An observational study in Cystic Fibrosis, Endothelial Dysfunction and Cardiovascular Risk Factor, sponsored by Liverpool Heart and Chest Hospital NHS Foundation Trust. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 40 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by Liverpool Heart and Chest Hospital NHS Foundation Trust · Observational
The goal of this observational study is to learn whether blood vessel health and function differ between adults aged 40 years or older with cystic fibrosis (CF) who are taking CFTR modulator therapy and healthy adults of the same age and sex. As people with CF now live longer, they may face a higher risk of heart and blood vessel disease and stroke.
The main question it aims to answer is:
Is the function of the arteries in the arm (measured by radial artery flow-mediated dilation and low-flow mediated constriction) reduced in people with CF compared with healthy controls?
Researchers will also compare the function of the neck (carotid) arteries, blood flow control in the brain, the reflexes that control blood pressure, and blood markers of inflammation and oxidative stress between the two groups. They will also look at whether these measures relate to memory and thinking, mood, and quality of life.
Participants will attend a single study visit of about 2.5 to 3 hours at Liverpool Heart and Chest Hospital (or Manchester Metropolitan University for some healthy controls). During the visit they will:
Background: Cystic fibrosis (CF) is associated with chronic systemic inflammation, oxidative stress and several cardiometabolic risk factors. Highly effective CFTR modulator therapy has greatly increased life expectancy, and the ageing CF population may therefore be at increasing risk of cardiovascular and cerebrovascular disease. Endothelial dysfunction has been reported in CF, but its physiological mechanisms, and the effects of CF on cerebrovascular function and autonomic control, are poorly understood.
Design: Single-centre, case-control, cross-sectional observational study. 100 participants will be recruited: 50 adults with CF aged 40 years or older receiving CFTR modulator therapy, recruited consecutively from the adult CF outpatient clinics at Liverpool Heart and Chest Hospital (LHCH), and 50 healthy controls matched for sex and age (within 4 years), recruited from the community. Each participant attends one visit. No study treatment is given.
Assessments: anthropometry (height, weight, BMI, waist/hip ratio, body fat percentage); radial artery low-flow mediated constriction (L-FMC) and flow-mediated dilation (FMD) by high-resolution ultrasound after 5 minutes of wrist cuff occlusion, in line with international guidelines; bilateral common carotid intima-media thickness (IMT) and carotid artery reactivity (CAR) to a 3-minute cold pressor test; 12-lead ECG, beat-to-beat finger blood pressure and breath-by-breath O2 and CO2; bilateral transcranial Doppler of the middle and posterior cerebral arteries to assess neurovascular coupling (visual stimulation protocol), spontaneous and dynamic cerebral autoregulation and baroreflex sensitivity (10 minutes supine rest, then sit-to-stand and 5 minutes of repeated 10-second squat-stand manoeuvres); blood sampling for full blood count, renal function, HbA1c, lipid profile, and inflammatory and oxidative stress markers (e.g. CRP, CK-MB, IL-1, IL-2, IL-6, TNF-alpha, superoxide dismutase, malondialdehyde, F2-isoprostanes) measured by ELISA; cognitive testing (Standardised Mini-Mental State Examination, Wisconsin Card Sorting Task, Lexical Decision Task); Hospital Anxiety and Depression Scale; and quality of life (RAND-36, EQ-5D-5L).
Sample size: Based on an effect size (Cohen's d) of 0.59 for FMD between people with CF and healthy controls (Clayton et al., 2025), 47 participants per group are needed for a two-tailed unpaired comparison at alpha 0.05 and 80% power. 50 per group will be recruited to allow for attrition.
Analysis: The primary analysis will compare radial artery L-FMC and FMD between groups. Secondary analyses will compare carotid IMT and CAR, neurovascular coupling, cerebral autoregulation, baroreflex function, and inflammatory and oxidative stress markers. Regression analyses in the CF group will examine associations between inflammatory and oxidative stress markers and vascular and autonomic measures, and between cognitive, mood and cerebrovascular measures.
The study is sponsored by LHCH and jointly funded by LHCH and Manchester Metropolitan University as part of a PhD programme.
1,609 studies on the registry are indexed under Cystic Fibrosis; 197 are open to participants now.
This study's planned enrollment of 100 is above the median of 85 across 491 observational studies indexed under Cystic Fibrosis.
Browse Cystic Fibrosis studies →Liverpool Heart and Chest Hospital NHS Foundation Trust is the lead sponsor of 33 studies on the registry; 6 are open to participants now.
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Adults aged 40 years or older with cystic fibrosis receiving CFTR modulator therapy, attending the adult CF outpatient clinics at Liverpool Heart and Chest Hospital (a regional centre serving Merseyside, Cheshire, Lancashire, Greater Manchester and North Wales), and healthy adults aged 40 years or older matched for sex and age, recruited from the local community including NHS and university staff and students.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Participants with CF:
Healthy controls:
Exclusion Criteria (all participants):
Adults aged 40 years or older with a confirmed diagnosis of cystic fibrosis, receiving CFTR modulator therapy at a recognised therapeutic dose and clinically stable (no pulmonary exacerbation or hospitalisation in the previous 4 weeks), recruited consecutively from the adult CF outpatient clinics at Liverpool Heart and Chest Hospital. Target n = 50. Participants attend a single study visit for vascular, cerebrovascular, autonomic, blood, cognitive and questionnaire assessments.
Other: Non-invasive vascular, cerebrovascular and autonomic assessment
Healthy adults aged 40 years or older, matched to participants with CF for sex and age (within 4 years), in sinus rhythm with normal blood pressure (below 140/90 mmHg) and taking no prescription medications other than contraceptives or hormone replacement therapy. Recruited from the local community (including NHS and university staff and students) via advertisements. Target n = 50. Participants attend a single study visit at Liverpool Heart and Chest Hospital or Manchester Metropolitan University for the same assessments as the CF group.
Other: Non-invasive vascular, cerebrovascular and autonomic assessment
No treatment is given. At a single visit of about 2.5 to 3 hours, participants undergo anthropometry; radial artery low-flow mediated constriction and flow-mediated dilation by ultrasound; carotid intima-media thickness and carotid artery reactivity to a cold pressor test; 12-lead ECG, beat-to-beat blood pressure and breath-by-breath gas monitoring; transcranial Doppler assessment of neurovascular coupling, cerebral autoregulation and baroreflex sensitivity (supine rest, sit-to-stand and squat-stand manoeuvres); venous blood sampling; cognitive testing; and anxiety, depression and quality of life questionnaires.
Radial artery flow-mediated dilation (FMD)
Percentage change in radial artery diameter
Time frame: Single study visit (Day 1)
Radial artery low-flow mediated constriction (L-FMC)
Percentage change in radial artery diameter
Time frame: Single study visit (Day 1)
Carotid artery reactivity (CAR)
Percentage change in common carotid artery diameter from 1 minute of rest to the peak response during 3 minutes of hand immersion in iced water (4 degrees C or below; cold pressor test), measured by high-resolution ultrasound. Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Carotid intima-media thickness (IMT)
Mean common carotid artery intima-media thickness (mm), measured bilaterally by B-mode ultrasound approximately 1 cm proximal to the carotid bulb in anterior, lateral and posterior views. Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Cerebral neurovascular coupling
Change in cerebral artery mean blood flow velocity (transcranial Doppler) in response to a standard visual stimulation protocol (alternating 30-second eyes open and eyes closed periods), expressed as percentage increase from eyes-closed baseline. Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Cerebral autoregulation (spontaneous and dynamic)
Relationship between beat-to-beat blood pressure and cerebral artery mean blood flow velocity (transcranial Doppler), assessed during 10 minutes of supine rest (spontaneous) and during 5 minutes of repeated 10-second squat-stand manoeuvres (dynamic), with continuous ECG and end-tidal gas monitoring. Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Baroreflex sensitivity and baroreflex effectiveness index
Cardiac baroreflex sensitivity (ms/mmHg) and baroreflex effectiveness index derived from continuous ECG and beat-to-beat finger blood pressure, during 10 minutes of supine rest (spontaneous) and during 5 minutes of repeated 10-second squat-stand manoeuvres (dynamic). Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Cognitive function
Cognitive performance assessed by the Standardised Mini-Mental State Examination (total score 0 to 30; higher scores indicate better cognitive function), the Wisconsin Card Sorting Task (e.g. categories completed and perseverative errors) and a Lexical Decision Task (accuracy and reaction time). Compared between adults with CF and age/sex matched healthy controls, and examined for association with neurovascular coupling.
Time frame: Single study visit (Day 1)
Anxiety and depression (Hospital Anxiety and Depression Scale)
Hospital Anxiety and Depression Scale anxiety and depression subscale scores (each 0 to 21; higher scores indicate more severe symptoms). Compared between adults with CF and age/sex matched healthy controls, and examined for association with neurovascular coupling.
Time frame: Single study visit (Day 1)
Health-related quality of life
Health-related quality of life assessed EQ-5D-5L (index value and visual analogue scale 0 to 100; higher scores indicate better health). Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Association between inflammatory/oxidative stress markers and vascular and autonomic function in CF
In participants with CF, regression analysis of the association between blood markers of inflammation and oxidative stress and measures of peripheral vascular function (FMD, L-FMC, carotid artery reactivity), cerebrovascular function (neurovascular coupling, cerebral autoregulation) and baroreflex function.
Time frame: Single study visit (Day 1)
Health-related quality of life
Health-related quality of life assessed by the RAND 36-Item Health Survey. Compared between adults with CF and age/sex matched healthy controls.
Time frame: Single study visit (Day 1)
Plan to share: Undecided
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Start is estimated for Oct 2026; primary completion for Jul 2029, 32 months later.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Liverpool Heart and Chest Hospital NHS Foundation Trust