CORONARY microvascular disease (CMD) was more effectively identified using a novel non-invasive index derived from coronary computed tomography angiography (CCTA), with new evidence showing a marked reduction in underdiagnosis when compared to current invasive diagnostic procedures.
CMD is common and associated with adverse cardiovascular outcomes, yet it is frequently overlooked in clinical practice. Diagnosis typically requires invasive coronary functional testing, which limits widespread use and contributes to missed cases, particularly in patients without obstructive coronary artery disease. To address this challenge, investigators evaluated an index of microcirculatory resistance derived from CCTA, termed IMRCT, as a complementary diagnostic approach.
Coronary Microvascular Disease Assessment Using CCTA
This retrospective cohort study included consecutive patients referred for invasive coronary functional assessment between January 2022 and March 2024 who had undergone CCTA within the preceding 30 days. IMRCT was calculated by blinded evaluators and compared with invasively measured index of microcirculatory resistance, with values of 25 or above indicating coronary microvascular disease.
The analysis comprised 176 patients and 216 coronary vessels. IMRCT demonstrated a strong correlation with invasive measurements at both the vessel level (correlation coefficient: 0.71; 95% confidence interval [CI]: 0.62–0.76; p<0.001) and the patient level (0.72; 95% CI: 0.64–0.78; p<0.001). Diagnostic performance was consistent, with areas under the curve of 0.82 at the vessel level and 0.81 at the patient level, supporting alignment with invasive reference standards rather than improved diagnostic accuracy.
The most clinically relevant finding emerged in patients with non-obstructive coronary artery disease, defined by CCTA stenosis under 50%, angiographic stenosis under 50%, or fractional flow reserve above 0.8. In these groups, use of IMRCT reduced CMD underdiagnosis rates from approximately 35–39% to below 6%.
Clinical Implications
Although limited by its retrospective design and single-centre setting, the study showed that IMRCT may serve as a valuable adjunct to existing diagnostic strategies. The simplicity and accuracy of the method could help improve CMD detection rates and reduce underdiagnosis, allowing microvascular-targeted therapies to be prescribed.
Future prospective studies are needed to determine how best to integrate CCTA-derived indices into routine clinical pathways and whether earlier identification of coronary microvascular disease can translate into improved patient management and outcomes.
Reference
Deng D et al. Non-invasive assessment of microcirculatory resistance by coronary computed tomography angiography. EuroIntervention. 2026; DOI:10.4244/EIJ-D-25-00671.
