Feasibility of optical coherence tomography for localizing and quantifying paclitaxel deposition after drug-coated balloon angioplasty

Introduction: Drug coated balloon (DCB) angioplasty aims to reduce restenosis rates. However, studies suggest that only 10–20% of the drug is delivered to the vessel wall. Given this significant barrier to success, intra-operative methods for evaluating drug deposition could improve outcomes. This study has two key aims: 1) to determine if optical coherence tomography (OCT) can detect paclitaxel crystals; 2) to establish if OCT can be used to quantify geographical drug deposition. Methods: A benchtop vessel imaging phantom was used to validate OCT detection of crystal deposition. OCT was performed before and after DCB angioplasty and post-intervention images were evaluated for signals consistent with paclitaxel crystals. Mean geographical drug deposition was measured by the percentage of luminal circumference demonstrating signal. This method was subsequently applied to 5 patent tibial artery specimens from patients who underwent lower extremity amputation due to peripheral artery disease and compared with 5 tibial artery specimens treated with plain old balloon angioplasty (POBA). Results: Paclitaxel crystal deposition was consistently identified on OCT in the benchtop phantom model. The mean geographical percentage deposition was 6.5%. In the patent arterial specimens, paclitaxel was also visualized, and mean geographical deposition was 11.3%. In contrast, no paclitaxel crystals were identified on OCT in the arteries treated with POBA. Conclusion: This study has shown that paclitaxel crystal can be identified and geographical deposition quantified using OCT. This could pave the way to optimizing DCB angioplasty and unlock our understanding of the mechanistic relationship of DCB angioplasty and plaque morphology.