Prediction of the debulking effect of rotational atherectomy using optical frequency domain imaging

Whether predicting the rotational atherectomy (RA) effect based on the position of optical frequency domain imaging (OFDI) is accurate remains uncertain. The aim of this study was to evaluate the predictive accuracy of OFDI in identifying RA location and area. Twenty-five patients who underwent RA with OFDI were included. On pre-RA OFDI images, a circle with the dimension of a Rota burr was drawn at the center of the OFDI catheter. The area where the circle overlapped with the vessel wall was defined as the predicted ablation area (P-area), and the actual ablated area (A-area) was measured. The predictive accuracy of OFDI was evaluated as follows: overlapped ablation area (O-area: overlapping P- and A-areas) divided by P-area = %Correct-area, and A-area - O-area divided by A-area = %Error-area. Cross-sections were separated into four categories based on the median values of %Correct- and %Error-area. Among 334 cross-sections, RA effects were confirmed in the predicted location in 87% of them. The median %Correct- and %Error-areas were 43.1% and 64.2%, respectively. Floppy wire, narrow lumen area, OFDI catheter close to the intima, and large arc of calcium were independently associated with good prediction (high %Correct-/low %Error-areas). Non-left anterior descending lesions, OFDI catheter far from the wire, and OFDI catheter and wire far from the intima were associated with irrelevant ablation (low %Correct-/ high %Error-areas). The accuracy of the OFDI-based predictions for RA effects was acceptable with regard to location, but not high with regard to area. Wire types, target vessels, and OFDI catheter and wire positions are important determinants for accurately predicting RA effect using pre-procedural OFDI.