Cardiology · 2 h ago
Microvascular resistance reserve was not associated with clinical events in ANOCA
This prospective, multicenter cohort study followed 553 patients with angina and nonobstructive coronary arteries (ANOCA) for a mean of 27.5 months. Continuous thermodilution-derived microvascular resistance reserve was not associated with the composite clinical outcome, although abnormal values were linked to worse angina scores at follow-up.
- Clinical event rates were similar across MRR categories.
- Abnormal MRR was associated with worse follow-up angina scores.
- The cohort included 553 patients from four Dutch centers.
- Observational findings do not establish benefit from MRR-guided care.
The prospective cohort included 553 consecutive patients with ANOCA who underwent continuous thermodilution testing at four centers in the Netherlands between July 2020 and June 2025. Patients were classified as having abnormal microvascular resistance reserve (MRR; <2.1), a gray-zone result (2.1–2.7), or normal microvascular function (≥2.7). Investigators assessed clinical events and patient-reported angina for up to three years; mean follow-up was 27.5 months. The primary outcome combined death, acute coronary syndrome, stroke, revascularization, repeat angiography without intervention, and unplanned acute care for angina or heart failure.
The composite outcome occurred in 19.1% of patients with abnormal MRR, 21.4% with gray-zone MRR, and 21.1% with normal MRR; differences were not significant (log-rank P=.85). Individual outcomes also did not differ. Overall, MRR was not associated with longitudinal Seattle Angina Questionnaire summary scores. However, at follow-up, the abnormal-MRR group had lower mean scores than the normal group (53.0 vs 60.1; P=.04), and fewer patients achieved a clinically relevant improvement (30.0% vs 59.1%; P=.02).
The findings do not support MRR as a predictor of clinical events in this cohort, but suggest a possible association with subsequent symptom burden. The observational design and symptom findings do not establish causality or show that MRR-guided management improves outcomes.
In practice
For patients with angina and nonobstructive coronary arteries, continuous thermodilution-derived MRR was not associated with the composite of clinical events over a mean 27.5 months in this prospective cohort of 553 patients. Abnormal MRR was associated with worse follow-up angina scores and less clinically relevant symptom improvement than normal MRR, but these observational associations do not establish causality. The study does not show that MRR-guided treatment changes outcomes or justify changing practice on its own.
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JAMA Cardiology: Microvascular Resistance Reserve and Outcomes in Angina and Nonobstructive Coronary Artery Disease ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.