Exploring the impact of age on microvascular function: Insights from the Coronary Microvascular Disease Registry

BACKGROUND: Coronary microvascular dysfunction (CMD) contributes to angina without obstructive coronary artery disease (ANOCA). Although aging is known to impact cardiovascular health, its effect on coronary microvascular function remains unclear. This study examined the relationship between age and microvascular function in patients with ANOCA. METHODS: We analyzed 304 patients from the Coronary Microvascular Disease Registry (CMDR) who underwent invasive microvascular assessment using bolus thermodilution. The patients were stratified into three age groups: <50 years (14.1 %), 50-65 years (50 %), and > 65 years (35.8 %). CMD was defined as a coronary flow reserve (CFR) <2.0, and an index of microcirculatory resistance (IMR) ≥25. CFR, IMR, and microvascular resistance reserve (MRR) were compared across age groups. RESULTS: The mean age was 61.6 ± 11 years, and 66.1 % were female. CFR declined with age (3.56 ± 1.6, 3.38 ± 1.98, 2.76 ± 1.53; p < 0.05), but CMD prevalence was similar across groups (16.3 %, 28.9 %, 31.2 %; p = 0.16). No significant differences were observed in IMR (p = 0.4) or MRR (p = 0.055). CONCLUSIONS: Although CFR decreases with advancing age, increased age does not appear to significantly influence the prevalence of CMD or other key microvascular parameters such as IMR and MRR. CLINICAL TRIAL REGISTRATION: Coronary Microvascular Disease Registry, clinicaltrials.gov, NCT05960474.