NEW research has shown that Murray law-based quantitative flow ratio (μQFR) demonstrates moderate diagnostic accuracy for assessing hemodynamically significant calcified coronary lesions, offering a viable wire-free alternative to fractional flow reserve (FFR) in clinical practice.
Calcified coronary lesions pose unique challenges for physiological assessment, often complicating traditional FFR measurements due to technical limitations. The DIAMOND study evaluated μQFR—an AI-driven, angiography-derived method requiring no pressure wires or hyperemia—against FFR in 120 moderate-to-severely calcified lesions (ACC/AHA B2/C). This two-center trial aimed to address gaps in evidence for μQFR’s performance in calcified arteries, where lesion complexity may impact diagnostic precision.
The study included 125 patients, with paired μQFR and FFR data available for 107 patients (120 lesions). μQFR analysis, blinded to FFR results, showed a mean FFR of 0.775 (95% CI: 0.757–0.793) and μQFR of 0.788 (95% CI: 0.772–0.805). μQFR achieved a sensitivity of 75% (95% CI: 65.6%–84.6%) and specificity of 77.8% (95% CI: 63.5%–92.0%), with an AUC of 0.813 (95% CI: 0.714–0.911). Positive and negative predictive values were 88.7% and 57.1%, respectively. These results align with prior studies showing μQFR’s robustness in calcified lesions24, where AUCs ranged 0.87–0.91 despite higher anatomical complexity2. Notably, coronary calcification did not significantly affect μQFR-FFR agreement2, reinforcing its utility in challenging cases.
These findings support μQFR’s integration into routine practice for calcified lesions, particularly when FFR is logistically or financially constrained13. Future research should focus on standardizing μQFR protocols, enhancing AI-driven automation to reduce operator variability1, and validating outcomes in large-scale trials. Clinicians may prioritize μQFR for initial screening, reserving FFR for borderline cases, thereby optimizing resource use without compromising diagnostic accuracy
Reference
Bennar W et al. Diagnostic accuracy of angiography-derived murray law-based quantitative flow ratio (μQFR) versus pressure-derived fractional flow reserve (FFR) in moderate to severe calcified coronary lesions—the DIAMOND study. Catheterization and Cardiovascular Interventions. 2025;DOI:10.1002/ccd.31553.
