The CatLet score: A new coronary angiographic scoring tool accommodating the variable coronary anatomy for the first time

Background: The SYNTAX score for decision makings or outcome predictions in coronary artery disease does not account for the variations in the coronary anatomy, which is a clear fallacy for patients with less typical anatomy than suggested by the SYNTAX score. The current study aimed to derive a new coronary angiographic scoring system accommodating the variability in the coronary anatomy. Methods: The 17-myocardial segment model and laws of competitive blood supply and flow conservation were utilized to derive this new scoring system. Results: We obtained 6 types of RCA dominance, 3 types of diagonal size and 3 types of left anterior descending artery (LAD) length, which together resulted in a total of 54 patterns of coronary artery circulation to account for the variability in the coronary anatomy among individuals. A Coronary Artery Tree description and Lesion EvaluaTion (CatLet) angiographic scoring system has been designed based on the above-mentioned reclassification scheme (htpp://www.catletscore.com, IE browser is required to run this calculator). Conclusions: This new CatLet angiographic scoring system accommodated the variability in the coronary anatomy and standardized the collection of the coronary angiographic data, which could facilitate the comparison and exchange of these data between different catheter labs. Its utility for predicting the clinical outcomes and standardizing the angiographic data collection will be investigated in a series of clinical trials enrolling "all-comers" with coronary artery disease (CAD).