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

Area of Science:

• Cardiology
• Interventional Cardiology
• Diagnostic Imaging

Background:

• Diagnosing significant left main coronary artery (LMCA) stenoses using anatomical criteria is challenging.
• Hemodynamic significance is typically defined by fractional flow reserve (FFR) ≤ 0.80.

Purpose of the Study:

• To evaluate if intravascular ultrasound (IVUS)-derived minimum lumen area (MLA) indexed to left ventricular (LV) mass improves diagnostic accuracy for LMCA stenoses compared to unindexed MLA.
• To compare MLA indexed to height, body surface area (BSA), and body mass index (BMI) against unindexed MLA.

Main Methods:

• Prospective enrollment of 52 patients with intermediate LMCA lesions.
• Performance of IVUS and FFR measurements in all patients.
• Primary endpoint: diagnostic accuracy of indexed vs. unindexed MLA for identifying hemodynamically significant LMCA stenoses.

Main Results:

• MLA indexed to LV mass showed the highest diagnostic accuracy (AUC = 0.91).
• At a cutoff of 29 mm²/kg, MLA/LV mass achieved 100% sensitivity and 100% negative predictive value (NPV), with 70% specificity.
• All MLA thresholds, indexed or unindexed, had low positive predictive values (PPV) ranging from 46% to 55%.

Conclusions:

• The MLA/LV mass ratio shows promise as an accurate tool for ruling out flow-limiting LMCA lesions.
• Further large-scale studies are required to validate the MLA/LV mass ratio across diverse populations and refine cutoff values.