Utility of CAD-RADS 2.0 Plaque Burden Grades and Stenosis Categories on Coronary CTA for Predicting Cardiac Events in Patients With Acute Chest Pain: A Multicenter Study.

Abstract

<b>BACKGROUND</b>. Coronary Artery Disease Reporting and Data System (CAD-RADS) 2.0 incorporated reporting of plaque burden grades in addition to stenosis categories. <b>OBJECTIVE</b>. The purpose of this study was to assess the usefulness of plaque burden grades and CAD-RADS categories, determined on coronary CTA by use of CAD-RADS 2.0, in predicting cardiac events in patients presenting to the emergency department (ED) with acute chest pain. <b>METHODS</b>. This retrospective study included patients who underwent coronary CTA after presenting to the ED with acute chest pain at one of four centers from January 2018 to December 2021. A single radiologist reviewed examinations at each center to assign a plaque burden grade by calculating a coronary artery calcium score on noncontrast images and to assign a CAD-RADS category by assessing vessel stenosis on contrast-enhanced CTA images, with both assignments made using CAD-RADS 2.0. The reviewing radiologist at each center also assessed examinations for the presence of high-risk plaque. The EMR was reviewed for cardiac events, reflecting a composite outcome of cardiac-related death, myocardial infarction, or hospitalization for unstable angina. Prognostic models were compared. <b>RESULTS</b>. The study included 2032 patients (1085 men and 947 women; mean age, 58.4 years). During a median follow-up of 15.2 months, 63 patients (3.1%) had cardiac events. In a multivariable Cox model adjusting for clinical variables, cardiac events showed significant independent associations with CAD-RADS 3 (HR = 7.1), CAD-RADS 4 (HR = 13.6), CAD-RADS 5 (HR = 17.6), and high-risk plaque (HR = 2.5) but not with plaque burden grades. For predicting cardiac events, the C statistic was 0.67 for a model including clinical variables; 0.74 for a model including clinical variables and plaque burden grades; 0.86 for a model including clinical variables, CAD-RADS categories, and high-risk plaque; and 0.87 for a model including clinical variables, plaque burden grades, CAD-RADS categories, and high-risk plaque. The model with clinical variables, CAD-RADS categories, and high-risk plaque but without plaque burden grades showed the highest net clinical benefit across threshold probabilities from 20% to 100%. <b>CONCLUSION</b>. Addition of plaque burden grades did not provide further prognostic benefit in models using CAD-RADS categories. <b>CLINICAL IMPACT</b>. Inclusion of an additional noncontrast acquisition for coronary artery calcium scoring within coronary CTA protocols may not improve risk stratification for patients presenting to the ED with chest pain.