Misclassification of carotid stenosis severity with area stenosis-based evaluation by computed tomography angiography: impact on erroneous indication to revascularization or patient (lesion) migration to a higher guideline recommendation class as per ESC/ESVS/ESO/SVS and CMS-FDA thresholds

Abstract

Intoduction Despite a growing understanding of the role played by plaque morphology, the degree of carotid lumen reduction remains the principle parameter in decisions on revascularization in symptomatic and asymptomatic patients. Computed tomography angiography (CTA) is a widely used guideline-approved imaging modality, with “percent stenosis” commonly calculated as %area reduction (area stenosis – AS). Aim We evaluated the impact of the non-linear relationship between diameter stenosis (DS) and AS (area = π • (diameter/2) 2 , so that in concentric lesions 51%AS is 30%DS and 75%AS is 50%DS) on stenosis severity misclassification using calculation of area reduction. Material and methods CTA and catheter quantitative angiography (cQA) were performed in 300 consecutive patients referred to a tertiary vascular centre for potential carotid revascularization (age: 47–83 years, 33.7% symptomatic, 36% female; referral stenosis of ≥ “50%”). CTA-AS was determined by agreement of 2 experienced radiologists; cQA-DS (pivotal trials standard reference, NASCET method) was calculated by agreement of 2 corelab analysts. Results For symptomatic lesion thresholds, CTA-AS-based calculation reclassified 76% of “< 50%” cQA-DS measurements to the “50–69%” group, and 58% of “50–69%” measurements to the “≥ 70%” group. For asymptomatic lesion thresholds, 78% of “< 60%” cQA-DS measurements were reclassified to the “60–79%” group, whereas 42% of “60–79%” cQA measurements crossed to the “≥ 80%” class. Overall, employing CTA-AS instead of cQA-DS enlarged the “60–79%” and “≥ 80%” lesion severity classes 1.6- and 5.8-fold, respectively, whereas the “≥ 70%” class increased 4.15-fold. Conclusions Replacing the pivotal carotid trials reference standard cQA-DS “%stenosis” measurement with CTA-AS-based “%stenosis” results in a large-scale lesion/patient erroneous gain of an “indication” to revascularization or migration to a higher revascularization indication class. In consequence, unnecessary carotid procedures may be performed in the absence of cQA verification. Until guidelines rectify the “%stenosis” measurement methods with different guideline-approved imaging modalities (and, where needed, re-adjust decision thresholds), CTA-AS measurement should not be used as a basis for carotid revascularization.

Clinical Characteristics and Outcomes of Aortic Arch Emergencies: Takayasu Disease, Fibromuscular Dysplasia, and Aortic Arch Pathologies: A Retrospective Study and Review of the Literature

“…CTA image acquisition was carried out with a 64-multi-detector-row CT system (Somatom 64, Siemens, Erlangen, Germany) using a routine imaging protocol. Biplanar and 3-dimensional reconstructions of the vessels were computed to characterize the anatomy of the aorta and its main branches [ 35 ].…”

“…A selective digital angiography of the index artery or arteries was performed using a Coroscop or Axiom Artis Zee angiograph (Siemens, Germany) with multiple angulated projections [ 33 , 35 , 36 ].…”

A Non-Coronary, Peripheral Arterial Atherosclerotic Disease (Carotid, Renal, Lower Limb) in Elderly Patients—A Review: Part I—Epidemiology, Risk Factors, and Atherosclerosis-Related Diversities in Elderly Patients

“…Intravascular imaging tools such as optical coherence tomography (OCT) and intravascular ultrasound (IVUS), as well as imaging of the atherosclerotic plaque using CT angiography (CTA) and magnetic resonance angiography (MRA), allow us to detect the coexistence of atherosclerotic lesions at various stages of development in an individual patient [ 49 , 50 , 51 , 52 , 53 ]. Necrotic lipid changes in atherosclerotic plaques, which may be ulcerated or even micro-ruptured, are not uncommon and may heal over time.…”

Quantifying Carotid Stenosis: History, Current Applications, Limitations, and Potential: How Imaging Is Changing the Scenario

“…In any case, it remains crucial to always declare the method being referenced when indicating the degree of stenosis, which, as we have seen, could be a potentially significant confounding factor if not done [26].…”