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

Abstract Background 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. Methods 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. Results 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]: P < .001). These values did not differ significantly between all groups with additional polishing runs. Similar results were observed for MSCA and MSCA gain. Conclusions These data suggest that additional polishing runs after standard RA procedure improves the debulked lesion volume, regardless of burr speed.