Shaping the tip of microcatheters for superselective catheterization: steam vs. manual methods

We aimed to evaluate and compare the shapeability and stability of five microcatheters commonly used in interventional radiology after steam shaping and manual shaping.

Steam shaping was performed using three mandrels of different angles: L(S) shape (90°), U(S) shape (180°), and O(S) shape (360°). Three manual shapes-L(M), U(M), and O(M)-were made to have a similar angle to their steam-shaped counterparts. The stability of the microcatheters was evaluated by passing them through a 5 F catheter and inserting microguidewires. The tip angles of the microcatheters and the angle change rates were compared between groups.

The mean angle of the microcatheters after steam shaping was 42.4°-54.1° for L(S) shape, 80.2°-96.7° for U(S) shape, and 130.7°-150.8° for O(S) shape. Five microcatheters showed significantly different mean angle reductions after passing through the 5 F catheter (17.4%-30.3%) and inserting microguidewires (24.1%-61.2%). Different microguidewires also caused significantly different mean angle reductions (34.6%-50.8%). The reduced angle caused by the guidewire was almost completely recovered after withdrawing it (93.2%-101.6%). Although manual-shaped microcatheters showed a 4.2%-6.3% greater angle reduction than steam-shaped microcatheters after passing through the 5 F catheter, the final tip angle was not significantly different between the two groups and was within 10%.

The tip angle of the microcatheters after steam shaping using mandrels may differ depending on the shape of the mandrel and the type of microcatheter used, and the stability varies depending on the type of microcatheter. The manual shaping of microcatheters can be a good alternative to steam shaping.