Core Laboratory Comparison of Angiography-Derived Indexes of Microvascular Resistance vs Pressure-Wire IMR and Absolute Resistance
Authors' conclusion
All 5 angio-IMR methods demonstrated poor diagnostic accuracy compared with PW-IMR and Rmicro, highlighting significant limitations in their clinical utility.
Study context
- Population
- Patients with angina and nonobstructive coronary arteries assessed for coronary microvascular dysfunction274 and 109 vessels
- Comparison
- Angio-IMR vs PW-IMR and Rmicro
- PW-IMRn = 270reference
- Rmicron = 42reference
- Outcome
- Per-vessel diagnostic performance of angio-IMR vs PW-IMR ≥25 and Rmicro ≥475 WU (ROC, Bland-Altman, confusion matrices)
Methodological detailscore laboratory, blinded
- Core laboratory
- Blinded
Performance
As reported in the abstract
Diagnostic performance of angio-IMR
| Test or model | AUC for PW-IMR ≥25 (all methods) | Accuracy, method E, PW-IMR ≥25 (angio-IMR ≥25 threshold) | Accuracy, method E, Rmicro ≥475 Wood units (WU) (angio-IMR ≥25 threshold) |
|---|---|---|---|
| Angio-IMR | 0.530 to 0.576 | 61.4% | 62.0% |
Angio-IMR
AUC for PW-IMR ≥25 (all methods)0.530 to 0.576
Accuracy, method E, PW-IMR ≥25 (angio-IMR ≥25 threshold)61.4%
Accuracy, method E, Rmicro ≥475 Wood units (WU) (angio-IMR ≥25 threshold)62.0%
- AUC for PW-IMR ≥25 not significant for any method
- P > 0.05
- 3 of 5 methods overestimated PW-IMR (mean bias), all with large random errors
- −20.72 to −26.36
Further findings
| Outcome | Angio-IMR | PW-IMR | Rmicro | |
|---|---|---|---|---|
| Reference index values | median 19.02 (IQR 12.79–28.08) | median 387.50 (IQR 312.00–501.00) WU | ||
| PW-IMR ≥25 | Not reported in the abstract | 81 of 274 vessels (29.6%) | Not reported in the abstract | Angio-IMR, Rmicro: not reported in the abstract |
| Rmicro ≥475 WU | Not reported in the abstract | Not reported in the abstract | 33 of 109 vessels (30.3%) | Angio-IMR, PW-IMR: not reported in the abstract |
Original publication
Core Laboratory Comparison of Angiography-Derived Indexes of Microvascular Resistance vs Pressure-Wire IMR and Absolute Resistance. JACC Cardiovasc Interv. Published 25 October 2025. doi:10.
Summarised from the published abstract; every number is checked against it