18F-GP1 Positron Emission Tomography and Bioprosthetic Aortic Valve Thrombus

JACC Cardiovasc Imaging. 2022 Jun;15(6):1107-1120. doi: 10.1016/j.jcmg.2021.11.015. Epub 2022 Jan 12.


Background: Bioprosthetic valve thrombosis may have implications for valve function and durability.

Objectives: Using a novel glycoprotein IIb/IIIa receptor radiotracer 18F-GP1, we investigated whether positron emission tomography (PET)-computed tomography (CT) could detect thrombus formation on bioprosthetic aortic valves.

Methods: Ex vivo experiments were performed on human platelets and explanted bioprosthetic aortic valves. In a prospective cross-sectional study, patients with either bioprosthetic or normal native aortic valves underwent echocardiography, CT angiography, and 18F-GP1 PET-CT.

Results: Flow cytometric analysis, histology, immunohistochemistry, and autoradiography demonstrated selective binding of 18F-GP1 to activated platelet glycoprotein IIb/IIIa receptors and thrombus adherent to prosthetic valves. In total, 75 participants were recruited: 53 with bioprosthetic valves (median time from implantation 37 months [IQR: 12-80 months]) and 22 with normal native aortic valves. Three participants had obstructive valve thrombosis, and a further 3 participants had asymptomatic hypoattenuated leaflet thickening on CT angiography. All bioprosthetic valves, but none of the native aortic valves, demonstrated focal 18F-GP1 uptake on the valve leaflets: median maximum target-to-background ratio 2.81 (IQR: 2.29-3.48) vs 1.43 (IQR: 1.28-1.53) (P < 0.001). Higher 18F-GP1 uptake was independently associated with duration of valve implantation and hypoattenuated leaflet thickening. All 3 participants with obstructive valve thrombosis were anticoagulated for 3 months, leading to resolution of their symptoms, improvement in mean valve gradients, and a reduction in 18F-GP1 uptake.

Conclusions: Adherence of activated platelets is a common and sustained finding on bioprosthetic aortic valves. 18F-GP1 uptake is higher in the presence of thrombus, regresses with anticoagulation, and has potential use as an adjunctive clinical tool. (18F-GP1 PET-CT to Detect Bioprosthetic Aortic Valve Thrombosis; NCT04073875).

Keywords: 18F-GP1; bioprosthetic aortic valve replacement; positron emission tomography-computed tomography; thrombus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aortic Valve / diagnostic imaging
  • Aortic Valve / surgery
  • Bioprosthesis*
  • Cross-Sectional Studies
  • Heart Valve Prosthesis*
  • Humans
  • Positron Emission Tomography Computed Tomography
  • Positron-Emission Tomography
  • Predictive Value of Tests
  • Prospective Studies
  • Thrombosis* / diagnostic imaging
  • Thrombosis* / etiology

Associated data

  • ClinicalTrials.gov/NCT04073875