Is a Low End-Diastolic Velocity Parameter Enough to Exclude an 80–99% Internal Carotid Artery Stenosis?

Abstract

Introduction —High resistive internal carotid artery (ICA) waveforms (high peak systolic velocity >250 cm/sec with low end-diastolic velocity (EDV) <125 cm/sec, having an external carotid artery waveform appearance) are uncommon and present a diagnostic challenge for intervention. Most ICA stenotic classifications rely on a greater EDV to delineate a critical stenosis of 80–99%. Methods —Review of a multiple-laboratory, single-center, Intersocietal Accreditation Commission-accredited, noninvasive vascular laboratory database for ICA carotid examinations performed from January 1, 2008 to November 1, 2012, with a positive stenotic range >60%. Medical records, archived ultrasound images, and correlative imaging studies were reviewed. Results —A total of 843 carotid duplex studies (1,686 arteries) positive for >60% stenoses of at least one side were reviewed. There were 102 duplex studies with high resistive ICA waveforms that were identified. Of these, 35 duplex studies had 40 correlative results, and 67 duplex studies did not have any correlative results. Of the 35 correlated duplex studies, median age was 78 years (range, 53–86 years). Gender distribution was 57% male. The median age of the male subjects was 77 years with a range of 63–82 years and the median age of female subjects was 73 years old with a range of 53–86 years. Seven of the 35 patients presented with symptoms of visual disturbance, transient ischemic attack, or syncope (21% symptomatic). Side distribution was 12 males and 8 females had right-side involvement, and 7 males and 7 females had left-side involvement. There was one female patient who had bilateral involvement. This provides us with 36 duplex ultrasound studies to correlate. Mean PSV was 369 cm/sec (range, 187–492 cm/sec). Mean EDV was 89 cm/sec (range 18–130 cm/sec). Average ICA/common carotid artery ratio was 6.2 (range, 3.2–12.5). Correlative computed tomography angiography was available for 12 of the studies, angiography for 10 of the studies, and surgical findings for 18 of the 35 studies. Conclusion —Assessing all Doppler parameter used to categorize an ICA stenotic range may be beneficial in determining the need for patient intervention. Sonographer impression of audible clues and cardiac history is helpful to the interpreting physician reviewing 2D images and waveforms.