# Prognostic Value of Cadmium-Zinc-Telluride Dedicated Cardiac SPECT Dynamic Myocardial Perfusion Quantitative Imaging in Patients with Coronary Chronic Total Occlusion: A Pilot Study

## TL;DR

This pilot study shows that CZT SPECT dynamic MPI can help predict poor outcomes in patients with coronary chronic total occlusion.

## Contribution

The study introduces CZT SPECT dynamic MPI as a novel tool for risk stratification in CTO patients.

## Key findings

- Lower stress myocardial blood flow and coronary flow reserve in CTO territory were linked to higher MACEs.
- Cut-off values for sMBF < 0.75 and CFR < 1.39 predicted MACEs with high sensitivity and specificity.
- Impaired sMBF or CFR significantly correlated with worse clinical outcomes in CTO patients.

## Abstract

Background: The prevalence of chronic total occlusion (CTO) lesions is as high as 30% in patients undergoing coronary angiography (CAG). Some CTO patients do not undergo revascularization due to procedural complexity and high risks. This study aimed to investigate the value of cadmium-zinc-telluride (CZT) SPECT dynamic myocardial perfusion imaging (MPI) for risk stratification and prognosis assessment in patients with coronary CTO. Methods: This study retrospectively included 62 patients who underwent CZT SPECT dynamic MPI examination and were diagnosed with CTO by angiography. The primary endpoint was major adverse cardiovascular events (MACEs), defined as cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, hospitalization for heart failure, late coronary revascularization, or hospitalization for unstable angina. Results: Over a median follow-up of 17 months (IQR 11–23), 15 MACEs occurred. The stress myocardial blood flow (sMBF) and coronary flow reserve (CFR) in the CTO territory were significantly lower in the MACEs group compared to the non-MACEs group (all p < 0.05). Receiver operating characteristic analysis determined the optimal cut-off values for predicting MACEs as sMBF < 0.75 (sensitivity 78.7%, specificity 73.3%, AUC = 0.74, p < 0.05) and CFR < 1.39 (sensitivity 70.2%, specificity 80.0%, AUC = 0.75, p < 0.01). Kaplan–Meier survival analysis showed that patients with impaired sMBF (p < 0.001) or impaired CFR (p < 0.01), defined by these cut-off values, had significantly worse clinical outcomes. Conclusions: The results of this study indicate that sMBF and CFR obtained from CZT SPECT dynamic MPI provide valuable prognostic prediction for patients with coronary CTO lesions, offering critical evidence for identifying high-risk patients requiring active intervention.