Key result
[68Ga]Ga-FAPI PET identifies severe aortic stenosis hemodynamics with up to ~0.89 AUC.
Why the study?
Early diffuse interstitial fibrosis in aortic stenosis is often difficult to detect with conventional imaging, and the usefulness of [68Ga]Ga-FAPI PET for evaluating myocardial remodeling in patients with severe AS had not yet been determined.
Does [68Ga]Ga-FAPI PET/CT detect early myocardial fibrotic activity and correlate with hemodynamic severity in patients with severe aortic stenosis undergoing TAVR?
Observational (n=18)
Does [68Ga]Ga-FAPI PET/CT detect early myocardial fibrotic activity and correlate with hemodynamic severity in patients with severe aortic stenosis undergoing TAVR?
[68Ga]Ga-FAPI PET/CT demonstrates diffuse left ventricular fibroblast activation in patients with severe aortic stenosis, suggesting its potential as a non-invasive biomarker of early myocardial fibrotic remodeling prior to TAVR.
Should not yet change TAVR evaluation in severe aortic stenosis; leaves open prospective validation of [68Ga]Ga-FAPI PET/CT for fibrosis assessment.
Background Aortic stenosis (AS) causes ongoing pressure overload on the left ventricle and leads to progressive myocardial remodeling. Early diffuse interstitial fibrosis often remains difficult to detect with conventional imaging techniques. Fibroblast activation protein (FAP)–targeted positron emission tomography (PET) can visualize activated fibroblasts and profibrotic activity. However, the usefulness of [⁶⁸Ga]Ga-FAPI PET in evaluating myocardial remodeling in patients with severe AS has not yet been determined. Methods This post-hoc analysis involved 18 patients with severe aortic stenosis who underwent [⁶⁸⁻Ga]Ga-FAPI PET/CT scans before transcatheter aortic valve replacement. Myocardial tracer uptake was measured as the tracer retention fraction through dynamic PET imaging, evaluated both globally and segmentally. The study also examined correlations between tracer retention and clinical data, cardiac magnetic resonance parameters, and invasive hemodynamics using correlation and receiver operating characteristic analyses. Results All patients showed widespread myocardial [⁶⁸Ga]Ga-FAPI uptake throughout the heart without focal hotspots, indicating diffuse tracer retention. Segmental retention was inversely related to age at both, 60 and 120 minutes post-injection, especially in basal, mid-ventricular, and apical regions at 120 minutes. Uptake in the mid-septal region was also inversely associated with mean transaortic gradients. ROC analysis showed the tracer could effectively distinguish hemodynamic severity in mid-septal segments, with AUC values up to 0.89. Conclusion In patients with severe aortic stenosis, [⁶⁸Ga]Ga-FAPI PET/CT demonstrated diffuse left ventricular fibroblast activation, with higher tracer retention in mid-septal segments and in younger individuals. These findings suggest that FAPI-PET may serve as a non-invasive biomarker of early myocardial fibrotic remodeling prior to transcatheter aortic valve replacement.Figure 1.Scatter PlotFigure 2.Tracer uptake patterns
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Hamzaraj et al. (2026) conducted an observational in Severe aortic stenosis (n=18). [68Ga]Ga-FAPI PET/CT vs. Clinical data, cardiac magnetic resonance parameters, and invasive hemodynamics was evaluated on Myocardial tracer retention fraction and discrimination of hemodynamic severity (AUC up to 0.89). [68Ga]Ga-FAPI PET/CT detected diffuse myocardial uptake in 100% of severe aortic stenosis patients and distinguished hemodynamic severity in mid-septal segments (AUC up to 0.89).
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