highway, which will eventually help run clinical trials (testing new treatments) and answer big questions about why some women get sick and others don't.

5. Why This Matters: The "Fairness" Factor

One of the biggest goals is fairness.

• The Analogy: Imagine a map that only shows roads in rich neighborhoods. If you live in a different area, the map is useless.
• The Fix: By letting anyone sign up online, PREG-HEART hopes to include women from all walks of life, all over the UK. This ensures that the medical advice doctors give in the future is based on real people, not just a select few.

Summary

PREG-HEART is a national, patient-led project that uses a website to gather a massive group of pregnant women with heart conditions. By letting women join directly, collecting their health data and leftover blood samples, and following them over time, the study aims to build a giant, diverse library of knowledge. This will help doctors finally understand how to keep mothers and babies safe, ensuring that the best care is available to everyone, regardless of where they live or who they are.

Technical Summary

Based on the provided preprint, here is a detailed technical summary of the PREGnancy, HEART Health and Cardiovascular Disease (PREG-HEART) Cohort Study.

1. Problem Statement

Cardiovascular disease (CVD) is a leading cause of maternal and neonatal morbidity and mortality in the UK, with prevalence rising due to improved survival of women with congenital/inherited heart disease and an increasing burden of acquired risk factors (e.g., obesity, hypertension). Despite this, critical gaps exist:

• Data Limitations: Current research relies on small, underpowered studies from highly selected patient cohorts within individual units.
• Management Gaps: The natural history of CVD in pregnancy, optimal management strategies, and long-term impacts on maternal health are poorly defined.
• Systemic Inequities: Existing clinician-directed registries (e.g., ROPAC) suffer from geographical bias, underrepresenting women in remote areas or socio-economically deprived regions. This exacerbates health inequalities, as maternal mortality is significantly higher in deprived areas and among Black and Asian women.
• Recruitment Barriers: Traditional recruitment methods place undue burden on clinicians and fail to capture the diversity of the real-world population.

2. Methodology

The PREG-HEART study is a national, prospective, observational cohort study designed as a direct-to-patient digital platform.

• Study Design:

  • Platform: A bespoke online portal (hosted on the Heart Hive infrastructure) allowing self-enrollment.
  • Participants:
    • Cases: Women aged ≥16 with any history of cardiovascular disease (current or prior pregnancy) diagnosed before, during, or within 6 months postpartum. Conditions include cardiomyopathies, valvular disease, congenital lesions, arrhythmias, coronary artery disease, hypertension, pulmonary hypertension, aortic disease, and connective tissue disorders.
    • Controls: Healthy pregnant women without diagnosed CVD.
  • Recruitment Strategy: Multi-channel approach including social media, patient charities, clinician referrals, and media campaigns to bypass geographical and institutional barriers.
  • Consent Process: Electronic, step-by-step informed consent with comprehension checks. Participants can opt-out of specific data linkages or biosample storage.

• Data Collection:

  • Baseline: Self-reported demographic, clinical, lifestyle, and obstetric history via online questionnaires.
  • Clinical Data Verification: Participants are encouraged to upload clinic letters and imaging/genetic results to a secure NHS email, which are then uploaded to the platform by the study team to improve accuracy.
  • Follow-up: A 6-month postpartum questionnaire for obstetric/neonatal outcomes.
  • Long-term Linkage: Consent is sought to link participant data with national health records (e.g., HES, ONS, NNRD, CPRD) for lifetime follow-up on cardiovascular, obstetric, and mortality outcomes.
  • Biosamples: Consent is obtained for the storage of leftover clinical blood samples (for future multi-omics analysis) and re-contact for future biosample collection (blood, saliva, urine).

• Governance:

  • Sponsored by Imperial College London.
  • Co-designed with a patient steering group and overseen by an Executive Steering Committee including patient representatives.
  • Approved by the West Midlands Solihull Research Ethics Committee.

3. Key Contributions

• Novel Recruitment Model: Shifts from clinician-led recruitment to a direct-to-patient digital model, aiming to create a cohort that is geographically, socio-economically, and ethnically representative of the wider UK population.
• Scalable Infrastructure: Establishes a national platform capable of supporting not just observational studies but also clinical trials and biomarker discovery.
• Comprehensive Data Integration: Uniquely combines self-reported data, uploaded clinical documents, national registry linkages, and a biobank for multi-omic research (genomics, proteomics, metabolomics).
• Patient-Centric Design: Patients are co-authors and active partners in study design, question formulation, and dissemination, ensuring the research addresses priority questions for the community.

4. Results

• Current Status: This paper serves as the protocol and rationale for the study.
• Pilot Phase: The study is initiating a 6-month pilot phase.
• Planned Metrics: The pilot will assess:
  • Feasibility of recruitment rates.
  • Case-mix of cardiovascular diagnoses.
  • Representativeness of the cohort regarding geography, socio-economic status, and ethnicity compared to the UK general pregnant population.
• Target: The pilot aims to enroll at least 25 participants with heart failure or cardiomyopathy (representing ~10% of expected cases over 6 months) to demonstrate feasibility.
• Outcome: No clinical results are presented yet; the immediate output is the validation of the recruitment platform and the characterization of the initial cohort's diversity.

5. Significance

• Addressing Evidence Gaps: By creating a large, deeply phenotyped cohort, PREG-HEART will enable robust epidemiological research into the natural history of CVD in pregnancy, which is currently hindered by small sample sizes.
• Reducing Health Inequalities: The direct-to-patient approach is specifically designed to include underrepresented groups (e.g., women in deprived areas or from minority ethnic backgrounds), thereby generating data that reflects real-world populations and can inform equitable care strategies.
• Clinical and Policy Impact: The study aims to improve risk stratification tools, guide management guidelines, and support the development of new biomarkers.
• Future Research Enablement: The platform will serve as a resource for future interventional trials and mechanistic studies, accelerating translational research in maternal cardiovascular health.
• National Capacity: It builds a sustainable national resource for collaborative research, moving beyond the limitations of single-center studies to a unified UK-wide effort.