Impact of Burr Speed and Polishing Run Sequences on Rotational Atherectomy Efficacy In Vitro

<h2>Abstract</h2><h3>Background</h3> The impact of burr speed on rotational atherectomy (RA) mechanical efficacy remains debated. We aimed to analyze the effect of different RA protocols on postinterventional luminal gain. <h3>Methods</h3> Procedures were performed in vitro on proximal left anterior descending artery with a 1.75-mm burr in a 3-dimensional–printed beating heart model. All lesions first underwent a high speed (HS; 180,000 revolutions per minute) pecking run followed by a HS polishing run of 30 seconds. This standard technique was completed by additional 30-second low speed (LS; 110,000 revolutions per minute) runs as follows: 1 (LS short group, n=28 lesions); 2 (LS midgroup, n=30 lesions), or 3 additional LS runs (LS long group, n=27 lesions), while the control group (n = 27 lesions) received no additional polishing. An additional HS long group in which 3 additional 30-second HS polishing runs were delivered following the initial standard steps was also created (n = 27 lesions). The specimens were analyzed by microcomputed tomography scan to measure the average luminal volume (ALV) and minimal cross-section area. <h3>Results</h3> The baseline lesion ALV and minimal cross -section area were and 128.57 mm³ and 1.56 mm², respectively. The final ALV was significantly higher in LS short (median, 158.9 mm³ [IQR, 150.0-164.9]), LS mid (median, 156.4 mm³ [IQR, 147.1-167.1]), LS long (median, 157.1 mm³ [IQR, 151.0-166.2]), and HS long groups (median, 156.6 mm³ [IQR, 149.0-169.9]) than control specimens (median, 146.8 mm³ [IQR, 137.5-157.3]: <i>P</i> < .001). These values did not differ significantly between all groups with additional polishing runs. Similar results were observed for MSCA and MSCA gain. <h3>Conclusions</h3> These data suggest that additional polishing runs after standard RA procedure improves the debulked lesion volume, regardless of burr speed.