Incremental prognostic value of 18F-FDG myocardial ischemic memory imaging for major adverse cardiovascular events in patients with suspected unstable angina.

Background: The additional prognostic value of ¹⁸F-FDG PET myocardial ischemic memory imaging for patients with suspected unstable angina (UA) is not well established. This study aimed to determine whether ¹⁸F-FDG PET imaging provides incremental prognostic information for predicting major adverse cardiac events (MACE) compared to clinical risk factors, GRACE score, and coronary artery calcium score (CACS) in suspected UA patients.

Methods: In this post-hoc analysis of a prospective study, 265 suspected UA patients (62.3% male, mean age 65.0±9.4 years) were enrolled. ¹⁸F-FDG positive was defined as focal or focal on diffuse uptake patterns. MACE included cardiovascular death, acute myocardial infarction, heart failure, rehospitalization for UA, and stroke. Multivariable Cox regression was used to identify predictors of MACE, and the incremental prognostic value of ¹⁸F-FDG PET imaging was assessed using C-index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

Results: Over a median follow-up of 25 months, 51 patients (19.2%) experienced MACE. ¹⁸F-FDG positive (HR=3.220, 95% CI: 1.630-6.360, P<0.001) , as well as ¹⁸F-FDG standardized uptake ratio (SUR) (HR=1.330, 95%CI: 1.131-1.564, P=0.0006) and Extent (HR=1.045, 95%CI: 1.028-1.062, P<0.0001), were independent predictors of MACE. The addition of ¹⁸F-FDG PET imaging significantly improved risk stratification beyond clinical factors, the GRACE score, and CACS, with improved C-index (0.769 vs 0.688, P=0.045), NRI (0.324, P=0.020), and IDI (0.055, P=0.027).

Conclusion: ¹⁸F-FDG PET myocardial ischemic memory imaging significantly improves prognostic assessment for suspected UA patients, providing valuable additional risk stratification beyond clinical risk factors, GRACE score, and CACS.