Comparison of the incidence of slow flow following rotational atherectomy to severely calcified coronary artery lesions between short single session and long single session strategies: the randomized ROTASOLO trial.

Slow flow is the most common complication of rotational atherectomy (RA). Compared with long single sessions, short single sessions may reduce the incidence of slow flow just after RA. This study aimed to compare the incidence of slow flow just after RA between short single session and long single session strategies. This multicenter, 1:1 randomized clinical trial was conducted at 3 hospitals in Japan. The short single session strategy was defined as repeating short single sessions (up to 15 s) of RA, whereas the long single session strategy was defined as repeating long single sessions (20-30 s) until the burr crossed the target lesion. The primary outcome was slow flow just after RA, which was defined as [(initial TIMI-frame count before RA) × 1.1 minus (TIMI-frame count just after RA)] less than 0. During the study period, 266 patients were included in the final study population and were randomly assigned to the Short single session group (n = 132) or the long single session group (n = 134). The protocol adherence rate was equally high in both groups (Short single session: 98.5% versus long single session 94.8%, p = 0.172). The incidence of slow flow just after RA was similar between the 2 groups (short single session:14.4% versus long single session: 14.9%, p > 0.999). In conclusion, this randomized trial did not show a benefit of the short single session strategy compared with the long single session strategy in RA with respect to the prevention of slow flow (Unique identifier: UMIN000047231).