Safety and feasibility of intravascular optical coherence tomography using a nonocclusive technique to evaluate carotid plaques before and after stent deployment.

Abstract Purpose: To evaluate the safety and feasibility of optical coherence tomography (OCT) in patients with carotid stenosis undergoing carotid artery stenting (CAS). Methods: In a prospective study, 25 consecutive patients (15 men; mean age 74±4 years) undergoing protected CAS were enrolled and underwent high-definition (homoaxial resolution 10 µm) OCT image acquisition before stent deployment, immediately after stent placement, and following postdilation of the stent (3 scans/patient). Pullbacks were started during a nonocclusive flush, mechanically injecting 24 mL of 50% diluted contrast at 6 mL/s to displace blood from the artery. Two independent physicians judged the quality of images on a predefined 1-10 scale. The proportions of specific agreement and kappa values (κ) were calculated. Results: No procedural or in-hospital neurological complications occurred (any stroke/death 0%). The technical success of OCT pullbacks was 97.3% (73/75). The total amount of contrast was 86±18 mL/patient. No significant alteration in glomerular filtration rate or any other significant adverse event occurred. The images obtained were of high quality (mean value 8.1 out of 10), with good inter- and intraobserver agreement (κ = 0.81-0.87 and κ = 0.95, respectively). OCT images revealed innovative features such as rupture of the fibrous cap, plaque prolapse, and stent malapposition in a high percentage of the patients (range 24%-100%). Conclusion: Intravascular OCT during a nonocclusive flush appears to be feasible and safe in carotid arteries. Since some original and unexpected information after CAS has been made available for the first time at such a high definition, future studies with OCT should focus on the interaction between carotid plaque and stent design, which might revolutionize our understanding of the mechanisms of carotid stenting, as well as influence our clinical policies.