Guidance of aortic ablation using optical coherence tomography

Purpose: There is a significant need for an imaging modality that is capable of providing guidance for intravascular procedures, as current technologies suffer from significant limitations. In particular, laser ablation of in-stent restenosis, revascularization of chronic total occlusions, and pulmonary vein ablation could benefit from guidance. Optical coherence tomography ( OCT), a recently introduced technology, is similar to ultrasound except that it measures the back-reflection of infrared light instead of sound. This study examines the ability of OCT to guide vascular laser ablation. Methods: Aorta samples underwent laser ablation using an argon laser at varying power outputs and were monitored with OCT collecting images at 4 frames. Samples were compared to the corresponding histopathology. Results: Arterial layers could be differentiated in the images sequences. This allowed correlation of changes in the OCT image with power and duration in addition to histopathology. Conclusions: OCT provides real-time guidance of arterial ablation. At 4 frames, OCT was successfully able to show the microstructural changes in the vessel wall during laser ablation. Since current ablation procedures often injure surrounding tissue, the ability to minimize collateral damage to the adjoining tissue represents a useful advantage of this system. This study suggests a possible role for OCT in the guidance of intravascular procedures.