Investigation of Factors Determining Hemodynamic Relevance of Leaflet Thrombosis after TAVI.

AIMS: To determine the conditions under which early hypoattenuated leaflet thickening (HALT) after transcatheter aortic valve implantation (TAVI) becomes hemodynamically relevant.

METHODS AND RESULTS: The study included 100 patients (age: 81.5 ± 5.5 years; female 63%), thereof 50 patients with HALT. After anonymization and randomization, blinded readers measured maximum thrombus thickness per prosthesis (MT_pr) and movement restriction (MR_pr) on ECG-gated whole heart cycle CTA. These measurements were compared with echocardiographic mean pressure gradient (mPG), its increase from baseline (ΔmPG) and doppler velocity index (DVI). Hemodynamic valve deterioration (HVD) was defined as mPG > 20mmHg. Age, body mass index, valve type, valve size, left ventricular ejection fraction and atrial fibrillation were considered as influencing factors.Multiple regression analysis revealed that only valve size (p = 0.001) and MT_pr (p = 0.02) had a significant influence on mPG. In an interaction model valve size moderated the effect of MT_pr on mPG significantly (p = 0.004). Subgroup analysis stratified by valve sizes showed a strong correlation between MT_pr and echocardiographic parameters for 23 mm valves (mPG: r = 0.57, ΔmPG: r = 0.68, DVI: r = 0.55, each with p < 0.001), but neither for 26 mm nor 29 mm valves (r < 0.2, p > 0.2 for all correlations). Six of seven prostheses with HVD had a 23 mm valve diameter, while one had 29 mm (p = 0.02).

CONCLUSION: Early HALT rarely causes significant mPG increase. Our study shows that valve size is a key factor influencing the hemodynamic impact of HALT. In small valve sizes, mPG is more likely to increase. Our study is the first to offer in vivo evidence supporting previous in vitro findings on this topic.