Is It Useful to Index the Minimum Lumen Area to Ventricular Mass to Identify Functional Left Main Coronary Stenosis?

Courtesy of Dr. Juan Manuel Pérez.

The assessment of intermediate left main coronary artery (LMCA) lesions remains a challenge, as angiography may either overestimate or underestimate their functional significance. The 2024 European Society of Cardiology (ESC) guidelines recommend the use of fractional flow reserve (FFR) and intravascular ultrasound (IVUS) for their assessment; however, applying a fixed minimum lumen area (MLA) cutoff to the entire population has diagnostic limitations.

The ARMYDA-FINISH study, a prospective, multicenter, observational trial, analyzed whether indexing IVUS-derived MLA to anthropometric parameters or to left ventricular mass (LVM) improves the detection of significant stenosis (defined as FFR ≤0.80).

The primary aim was to compare the diagnostic performance of indexed MLA (to height, body surface area [BSA], body mass index [BMI], and LVM) against non-indexed MLA in predicting functionally significant stenosis. Fifty-two consecutive patients with isolated intermediate LMCA lesions (25–69% according to quantitative coronary angiography [QCA]) were enrolled between May 2021 and October 2024 at three Italian centers. They all systematically underwent IVUS and FFR.

The mean age of the cohort was 69 years; 77% of subjects were men. The average BMI was 25 kg/m² [interquartile range [IQR] 24–29] and the BSA, 1.9 ± 0.2 m². All patients had preserved left ventricular function. The mean LVM was 187.4 g, with no significant difference between groups with FFR >0.80 and ≤0.80 (186.6 g vs 218.0 g; p = 0.17). Of the 52 patients, 40 (77%) had FFR >0.80 and 12 (23%) had FFR ≤0.80. According to QCA, those with FFR ≤0.80 showed greater morphological severity: higher-percent stenosis (56.2 ± 6.3% vs 43.7 ± 8.1%; p <0.001), smaller minimum lumen diameter (2.04 ± 0.66 mm vs 2.54 ± 0.71 mm; p = 0.035), and longer lesion length (13.0 ± 6.4 mm vs 8.5 ± 4.3 mm; p = 0.006), compared with patients with FFR >0.80. Lesion location was ostial in 36.5% of cases, in the vessel body in 17.3%, and at the bifurcation in 46.2%.

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In terms of outcomes, IVUS-derived MLA was significantly smaller in patients with FFR ≤0.80 compared with those with FFR >0.80 (4.40 mm² vs 6.80 mm²; p <0.001). MLA indexed to LVM reported the best diagnostic performance, with an area under the curve (AUC) of 0.91 (p <0.001) and an optimal cutoff value of 29 mm²/kg (100% sensitivity and negative predictive value, and 70% specificity). Alternative indices based on height, BSA, or BMI showed lower AUC values, between 0.84 and 0.85.

Conclusion

An MLA value >29 mm² per kg of LVM (MLA/LVM index ≥29 mm²/kg) reliably rules out significant LMCA stenosis. However, given its low specificity, a value below this threshold does not necessarily confirm the presence of significant stenosis, and FFR therefore remains indispensable in such cases. Future studies with larger sample sizes will be needed to validate these findings and establish universal cutoff values.

Original Title: Minimum Lumen Area Indexed to Left Ventricular Mass to Identify Functionally Significant Left Main Coronary Stenoses.

Reference: Giuseppe Patti, et al. – Catheterization and Cardiovascular Interventions, 2025; https://doi.org/10.1002/ccd.70026.