Subclinical leaflet thrombosis: should we be concerned?

Since the first transcatheter aortic valve implantation (TAVI) on 16 April 2002, by the late Alain Cribier, as a percutaneous treatment for aortic stenosis, multiple studies have demonstrated the efficacy and safety of this approach. Over the last decade, with a refinement in imaging techniques and broad use of TAVI bioprostheses, subclinical leaflet thrombosis (SLT), quantified via four-dimensional computed tomography angiography (4D-CTA) and the imaging correlates, hypoattenuated leaflet thickening (HALT) and reduced leaflet motion have been identified as early complications after TAVI. In the clinical reality of patients without an indication for oral anticoagulation, core lab rates of HALT at 30 days and 1 year have been described at 24.5% and 32.0%, respectively1. Additionally, HALT does fluctuate regardless of medical therapy: most of the patients who had it at 1 month were not the same as those who had it at 1 year.

The impact of SLT on cardiovascular outcomes and early degeneration of TAVI bioprostheses remains poorly understood, with conflicting results reported in the literature. Hence, as controversy surrounds the clinical relevance of SLT, we should be considering several...