RS33 - Longitudinal End Diastolic Velocity Changes in Asymptomatic Moderate Carotid Artery Stenosis: Divergent trends in progressive and non-progressive disease

Objectives: While carotid stenosis increases the risk for stroke, no clear guidelines exist about the duration of surveillance of asymptomatic carotid disease. As most individuals with carotid stenosis do not need surgery or experience a stroke, there may be limited benefit from longitudinal surveillance. We aim to describe the characteristics of patients with stable stenosis as a step in developing criteria for identifying low-risk patients.

Methods: A retrospective cohort study of 14,000 patients underwent 31,000 carotid duplex ultrasounds read at our institution-based IAC-accredited vascular lab between 2015 and 2024. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were extracted from reports, while patient demographics including co-morbidities, surgical data, and medication prescription data were abstracted from the electronic health record. Carotid arteries with 50-79% stenosis at the index screen were included. The primary outcome was time to disease progression, defined as either a clinically significant event (symptomatic disease or carotid intervention), or an increase to at least 80% stenosis. Linear regression and survival analysis were performed to identify differences between progressive and non-progressive disease.

Results: A total of 10,860 carotid arteries were included in the final analysis, with 1,807 (16.64%) of the arteries demonstrating progression over the study period. Table 1 shows descriptive statistics of the non-progressive and progressive population. Non-progressive patients were significantly older at their first ultrasound, had fewer overall ultrasounds, were less likely to have a positive smoking history, and were less likely to be prescribed aspirin, or a different antiplatelet agent throughout the study period. On linear regression, non-progressive carotid arteries had significantly lower mean velocity measurements at the initial duplex ultrasound (PSV 184.6cm/s vs 206.7cm/s (p < 0.001), EDV 43.6 vs 52.5 (p < 0.001)) (Figure 1). There was no difference in the rate of change for PSV in the progressive stenosis arteries versus the non-progressive stenosis arteries over time (p=0.534). Compared to non-progressive carotid arteries that decreased EDV over time, progressive carotid arteries significantly increased EDV by an average of 0.78 cm/s/year (95%CI: 0.01, 1.56), p=0.048). The median time to progression was 8.1 years, and the median follow-up time was 2.21 years.

Conclusions: These data demonstrate a significant difference in initial internal carotid artery velocities as well as the slope for additional studies among patients who progress to severe stenosis or symptomatic disease. While future research is needed to elucidate characteristics that differ between progressive and non-progressive carotid disease, the longitudinally divergent EDV trends suggest criteria for de-escalation of routine surveillance.