The incidence of slow flow after rotational atherectomy of calcified coronary arteries: A randomized study of low speed versus high speed

OBJECTIVES: The purpose of this randomized trial was to compare the incidence of slow flow between low-speed and high-speed rotational atherectomy (RA) of calcified coronary lesions. BACKGROUND: Preclinical studies suggest that slow flow is less frequently observed with low-speed than high-speed RA because of less platelet aggregation with low-speed RA. METHODS: This was a prospective, randomized, single center study. A total of 100 patients with calcified coronary lesions were enrolled and randomly assigned in a 1:1 ratio to low-speed (140,000 rpm) or high-speed (190,000 rpm) RA. The primary endpoint was the occurrence of slow flow following RA. Slow flow was defined as slow or absent distal runoff (Thrombolysis in Myocardial Infarction [TIMI] flow grade ≤ 2). RESULTS: The incidence of slow flow in the low-speed group (24%) was the same as that in the high-speed group (24%) (P = 1.00; odds ratio, 1.00; 95% confidence interval, 0.40-2.50). The frequencies of TIMI 3, TIMI 2, TIMI 1, and TIMI 0 flow grades were similar between the low-speed (TIMI 3, 76%; TIMI 2, 14%; TIMI 1, 8%; TIMI 0, 2%) and high-speed (TIMI 3, 76%; TIMI 2, 14%; TIMI 1, 10%; TIMI 0, 0%) groups (P = 0.77 for trend). The incidence of periprocedural myocardial infarction was the same between the low-speed (6%) and high-speed (6%) groups (P = 1.00). CONCLUSIONS: This randomized trial did not show a reduction in the incidence of slow flow following low-speed RA as compared with high-speed RA (UMIN ID: UMIN000015702).