Inter-vessel heterogeneity in coronary microvascular dysfunction: A three-vessel physiological assessment

Coronary microvascular dysfunction (CMD) is typically assessed in the left anterior descending artery (LAD); however, inter-vessel differences involving the left circumflex (LCX) and right coronary arteries (RCA) remain unclear. We investigated inter-vessel variations in CMD and their associations with patient characteristics.

We retrospectively analyzed 91 patients (overall cohort) to evaluate patient characteristics across different coronary microvascular dysfunction (CMD) phenotypes based on physiological cutoffs: isolated CFR impairment, isolated IMR impairment, and combined impairment. Additionally, in a subgroup of 34 patients who successfully underwent physiological assessments in all three major coronary arteries (three-vessel cohort), we compared the CMD diagnostic rates between LAD-only and three-vessel assessments and evaluated vessel-specific correlations between CFR and IMR. In the Overall cohort, analysis of vessel-specific phenotypes revealed that patients with isolated IMR impairment in the LAD had a significantly higher body mass index (26.4 ± 4.90 kg/m², p = 0.038). In the RCA, patients with isolated CFR impairment were significantly older (77.0 ± 9.18 years, p = 0.044). In the three-vessel cohort, the CMD diagnostic rate was significantly higher with a three-vessel assessment than with an LAD-only assessment (52.9% vs. 23.5%, p = 0.044). Furthermore, a significant inverse correlation between CFR and IMR was observed only in the LCX (r = -0.326, p = 0.033).

Coronary microvascular physiology varies across the LAD, LCX, and RCA, indicating that conventional LAD-only assessments may underestimate CMD burden. These preliminary retrospective findings require validation in prospective, multicenter studies before routine clinical adoption.