Progression of Moderate to Severe Carotid Disease

Abstract

This study was conducted to (1) investigate the effect of patient demographics, risk factors, laboratory data, medications, and baseline disease burden, as well as the definition of disease progression, on the incidence and timing of carotid disease progression in patients with moderate to severe carotid disease after serial duplex studies and (2) develop an evidence-based algorithm for monitoring patients with asymptomatic moderate to severe carotid disease. In this retrospective record-review study, 509 patients underwent serial carotid duplex studies after an initial study showed a peak systolic velocity (PSV) of ≥120 cm/s and an end diastolic velocity of <140 cm/s in one or both internal carotid arteries (ICAs). Kaplan-Meier analyses were done to determine the effects of demographic characteristics, comorbid diseases, medications, laboratory values, and baseline severity of disease. The analyses were conducted using three independent definitions for progression: ICA diastolic velocity ≥140 cm/s (strict), ICA/common carotid artery (CCA) ratio ≥4.0 (moderate), and ICA PSV ≥250 cm/s (liberal). Receiver operator characteristic (ROC) curve analyses were conducted to identify duplex velocity criteria most useful for identifying risk of progression. Using strict criterion, univariate analysis revealed male gender (hazard ratio [HR], 2.47; 95% confidence interval [CI], 1.06-5.72; P = .0356) initial PSV ≥200 (HR, 4.31; 95% CI, 1.97-9.43; P = .0003), and ICA/CCA ratio ≥3 (HR, 2.83; 95% CI, 1.35-5.91; P = .0057) were significantly associated with progression. Initial PSV (moderate, liberal criteria), ICA/CCA ratio (moderate, liberal), age (moderate), and male gender (moderate, liberal) were significantly (P < .05) associated with progression. No comorbid conditions, initial laboratory values, or medications influenced progression. Cox regression analyses revealed significant differences in progression risk based on the initial PSV and ICA/CCA ratios using all criteria. ROC curve analysis suggests that a PSV of 200 cm/s provides an appropriate threshold identifying “high risk” of disease progression (sensitivity, 95.9%; specificity, 67.9%) when strict criteria for progression are used. The only predictors of progression, consistent with all definitions of progression are the severity of disease at the initial presentation as determined by the PSV or ICA/CCA ratio. ROC curve analysis suggests that 200 cm/s is an appropriate PSV threshold, predicting disease progression if strict criteria are used.