FAPI-SPECT Imaging: A Promising Tool for Predicting LV Remodeling After MI, Study Reveals

The researchers revealed that the novel method demonstrated abnormal cellular activity five days after a heart attack and detected so-called left ventricular (LV) remodeling after one year.

"The results of this study could transform post-acute myocardial infarction (MI) patient management by allowing for the early identification of individuals at risk for adverse left ventricular remodeling," Cuncun Hua, Capital Medical University, Beijing, China, and colleagues wrote in Journal of Nuclear Cardiology.

Left ventricular remodeling following a heart attack is a detrimental process characterized by cellular and structural changes in the myocardium, where the activation and proliferation of fibroblast cells play a crucial role. This remodeling can result in increased scar tissue formation in the heart, which is linked to the development of heart failure.

While PET imaging using F-18- and gallium-68 (Ga-68)-labeled fibroblast activation protein inhibitor (FAPI) radiotracers is well-established for assessing this activity, the authors noted that the use of Tc-99m FAPI-SPECT is gaining popularity due to its greater cost-effectiveness.

Against the above background, the researchers aimed to evaluate the predictive utility of 99mTc-radiolabeled fibroblast activation protein inhibitor (99mTc-HFAPi) single-photon emission computed tomography imaging in post-acute myocardial infarction (AMI) patients for evaluating 12-month left ventricular (LV) remodeling.

Fifty-eight patients with AMI (46 males, median age 61 [53, 67] years) underwent baseline 99mTc-HFAPi imaging (5 ± 2 days after MI), perfusion imaging (6 ± 2 days after MI), and echocardiography (2 ± 2 days after MI). Additionally, 15 patients received follow-up 99mTc-HFAPi and perfusion imaging, while 30 had follow-up echocardiography. Myocardial 99mTc-HFAPi activity was evaluated at the individual patient level. Left ventricular remodeling was defined as a ≥10% increase in left ventricular end-diastolic diameter (LVEDD) or left ventricular end-systolic diameter (LVESD) from baseline to follow-up echocardiography.

The study led to the following findings:

• AMI patients displayed localized but non-uniform 99mTc-HFAPi uptake, exceeding perfusion defects.
• Baseline 99mTc-HFAPi activity exhibited significant correlations with BNPmax, LDHmax, cTNImax, and WBCmax, inversely correlating with LVEF.
• After 12 months, 36.66% of patients experienced LV remodeling.
• Univariate regression analysis demonstrated an association between baseline 99mTc-HFAPi uptake extent and LV remodeling (OR= 2.14).

"99mTc-HFAPi SPECT imaging holds promise in predicting LV remodeling post-myocardial infarction, providing valuable insights for patient management and prognosis," the researchers wrote.

"This identification could lead to personalized interventions, potentially enhancing clinical outcomes and decreasing the risk of heart failure development," they concluded.

Reference:

Hua, C., Xi, X., Zhang, Y., Suo, N., Tu, B., Liu, Y., Yang, X., Liu, X., Su, P., Xie, B., Yang, M., & Wang, Y. (2024). 99mTc-HFAPi SPECT Imaging Predicts Left Ventricular Remodeling After Acute Myocardial Infarction. Journal of Nuclear Cardiology, 101910. https://doi.org/10.1016/j.nuclcard.2024.101910