Microscopic evaluation of mechanical burr degradation mechanisms after rotational atherectomy

Abstract

Abstract Background Rotational atherectomy is a highly effective technique to facilitate percutaneous intervention on highly calcified coronary lesions. In some cases, despite numerous passages of the burr, successful crossing of the lesion is impossible. Empirical evidence shows that burr replacement is usually successful, therefore suggesting possible mechanical wear of the tool, however this hypothesis was never tested. Aims The aim of this study was to asses the possible mechanisms of mechanical burr degradation after rotational atherectomy in scanning electron microscope. Methods Burrs after the procedure were cleaned and examined in the scanning electron microscope. In order to facilitate the quantification of possible changes burrs were divided into 7 areas in which the analysis was carried out separately according to preestablished protocol. There were several methods applied to determine the degree of tool wear. The first one was to count the number of pull-outs of the diamond coating. Secondly we used image analysis to determine the dark phase share in the particular areas, which corresponds to the amount of the diamond phase. Finally we compared new burrs with used ones to asses weather any signs of mechanical wear of the tool were visible. Examples of burr division and applied methods are presented in Figure 1. Results We included 13 burrs into our analysis, 2 new ones and 11 that were used for various amount of time during the procedure (24 to 540 seconds, mean 132 seconds). Except for one area there were no differences between new and used burrs in regard of studied parameters. Results are presented in Table 1. Conclusions Our study showed no signs of mechanical wear of rotablation burrs during the procedure. Further studies are needed to evaluate other possible causes of burr's loss of grinding properties such as covering by biological particles etc. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Wrocław Medical University