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

BACKGROUND

The additional prognostic value of 18F-flurodeoxyglucose positron emission tomography (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 (MACEs) compared to clinical risk factors, Global Registry of Acute Coronary Events (GRACE) score, and coronary artery calcium score (CACS) in patients with suspected UA.

METHODS

In this post hoc analysis of a prospective study, 265 patients suspected with UA (62.3% male, mean age: 65.0±9.4 years) were enrolled. 18F-FDG positivity was defined as focal or focal on diffuse uptake patterns. MACEs included cardiovascular death, acute myocardial infarction, heart failure, rehospitalization for UA, and stroke. Multivariable Cox regression was used to identify predictors of MACEs, and the incremental prognostic value of 18F-FDG PET imaging was assessed using the Concordance Index (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 MACEs. 18F-FDG positivity (hazard ratio [HR]=3.220, 95% confidence interval [CI]: 1.630-6.360, P<.001), as well as 18F-FDG standardized uptake ratio (HR=1.330, 95% CI: 1.131-1.564, P=.0006) and Extent (HR=1.045, 95% CI: 1.028-1.062, P<.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 (.769 vs .688, P=.045), NRI (.324, P=.020), and IDI (.055, P=.027).

CONCLUSION

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