Digital Variance Angiography for Contrast Media Dose Reduction in Carotid Artery Stenting

Investigation of Dose Management Capabilities of Digital Variance Angiography: Contrast Media Dose Reduction in Patients Undergoing Carotid Artery Stenting - a Prospective Randomized Clinical Trial

Digital Variance Angiography (DVA) is a new tool in medical imaging with a proven image quality reserve (1, 2). Previous studies have demonstrated the quality reserve of DVA in angiographic studies (1, 2), which allowed us to reduce contrast media use by 50% in carotid artery angiographic studies without affecting the image quality (3). CAS is an alternative treatment option for carotid artery revascularization in selected patient groups. Similar to most of the minimally invasive endovascular interventions, CAS also carries the risk of contrast-induced acute kidney injury, which is considered to be an independent predictor of 30-day major adverse events (4). The aim of this study is to apply DVA in patients undergoing carotid artery stenting (CAS) and utilize this technique to reduce contrast dose during the interventions, without affecting the intraprocedural radiation dose and the clinical outcome of the procedures. Investigators believe that the reduction in contrast media use and the associated image quality with the technique of DVA imaging can be incorporated into the everyday clinical practice, and will play an important role in improving the rate of contrast-induced acute kidney injury.

Radiocontrast media reduction, X-ray angiography, Digital Variance Angiography, Digital Subtraction Angiography, carotid artery stenting, Kinepict

Enrolled participants will undergo carotid artery stenting with different image acquisition protocol of the pre-and postinterventional angiographies from anteroposterior and lateral views, and intraoperative angiographies with C-arm angulations based on the operator's decision. In the active comparator group, a standard contrast media dose and DSA images will be used for diagnosis whereas in the experimental group a reduced contrast media dose will be applied (50% decrease compared to the standard DSA protocol) and the operator will use DVA images for the diagnosis.

Reduced contrast media protocol: extracranial carotid artery intervention (2-4 fps according to the institutional protocol). Contrast administration with an automatic contrast injector: angiographic image acquisitions will be performed with 6 ml of 50% contrast media (3 ml iodined contrast media, 3 ml physiologic saline) with a 3 ml/s flow rate. DSA and DVA images will be calculated; DVA images will be used for diagnosis and interventions.

Standard contrast media protocol: extracranial carotid artery intervention (2-4 fps according to the institutional protocol). Contrast administration with an automatic contrast injector: angiographic image acquisitions will be performed with 6 ml iodined contrast media with a 3 ml/s flow rate. DSA and DVA images will be calculated; DSA images will be used for diagnosis and interventions.

Arterial access, Preinterventional selective carotid artery angiography, Carotid artery stenting, Postinterventional selective carotid artery angiography

Radial, brachial or femoral arterial access is gained by using the Seldinger technique. The common carotid artery (CCA) is catheterized. Selective angiography is performed from the anteroposterior and lateral view without magnification. Initial angiograms are performed with standard contrast media protocol in anteroposterior and lateral views without magnification with the sheath placed in the common carotid artery. The carotid arterial lesion is crossed and an embolic protection device is deployed in the internal carotid artery. Carotid artery stenting is performed in a standard fashion. Post-stenting angiographies are obtained with the standard contrast media protocol in anteroposterior and lateral views without magnification with the sheath placed in the CCA. Pre- and post-stenting angiographies are performed with the same sheath position. DSA and DVA images will be calculated on a commercially available image processing workstation and the Kinepict Medical Imaging Tool.

Arterial access, Preinterventional selective carotid artery angiography, Carotid artery stenting, Postinterventional selective carotid artery angiography

Radial, brachial or femoral arterial access is gained by using the Seldinger technique. The common carotid artery (CCA) is catheterized. Selective angiography is performed from the anteroposterior and lateral view without magnification. Initial angiograms are performed with the reduced contrast media protocol in anteroposterior and lateral views without magnification with the sheath placed in the common carotid artery. The carotid arterial lesion is crossed and an embolic protection device is deployed in the internal carotid artery. Carotid artery stenting is performed in a standard fashion. Post-stenting angiographies are obtained with the reduced contrast media protocol in anteroposterior and lateral views without magnification with the sheath placed in the CCA. Pre- and post-stenting angiographies are performed with the same sheath position. DSA and DVA images will be calculated on a commercially available image processing workstation and the Kinepict Medical Imaging Tool.

Observations based on a 5-level Likert scale (1-poor image quality, 3-medium image quality, 5-outstanding image quality)

Number of occasions when the reduced contrast media protocol has to be switched back to conventional protocol because of the unsuitable image quality

The difference between the normal reference segment diameter and the minimum lumen diameter of the treated lesion after CAS (%)

Focal neurological symptoms ipsilateral to the treated carotid artery during the postprocedural observation period

Inclusion Criteria: Age > 18 y Carotid stenosis defined as: Stenosis ≥70% by computer tomography angiography (NASCET criteria); OR by duplex-ultrasound with ≥70% stenosis defined by a peak systolic velocity of at least 230 cm/s Carotid stenosis is treatable with CAS Exclusion Criteria: History of stroke or TIA ipsilateral to the stenosis within 30 days of randomization Acute myocardial infarction Severe chronic kidney disease: GFR>30ml/min/m2 Severe heart failure: NYHA IV Severe liver failure: Child-Pugh 3 Iodine contrast allergy Coagulopathy Hematological bleeding disorders

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