Angiographic Characteristics of Intermediate Stenosis of the Left Anterior Descending Artery for Determination of Lesion Significance as Identified by Fractional Flow Reserve

Previous studies have shown a poor correlation between angiographic assessment of stenosis grade (%) and its functional assessment by fractional flow reserve (FFR). This study aimed to investigate whether a more comprehensive evaluation of the coronary angiogram may contribute to a better identification of flow-limiting stenoses. Coronary angiograms of 1,350 patients (1,883 lesions) were retrospectively analyzed for stenosis grade (eyeballing, %) and matched with FFR values. Angiography-derived optimal cut-off values and intervals delineating the [90% sensitivity–90% specificity] range were 50.8% [42.5–65.0%] for the left main (LM), 62.2% [50.0–72.5%] for the proximal (prox)/mid left anterior descending (LAD) artery, 66.3% [57.5–77.5%] for the prox/mid right coronary artery (RCA), 70.5% [60.0–80.0%] for the prox left circumflex/first obtuse marginal (LCX/OM1), and 71.4% [62.5–82.5%] for the more distal segments. In patients with intermediate LAD lesions, 5 angiographic parameters were identified as independent predictors of flow limitation: (1) a 30–50% lesion prox to the lesion of interest, (2) lesion length >20 mm, (3) distal take-off of all diagonal branches ≥2 mm diameter, (4) “apical wrap” of LAD, and (5) collaterals to an occluded LCX/RCA. Based on these results, a risk score (P20-DAC2) for prediction of flow limitation in intermediate LAD lesions was derived. In conclusion, a comprehensive evaluation of the coronary angiogram–in which besides stenosis grade also other lesion/vessel characteristics are evaluated–can lead to a more accurate identification of functionally significant coronary stenoses.