Minimum Lumen Area Indexed to Left Ventricular Mass to Identify Functionally Significant Left Main Coronary Stenoses

Diagnosing significant left main coronary artery (LMCA) stenoses based on anatomical criteria remains challenging. The ARMYDA FINISH multicenter study evaluated whether indexing intravascular ultrasound (IVUS)-derived minimum lumen area (MLA) provides greater diagnostic accuracy than unindexed MLA for detecting hemodynamically significant LMCA stenoses, defined as a fractional flow reserve (FFR) ≤ 0.80.

Fifty-two patients with angiographically-intermediate isolated LMCA lesion were prospectively enrolled. All patients underwent IVUS and FFR measurements. Primary endpoint was the diagnostic accuracy of MLA indexed to height, body surface area (BSA), body mass index (BMI) and left ventricular (LV) echocardiographic mass in identifying hemodynamically significant LMCA stenoses compared to unindexed MLA. Secondary endpoints were the diagnostic sensitivity, specificity, and predictive values of indexed vs unindexed MLA cutoffs.

Overall, 40 patients (77%) had FFR  > 0.80 and 12 (23%) FFR  ≤ 0.80. MLA indexed to LV mass achieved the highest area under the receiver operating characteristic curve (AUC = 0.91, 95% CI: 0.83-0.99; p < 0.001), compared to unindexed MLA (AUC = 0.86) and MLA indexed to height, BSA or BMI (AUC range = 0.84-0.85). At a cutoff of 29 mm²/kg for MLA/LV mass, sensitivity and negative predictive value (NPV) were both 100%, and specificity was 70%. All MLA thresholds (whether indexed and unindexed) exhibited low positive predictive value (PPV), ranging from 46% to 55%.

MLA/LV mass ratio may represent an accurate diagnostic tool for "ruling out" flow-limiting LMCA lesions. Future large studies are needed to validate the MLA/LV mass ratio in diverse clinical settings and refine its cutoff values.