Poor cardiopulmonary fitness is an important risk factor for postoperative complications, yet a feasible, objective and prognostically accurate method to assess preoperative fitness has not been established. The 6 min walk test (6MWT) is a simple, inexpensive and widely applicable measure that shows promise for predicting postoperative risk. However, robust data are lacking on whether the 6MWT accurately predicts complications, provides incremental prognostic value beyond routinely collected clinical factors or outperforms simpler alternatives such as questionnaires, cardiac biomarkers or grip strength testing. The Functional Assessment for Surgery by a Timed Walk (FAST Walk) study is designed to address these knowledge gaps by evaluating whether the 6MWT improves prediction of key postoperative outcomes compared with clinical factors and simpler measures of fitness.

The FAST Walk study is an international multicentre prospective cohort study of 1672 adults (≥40 years) undergoing major elective non-cardiac surgery at centres in Canada, Hong Kong, Australia, Spain and the Netherlands. Participants complete a preoperative 6MWT and baseline assessments of comorbidities, self-reported cardiopulmonary fitness (MET: Re-evaluation for Perioperative Cardiac Risk questionnaire), biomarkers (N-terminal pro-B-type natriuretic peptide) and grip strength. The primary outcome is 30-day death or major postoperative complication, defined as Clavien-Dindo grade II or higher. Secondary outcomes are (1) death or new significant disability at 90 days after surgery and (2) days alive and out of hospital at 30 days after surgery. Disability is measured using the short-form WHO Disability Assessment Schedule 2.0 instrument. Multivariable regression models and complementary metrics of prediction performance will be used to determine whether 6MWT distance adds prognostic value beyond routinely collected clinical factors and simpler measures of fitness.

The FAST Walk study has received research ethics board approval at all participating sites. Recruitment commenced in June 2024, with completion of participant follow-up expected in 2026. Findings will be disseminated through peer-reviewed publications and conference presentations, with the primary results anticipated in 2027.

NCT06412367.

Early-onset chronic liver disease (CLD) and its subsequent clinical progression have systemic impact. Its trajectory coincides with critical periods of brain development. In this study, we will test the hypothesis that early-onset CLD is associated with neurodevelopmental and psychiatric symptoms and delineate their neurobiological underpinnings through multimodal neuroimaging.

This study will recruit 100 patients with biliary atresia and 50 patients with other types of early-onset CLD, aged between 6 and 30 years, under the primary care of Paediatric Liver Services at King’s College Hospital, London, UK. Cognitive performance and autism-related behaviours will be evaluated with neurodevelopmental assessments. Participants and their parents will complete questionnaires addressing neurodevelopmental and psychiatric outcomes in everyday life, and quality of life. Multimodal neuroimaging will be conducted using electroencephalography (EEG); eye-tracking; structural, functional and diffusion MRI; and magnetic resonance spectroscopy (MRS). Clinical information will be collected from patients’ medical records and bio samples. Data of 222 neurotypical controls and 307 neurodivergent controls without CLD will be pooled from the Longitudinal European Autism Project with a similar study protocol. Neurodevelopmental and psychiatric outcomes will be compared with normative values and between groups. Associations with clinical risk factors will be explored using multivariable regression. Neuroimaging markers will be compared between groups and associations with neurodevelopmental outcomes and clinical risk factors will be tested using multivariable regression. Individual deviation from normal brain development will be quantified using Bayesian modelling and will be associated with neurodevelopmental outcomes.

This study was approved by the National Health Service Health Research Authority’s ethical committee (REC reference: 22/PR/1587). Findings from this study will be published in peer-reviewed journals, presented at national and international conferences and shared with patients and their families for widespread dissemination of the results.