High-intensity transient signals during transcatheter aortic valve implantation assessed by ultrasonic carotid artery blood-flow monitoring: A single center prospective observational study.

Background: No reports to date have assessed the procedural patterns of high-intensity transient signals (HITS) by monitoring blood flow in cervical arteries. The aim of this study was to examine the sequential distribution of HITS in each procedural phase and predictive factors for HITS during transcatheter aortic valve implantation (TAVI) by monitoring blood flow in the common carotid artery.

Methods: This prospective observational study included 73 patients who underwent TAVI via the transfemoral artery approach. We continuously evaluated and analyzed HITS from administration of heparin to valve implantation.

Results: HITS peaked during balloon valvuloplasty (BAV), amounting to almost 30% of the total HITS count, followed by valve implantation [BAV 141 (73-186) and valve implantation 86 (64-126), respectively]. In univariate and multivariate analysis, the Agatston score of the aortic valve and low-density lipoprotein were confirmed as independent predictors of HITS frequency with logarithmically converted coefficients of 0.00015 (p < 0.001) and 0.0032 (p = 0.027), respectively.

Conclusions: These results provide the first evidence that micro-emboli deriving from calcified burden were scattered primally during BAV, followed by valve implantation. The Agatston score may be a predictor for the amount of HITS.