Pressure-Derived Indices in the Left Main Coronary Artery: Insights From Comprehensive In Vivo Hemodynamic Studies of Diseased and Unobstructed Vessels
Authors' conclusion
Microvascular resistance in the LAD is lower than in the LCx territory. Consequently, fractional flow reserve and nonhyperemic pressure-derived indices are lower in the LAD than the LCx. These findings have important implications for how LMCA atheroma should be assessed in clinical practice and also suggest the need for territory-specific thresholds for defining abnormal microvascular function and epicardial conductance.
Study context
- Population
- Patients with isolated left main coronary artery (LMCA) disease and patients with unobstructed coronary arteriespatients enrolled (mean age 65±10 years, 56% male)
- Participants
- 80 patients
- Comparison
- Fractional flow reserve, instantaneous wave-free ratio, and microvascular resistance reserve values in the left anterior descending (LAD) were compared with those of the LCx.
- Outcome
- Fractional flow reserve (isolated LMCA disease)
Main finding
As reported in the abstract
LAD
0.74
± 0.11
LCx
0.81
± 0.11
P < 0.0001
Further findings
| Outcome | Isolated LMCA disease | Unobstructed coronary arteries | LAD | LCx | P value | |
|---|---|---|---|---|---|---|
| Instantaneous wave-free ratio (isolated LMCA disease)LAD vs LCx · lower in the LAD | Not reported in the abstract | Not reported in the abstract | 0.89 (range in brackets 0.76–0.92) | 0.94 (range in brackets 0.88–0.97) | P < 0.0001 | isolated LMCA disease, unobstructed coronary arteries: not reported in the abstract |
| Microvascular resistance reserve, LAD vs LCxDiseased LMCA: 3.57±1.40 versus 2.50±0.81; higher in the LAD | P < 0.0001 | |||||
| Microvascular resistance reserve, LAD vs LCx | P < 0.0001 | |||||
| Microvascular resistance reserve, diseased vs unobstructed LMCA cohortsLAD territory: similar | P = 0.56 | |||||
| Microvascular resistance reserve, diseased vs unobstructed LMCA cohortsLCx territory: comparable | P = 0.88 |
- Microvascular resistance reserve, LAD vs LCx: unobstructed LMCA: 3.40±0.78 versus 2.47±0.68; higher in the LAD
Misclassification rate of functionally significant coronary disease when measured in the LCx
- Fractional flow reserve
- 21%
- Instantaneous wave-free ratio
- 28%
Original publication
Pressure-Derived Indices in the Left Main Coronary Artery: Insights From Comprehensive In Vivo Hemodynamic Studies of Diseased and Unobstructed Vessels. Circ Cardiovasc Interv. Published 12 May 2025. doi:10.
Summarised from the published abstract; every number is checked against it