Coronary disease & ACSCohort study
Microvascular resistance reserve: diagnostic and prognostic performance in the ILIAS registry
- Registry-based cohort study
- global registry
Authors' conclusion
MRR seems a robust indicator of the microvascular vasodilator reserve capacity. Moreover, in line with its theoretical background, this study suggests a diagnostic advantage of MRR over other indices of vasodilatory capacity in patients with hemodynamically significant epicardial coronary artery disease.
Study context
- Population
- Patients with stable symptoms and a clinical indication for coronary angiography (global ILIAS Registry)
- Participants
- 1,481 patients
Main finding
As reported in the abstract
MRR diagnostic and prognostic performance
- Median microvascular resistance reserve (MRR) [Q1-Q3: 2.32-3.86]
- 2.97
- Correlation MRR vs coronary flow reserve (CFR) (Rs), P < 0.005
- 0.88
- CFR–MRR difference increased with decreasing fractional flow reserve (FFR): R2 = 0.34; Coef. 95% CI −3.05--2.73; P < 0.005
- −2.88
- MRR independently associated with major adverse cardiac events (MACE) at 5 years: HR
- 0.78 (95% CI 0.63-0.95; P = 0.024)
- MRR independently associated with target vessel failure (TVF) at 5 years: HR
- 0.83 (95% CI 0.76-0.97; P = 0.047)
- Optimal MRR cut-off
- 3.0
Observational data: associations, not effects.
Further findings
MACE and TVF by MRR cut-off 3.0 in vessels with FFR <0.75 · 5-year follow-up
- Only abnormal MRR significantly associated with MACE and TVF in vessels with functionally significant epicardial disease (FFR <0.75)
Original publication
Microvascular resistance reserve: diagnostic and prognostic performance in the ILIAS registry. Eur Heart J. Published 23 June 2023. doi:10.1093/eurheartj/ehad378
Summarised from the published abstract; every number is checked against it