Prognostic significance of stress dynamic myocardial CT perfusion: comparison with CT-FFR and CT angiography stenosis-the multicenter VALIDITY trial.

Objectives: This study aimed to investigate the prognostic significance of stress dynamic myocardial CT perfusion imaging (CTP) and determine whether it has incremental advantages over coronary computed tomography angiography (CTA)-derived parameters.

Methods: This prospective multicenter study included patients with suspected coronary artery disease who had undergone coronary CTA and CTP and were followed for 6 years. The endpoint was time-to-first major adverse cardiovascular event (MACE). MACEs included all-cause mortality, cardiac death, nonfatal myocardial infarction, unstable angina, late revascularization, and heart failure or aggravated angina symptoms requiring hospitalization. The CTP-derived absolute myocardial blood flow (MBF), relative MBF ratio (r-MBF), and the CTA-derived fractional flow reserve (CT-FFR) and stenosis were analyzed. The independent predictors, time-to-event distributions and the incremental prognostic value of CTP over CTA-derived parameters were assessed.

Results: A total of 226 patients (66.7 ± 11.3 years, 37.6% women) were enrolled with a median follow-up time of 1233 days. Twenty-one patients (9.29%) experienced MACEs and ten patients (4.4%) experienced hard MACEs. The r-MBF was the only independent predictor for MACEs in both all patients (hazard ratio [HR]: 0.82 (0.69-0.97), p = 0.01) and patients available for CTA stenosis (%) and CT-FFR calculation (HR: 0.72 (0.57-0.91), p = 0.006). The incremental prognostic significance of r-MBF over CT-FFR was confirmed after combining with CTA-derived parameters (concordance index: 0.919 vs. 0.811; p < 0.01). Patients with r-MBF < 0.77 were more likely to experience MACEs and have a lower average survival time (1565 vs. 1790 days; p < 0.01) after stent implantation.

Conclusions: CTP-assessed r-MBF was independently correlated with MACEs and provided incremental prognostic significance.

Key points: Question The prognostic significance of CT perfusion (CTP) lacks sufficient support from clinical research. Findings In this Chinese population, CTP has the strongest prognostic significance, over CT-Fractional Flow Reserve (FFR) and CTA stenosis in predicting major adverse cardiovascular events (MACEs). Clinical relevance Relative myocardial blood flow ratio had the strongest prognostic value and incremental advantages in predicting MACEs beyond CT-FFR and coronary CTA stenosis quantification, as well as advantages in patients with stents, aiding in personalized diagnosis and treatment plans.