Thrombosis of Bioprosthetic Aortic Valve: Is the Entire Arsenal Deployed?

Abstract

The proliferation of transcatheter aortic valve implantation has alerted clinicians to a specific type of prosthetic degeneration represented by thrombosis. The pathogenesis of this clinical or subclinical phenomenon, which can occur in up to 15% of both surgical and percutaneous procedures, is poorly understood, as is its potential impact on patient prognosis and long-term bioprosthesis durability. Based on this lack of knowledge about the real meaning and importance of bioprosthetic valve thrombosis, the aim of the present review is to draw the clinicians' attention to its existence, starting from the description of predisposing factors that may require a closer follow-up in such categories of patients, to an in-depth overview of all available imaging modalities with their respective pros and cons. Finally, a glimpse into the future of technology and biomarker development is presented. The hope is to increase the rate of bioprosthetic diagnosis, especially of the subclinical one, in order to understand (thanks to a strict and prolonged follow-up) if it can only be considered as an incidental tomographic entity without significant clinical consequences, or, on the contrary, if it is associated with neurological events or accelerated bioprosthetic degeneration. Nevertheless, despite the technical advances of echocardiography and cardiac tomography in terms of accurate bioprosthesis thrombosis detection, several diagnostic and therapeutic issues remain unresolved, including possible prevention strategies, tailored treatment protocols, and follow-up modalities.

Keywords: aortic valve; bioprosthesis; computed tomography; echocardiography; thrombosis.

Fig. 1.

Native bicuspid valve experiencing TAVI thrombosis. (A) Axial view of the native valve showing bicuspid morphology with calcific raphe between the coronary cusps. (B) Axial, sagittal oblique and coronal oblique view of the transcatheter heart valve displaying post-procedural thrombosis of the non-coronary sinus. TAVI, transcatheter aortic valve implantation.

Fig. 2.

Hypoattenuated lesions at CT. (A) Short axis view of the transcatheter heart valve showing thickened and hypoattenuating leaflets. (B) Coronal oblique view. (C) Sagittal oblique view. (D) CT attenuation levels lower than those observed within the myocardium ($\le$90 HU) suggesting a thrombus. CT, computed tomography; HU, hounsfield units.