Angio-IMR demonstrated high diagnostic performance for detecting CMD in patients undergoing invasive coronary angiography (ICA). The study presented at the American Heart Association (AHA) 2025 Scientific Sessions evaluated Angio-IMR against invasively measured IMR, the reference standard for CMD diagnosis.

The prospective multicentre study enrolled 335 patients (mean age 63 ± 10.6 years; 56% male), comprising 394 coronary vessels, across three tertiary centres in Australia. Participants were divided into derivation (n = 124) and validation (n = 124) cohorts. Angio-IMR analyses were performed centrally and blinded. Significant CMD was defined as invasive IMR > 25.

CMD was present in 27% of vessels in the derivation cohort and 23% in the validation cohort. Angio-IMR showed moderate correlation with invasive IMR (r = 0.47 and r = 0.33, respectively). Diagnostic performance was strong, with area under the receiver operating characteristic curve values of 0.82 and 0.76 (both p < 0.001). An Angio-IMR threshold > 21 optimized test performance, yielding sensitivities of 94.9% and 89.0% and negative predictive values of 95.9% and 92.0% in the derivation and validation cohorts, respectively.

These findings indicate that Angio-IMR reliably identifies CMD and supports non-invasive disease exclusion.