When should fractional flow reserve be performed to assess the significance of borderline coronary artery lesions: Derivation of a simplified scoring system

Objectives To derive a simplified scoring system (SSS) that can assist in selecting patients who would benefit from the application of fractional flow reserve (FFR). Background Angiographers base decisions to perform FFR on their interpretation of % diameter stenosis (DS), which is subject to variability. Recent studies have shown that the amount of myocardium at jeopardy is an important factor in determining the degree of hemodynamic compromise. Methods We conducted a retrospective multivariable analysis to identify independent predictors of hemodynamic compromise in 289 patients with 317 coronary vessels undergoing FFR. A SSS was derived using the odds ratios as a weighted factor. The receiver operator characteristics curve was used to identify the optimal cutoff (≥ 3) to discern a functionally significant lesion (FFR ≤ 0.8). Results Male gender, left anterior descending artery apical wrap, disease proximal to lesion, minimal lumen diameter and % DS predicted abnormal FFR (≤ 0.8) and lesion location in the left circumflex predicted a normal FFR. Using a cutoff score of ≥ 3 on the SSS, a specificity of 90.4% (95% CI: 83.0–95.3) and a sensitivity of 38.0% (95% CI: 31.5–44.9) was generated with a positive predictive value of 89.0% (95% CI: 80.7%–94.6%) and negative predictive value of 41.6% (95% CI: 35.1%–48.3%). Conclusions The decision to use FFR should be based not only on the % DS but also the size of the myocardial mass jeopardized. A score of ≥ 3 on the SSS should prompt further investigation with a pressure wire.