The prognostic value of quantitative myocardial blood flow and flow reserve by dynamic CZT-SPECT for major adverse cardiovascular events.

PURPOSE: Cadmium-zinc-telluride single-photon emission computed tomography (CZT SPECT) enables myocardial blood flow (MBF) quantification using 99mTc-labeled tracers; however, its prognostic value is less well established. This study evaluated the prognostic value of CZT SPECT-derived MBF and myocardial flow reserve (MFR) for major adverse cardiovascular events (MACEs) in patients with suspected ischemic heart disease. METHODS: We retrospectively included 1,007 consecutive patients who underwent dynamic [99mTc]Tc-sestamibi myocardial perfusion imaging using a CZT D-SPECT camera from June 2018 to May 2021, after excluding those who underwent early revascularization within 90 days. MBF and MFR were quantified using Corridor 4DM software with a net retention model. A MACE was defined as a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, heart failure hospitalization, or late coronary revascularization. Maximally selected rank statistics were used to determine the optimal thresholds for stress MBF and MFR. RESULTS: During a median follow-up of 49 months, MACEs occurred in 191 patients (19.0%). The optimal cutoffs were 1.96 mL/g/min for stress MBF and 1.98 for MFR. Abnormal flow was associated with worse MACE-free survival (χ² = 87.2, p < 0.001). In multivariable analysis, MFR and resting MBF remained independent predictors of a MACE after adjusting for clinical risk factors, stress left ventricular ejection fraction, and stress total perfusion deficit (sTPD). Quantitative flow assessment provided incremental risk stratification in patients with sTPD < 15%. CONCLUSION: CZT SPECT-derived MBF and MFR provided independent prognostic information beyond conventional risk factors and static perfusion assessment, supporting their role in refining clinical risk stratification.