Abstract Background It has been reported that optical coherence tomography (OCT) can visualize high-intensity spots on luminal surface after drug coated balloon (DCB). However, the previous reports used visual assessment and quantitative analysis of these granules has not yet established. Furthermore, frequencies of bright granules across DCB types have not been reported. This study aimed to establish quantitative methods for evaluating high-intensity granules on OCT post-DCB. Using an in vitro model with three DCBs types, OCT-based criteria were defined and were applied in human coronary imaging. Methods/Results In tubular silicone phantoms, OCT was repeated before and after balloon dilatation with three types of paclitaxel or sirolimus DCBs (SeQuent Please Neo 3.0x30 mm, RESTORE 4.0x25 mm, MagicTouch 3.0x15 mm). OCT pullback was performed using a dragonfly catheter (Abbott Vascular, Santa Clara, CA, USA) at the speed of 18 mm/sec, resulting in a longitudinal interval of 100 µm between each cross-section. Quantitative analysis of light intensity, light attenuation and backscattering was performed in each OCT pullback using QCU-CMS software (LKEB, Leiden University, Leiden, The Netherlands). Using the attenuation map function, a two-dimensional carpet-out view was created. The attenuation value setting was adjusted so that the number of high-intensity attenuating intraluminal mass detected by the software matches with the numbers detected visually. The change in the optical signal on the luminal surface was also assessed visually in OCT before and after DCB. The new luminal appearance of a high-intensity granular signal on OCT associated with light-intensity attenuation lagging behind the granular structure was assumed to be the detection of crystalline or amorphous structure of paclitaxel or sirolimus. The count of these OCT was visually assessed after the inflation of each DCB. In OCT images acquired in humans prior to and post DCB dilatation, quantitative attenuation analysis was performed using the same cut-off criteria as established in ex-vivo experiments. The OCT pullback was performed at 36 mm/sec with a longitudinal interval of 200 µm between each cross-section. In visual assessment on OCT imaging, in MagicTouch, 25 high-intensity granules were visualised. In RESTORE, 79 was visualised. In SeQuent Please, 300 high-intensity granules were visualised. Conclusion Attenuation map function derived from OCT images enabled visualisation of drug granules across the entire vessel treated with DCBs. The comprehensive results will be presented at the conference.
Miyashita et al. (Sat,) studied this question.