Imaging of Myocardial α_vβ₃Integrin Expression for Evaluation of Myocardial Injury After Acute Myocardial Infarction

Abstract

[⁶⁸Ga]Ga-NODAGA-Arg-Gly-Asp (RGD) is a PET tracer targeting α_vβ₃ integrin, which is upregulated during angiogenesis soon after acute myocardial infarction (AMI). We prospectively evaluated determinants of myocardial uptake of [⁶⁸Ga]Ga-NODAGA-RGD and its associations with left ventricular (LV) function in patients after AMI. <b>Methods:</b> Myocardial blood flow and [⁶⁸Ga]Ga-NODAGA-RGD uptake (60 min after injection) were evaluated by PET in 31 patients 7.7 ± 3.8 d after primary percutaneous coronary intervention for ST-elevation AMI. Transthoracic echocardiography of LV function was performed on the day of PET and at the 6-mo follow-up. <b>Results:</b> PET images showed increased uptake of [⁶⁸Ga]Ga-NODAGA-RGD in the ischemic area at risk (AAR), predominantly in injured myocardial segments. The SUV in the segment with the highest uptake (SUV_max) in the ischemic AAR was higher than the SUV_mean of the remote myocardium (0.73 ± 0.16 vs. 0.51 ± 0.11, <i>P</i> < 0.001). Multivariable predictors of [⁶⁸Ga]Ga-NODAGA-RGD uptake in the AAR included high peak N-terminal pro-B-type natriuretic peptide (<i>P</i> < 0.001), low LV ejection fraction, low global longitudinal strain (<i>P</i> = 0.01), and low longitudinal strain in the AAR (<i>P</i> = 0.01). [⁶⁸Ga]Ga-NODAGA-RGD uptake corrected for myocardial blood flow and perfusable tissue fraction in the AAR predicted improvement in global longitudinal strain at follow-up (<i>P</i> = 0.002), independent of peak troponin, N-terminal pro-B-type natriuretic peptide, and LV ejection fraction. <b>Conclusion:</b> [⁶⁸Ga]Ga-NODAGA-RGD uptake shows increased α_vβ₃ integrin expression in the ischemic AAR early after AMI that is associated with regional and global systolic dysfunction, as well as increased LV filling pressure. Increased [⁶⁸Ga]Ga-NODAGA-RGD uptake predicts improvement of global LV function 6 mo after AMI.