Introduction/Purpose While vessel angiography provides good information about the vessel lumen and can identify vessel wall irregularities as well as intraluminal filling defects, it lacks in providing information about the architecture of the vessel wall itself. Optical Coherence Tomography (OCT) is an intravascular imaging modality that shows a highly defined cross-sectional image of the vessel wall composition. Currently, OCT is used in coronary interventions. We believe that OCT may be a valuable tool in characterizing carotid atherosclerotic lesions and provide information about carotid plaque morphology and the need for treatment in asymptomatic <50% stenoses. During an intervention, OCT can help define treatment strategy, allow for a more accurate stent size selection and definition of landing zones as well as choice of angioplasty balloon diameters. Post-procedurally, OCT is able to reduce stent failure by better identifying stent dissections, incomplete wall apposition and tissue protrusion, all of which are factors that could result in stent thrombosis if undetected. Use of OCT for carotid lesions is currently off-label.

Materials and Methods We retrospectively reviewed our neurointerventional database and identified all patients in whom OCT was used as an adjunct tool to evaluate carotid artery disease. OCT detects single-scattered light from biological tissues, generating images with an axial resolution of 10-15 μm or better. Patient cross-sectional images, carotid Duplex scans and angiograms were reviewed. OCT images were analyzed in conjunction with the available imaging. Patient characteristics, procedural information and patient outcome data was collected.

Results OCT catheters are available in 23 or 27 mm lengths from lens to tip distance. OCT requires use of an optical fiber and small focusing lens to illuminate and collect backscattered light from the artery wall, while rotating and pulling back the catheter optics at high speed through the lumen of the carotid artery. The imaging speed enables a safe and efficient acquisition of volumetric OCT data over arterial segments of up to 75 mm, during a short intra-arterial contrast injection. The use of contrast is necessary as the red blood cells are highly scattering particles and need to be displaced from the artery lumen to clear the imaging field-of-view. Seven patients (3 females) with mean age of 72 years (range 64-80 years) were identified. Patient vascular risk factors included hypertension (85.7%), hyperlipidemia (57.1%), Smoking (current and former; 57.1%) and diabetes mellitus (57.1%). Four lesions involved the left ICA and 3 lesions the right ICA. One patient did not show an ICA stenosis despite suspicion on cross-sectional imaging. Another patient showed no stenosis but free-floating clot due to acute plaque rupture. In all other patients, ICA stenoses ranging from 65 - 83% were identified based on angiographic assessment. All procedures were performed via femoral access. Based on imaging findings, 6 carotid stenting interventions were performed.

Conclusion OCT may be a valuable adjunct tool during carotid artery stenting, especially for plaque characterization in non-stenotic carotid artery disease. OCT catheters can be easily delivered, even in tortuous anatomy. Operators may feel more confident in their management decisions and choice of devices.

Disclosures A. Kuhn: None. J. Singh: None. S. Sarid: None. M. Garcia: None. A. Puri: 1; C; NIH, Microvention, Cerenovus, Medtronic Neurovascular and Stryker Neurovascular. 2; C; Medtronic Neurovascular, Stryker NeurovascularBalt, Q’Apel Medical, Cerenovus, Microvention, Imperative Care, Agile, Merit, CereVasc and Arsenal Medical. 4; C; InNeuroCo, Agile, Perfuze, Galaxy and NTI.