SCAPIS 2 spectrum: rationale, objectives and design of a microvascular dysfunction sub-study within the Swedish CArdioPulmonary bioImage study.

The microvasculature forms the interface for nutrient exchange and signaling between the blood and tissues. Its dysfunction is increasingly recognized as a key mechanism underlying various cardiovascular diseases, including heart failure, ischemic heart disease, atherosclerosis, stroke and vascular dementia. Early detection of these subclinical processes using non-invasive assessments could facilitate timely interventions and provide mechanistic insights to prevent disease progression. SCAPIS 2 Spectrum is a prospective cross-sectional phenotyping sub study of the Swedish Cardiopulmonary Bioimage Study, recruiting up to 900 participants aged 58–75 years. The study is organized into four overlapping phenotype groups: (1) those with obstructive coronary artery disease, (2) angina with non-obstructive coronary arteries, (3) metabolic syndrome with type 2 diabetes, and (4) those with diastolic dysfunction, each compared with controls drawn from the same cohort. All participants undergo a comprehensive skin microvascular assessment at rest and following various local provocations and those without exclusion criteria or obstructive coronary artery disease will also undergo stress cardiovascular magnetic resonance imaging to assess myocardial perfusion. Descriptive statistics, association analysis, multivariable regression and exploratory modelling will be employed to investigate associations between device-derived parameters in skin microcirculation and myocardial perfusion. Circulating biomarkers will be incorporated as candidate features in exploratory analysis. Ethical approval has been obtained from the Swedish Ethical Review Authority and the Swedish Medical Products Agency (CIV-ID 23-12-045355). Study results will be disseminated through peer-reviewed publications, national and international conference presentations. Clinical Trial Registration https://clinicaltrials.gov/study/NCT07359768?term=scapis%202%20spectrum&viewType=Card&rank=1&tab=study , ClinicalTrials.gov ID: NCT07359768.