Background: Long-term changes of asymptomatic early hypo-attenuated leaflet thickening (HALT) after transcatheter aortic valve implantation (TAVI) on CTA have not been described yet.

Aims: Investigation of changes of HALT on CTA in the long-term.

Methods: In this prospective observational study, ten patients (79±6years, three female) diagnosed with HALT early after TAVI underwent follow-up CTA after a median of 4.1 years (interquartile range 3.6;4.9years). Leaflet thickening (mm), thrombus extent (5-point scale: (0) no, (I) <25%, (II) 25-50%, (III) 50-75%, (IV) >75% leaflet involvement), and leaflet motion (4-point scale: (0) normal, (I) mildly reduced, (II) severely reduced, (III) abrogated mobility) were assessed.

Results:

The number of leaflets affected by HALT increased from 15/30(50%) to 23/30(78%) on follow-up CT scans (p=0.021). Thirteen leaflets (43%) showed persistent or increasing changes and ten (33%) new evidence of HALT. HALT had resolved in two leaflets. Mean leaflet thickness increased from 1.1±0.7mm to 1.8±1.3mm (P=0.003), mean leaflet involvement from 0.9±1.1 to 1.6±1.3 units (P=0.007), and the mean leaflet restriction score from 0.9±1.1 to 1.6±1.3 units (P=0.005). Individual leaflet analysis showed a significant increase in leaflet involvement (0.9±1.1 to 1.5±1.3, P=0.034) and in the restriction score (0.3±0.5 to 0.7±0.7, P=0.046) in the right coronary leaflet. There was no calcification on any leaflet. Echocardiography demonstrated a trend to a decrease in velocity ratio (0.55±0.15 to 0.48±0.09, P=0.051).

Conclusions: In patients diagnosed with early HALT, computer tomographic changes including leaflet thickness and leaflet restriction increase in the long-term suggesting a role for HALT in the development of chronic valve deterioration.