The independent and incremental value of ultrasound carotid plaque length to predict the presence and severity of coronary artery disease: analysis from the carotid plaque length prospective registry

AIMS: Data regarding the relationship between carotid plaque length (CPL) and coronary artery disease (CAD) are lacking. This study aimed to assess the predictive value of CPL for the severity of CAD. METHODS AND RESULTS: We prospectively enrolled 2149 consecutive patients who underwent both first coronary angiography and carotid ultrasonography with measurements of intima-media thickness (IMT), plaque score (PS), and CPL. In total, 1408 (65.5%) patients had CAD (defined as stenosis ≥50%), and 741 (34.5%) patients had no CAD. Patients with CAD had longer maximal CPL than those without CAD (P < 0.001). The severity of CAD, measured by the Gensini score (GS), was closely correlated with max-CPL (rs = 0.560), followed by PS (rs = 0.486) and mean-IMT (rs = 0.292). Multivariate analysis revealed that max-CPL remained independently associated with CAD and high-GS after adjustment for traditional risk factors (TRF). Max-CPL, compared with PS or mean-IMT, had significantly higher discrimination value for predicting high-GS [area under the curve (AUC) 0.819 vs. 0.769 vs. 0.634, P < 0.001]. At a cut-off value for the max-CPL of 6.3 mm, the sensitivity and negative predictive value for high-GS were 84.6% and 89.1%, respectively. Furthermore, the addition of max-CPL significantly improved the discrimination (AUC 0.832 vs. 0.720, P < 0.001) and reclassification (net reclassification improvement = 0.431, P < 0.001) over TRF for high-GS. CONCLUSION: Ultrasound max-CPL provides independent and incremental predictive value for the clinical severity of CAD over TRF and seems a simple useful marker in CAD risk stratification.